This article contains a representative list of notable databases and search engines useful in an academic setting for finding and accessing articles in academic journals, institutional repositories, archives, or other collections of scientific and other articles. Databases and search engines differ substantially in terms of coverage and retrieval qualities.[1] Users need to account for qualities and limitations of databases and search engines, especially those searching systematically for records such as in systematic reviews or meta-analyses.[2] As the distinction between a database and a search engine is unclear for these complex document retrieval systems, see:
The terms "free", "subscription", and "free & subscription" will refer to the availability of the website as well as the journal articles used. Furthermore, some programs are only partly free (for example, accessing abstracts or a small number of items), whereas complete access is prohibited (login or institutional subscription required).
The "Size" column denotes the number of documents (articles, publications, datasets, preprints) rather than the number of citations or references. The database itself should be the primary source of statistics, and if it is not accessible, the independent estimates released as journal papers should be. Notably, Google Scholar does not offer such detail, but the database's size has been calculated.[2]
The main academic full-text databases are open archives or link-resolution services, although others operate under different models such as mirroring or hybrid publishers. Such services typically provide access to full text and full-text search, but also metadata about items for which no full text is available.
This list focuses on general-purpose services; OpenDOAR can be used to find thousands of open-access repositories. The table is sorted by the number of works for which full-text is made available.
Name
Discipline(s)
Size (full-texts)
Description
Access cost
Provider(s)
25,000,000
Focus on fulltext search of open access journals and conference proceedings
Free
Yes
9,800,000[4] (207,000,000 metadata[5])
A full text aggregator of all open access papers from repositories (institutional, subject, preprints, etc.) and journals. Around 20 million monthly active users.
Free
No[4]
8,401,126
Replaced CiteSeer, and ChemXSeer. Mainly Computer science, Statistics, Mathematics.
Free
Semi-free[7]
10,500,000
Full-text aggregator of open access journals and papers (>17,000 journals) from all academic disciplines.
Free
No[9]
8,100,000[10] (200,000,000 metadata[11])
Mostly computer science and biomedical publications. Powered by semantic analysis.
Free
Semi-free[10]
Allen Institute for Artificial Intelligence
7,500,000 (39,000,000 metadata)
Abstracts & full text ( 7.5 million) biomedical and life sciences articles (Dec 2020). Includes text mining tools and links to external molecular and medical data sets.
Free
Yes
PubMed Central (PMC)[13]
7,500,000
Free full-text archive of publications and preprints
Free
Yes
4,000,000[citation needed]
Commercial social networking site for scientists and researchers. Over 19 million registered users that share their articles, datasets and other research output.
Free
No
950,733
Research papers from more than 55 disciplines
Free & Subscription
No
760,000 (2,000,000 metadata)[14]
An open-access database for French researchers. Organized into institution and domain portals.
Free
Yes
CNRS's Centre pour la Communication Scientifique Directe (CCSD)
90,000 (3,200,000 metadata)[16]
Working papers, journal articles, books, books chapters and software components (including 1.2 million full-text articles)
Free
IDEAS: Federal Reserve Bank of St. Louis
EconPapers: Örebro University School of Business
70,000[17] (2,540,317 metadata)
Index journals, books, open access archives, and personal pages maintained by academics
Free
Unknown (1,500,000 metadata)
Education literature and resources dating back to 1966.
Free & Subscription
United States Department of Education (available by subscription from OCLC, CSA)
3,000,000[21]
Pre-prints, mainly computer science, mathematics, statistics, chemistry, and biology.
Free
Yes
Synthical
Unknown (31,266,280[23]
Focus on scholarly content including full-text papers, conference proceedings, indexed journals, books, and book chapters from open access sources. Content is available in 38 languages, covering various subjects and disciplines.
Free & Subscription
Yes
Name
Discipline(s)
Size
Description
Access cost
Provider(s)
12,021,578
Covers agriculture, forestry, animal husbandry, aquatic sciences and fisheries, human nutrition, extension literature from over 100 countries. Indexes unpublished scientific and technical reports, theses, conference papers, government publications.
Free
4,485,534
2.4 million digital images from archive material, 1 million of books, 40,000 high quality scans of ancient sculptures, 300 volumes of ancient books with more than 60,000 pages
Free
265,034,285
Online service used to index and search academic social networks
Free
4,900,000
Part of Web of Science. 1,800 journals across 28 arts & humanities disciplines. Records back from 1975 to present.
Subscription
Astrophysics, Geophysics, Physics
13,300,000
Publications in Astronomy and Astrophysics, Physics, and the arXiv e-prints
Free
3,000,000
Provides information on topics such as biblical studies, world religions, church history, and religion in social issues
Subscription
259,497,239
Metadata for 260 million documents from more than 8,000 content providers
Free
5,600,000
Reviews of periodicals and books – including those on tape and electronic media
Subscription
2,500,000
Reviews covering over 2.5 million titles
Subscription
10,000,000
Bibliographic information service providing access to applied life sciences literature.
Subscription
7,800,000
Journal articles about nursing, allied health, biomedicine and healthcare. Covers 5,500 journals (English and other language).
Subscription
22,000,000
Database of articles in the Japanese language from 3600 journals
Free & Subscription
National Institute of Informatics
160,000,000
A Chinese bibliographic database
Free & Subscription
207,000,000[5]
Around 20 million monthly active users.
Free
111,231,936
An official Digital Object Identifier (DOI) Registration Agency of the International DOI Foundation. Metadata about publications, datasets, grants, preprints from 17,633 members (journals, publishers, etc.)
Free
20,000,000
Commercial website that sells access to scientific and scholarly articles from a large range of academic publishers (over 1700 journals). Limited free access.
Free & Subscription
302,000,000
Publications, books and book chapters, preprints and conference proceedings (linked to data sets, funding, publications, patents, clinical trials, and policy documents). Based on CrossRef. Contains citation-based indicators and Altmetric attention scores.
Free & Subscription
Digital Science & Research Solutions Ltd
8,265,735
Articles from 18,652 open access journals (Dec 2022)
Free
Infrastructure Services for Open Access (IS4OA)
5,387,041
Comprehensive list of papers from major computer science conferences and journals
Free
Leibniz Center for Informatics and University of Trier
10,000,000
Covers journals, working papers & conferences in business studies and economics
Free
ZBW- German National Library of Economics– Leibniz Information Centre for Economics (ZBW)
1,600,000
Covers articles and other materials dating back to 1969
Subscription
American Economic Association (available from EBSCOhost, ProQuest, OVID, and AEA)
32,000,000
Biomedical database with a focus on drug and pharmaceutical research. Rrecords from over 8,500 journals (1947–present).
Subscription
Food science, Food technology, Nutrition
1,500,000
The database of information on food science, food technology and nutrition
Subscription
IFIS Publishing (available via EBSCOhost, IHS Inc., Ovid, Proquest Dialog, STN and Web of Science)
4,000,000
Records from 3,500 journals in 40 languages
Subscription
American Geosciences Institute
389,000,000
The biggest academic database & search engine (over 390 million records, unofficial estimate)
Free
8,000,000
Australasian aggregator of bibliographic databases and journals
Subscription
RMIT Training Pty Ltd (RMIT Training)
Physics, Engineering, Computer Science
18,000,000
Contains records in physics, electrical engineering, electronics, communications, control engineering, information technology, manufacturing, production, and mechanical engineering.
Subscription
Nuclear Physics, Nuclear Energy, Medical Physics
4,600,000
A leading bibliographic and grey literature repository covering all areas of nuclear science and technology.
Free
International Atomic Energy Agency
1,000,000
Focus on the history of philosophy and continental philosophy.
Subscription
Université Catholique de Louvain (available from Peeters Publishers)
71,692,382
J-Gate is an electronic gateway to global e-journal literature (articles from 58,000 journals)
Free & Subscription
228,108,724
Serves global patent and scholarly knowledge as a public good to inform science and technology enabled problem solving.
Free & Subscription
3,600,000
Records from 650 math journals (early 1800–present)
Subscription
26,000,000
Easy-to-use interface to search and retrieve citations and abstracts from 5,200 journals via MeSH vocabulary
Free
90,000,000
Database includes more than 90 million scientific publications and 12 million patents.
Free
44,187,016
Japanese. Catalog for the National Library of Japan.
Free
30,000,000
Covers records contributed by over 1,500 organizations
Free
242,000,000
Scientific Knowledge Graph aggregating, deduplicating, enriching metadata of publications, research data, research software, and other products, with citations links and links to funders and grants - core service in support of the European Open Science Cloud
Free
OpenAIRE AMKE (not-for-profit)
205,000,000[46]
Index and metadata for all scholarly output.
Free
3,700,000
Focus at behavioral science and mental health. Coverage 1887–present.
Subscription
30,000,000
A database primarily of references and abstracts on life sciences and biomedical topics. Includes MEDLINE, PubMed Central, and Bookshelf.
Free
Civil Engineering, Architecture
1,600,000
Bibliographic database for planning and building related publications, chronological coverage since 1975. Focus: German-language publications, journal articles, book chapters, conference papers, research reports.
Subscription
35,409,829
A bibliographic database of scientific publications in Russian
Free
66,000,000
Natural and physical sciences, social sciences, and humanities. Incorporates arXiv, PubMed, and SciELO. Integrated with ORCID Altmetric uids. Articles from >25,000 journals.
Free
ScienceOpen Inc.
78,000,000
Records from over 20,500 titles from over 5,000 international publishers
Subscription
171,000,000
Includes other products, such as Social Sciences Citation Index, Science Citation Index, Biological Abstracts & The Zoological Record
Subscription
6,600,000
Scholarly articles in Japanese
Free & Subscription
4,000,000
Mainly reviews and abstracts.
Free
3,500,000
Unofficial register of scientific names & papers in zoology. Coverage 1864–present.
Subscription
Services with less than a million searchable records.
Name
Discipline(s)
Size
Description
Access cost
Provider(s)
Several versions: Complete, Elite, Premier, and Alumni Edition
Subscription
Aerospace, Aeronautics, Astronautics
Provides indexing and abstracts from current serial and non-serial titles, including content from AIAA and NASA
Subscription
African Journals OnLine (AJOL)[51]
185,649
Scholarly journals published in Africa
Free & Subscription
Includes information on aging-related topics, including economics, public health and policy
Subscription
Provides public access to information on agriculture and allied fields (17th century - present)
Free & Subscription
NAL (free access NAL, subscription access ProQuest, OVID)
Chinese e-content provider of Chinese academic e-journals, Taiwanese academic e-journals, classical art images
Subscription
505,481
Selection of analytical chemistry articles published by the Royal Society of Chemistry (around 100 journals)
Subscription
Indexes only (no abstracts or full-text) the anthropology journals received by The Anthropology Library at The British Museum
Free & Subscription
670,000
An index of journals primarily from Tozzer Library, as well as other open-access journals (660 journals with more than 670,000 articles)
Free & Subscription
Harvard University (non-Harvard access provided by OCLC)
Multidisciplinary
Directory of archival materials from American and international institutions, including over five million records
Free
150,000
All civil engineering disciplines including structural engineering, geotechnical engineering, transportation engineering, construction engineering, environmental engineering, engineering mechanics, sustainability, water resources, irrigation. hydraulics, hydrology, waterways, urban planning, cold regions ...
Free & Subscription
The articles, news items, book reviews and editorials from 63 English language military and aeronautical periodicals
Free
Biomedical research literature published from more than 4,000 journals internationally.
Subscription
35,000
Database to discover, evaluate, and compare journals. Journal listings include publication info, submission guidelines, and metrics.
Subscription
Approximately 8,000 journals, technical reports, dissertations, conference proceedings, and new books
Subscription
60,000
Covers about 500 Chinese academic journals of humanities and social sciences
Subscription
7,900
Contains records describing publications about all aspects of human health in the circumpolar region
Free
270,000
A bibliographic database covering all of ASCE's publications since 1872
Free
American Society of Civil Engineers
Includes reviews of research to promote evidence-based healthcare.
Subscription
Part of Web of Science. Contains 7 discipline-specific subsets.
Subscription
13,096
bio-bibliographic data about illustrators of published scientific works from c.1450 until 1950 in 100+ countries, with 20 search fields
Free
compiled by the Section for History of Science & Technology, University_of_Stuttgart
Contains over 2,500 journals (including 700 journals from Poland).
Free
266,000
Provides free public access to over 266,000 full-text documents and bibliographic citations of Department of Energy (DOE) research report literature. Documents are primarily from 1991 forward.
Free
860,000
Covers articles from 1100+ journals from India from scientific, technical, medical, and social sciences
Subscription
Open-access knowledge management system incorporating grants, publications, conferences in natural and social & behavioral sciences
Free
An open access digital library for the field of high energy physics (HEP) (operates since the 1970s)
Free
CERN, DESY, Fermilab, SLAC and IHEP
37,000
Contains information on university philosophy departments and programs, philosophical societies, research centers, journals, and philosophy publishers in the U.S., Canada, and approximately 130 other countries.
Free & Subscription
Philosophy Documentation Center
440,000
A multidisciplinary bibliographic database covering Europe, North Africa and the Middle East for the entire period from AD 300 to 1500
Subscription
Leeds University (available from Brepols Publishers)
Catalogues over 39,000 journals' information (the description, aims, scope, journal abbreviation, journal homepage link, subject category and ISSN).
Free & Subscription
Index property and open access journals in the arts, humanities, ecology, science, biomedical, business and economics.
Free
David Haden
Over 860,000 bibliographical entries, including keywords, abstracts, and links to the full text.
Subscription
Société Internationale de Bibliographie Classique (available from Brepols Publishers)
Electronic database for legal and public-records related information
Subscription
550,000
A free archive of linguistics articles, with a focus on syntax, semantics, phonology and morphology
Free
Interface for searching MEDLINE, ClinicalTrials.gov, FDA Drug Labels, PubMed Central, and Patent Abstracts.
Subscription
An open-access database of Latin and Ancient Greek dictionaries
Free
N/A
Crowdsourced database of research documents. Over 100M documents uploaded by the researchers plus data from repositories (e.g. PubMed and arXiv)
Free & Subscription
225,000
Abstracts of scholarly journal articles, agency and NGO reports, audiovisual products, and conference proceedings.
Free
United States Department of Justice, Office of Justice Programs
700,000
Indexes European grey literature
Free
Institut de l'information scientifique et technique
An open and independent registry for contributor identification in research and academic publishing. List: biography, education, employment, works, grants, peer-review. Over 9.3 million profiles.
Free
Applied ethics, Philosophy, Religious studies
Journals, series, conference proceedings, and other works from several countries online
Free & Subscription
Philosophy Documentation Center
Philosophy, applied ethics, religious studies
Journals and series, online access for institutions with print
Free & Subscription
Philosophy Documentation Center
Service for academics to track their peer review and editorial contributions for academic journals. Merged with ResearcherID
Free
800,000
Datasets and offers, where available, full-text linking, links to additional information and link resolving
Free
Leibniz Institute for Psychology Information
Reference guide to articles in >470 periodical magazines and journals, organized by article subject (1890 to present)
Subscription
40,000
Primary documents from the history of rock and roll. Articles, including interviews, features and reviews, which covered popular music from blues and soul
Free & Subscription
640,000
>35 distinct professional disciplines (architecture - zoology) relevant to preventing unintentional injuries, violence, and self-harm
Free
A gateway to government science information and research results from over 60 databases, over 2,200 websites, and over 200 million pages.
Free
Part of Web of Science. 24,000+ journals across 254 subject disciplines.
Subscription
Engineering & Technology, Medical Science, Basic Science, Human Sciences
An Iranian index of academic journals and access to full text or metadata
Free
Scientific Information Database
80,000
A bibliographic database, a national citation index, an Open Access full-text journal repository and an electronic publishing platform. Articles from >230 journals.
Free
CEON/CEES - Centre for Evaluation in Education and Science
SNAC (Social Networks and Archival Contexts)
Multidisciplinary
Directory of archival materials grouped by subject entity
Free
Part of Web of Science
Subscription
Scholarly open access resources in different language (mainly Chinese)
Free & Subscription
China Educational Publications Import and Export Corporation
336,000
Provides serials for periodicals
Subscription
80,000
European vocational education and training (VET) literature
Free
Over 40,000 databases of case law, state and federal statutes, administrative codes, newspaper and magazine articles, public records, law journals, law reviews, treatises, legal forms and other information resources
Subscription
Unified catalog of member libraries' catalogs
Free & Subscription
OCLC Inc.
A union catalog that itemizes the collections of 17,900 libraries in 123 countries
Free & Subscription
Content by most academic publishers is indexed by CrossRef, DOAJ and/or DataCite. Some publishers are also listed separately in the table below.
Name
Discipline(s)
Size
Description
Access cost
Provider(s)
2,892,573
Collection of all ACM publications, including journals, conference proceedings, technical magazines, newsletters and books
Subscription
Association for Computing Machinery
A collection of peer-reviewed electronic resources on chemical measurements and instrumentation
Free
A bibliography of monographs on the Middle Ages. As of 2018, it contains about 65,000 fully classified bibliographic records.
Subscription
University of Poitiers (available from Brepols Publishers)
Biology, Ecology, Environmental Science
Full-text from >180 scientific journals in Biodiversity Conservation, Biology, Ecology, Environmental Science, Entomology, Ornithology, Plant Science, and Zoology.
Free & Subscription
Computer Science, Engineering, Electronics
5,360,654
Over 5 million records.
Subscription
5,000,000
Covers articles from 13,000 journals
Free & Subscription
12,000,000
Journal articles, books, and primary sources in 75 disciplines (1870–present)
Free & Subscription
60,000
Offers four international-scale publication and information platforms in the humanities and social sciences (10,661 books, 549 journals, 3793 blogs, 45,591 events).
Free
Cléo (UMS 3287) CNRS EHESS University of Avignon
MUSE's online journal collections are available on a subscription basis to academic, public, special, and school libraries. More than 2,500 libraries worldwide subscribe.
Subscription
Project MUSE, Johns Hopkins University Press
573,525
Database and a model for cooperative electronic publishing in developing countries (mostly South America and Africa). Indexes >1700 journals.
Free
18,000,000
Content from more than 4,000 academic journals and 30,000 e-books
Subscription
13,859,779
Journals, books, series, protocols, reference works and proceedings
Free & Subscription
The following services are no longer operating; this may be because they were not updated, abandoned entirely, replaced by other, etc.
Name
Discipline(s)
Description
Access cost
Provider(s)
A meta search engine for 50 major bioinformatic databases and projects. Project appears to be not available anymore.
Free
Liebel-Lab KIT from Karlsruhe Institute of Technology
Not available. Ceased operations as of March 30, 2019
Free
Oversity Ltd.
The project seems abandoned in 2018
Free
Mathematics, Computer science, Physics
Semi-autonomous citation index of free online research. Not available; ceased operations in 2013
Free
Replaced by citeSeerX.
Free
Web-based retrieval application that provided language-independent access to the information contained in Chemisches Zentralblatt
Subscription
An electronic archive for self-archive papers in Psychology, Neuroscience, Linguistics, Computer Science, Philosophy, Biology, and Medicine. Contains over 2000 free articles. Not updated since 2017.
Free
One of the oldest (if not the oldest) bibliography collections freely accessible on the Internet (founded 1993). Contains 4.2 million records. Not updated since 2017.
Free
Limited free search. Not updated since 2017.
Subscription
American Statistical Association and the Institute of Mathematical Statistics
Electronic version of Engineering Index
Subscription
Descriptions of women's history collections from sources in the UK, as well as women's history websites.
Free
London Metropolitan University
Public Health
Specialist abstracting and indexing database dedicated to public health research and practice. Contains scientific records from 1973 to the present.
Subscription
An electronic bibliography for most of HCI for researchers, developers, educators, and students. Over 126,000 publications. Not updated since 2018.
Free
A bibliography of academic publications on European culture and history in the 16th and 17th centuries. It seems that the database is not available and not updated since 2013.
Subscription
Meteorology, Astrophysics, Geology
Over 508,379 records from 654 journals. It seems that the database is not available and not updated since 2009.
Subscription
American Meteorological Society (available from Dialog and CSA).
Covered publications from over 49,000 journals. Retired on December 31, 2021.[72]
Free
Index of books, journals, dissertations, and other documents. Merged with PhilPapers.
Subscription
Philosophy Documentation Center
A collection of population, family planning and related reproductive health and development literature. Retired in 2019.
Free
Knowledge for Health, Center for Communication Programs, JHSPH
Emphasis on books and journal articles in the humanities and social sciences. Closed down on December 21, 2020
Subscription
A gateway to results of DOE research and development and major R&D accomplishments of interest to DOE. Not working from 2014
Free
Research articles and patents from 45k+ journals and preprint servers. Uses content recommendation concept.
Subscription
Journals
Papers
Other publication types
Impact and ranking
Reform and access
Versioning
Related topics
Lists
