Which sources should I search?
We currently support 22 different literature sources, and provide automated translations (of your search strategy) for many more. Here’s a brief summary of each to help you decide which ones are right for you:
ACM digital library
A bibliographic database that categorizes and abstracts most computing literature, including all ACM publications and literature from other publishers. Offers good support for structured searching. Suitable for academics and researchers.
Further details: ACM search help, operators and field tags
Bing
A web search engine operated by Microsoft. Can be used to search 3rd party sites (e.g. LinkedIn, Twitter, GitHub, Stack Overflow, etc.) using x-ray search. Offers limited support for structured searching. Best suited for recruiters and generic search needs.
Further details: Bing search help, operators and field tags
CORE
CORE (COnnecting REpositories) is the world’s largest collection of open access research papers. It provides a comprehensive bibliographic database of the world’s scholarly literature, collecting and indexing research from repositories and journals. Suitable for academics and researchers.
Further details: About CORE
Epistemonikos
A multilingual database of health evidence, and the largest source of systematic reviews relevant for health-decision making. Covers a broad range of sources with basic support for structured searching. Suitable for health professionals, researchers and health decision-makers.
Further details: Epistemonikos search help, operators and field tags
EuropePMC
Europe PMC provides comprehensive access to life sciences literature from trusted sources. It contains 45.1 million abstracts and 10.2 million full text articles, including research articles, preprints, micropublications, books, reviews, and protocols. Suitable for information professionals and researchers.
Further details: About EuropePMC
ERIC
An online digital library of 1.5 million bibliographic records of journal articles and other education-related materials. Offers extensive support for structured searching. Suitable for academics, researchers, educators and policymakers.
Further details: ERIC syntax guide, operators and field tags
The most used search engine on the web. Can be used to search 3rd party sites (e.g. LinkedIn, Twitter, GitHub, Stack Overflow, etc.) using x-ray search. Offers inconsistent support for structured searching. Best suited for recruiters and generic search needs.
Further details: Google search help, operators and field tags
Google Patents
A freely accessible search engine that indexes over 120 million patent publications from 100+ patent offices around the world. Offers extensive (although somewhat idiosyncratic) support for structured searching, including classification codes, proximity, field searching, and searching by metadata.
Further details: Google Patents searching guide, operators and field tags
Google scholar
A freely accessible search engine that indexes some 389 million records of scholarly literature available on the web. Extremely broad coverage, but offers inconsistent support for structured searching so best used for initial scoping searches or in combination with other databases.
Further details: Google Scholar search help, operators and field tags
IDEAS
IDEAS is the largest bibliographic database dedicated to Economics and available freely on the Internet. Based on RePEc, it indexes over 3,500,000 items of research, including over 3,200,000 that can be downloaded in full text. Offers basic support for structured searching. Suitable for academics and researchers.
Further details: IDEAS search help, operators and field tags
IEEE Xplore
A research database of over 5 million scholarly records in electrical engineering, computer science and electronics. Offers extensive support for structured searching. Suitable for academics and researchers.
Further details: Xplore syntax guide, operators and field tags
JSTOR
JSTOR is a digital library for the intellectually curious, helping everyone discover, share, and connect valuable ideas. It provides access to more than 12 million journal articles, books, images, and primary sources in 75 disciplines. Suitable for academics and researchers.
Further details: JSTOR search help
Lens Patents
A free platform for discovery of patent literature, with over 144 million patent records from over 95 different jurisdictions. Offers extensive support for structured searching. including classification codes, proximity, field searching, and searching by metadata.
Further details: Lens Patents syntax guide, operators and field tags
Lens scholar
A free platform for discovery of scholarly literature, with over 200 million records sourced from PubMed, Crossref, Microsoft Academic Graph and CORE. Covers a broad range of scientific disciplines, and offers extensive support for structured searching.
Further details: Lens Scholar syntax guide, operators and field tags
Open Access Theses and Dissertations
OATD aims to be the best possible resource for finding open access graduate theses and dissertations published around the world. Metadata (information about the theses) comes from over 1100 colleges, universities, and research institutions. Suitable for information professionals and researchers.
Further details: OATD FAQ
Openalex
OpenAlex indexes over 250M scholarly works from 250k sources, with extra coverage of humanities, non-English languages, and the Global South. These works are linked to 90M disambiguated authors and 100k institutions, as well as enriching them with topic information, SDGs, citation counts, and much more. Suitable for information professionals and researchers.
Further details: About OpenAlex
Public Library of Science
PLOS is a nonprofit, Open Access publisher empowering researchers to accelerate progress in science and medicine by leading a transformation in research communication. Suitable for information professionals and researchers.
Further details: About PLOS
Pubmed
A freely accessible database of more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Offers extensive support for structured searching. Suitable for information professionals and researchers.
Further details: Pubmed syntax guide, operators and field tags
Semantic Scholar
A free, AI-powered research tool for scientific literature. Semantic Scholar indexes over 200 million academic papers sourced from publisher partnerships, data providers, and web crawls. Suitable for information professionals and researchers.
Further details: Semantic Scholar FAQ
Trip Database
A free clinical search engine whose primary function is to help clinicians identify the best available evidence with which to answer clinical questions. Offers basic support for structured searching. Suitable for information professionals, researchers and clinicians.
Further details: Trip syntax guide, operators and field tags
Virtual Health Library
A database of scientific and technical literature in health with over 1 million articles from more than 900 journal titles, theses and dissertations, books and book chapters, conference papers, government documents, and publications from international organizations, all published in Latin America and the Caribbean.
Further details: VHL search help
Yandex
The world’s 5th largest search engine, and the largest on the Internet in Russian. Can be used to search 3rd party sites (e.g. LinkedIn, Twitter, GitHub, Stack Overflow,, etc.) using x-ray search. Offers limited support for structured searching. Best suited for recruiters and generic search needs.
Further details: Yandex syntax guide, operators and field tags
What if my favourite source isn’t listed?
We also provide query translations for the following databases:
You can find these on the Query tab of the PubMed Results pane. Note that controlled vocabulary terms will still need to be translated manually.
What sources can I search in future?
In due course we will be rolling out further integrations, and 2Dsearch can be customized to search proprietary databases (for further details please contact us).