Monographs and journals
The Directory of Open Access Books (DOAB) lists academic peer-reviewed Open Access books. Metadata are displayed, full texts are accessible via the publisher’s website or repository.
Plugins and search engines
Unpaywall is a plugin for the Mozilla Firefox and Google Chrome browsers. If a user search discovers a research paper that the user’s institution is not licensed to access, Unpaywall will automatically list any available free-to-read OA versions of the paper.
1findr is a search engine for scholarly and scientific documents, particularly open access works. 1findr provides a searchable index of 90 million peer-reviewed journal articles, of which 27 million are OA articles that can be downloaded legally and free of charge. In addition to its pure search capabilities, 1findr can also export bibliographic data from articles and allows the user to examine the article’s Altmetrics scores and any references to it on Twitter, in blogs or in the Mendeley reference manager.
BASE, the Bielefeld Academic Search Engine, is the world’s largest specialist search engine for open access publications in journals and repositories. As BASE not only indexes open access content, users should configure the search options so that only OA documents are displayed.
Google Scholar – Special search engine for academic papers and scholarly publications. Open access texts can often be distinguished in the list of search results by the [PDF] or [HTML] labels. The [HTML] label in particular can be misleading, as only part of a work may be accessible, such as certain chapters of a book in Google Books.
SHERPA/RoMEO provides a summary of the permissions given by journal publishers as part of their copyright and author self-archiving policies.
SHERPA/Juliet provides information on the policies applied by research funding bodies. These policies set out the requirements on how research data and publications from funded projects should be managed.
ROARMAP (Registry of Open Access Repository Mandates and Policies) is a searchable database of the open access policies adopted by universities, research institutions and research funding bodies.
OpenDOAR (Directory of Open Access Repositories) and ROAR (Registry of Open Access Repositories) are indexed lists of open access repositories around the world. These quality-controlled listings also allow the user to search the contents of the indexed repositories.
re3data (Registry of Research Data Repositories) is a global directory of repositories for research data from all academic disciplines.