Browser extension which searches over 50,000 journals and open-access repositories.
Browser extension which uses existing open access aggregators of repositories and open sources to locate the requested work; if no open-access copy can be found, the extension will ask the work's author to share a copy.
Browser extension which searches for an open access alternative from its vast database of Open Access articles. The extension is free, but registration is required.
Use any/all of the browser extensions to help locate open access copies of articles found through database and search engine search results.
PubMed® comprises more than 30 million citations for biomedical literature from MEDLINE, life science journals, and online books. Citations and abstracts are free, when available; full text articles are often not free.
You can limit PubMed search results to only articles available for free through PubMed Central by selecting the Free full text filter in the Text availability filter section. The Full text filter will often, though not always, yield results with links to open access content not included in PMC.
Agricola, produced by the National Agricultural Library (NAL), consists of two subsets of records. The first contains citations for journal articles that include abstracts. The second consists of bibliographic records describing monographs, serials, audiovisual materials and online content from around the world.
PubAg is the U.S. Department of Agriculture (USDA), National Agricultural Library's (NAL) search system for agricultural information.
You can limit PubAg search results to only articles available for free through PubMed Central by selecting the Full text filter in the Text availability filter section.
Google's academic search engine. Citations within Google Scholar are free, but free full text is often not available. When available, links to free full text resources will appear to the right of the citations.