One study says that approximately 50% of published papers are now freely available through repositories and preprint servers. Several new tools and plugins are available to detect free versions.
Find open-access versions of paywalled research papers, instantly with this web browser extension for Chrome and Firefox. A green “unlock” sign means that a free version of the paper is available elsewhere. A gray “lock” icon means that a free version was not found.
Free web-browser plug-in to find legally-accessible copies of paywalled papers with one click. Users can click on a button to bring up the available PDF. Registration is required.
If this plug-in can't find the open article, it allows you to automatically email the author to request the article.
A browser extension that links a user to PDFs for articles available through ODU Libraries on the web. Works best with publisher websites and Wikipedia.
LibKey is integrated into many of our databases (EbscoHost, ProQuest, Science Direct, Web of Science, etc).
This extension adds a browser button for easy access to Google Scholar from any web page.
http://doai.io/[doi] DOAI
(Digital Open Access Identifier)
A DOI resolver that takes you to a free version of the requested article, when available. Use http://doai.io/ before a DOI. Example: http://doai.io/10.1016/j.jalgebra.2015.09.023 -- Info at: http://doai.io