There are a number of browser extensions or plug-ins for Chrome, Firefox, and Safari which can be installed to facilitate finding articles which are open access:
Unpaywall
Unpaywall
External link. makes finding OA-articles easy for the individual user by installing a plug-in on Chrome or Firefox. Content from Unpaywall is also integrated External link. into other services such as databases and link-resolvers.
Open Access Button
You can search Open Access Button directly on their website or download an extension for Chrome which makes finding open access articles easy. They also offer integrated services for libraries External link., as interlibrary loans (ILL/DDS). When OA Button hits a paywall, the service also sends off requests to authors External link. asking them to deposit their articles in a subject or institutional repository in order to make their research open. Open Access Button is a non-profit organisation.
Google Scholar Button
Google Scholar Button External link. is a browser extension available for Firefox, Chrome, and Safari. The extension makes finding full-text open access articles in Google Scholar External link. easier and allows access to closed articles which a user has access to via their own institution’s subscriptions, by configuring Google Scholar with your library’s URL.
Lazy Scholar
The Lazy Scholar External link. extension finds open access articles and provides metrics and citations. Additionally, it can include articles behind paywalls via a user’s own institution’s subscriptions.
Kopernio
Kopernio External link. is an extension finding both open access versions of articles and articles which users have access to via institutional subscriptions. The service is free but belongs to Clarivate Analytics External link. and you need to register in order to use the extension.