WHAT IS UNPAYWALL?
Unpaywall is a service that maintains a database of links to full-text articles from open-access sources all over the world. The content is harvested from legal sources including repositories run by universities, governments, and scholarly societies, as well as open content hosted by publishers themselves.
Unpaywall focuses on providing greater access to several types of open content:
How do I find Unpaywall via the Connelly Library?
Remember that even if the article is not available in Unpaywall, you can do an ILL – which is now very fast!