unpaywall

This extension (both Chrome and Firefox) pops up when you are at a journal abstract. Clicking on it will legally serve you free access to this content (if at all possible).

http://unpaywall.org/

“Why did you make it?Now more than ever, humanity needs to access our collective knowledge, not hoard it behind paywalls. Lots of researchers feel the same; that’s why they upload their papers to free, legal servers online. We want to help bring that open access content to the masses.

We find fulltext for 65-85% of articles, depending on their topic and year of publication. We think that’s a game-changer for the publishing industry. Now that most articles are free, why subscribe? Over the longer term, we’ll keep getting even better as mandatory open access requirements begin to take effect in the US, UK, Europe, and elsewhere.”