The Chrome extension Unpaywall does exactly that. https://chrome.google.com/webstore/detail/unpaywall/iplffkdpngmdjhlpjmppncnlhomiipha https://chrome.google.co

The Chrome extension Unpaywall does exactly that. https://chrome.google.com/webstore/detail/unpaywall/iplffkdpngmdjhlpjmppncnlhomiipha https://chrome.google.com/webstore/detail/unpaywall/iplffkdp... It doesn't bat 1.000, of course, but it is successful often enough to be useful.