HighWire Press host journals from SAGE, Oxford University Press, and a large number of society publishers, mainly in Medicine and the Biosciences (e.g. BMJ and PNAS).
A very handy feature of HighWire Press journals is that HighWire articles cited by another HighWire article are free!
For example, if you want to access the full-text of this article in Science Translational Medicine:
it seems that you can't because we don't subscribe to that journal.
Below the abstract it shows that it has been cited by an article in Cancer Research:
We subscribe to Cancer Research, and both Cancer Research and Science Translational Medicine are hosted by HighWire Press so that means we can access the Science Translational Medicine article, as long as we do so via the Cancer Research article!
So go to: http://cancerres.aacrjournals.org/content/70/20/8036.abstract and then click on the Full Text link (not Full Text PDF) to get to http://cancerres.aacrjournals.org/content/70/20/8036.full.
You need to be on-campus or using Apps Anywhere to get access – the next step won’t work if your URL includes .ezproxy.liv.ac.uk because we haven’t configured EZproxy to work with Science Translational Medicine.
Scroll down to the references and you see the article you want is number 27 and has a free full text link. Follow that link and you will be able to access the Science Translational Medicine article because you have been referred to it from Cancer Research. (Actually, if you have come via EZproxy then right-click on the FREE Full Text link, copy the shortcut, paste it into your browser's location bar and then delete the .ezproxy.liv.ac.uk bit of the URL before you hit Return).
For a full list of HighWire Press journals, see http://highwire.org/lists/allsites.dtl.