That excellent database ABI Inform has a rather nice new feature.
When you look at your search results you may notice that some of the articles have a little 'link to full text' option under them. This takes you to other databases that have full text when ABI itself doesn't. It only appears where it knows that there is full text available somewhere else.
[Note! This has only been set up in the last couple of days and some of the links don't seem to be working yet, but most do and we're working on the rest.]