A posting to MEDLIB-L asked if anyone knew of any other acronym websites, but I have to say I did not know about this one. It looks good. The ARGH Biomedical Acronym Resolver is compiled automatically from Medline (so sometimes the same acronym is resolved in two different, but very similar, ways) at the UT Southwestern Computational Biology Group, at UT Southwestern Medical Center, Dallas.
You can put in an acronym and get the expansion - I tried RA, and got a long list, and also BLAST, which is where I got the two variants. You can also put in a phrase and get the acronyms. I tried quality of life and learnt that you need to click the submit button and not just press enter.
ARGH Biomedical Acronym Resolver is at http://invention.swmed.edu/argh/, where there are links to other data mining projects that I will come back to.