Well, according to the Mobipocket site here:
http://www.mobipocket.com/en/Downloa...ailsReader.asP
the Blackberry will read books in mobi/prc format.
And the mobipocket site has a lot of medical books, e.g.
http://www.mobipocket.com/en/ebooks/...sp?language=en
But you may also want to see whether you can get them cheaper elsewhere.
I hope this helps.