I'm not sure exactly what the Alabama Virtual Library is, but perhaps you could look at some of the articles that Storm Crow has linked and then search for the ORIGINAL study in the library? Of course that depends on how much information is in there.

That and maybe double check with your professor regarding resources. I have a hard time believing that a college professor wouldn't allow you to cite a study from a major medical journal (just be sure you're citing the original study and not a third party article about the study).