Should "A lot of clinical research" be "A lot of clinical studies"?

why change it? what do you think is the matter with it the way it stands?

IMHO, "research" is a concept about the entire system. You cannot say "a lot of the entire system."

not so. it can be one study, a bunch of studies, even just a part of a study, even just an hour's work. it can be an occupational description. it can be the corpus of all studies. It's a very mutable term, and perfectly appropriate as used. it can also be, as in your quote, a study of studies, rather than new research itself.