An interesting study of publications in cardiovascular journals is coming out soon in the journal Circulation. The abstract seems to tell the story. In the decade 1997-2007 15.6% of the publications had zero citations after five years. Not even self-cites. 46.0% were considered "poorly cited" (defined as having ≤5 cites).
Is there any reason to believe these numbers wouldn't apply to all biomedical science beyond "my sub-field is special"?