HealthBase is a health information search tool created by Netbase that should be on your short list of resources.
Search results are drawn from a diverse range of resources, including WebMD, PubMed, Medline Plus, and the Mayo Clinic. NetBase uses a semantic-based indexing system to obtain the context of articles, and provides targeted results categories to allow the user to find specific information on their topic.
It is a very useful service, with the usual caveats regarding health information on the web (they also index health information from Wikipedia, so be sure to check sources).
found via ResourceShelf and TechCrunch
