Gathering information from many of the top medical professional sites such as PubMed, NIH, and Merck, this search engine provides information from peer level sources. Partnered with Healthline.com and Google Custom Search, the results offered are from a full search engine. They also offer a "reference desk of hard-to-find medical resources."
MedNets. Ranked number 4 of 95 in Google’s medical directory, this metasearch engine provides information from journals, associations, news sources, and more. MedNets offers a search specifically for medical professionals in addition to one for the general public. The professional version can be customized by specialty.
Hardin MD. Sponsored by the University of Iowa, this site allows you to search for a disease or general health topic alphabetically to get links to a variety of online articles and photos about each disease. You can also view photos from classic medical books via this site.
Welch Medical Library. While this site is specifically for those associated with Johns Hopkins Medical Institutions, it offers a search feature for articles published in medical journals and online. Many of the full articles are available for a fee, while others are free of charge. In addition to the powerful search engine, they also have Subject Guides under the "eResources" section that offers links to topics ranging from Alternative Medicine to Grants and Funding to Writing and Publishing.