Here's some of the answers from other times this was asked.

http://www.askpedia.com/q/3094E/What_is_...


http://www.askpedia.com/q/30D55/What_is_...

Web sites Like the CDC Center for Disease Control
Anything found on the Stanford School of Medicine web site....
Forbs....
USA Today web site...
Mayo Clinic web site...
The Science Daily web site
Journal of Occupational & Environmental Medicine's web site
United Spinal's Action Online Magazine
The Journal of theAmerican Medical Association
The New York Times Company web site
Society for Neuroscience
U.S. Department of Health and Human Services

Basically websites you KNOW contain reliable information
Are you doing this for school? If so, these should be helpful!