http://www.ncbi.nlm.nih.gov/pubmed/
http://www.medical-journals.com/
http://www.freemedicaljournals.com/
http://highwire.stanford.edu/lists/freeart.dtl
http://www.dmoz.org/Science/Publications/Journals/Free_Online_Journals/
http://www.medmatrix.org/
http://www.diseasesdatabase.com/
http://www.rarediseases.org/search/rdbsearch.html
http://www.healthandenvironment.org/tddb
http://www.nlm.nih.gov/medlineplus/
http://www.medicinenet.com/script/main/hp.asp
http://www.rxlist.com/script/main/hp.asp
http://www.mayoclinic.com/
http://www.symptoms101.com/
http://www.healthline.com/
http://www.doctorslounge.com/primary/diseases/
http://hpdrc.cs.fiu.edu/med.resource/
http://www.goomedic.com/symptoms-and-diseases-database-free-open-source-php-mysql-patients-records-project.html
http://www.medicalmnemonics.com/
http://www.gideononline.com/
http://nursepractitionerdegree.org/25-free-online-medical-databases-to-learn-about-any-disease.html