ebrary - A growing collection of full-text books.

MD Consult - Access to 50 leading medical reference books.

The Merck Manuals - Includes the full text of The Merck Manual of Diagnosis and Therapy. 

Merriam Webster Medical Dictionary - Available through MedlinePlus.gov. 

NCBI Bookshelf - A searchable collection of full-text biomedical books. 

The Infectious Diseases of Haiti - Provided by GIDEON (Global Infectious Disease and Epidemiology Network).