http://www.amedeo.com/index.htm

It allows free access to medical literature (abstracts and some full texts) related to infectious diseases, disorders of the cardiovascular system, of the respiratory system, of the kidney, and of the gastrointestinal system, immunology, hematology, oncology, endocrinology and metabolism, neurologic and psychiatric disorders, women´s and men´s health, ophthalmology, otorhinolaryngology, dermatology, surgery, dentistry, intensive care, rehabilitation, diagnostic procedures, nutrition, and substance abuse.