The CureHunter Discovery Engine is the world's only fully unified and integrated numeric index of all known drugs, biologically active agents, diseases and empirical statements of all effective clinical outcomes published in the United States National Library of Medicine. Aimed at doctors and medical professionals, CoreHunter has launched a free visualization tool (no login or registration required) called the Visual Medical Dictionary. It's a slick, usable and well-thought application that can be of great use to any medicine curious person.
The CHI Visual Medical Dictionary provides auto-completion style instant lookup of diseases, drugs and therapeutic techniques. It also goes beyond regular dictionaries by displaying an ontology context tree and interactive network graph of related drugs, diseases and therapies. The graph navigation resembles in many ways the now classic Visual Thesaurus by Thinkmap, which allows the exploration/expansion of one node at a time.