Veterinary Information Network (VIN) covers veterinary medicine and was created for, and developed by, veterinarians. The searchable discussion boards are a valuable tool for clinical medicine. DVM students are given free access while in veterinary school (as are veterinary faculty and staff). View a ten minute video to learn more about VIN.
The "Three Concept Approach" often gives good results -- Enter a term for each of the following:
dogs AND diabetes AND diagnosis