Internal medicine and surgery are the first-level branches of the hospital, cardiovascular medicine and digestive medicine are the second-level branches, and nephrology and diabetes are the third-level branches. Small hospitals have only first-class branches, while large and medium-sized hospitals have second-and third-class branches.

Internal medicine is a department with drug therapy as the main means. The main branches are: cardiovascular medicine, gastroenterology, respiratory medicine, urology (nephrology), neurology, hematology and endocrinology;

Surgery is a professional department with surgical resection and repair as the main treatment means. In recent years, with the application of microsurgery technology, surgery has made great progress. The principles of specialty setting of surgery in hospitals are similar to those of internal medicine, and usually correspond to internal medicine. The main branches are: general surgery, cardiothoracic surgery, urology, orthopedics, neurosurgery and burn plastic surgery.

I suggest going to the website of Peking Union Medical College Hospital, where the branches are very detailed.