Cardiovascular diseases, blood diseases, respiratory diseases. According to the requirements of China Postdoctoral Science Fund, the clinical medical contents of this degree fund include cardiovascular diseases, hematological diseases, respiratory diseases, digestive diseases, endocrine and metabolic diseases, nephropathy, rheumatism and infectious diseases. Postdoctoral students, referred to as "Hou Bo" for short, refer to those who engage in academic research in institutions of higher learning or research institutions after obtaining doctoral degrees.