Crc follow-up refers to the clinical coordinator, whose main job is to assist the doctor in charge of the project to complete various tasks according to the requirements of GCP and research plan; Assist in screening, grouping and follow-up of subjects; Assist in collecting, archiving and managing research data. Work experience of clinical coordinator: rich knowledge of clinical medicine and health statistics. Strong communication and coordination ability, persuasion ability, organization and planning ability, good health, good image and good temperament. Education and training: College degree or above in medicine, nursing or pharmacy, GCP certificate.