9Barrows H ,Tamblyn R. Medical Education.Volume 1, "Prob- lem-based Learning: an approach to medical education"[ M ]. New York: Springer Publishing Company, 1980:10.
10Karpa KD, Vrana KE. Creating a Virtual Pharmacology Curriculum in a Problem-Based Learning Environment: One Medical School's Experience[J). Acad Med, 2013, 88(2): 198-205.