辽宁省医学高峰建设专项经费资助项目4010218;中国医科大学"十二五"医学教育科学研究课题资助项目No.YDJK2012012. Project supported by the Medical Peak Vonstruction Special Fund of Liaoning Province4010218;the Twelfth Five Years Plan of Medical Education Scientific Research of China Medical UniversityYDJK2012012