5Ransey PC,, Carline JD, lnui Ts. Changes over time in the knowledge base of practicing internists[J]. JAMA, 1991,266:1103- 1107.
6Shin JH, Haynes RB, Johnston ME. Effect of problem- based, self- directed undergraduate education on life long learning [ J ]. Can Med Assoc J,1993,148:969 -976.
7Sackett D L, Rosenberg W M, Gray J A, et al. Evidence-based medicine: what it is and what it is not. Br Med J, 1996, 312:71 -72
