[文献资料]主要参考文献

1 ﹒ Sackett DL，et al ． Clinical Epidemiology ． Ab asiss ciencef or clinicalm edicine ． 2nded ． Boston：LittleB rown ． 1992.4 ﹒ BMJ publishingG roup ． Clinical Evidence，A Compendiumo ft heb esta vailablee videncef or effectiveh ealth care ． 1issue ． London， ......