共 19 条
- [2] A NEW METHOD OF CLASSIFYING PROGNOSTIC CO-MORBIDITY IN LONGITUDINAL-STUDIES - DEVELOPMENT AND VALIDATION [J]. JOURNAL OF CHRONIC DISEASES, 1987, 40 (05): : 373 - 383
- [3] COHEN JW, 1989, HEALTH SERV RES, V24, P33
- [7] Bias and causal associations in observational research [J]. LANCET, 2002, 359 (9302) : 248 - 252
- [8] Early versus delayed laparoscopic cholecystectomy for acute cholecystitis [J]. COCHRANE DATABASE OF SYSTEMATIC REVIEWS, 2006, (04):