6Nordstrom M, Lindblad B, Bergqvist D, et al. A prospective study of the incidence of deep-vein thrombosis within a defined urban popula,tion[ J]. J Intern Med,1992,232(2) :155 ～ 156.
8Nurmohamed MT, Rosendaal FR, Buller HR, et al. Low molecular weight heparin versus standard heparin in general and orthopedics surgery: a meta-analysis [ J ]. Lancet, 1992,340 ( 8810 ): 152.
