Knowledge, attitudes and practices of combined oral contraceptives in Tianjin obstetrics and gynecology personnels

HUO Yan, ZHANG Yujuan, WANG Jianmei△, YANG Jing, XIE Guohua

Tianjin Medical Journal . 2015, (3): 311 -314 . DOI: 10.11958/j.issn.0253-9896.2015.03.024