全面二孩政策下河北省异位妊娠患病状况的多中心研究
张欢欢,郭艳巍,张金环,杨佳琦,单伟颖
Prevalence of Ectopic Pregnancy in Hebei Province during the Implementation of Universal Two-child Policy:a Multicenter Study 
ZHANG Huanhuan,GUO Yanwei,ZHANG Jinhuan,YANG Jiaqi,SHAN Weiying
中国全科医学 . 2021, (8): 1017 -1021 .  DOI: 10.12114/j.issn.1007-9572.2020.00.330