Mao, Yu
Wang, Yimin
Dong, Lixin
Zhang, Yunjie
Zhang, Yanqiu
Wang, Chao
Zhang, Qiang
Yang, Sen
Cao, Liyan
Zhang, Xinyuan
Li, Xin
Fu, Zhanzhao
Funding for this research was provided by:
Scientific Research Fund of Hebei Health and Family Planning Commission (20181192)
Article History
Received: 22 March 2019
Accepted: 15 August 2019
First Online: 5 September 2019
Ethics approval and consent to participate
: The Medical Ethics Committees of First Hospital of Qinhuangdao approved this study.
: Not applicable.
: The authors declare that they have no competing interests.