Funding for this research was provided by:
the Key Scientific and Technological Research Projects of Hebei Health and Family Planning Commission (20180411)
Text and Data Mining valid from 2019-08-14
Received: 3 July 2019
Accepted: 7 August 2019
First Online: 14 August 2019
Ethics approval and consent to participate
: This clinical trial was approved by the Ethics Committee of the Third Hospital of Hebei Medical University and in strict conformity with the guidelines stated in the Declaration of Helsinki.
: All authors have given consent for publication.
: The authors declare that they have no competing interests.