Funding for this research was provided by:
health system and birth control commission of Fujian province (2015-1-43)
professor fund of Fujian medical university (JS15017)
Article History
Received: 16 January 2018
Accepted: 11 April 2018
First Online: 24 April 2018
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.