Funding for this research was provided by:
National Natural Science Foundation of China (No. 81403220)
Tianjin Health and family planning-high level talent selection and training project
Tianjin Science and Technology Committee (No. 17ZXMFSY00190)
Tianjin health and family planning commission (No. 2017003)
Article History
Received: 16 April 2020
Accepted: 9 May 2020
First Online: 19 June 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: N/A.
: Our study protocol was approved by the Institutional Review Board of First Teaching Hospital of Tianjin University of TCM, Tianjin, China.