Funding for this research was provided by:
Young Scientists Fund (NSFC71603064)
Ministry of Education in China (17YJAZH014)
Text and Data Mining valid from 2019-09-02
Received: 4 November 2018
Accepted: 24 July 2019
First Online: 2 September 2019
Ethics approval and consent to participate
: This study procedure was approved by the Ethics Committee of Harbin Medical University. All participants provided written informed consent. The questionnaire was treated as confidential and anonymous.
: Not applicable.
: The authors declare that they have no competing interests.