Funding for this research was provided by:
China Postdoctoral Science Foundation (2019M653685)
Project of Shaanxi Social Science Foundation (2019S038)
Research Program Foundation of Xi’an Jiaotong University (XZD012019024)
Text and Data Mining valid from 2019-11-06
Received: 20 June 2018
Accepted: 23 October 2019
First Online: 6 November 2019
Ethics approval and consent to participate
: The Ethics Committee of Xi’an Jiaotong University Health Science Center approved this study (approval number 2015–644). Each respondent agreed to participate in this interview and provided informed consent.
: The consent is not required due to the retrospective nature of the research.
: The authors declare that they have no competing interests.