Text and Data Mining valid from 2020-04-21
Received: 7 November 2019
Accepted: 30 March 2020
First Online: 21 April 2020
Ethics approval and consent to participate
: The study protocol was approved by the Chongqing Medical University Ethics Committee. All the participants will sign an informed consent form. Summary data will be used only for statistical analysis to ensure that personal information is not leaked.
: Not applicable.
: The authors declare that they have no competing interests.