Funding for this research was provided by:
Beijing Science and Technology Program (D171100003217001)
Text and Data Mining valid from 2019-08-12
Received: 11 May 2019
Accepted: 29 July 2019
First Online: 12 August 2019
Ethics approval and consent to participate
: The Peking University Third Hospital Medical Science Research Ethics Committee approved the study before initiation.
: Not applicable.
: The authors declare that they have no competing interests.