Funding for this research was provided by:
Taishan Scholar Foundation of Shandong Province (tsqn20161079, ts201511109)
Qingdao Key Health Discipline Development Fund
Text and Data Mining valid from 2020-02-22
Received: 31 May 2019
Accepted: 11 February 2020
First Online: 22 February 2020
Ethics approval and consent to participate
: This study was approved by the ethic committee of Qingdao Municipal Hospital. Written informed consent form was obtained from all participants or their legal representatives.
: Not applicable.