Text and Data Mining valid from 2019-12-01
Received: 25 June 2019
Accepted: 19 December 2019
First Online: 30 December 2019
Ethics approval and consent to participate
: The ethics committee of The Third Hospital of Hebei Medical University approved the study. This study was written informed consent from the patients.
: Not applicable.
: The authors declare that they have no competing interests.