Funding for this research was provided by:
National Natural Science Foundation of China (NO.81700483)
Text and Data Mining valid from 2019-07-04
Received: 22 September 2018
Accepted: 7 June 2019
First Online: 4 July 2019
Ethics approval and consent to participate
: The study protocol was reviewed and approved by the Ethics Committee of Army Medical University and all methods were performed in accordance with the relevant guidelines and regulations. As a retrospective observational study and all subjects were anonymized, informed consent was not required.
: Not applicable.
: The authors declare that they have no competing interests.