Funding for this research was provided by:
Shengjing freedom research fund of Siyu Sun.
Text and Data Mining valid from 2020-03-12
Received: 8 July 2019
Accepted: 4 March 2020
First Online: 12 March 2020
Ethics approval and consent to participate
: This was a retrospective study. It was approved by our institution’s Institutional Review Board (Shengjing Hospital of China Medical University) and written informed consent was obtained from all subjects.
: Not Applicable.
: The authors declare that they have no competing interests.