Funding for this research was provided by:
National Natural Science Foundation of China (NSFC, 81572542, NSFC, 81874196)
Text and Data Mining valid from 2019-11-15
Received: 2 September 2019
Accepted: 17 October 2019
First Online: 15 November 2019
Ethics approval and consent to participate
: No applicable.
: Not applicable.
: All authors declare that they have no competing interests.