Funding for this research was provided by:
National Natural Science Foundation of China (81671936)
Text and Data Mining valid from 2020-02-10
Version of Record valid from 2020-02-10
Article History
Received: 12 November 2019
Accepted: 27 January 2020
First Online: 10 February 2020
Ethics approval and consent to participate
: Not applicable.
: Not applicable.
: The authors declare that they have no competing interests.