Funding for this research was provided by:
National Natural Science Foundation of China (31501704)
Text and Data Mining valid from 2019-09-05
Received: 11 March 2019
Accepted: 3 September 2019
First Online: 5 September 2019
Compliance with ethical standards
: The authors declare that they have no conflict of interest.
: This article does not contain any studies with human participants or animals performed by any of the authors.