Funding for this research was provided by:
National Natural Science Foundation of China (31772240)
Text and Data Mining valid from 2019-06-20
Received: 28 March 2019
Accepted: 12 June 2019
First Online: 20 June 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 and/or animals performed by any of the authors. The formal consent is not required in this study.