Funding for this research was provided by:
National Natural Sciences Fund Project of China (81372529)
Text and Data Mining valid from 2019-01-25
Received: 31 May 2018
Revised: 12 November 2018
Accepted: 15 November 2018
First Online: 25 January 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.