Funding for this research was provided by:
National Social Science Fund Project (15BJY164)
the Ministry of Education Humanities and Social Sciences Fund Project (14YJA790034)
Text and Data Mining valid from 2018-01-24
Received: 10 May 2017
Accepted: 28 December 2017
First Online: 24 January 2018
: The authors declare that we have no competing interests.