Funding for this research was provided by:
the Human Social Science Research Program of the Ministry of Education (14YJA190011)
the Fundamental Research Funds for the Central Universities (SWU1509107)
Text and Data Mining valid from 2018-11-29
First Online: 29 November 2018
Compliance with Ethical Standards
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
: Informed consent was obtained from all individual participants included in the study.
: Author A declares that he/she has no conflict of interest. Author B declares that he/she has no conflict of interest.