Funding for this research was provided by:
Social Development Research Program of Liaoning Province (2011225020)
Text and Data Mining valid from 2018-09-10
Received: 23 April 2018
Accepted: 3 September 2018
First Online: 10 September 2018
Ethics approval and consent to participate
: This study complies with the Declaration of Helsinki, and Shengjing Hospital of China Medical University Research Ethics Committee approved the research protocol. Written informed consent was formally obtained from all participants.
: Not applicable.
: The authors declare that they have no competing interests.
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