Funding for this research was provided by:
Health Scientific Research Project of Shaanxi Province (2014D47)
Text and Data Mining valid from 2019-01-08
Received: 21 May 2018
Accepted: 21 December 2018
First Online: 8 January 2019
Ethics approval and consent to participate
: All participants were voluntary and provided written informed consent before taking part in this research. This study was approved by the Research Ethics Committee of the First Affiliated Hospital of Xi′an Jiaotong University, and in compliance with the Declaration of Helsinki. The design and performance of this study involving human subjects were obviously described in a research protocol.
: Not applicable.
: The authors declare that they have no competing interests.
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