Funding for this research was provided by:
China Food and Drug Administration (ZG2016-2)
Text and Data Mining valid from 2018-04-29
Received: 30 December 2017
Accepted: 16 April 2018
First Online: 29 April 2018
Compliance with ethical standards
: Ethics approval for this study was granted by The Ethics Committee of the Peking Union Medical College (PUMC).