Funding for this research was provided by:
National Natural Science Foundation of China (81872676)
Beijing Hospitals Authority Youth Programme (QML 20181207)
Beijing Municipality Natural Science Foundation (7192063)
Special Fund of the Pediatric Medical Coordinated Development Center of Beijing Municipal Administration of Hospitals (XTYB201806)
Text and Data Mining valid from 2019-11-14
Received: 8 August 2019
Accepted: 29 October 2019
First Online: 14 November 2019
Ethics approval and consent to participate
: This paper is a systematic review, so ethical approval and consent is not required.
: Not applicable.
: The authors declare that they have no competing interests.