Funding for this research was provided by:
Major Science and Technology Plan Project of Hainan Province (ZDKJ201804)
Text and Data Mining valid from 2020-02-22
Received: 25 October 2019
Accepted: 11 February 2020
First Online: 22 February 2020
Ethics approval and consent to participate
: Ethical approval is not required for this systematic review.
: Not applicable.
: The authors declare that they have no competing interests.