Funding for this research was provided by:
Key Projects in the National Science and Technology Program during the Thirteen Five-year Plan Period (2016YFD0400603)
Text and Data Mining valid from 2019-11-26
Received: 25 June 2019
Accepted: 6 November 2019
First Online: 26 November 2019
Ethics approval and consent to participate
: This study is in compliance with the highest ethical standards. There was no human participant being recruited, no animals, tissues, cells, body fluid, or any living creatures being involved, therefore, no Institutional Review Board (IRB) approval is necessary and no informed consent obtained.
: This review article does not recruit human subjects, and no intervention was applied to any subjects. Neither did we include any individual personal data nor information/documents. Therefore, consent for publication is not applicable for this article. Authors declare that there is no competing interest.
: QH, QT, JS, MY and XL reached agreements on the proposal, delivery and outcomes of this study and have no conflicts of interest.