Xia, Xiaohui
Chao, Liang
Nan, Chen
Yin, Xuejuan
Zheng, Huifang
Zhang, Sheping
Funding for this research was provided by:
National Education Planning Leading Group Office(CN)
Article History
Received: 16 November 2021
Accepted: 11 July 2022
First Online: 18 July 2022
Declarations
:
: The ethical review was provided by the Science and Technology Department of Lanzhou City University. As the legal guardian of preschool children, three kindergartens provided written informed consent. The research was carried out in compliance with the Helsinki Declaration and all methods were performed in accordance with the relevant guidelines and regulations.
: Not applicable.
: The authours declare that they have no competing interests.