. 2021 Mar 19;9:652842. doi: 10.3389/fpubh.2021.652842
Copyright © 2021 Yan, Zhang, Chen, Jiang, Liu, Zhou, Huang, Zhou, Guan, Ding, Chen, Lan, Fu, Wu, Li and Yang.
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Figure 1.
Flow diagram of the study selection process for this meta-analysis.