. 2021 Jul 1;8:662340. doi: 10.3389/fmed.2021.662340
Copyright © 2021 Zhu, Zhang, Wang, Yao, Ren, Chen, Jin, Guo, Liu, Zheng, Chen, Guo, Li, Du, Xi, Li, Huang, Li and Yu.
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Figure 1.
Flow diagram of the selection process of patients.