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. 2022 Apr 26;10(12):3773–3786. doi: 10.12998/wjcc.v10.i12.3773

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©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.

This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed following the Creative Commons Attribution-Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/

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Flow diagram of study selection (up to June 2021). CBM: Chinese Biological Medical database; CNKI: China National Knowledge Infrastructure; VIP: China Science and Technology Journal database; WF: Wanfang database and foreign language databases including PubMed, Embase, Cochrane Library, Web of Science, etc.