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. 2022 Nov 1;13:1035229. doi: 10.3389/fphar.2022.1035229

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Copyright © 2022 Wu, Huang, Qi, Li, Zhang, Jiang, Wang, Zhang, Jiang, Chen and Ying.

This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

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(A) Network clustering map of keywords’ co-occurrence analysis based on VOSviewer. The minimum threshold for the number of keyword frequencies is 40. Keywords were divided into 5 clusters: cluster 1 (red), cluster 2 (green), cluster 3 (blue), cluster 4 (yellow), and cluster 5 (purple). Each keyword is represented as a node, and the node size is proportional to the frequency. The line between nodes denotes a co-occurrence relationship. The distance between nodes denotes the degree of relevancy, and the closer the distance, the higher the degree of relevancy. (B) Overlay map of keywords’ co-occurrence analysis based on VOSviewer. The node color denotes the corresponding average occurrence time according to the color gradient in the lower right corner. Nodes displayed in blue represent keywords that appear relatively early, while nodes displayed in red represent keywords that appear later. (C) Top 20 keywords with the highest occurrence times.