Fig. 3From: Emerging trends and hotspot in gut–lung axis research from 2011 to 2021: a bibliometrics analysisCo-occurrence analysis of countries. A Country co-occurrence map. B Cooperation network of the United States. C Cooperation network of China. The size of the node represents the number of publications. The link between nodes represents the existence of cooperation. The thickness of the lines represents the closeness of cooperation, and the thicker the lines are, the closer the cooperation isBack to article page