Fig. 2From: A bibliometric analysis of malaria research in China during 2004–2014Sub-networks for keywords in malaria research of China, 2004–2014. *The size of nodes indicates the keywords centrality, and the thickness of the lines indicates the co-occurrence frequency of keywords pairs. a represents the keyword pairs with a co-occurrence frequency ≥45, b denotes ≥30 and c represents ≥15Back to article page