Fig. 1From: Disease causality extraction based on lexical semantics and document-clause frequency from biomedical literatureEvolution of disease networks from association to causality: a Disease network with association only between the diseases. b Simple causal disease network that shows the prior–posterior relationship of diseases. c Causal disease network that considers the semantic strength of causality terms based on lexicon analysis. d Causal disease network that reflects the different strengths of causality terms and causal frequencies extracted from documentsBack to article page