Medical Words Network: Point-wise mutual information matrix

Network analysis was used to explore how the medical sciences have evolved between 1980 and 2015 based on the shared words contained in more than 9 million PubMed abstracts. All abstracts in PubMed until January 2015 inclusive were uploaded using contact with Application Programming Interface (API) of the National Library of Medicine (http://www.nlm.nih.gov/api/). We only included entities with English abstracts for the analysis (9,592,193 in total). Words that were used more than 2000 times were considered for further analysis and the point-wise mutual information (PMI) between all permutations of two words were calculated. Attached files contain the PMI of medical words used more than 2000 times in each time period.