"Pennsylvania" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus,
MeSH (Medical Subject Headings). Descriptors are arranged in a hierarchical structure,
which enables searching at various levels of specificity.
State bounded on the north by New York and Lake Erie, on the east by Delaware and New Jersey, on the south by Delaware and Maryland, and on the west by Ohio and West Virginia.
This graph shows the total number of publications written about "Pennsylvania" by people in this website by year, and whether "Pennsylvania" was a major or minor topic of these publications.
To see the data from this visualization as text, click here.