  Demonstrating the practical value of public research has been an important
subject in science policy. Here we present a detailed study on the evolution of
the citation linkage between life science related patents and biomedical
research over a 37-year period. Our analysis relies on a newly-created dataset
that systematically links millions of non-patent references to biomedical
papers. We find a large disparity in the volume of science linkage among
technology sectors, with biotechnology and drug patents dominating it. The
linkage has been growing exponentially over a long period of time, doubling
every 2.9 years. The U.S. has been the largest producer of cited science for
years, receiving nearly half of the citations. More than half of citations goes
to universities. We use a new paper-level indicator to quantify to what extent
a paper is basic research or clinical medicine. We find that the cited papers
are likely to be basic research, yet a significant portion of papers cited in
patents that are related to FDA-approved drugs are clinical research. The U.S.
National Institute of Health continues to be an important funder of cited
science. For the majority of companies, more than half of citations in their
patents are authored by public research. Taken together, these results indicate
a continuous linkage of public science to private sector inventions.
