View More View Less
  • 1 Institute for Scientific Information® 3501 Market Street 19104 Philadelphia Pennsylvania (USA) 3501 Market Street 19104 Philadelphia Pennsylvania (USA)
Restricted access


The specialty of collagen research is tracked over a ten year period, 1970–1979, using the methodology of co-citation cluster strings. Independently obtained annual clusters are linked together over time by the percentage of highly cited documents countinuing from year to year. All inter-year links are clustered by single-linkage to form the strings, one of which corresponds to the collagen specialty. Maps of the individual year clusters within the string reveal an alternating pattern of expansion/innovation followed by contraction/consolidation. At the same time the subject focus of research gradually shifts. The institutional affiliation and funding sources for highly cited documents show a trend from early dominance by a few institutions and sources to a multiplicity and collaboration of centers and sources later on, due in part to the migration of researchers from an initially dominant institution.