The evolution of the clinical investigator.
D004739:England; D049669:History, 16th Century; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D006801:Humans; D007558:Italy; D012106:Research / Q000266:history*; D012108:Research Personnel / Q000266:history / Q000639:trends; D014481:United States