The direction of medical research.
D003140:Communicable Disease Control; D004782:Environmental Health; D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049690:History, Ancient; D006801:Humans; D011314:Preventive Health Services / Q000639:trends*; D011315:Preventive Medicine / Q000266:history / Q000639:trends*; D012106:Research; D012959:Socioeconomic Factors