Health care research in social security.
D000368:Aged; D003153:Community Health Services; D003365:Costs and Cost Analysis; D003695:Delivery of Health Care; D004469:Economics, Hospital; D004470:Economics, Medical; D006077:Government Agencies; D006739:Hospital Administration; D006801:Humans; D007348:Insurance, Health; D007753:Laboratories; D006278:Medicare; D012106:Research; D012109:Research Support as Topic; D012943:Social Security; D014481:United States