Determinants of medical care utilization: physicians' use of laboratory services.
D000367:Age Factors; D005249:Fees and Charges; D006123:Group Practice; D007354:Insurance, Major Medical; D007388:Internal Medicine; D007753:Laboratories / Q000706:statistics & numerical data*; D007857:Leadership; D009922:Oregon; D010820:Physicians / Q000706:statistics & numerical data; D012577:Schools, Medical