Changes in cholelithiasis in Tianjin in the past 30 years.
D000328:Adult; D001196:Ascariasis / Q000150:complications; D002681:China; D002769:Cholelithiasis / Q000453:epidemiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged