[An investigation on gallstones with gray-scale ultrasound].
D000328:Adult; D002681:China; D002769:Cholelithiasis / Q000453:epidemiology*; D005260:Female; D042882:Gallstones / Q000453:epidemiology; D006801:Humans; D008297:Male; D008403:Mass Screening; D014463:Ultrasonography / Q000379:methods*