title: [Characteristics of HBsAg subtype distribution in the Beijing area].
authors: X Q
authors: XQ
authors: Huang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D002681:China; D005260:Female; D006509:Hepatitis B / Q000235:genetics* / Q000635:transmission; D006514:Hepatitis B Surface Antigens / Q000145:classification*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D006514:Hepatitis B Surface Antigens