Co-occurrence of health-risk behaviors among Beijing middle school students, China.
D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D002681:China / Q000453:epidemiology; D005260:Female; D015438:Health Behavior; D006801:Humans; D008297:Male; D012309:Risk-Taking; D013334:Students / Q000523:psychology*; D011795:Surveys and Questionnaires