DESIGN: a single sampling study.
设计：单一样本研究。
Methods a stratified sampling study on the epidemiological feature of fatty liver was conducted among 1992 workers from 4 factories of Ma 'anshan iron and steel general company.
方法采用分层整群抽样方法，抽取马钢公司四个工厂共1992名职工进行脂肪肝的流行病学调查。
Method:A cluster sampling study on the condition of injuries was conducted among 1059 rural inhabitants in a certain township in Tongjiang County, Sichuan province from Jan 1998~Jan 1999.
方法：采用整群抽样方法，对四川省通江县某乡1059名农村居民一年中伤害发生情况进行调查。
Method:A cluster sampling study on the condition of injuries was conducted among 1059 rural inhabitants in a certain township in Tongjiang County, Sichuan province from Jan 1998~Jan 1999.
方法：采用整群抽样方法，对四川省通江县某乡1059名农村居民一年中伤害发生情况进行调查。
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