Methods The injury in486primary school pupils and middle school students were sampled and surveyed by tratified-cluster random sam-pling and questionnaire survey in the previous year.

 
  • 方法以分层整群随机抽样的方法,问卷调查深圳市龙岗区486名中小学生过去1年中伤害的发生情况。
今日热词
目录 附录 查词历史