Methods 0 residents aged to years of Changping District, Shunyi District, Daxing District and Fangshan District were selected by stratified random sample method, questions were asked and all the investigators were trained.
Methods 0 residents aged to years of Changping District, Shunyi District, Daxing District and Fangshan District were selected by stratified random sample method, questions were asked and all the investigators were trained.
方法采取分层随机抽样方法,从昌平、顺义、房山、大兴四区随机抽取～岁的农村户口居民0人,采用统一的行为危险因素监测调查表,由统一培训的调查员入户调查。