问卷调查

Methods A stratified random cluster sample of12637students in32schools were investigated with an anonymous questionnaire.

采用整群抽样的方法，抽取上海市有代表性的32所学校共计12637名大中学生，进行无记名问卷调查。

Methods A cluster stratified sample of315undergraduates were investigated with a closed questionnaire,and301questionnaires were available.

采用分层整群抽样法，抽取贵州省在校大学生315名进行无记名封闭式问卷调查，获得有效问卷301份。

Methods A stratified cluster sample of1007college students were questionnaired.

采用分层整群抽样的方法，对广州市1007名大学生进行问卷调查。

Methods A cluster random stratified sample of404medical college students were investigat-ed with a self-administered questionnaire.

采用分层整群抽样方法对404名医学生进行自填问卷调查。

Objective To study the interrelation of life habit,knowledge and consciousness in preventing infectious disease,and to provide evidence for health education of infectious diseases.Methods A stratified cluster sample of1007college students were questionnaired.

目的 了解学生日常生活习惯、传染病防治知识、防治意识的状况及其相互关系，开展大学生传染病防治健康教育提供依据方法采用分层整群抽样的方法，对广州市1007名大学生进行问卷调查。

Methods With stratified clustered sampling method, 375 college students were chosen to complete the questionnaire.

采用分层随机抽样方法，在杭州市的大学中抽取大学生375名进行问卷调查。

Methods Study subjects were selected through stratified sampling and data were collected through questionnaire and physical examination.

方法］采用分层整群抽样的方法获取研究样本，采用问卷调查和体检相结合的方法收集相关信息。

Methods A self-developed questionnaire was used to investigate 2600 old persons selected in 26 provinces by stratified sampling.

方法在26省按照城乡和男女分层抽样，对2600名老年人进行问卷调查，并对有效的2414份问卷进行数据统计学处理。

Methods The Knowledge of occupational hazard and prevention in different enterprises was investigated by stratified random sampling.

方法采用整群抽样的方法对不同行业的外资企业农民工进行职业病危害因素认知及其防护知识的问卷调查和统计分析。

In this paper, 236 SMEs of different types of ownership and from different industries are investigated using a stratified sampling method.

本文采用分层抽样方法，对236家不同所有制、具有行业代表性的中小企业展开了问卷调查。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。