皮皮学，免费搜题
登录
搜题
【单选题】
In a cohort study the subjects should be selected as follows:A.
The exposed and unexposed groups are selected from the population who have had the outcome disease
B.
The exposed group is selected from the diseased population and unexposed group is selected from the population without the disease
C.
The exposed group is selected from the population without disease and unexposed group is selected from the population with the disease
D.
The exposed and unexposed groups are selected from the population who have not had the outcome disease
E.
Two groups with or without exposure are selected from any population.
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】变频器有哪几部分组成?交直交变频器主电路有哪几部分组成
【多选题】再生硅胶的注意事项是什么，正确的是（）
A.
排尽氮气中所带有的水分
B.
保护气部分断开的阀门必须关严，安全阀处于正常工作状态
C.
置换合格后，电加热器应先送电，后送气
D.
置换后O 2 含量一定小于0.5%
【简答题】胶水注意事项是什么?
【简答题】电路有哪几部分组成