求翻译：现场调查是研究外源性化学物对接触人群健康影响的主要方法，对确定外源性毒物的有害效应极为重要。(1)描述性流行病学调查：提出病因假设，已知病因了解严重程度( 2)分析性流行病学调查：验证假说，确定因果关系。是什么意思？

Site investigation is the study of exogenous chemicals on human health effects of exposure to the main method of determining the harmful effects of exogenous toxins is very important. (1) Descriptive epidemiology: assumptions made causes, to understand the severity of a known cause (2) analytical ep

正在翻译，请等待...

The scene investigation is studies the exogenetic chemical material to contact the crowd health influence the main method, is extremely important to the determination exogenetic poison harmful effect.(1) descriptive epidemiology investigation: Proposes the cause of disease supposition, known cause o

Field is the study of exogenous chemicals on the health effects of exposure methods, is vital to determine the harmful effects of exogenous toxins. (1) descriptive Epidemiology: make etiological assumptions and known-cause understanding severity (2) analytical Epidemiology: verify the hypothesis, es

Field is the study of exogenous chemicals on the health effects of exposure methods, is vital to determine the harmful effects of exogenous toxins. (1) descriptive Epidemiology: make etiological assumptions and known-cause understanding severity (2) analytical Epidemiology: verify the hypothesis, es