系统抽样法又叫做等距抽样法或机械抽样法，是依据一定的抽样距离，从总体中抽取样本。要从容量为N的总体中抽取容量为n的样本，可将总体分成均衡的若干部分，然后按照预先规定的规则，从每一部分抽取一个个体，得到所需要的样本的抽样方法。
方法应用系统抽样法进行现场查螺，现场和实验室模拟水淹实验观察钉螺存活情况。
Methods Systematic sampling method was used in field Oncomelania investigation, and laboratory and field simulating drowning methods were also performed to observe survival of Oncomelania.
方法：用分层随机抽样法确定调查点。 用尼龙袋集卵孵化法、顶管孵化法分别对人畜进行查病，用系统抽样结合环境抽样法开展螺情调查。
Methods: Using stratified sampling method to determine the survey places, The schistosomiasis in people and livestock were surveyed by the methods of nylon bag incubation and top - tube incubation.
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