What makes these exposures a source of infection is probably not any one exposure but the cumulative nature of being exposed frequently over the course of time.

这些接触是一个感染源，也许这并不是因为任何一次接触，而是长期经常接触的累积性质所致。

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Conclusions Imaging procedures are an important source of exposure to ionizing radiation in the United States and can result in high cumulative effective doses of radiation.

结论：在美国，影像操作是一个重要的电离辐射暴露来源，并可导致较高的辐射累积有效剂量。

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By using this model, the current cumulative oil generating intensity and amount for immature source rocks of Qianjiang formation were calculated in JJ, QQ, XX Depressions, the Jianghan Basin.

应用该模型测算了江汉盆地JJ、QQ、XX凹陷潜江组未熟烃源岩在现今的累积生油强度和生油量。

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An source at the company tells me that when the full roster of celebs is revealed, the cumulative fan-base on social media will reach 200 million.

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