Only use your cell phone to establish contact or for conversations lasting a few minutes, as the biological effects are directly related to the duration of exposure.

把手机用于保持基本联络，或只进行几分钟时长的通话。因为手机辐射对人的生理影响与通话时间长短相关。

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Call history for each contact also shows the call status, time and duration of the call.

要求每个联系人的历史也显示呼叫状态，时间和通话时间。

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The dependence of binding frequency on contact duration was measured.

微管实验测量了粘附频率对接触时间的依赖关系。

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The subpoenas sought the phone numbers with which the AP journalists had contact and the duration of those calls.

WSJ: U.S. Obtains Wide AP Phone Records in Probe