短語詞組短語threshold d limit value 閾限值threshold limit value tlv 允許濃度值biological threshold limit value 生物閾限值dangerous threshold limit value 危臨界濃度laser threshold limit value 能量閾值exposure threshold limit value [生理]暴露閾限值threshold limit value -ceiling 上限值heat exposure threshold limit value 熱接觸閾限值 返回 threshold limit value