OBJECTIVE: To assess the effect of blood lead level on t cell subgroup of children, and the association of t cell subgroup with thresholdlimitvalue of blood lead level.
目的：评估血铅对儿童T细胞亚群的影响，以及血铅临界值与T细胞亚群的关系。
2
Objective: To investigate the acute and accumlative toxicities of hydroquinone in mice and rats and to provide the information for establishing the thresholdlimitvalue of hydroquinone.
目的：研究氢醌对小鼠和大鼠的急性毒性和蓄积毒性，为建立卫生标准提供资料。
3
While the thresholdvalue reaches its upper limit the optimization design is finished, thus the final distribution form and its sectional dimensions of the reinforced ribs were obtained.