Trace Nb微量铌
tracen.痕迹;微量;踪迹v.追踪;描绘;找出根源
trace-element fertilizer[化] 微量元素肥料
trace of aircraft and ship飞机和飞船轨迹
trace of electron scanning电子扫描
trace fragrance components微量香味成分
trace arsenic and selenium痕量砷和硒
Trace lead contained water含微量铅水体
Trace elements in the blood血液微量元素