知母中的主要成分()
A.三萜皂苷
B.新木脂素
C.香豆素
D.甾体皂苷
E.生物碱
参考答案:D
An investment strategy that seeks to grow portfolio value over time through capital gains and reinvestment of current income is most likely appropriate if the investment objective is:()
A. total return.
B. current income.
C. capital appreciation.
简述气相色谱法测定环境空气中肼和偏二甲基肼时,采集样品后,样品的前处理过程。