在大黄总蒽醌的提取液中,若要分离大黄酸、大黄酚、大黄素、芦荟大黄素、大黄素甲醚,采用

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问题:

在大黄总蒽醌的提取液中,若要分离大黄酸、大黄酚、大黄素、芦荟大黄素、大黄素甲醚,采用哪种分离方法最佳

A.pH梯度萃取法

B.氧化铝柱色谱法

C.分步结晶法

D.碱溶酸沉法

E.pH梯度萃取法与硅胶柱色谱结合法

考点:中药执业药师中药学专业知识(二)中药执业药师中药学专业知识(二)
题型:单项选择题

阅读下面短文, 从方框内选择恰当的句子填入短文空白处,使短文内容完整、意思连贯。

There is a strange train which can not move on the railway. It has no seats ,no tables, no windowns, even no wheels.       小题1:     .

It is very strange.It can take a great many people to go to different places at the same time.       小题2:      .To my surprise,it is free for everyone.       小题3:     , and it can also take you to failure(失败).It even can cause you death.

Its speed is strange,too.The speed changes all the time.      小题4:    . If you think it’s fast,so it is.If you think it’s slow, so it also is.At different time you may think the speed is different. And at the same time different people may think different,too.

You can’t wait to know what this train is.      小题5:      .We are all on this train now. It’s “time”.I think it is going fast now.

A.And the change depends on you.

B.Let me tell you.

C.But there is not any stop along the way.

D.It can lead you to success.E.But it is still moving.

题型:单项选择题

公文成文日期以加盖印章之日为准。( )

题型:单项选择题

当流量、管长和管子的摩擦系数等不变时,管路阻力近似地与管径的()次方成反比。

A、2

B、3

C、4

D、5

题型:单项选择题

近年来,我国文化产业发展势头强劲,文化生产力在我国经济总体格局中的作用越来越突出。这主要体现了                      (   )  

A.经济对文化的决定作用

B.文化在经济中的基础作用  

C.文化与经济相互交融

D.文化与政治相互交融

题型:单项选择题

EPON C220 T12版本的全局广播包抑制数默认是多少?()

A.100

B.200

C.300

D.400

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