采用氢氧化钠等碱性溶液从氯仿中萃取生物碱的原理 A.利用生物碱的碱性差异 B.利用生

题型:单项选择题

问题:

采用氢氧化钠等碱性溶液从氯仿中萃取生物碱的原理

A.利用生物碱的碱性差异
B.利用生物碱特殊官能团的性质
C.利用生物碱或生物碱盐溶解度的差异
D.利用各生物碱极性差异而与吸附剂作用的强弱不同
E.利用各生物碱在两相(固定相和流动相)中分配系数的差异

考点:药学职称考试药师基础知识中级主管药师基础知识
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甲、乙两人从G点出发,甲向北行,乙向东行,如果前进的方向保持不变,那么

A.两人都能回到原出发地点

B.两人都不能回到原出发地点

C.只有甲能回到原出发地点

D.只有乙能回到原出发地点

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呕吐呈喷射状者是因( )

A.热伤胃肠

B.脾胃阳虚

C.热扰神明

D.食滞胃脘

E.饮邪犯胃

题型:单项选择题

Plants are very important living things. Life could not go if there were no plants. This is because plants can make food from air, water and sunlight. Animals and man cannot make food from air, water and sunlight. Animals get their food by eating plants and other animals. So animals and man need plants in order to live. This is why we find that there are so many plants around us.

If you look carefully at the plants around you, you will find that there are two kinds of plants: flowering plants and non-flowering plants.

Flowering plants can make seeds. The seeds are protected by the fruits. Some fruits have one seed, some have two, three or four, and some have many seeds. But a few fruits have no seeds at all. An example of a fruit without seeds is the banana fruit.

Most non-flowering plants don’t grow from seeds. They grow from spores. Spores are so small and light that they can float in the air. We may say that spores are quite the same as he seeds. When these spores fall on wet and shady places, they usually grow into new plants.

小题1:The main idea of the passage is that      .

A.plants are important for life

B.plants cannot grow without air

C.there are many plants around us

D.we cannot live without water小题2:Which of the following is NOT TRUE?

A.Plants can be divided into main types: flowering plants and non-flowering plants.

B.All fruits have seeds in them.

C.Seeds are protected by the fruits.

D.Some plants grow from spores.小题3:The underlined word "non-flowering" means        .

A.开花的

B.有花的

C.多花的

D.不开花的小题4:In “shady places” there is        .

A.a lot of sunshine

B.a lot of water

C.no water

D.little sunshine

题型:单项选择题

如图所示,光滑水平面上有一小车,车上有一木块,当水平恒力F作用在木块上时,小车和木块开始运动,且小车和木块间无相对滑动,小车质量为M,木块质量为m,它们共同加速度为a,木块与小车间的动摩擦因数为μ,则在运动过程中

[ ]

A.木块受到的摩擦力一定是μmg

B.木块所受各力的合力为F

C.小车受到的摩擦力为

D.小车所受各力的合力为

题型:单项选择题

有关商法与经济法在法律理念上的区别说法正确的是()。

A.商法注重意思自治原则,经济法信守国家统治原则

B.商法注重平等交易原则,经济法信守强制主义原则

C.商法注重诚实信用原则,经济法信守国家统治原则

D.商法注重强制主义原则,经济法信守意思自治原则

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