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简述帕金森病的药物治疗。

答案

参考答案：

帕金森病的药物治疗：主要通过维持纹状体内乙酰胆碱和多巴胺两种神经递质的平衡，使临床症状得以改善。（1）抗胆碱药：适于震颤突出且年龄较轻的患者。常用药物：安坦（artanE.，青光眼和前列腺肥大者禁用。长期使用抗胆碱药物可影响记忆功能，对老年患者尤应引起注意。（2）金刚烷胺：适用于轻症患者。（3）多巴胺替代疗法：可补充黑质纹状体内多巴胺的不足，是帕金森病最重要的治疗方法。由于多巴胺不能透过血脑屏障，采用替代疗法补充其前体左旋多巴，当左旋多巴进入脑内被多巴胺能神经元摄取后脱羧转化为多巴胺而发挥作用。复方左旋多巴系由左旋多巴和外周多巴胺脱羧酶抑制剂组成。长期（5～12年）服用左旋多巴出现的主要并发症有症状波动、运动障碍（异动症）。（4）多巴胺受体激动剂：多巴胺受体激动剂通过直接刺激突触后膜多巴胺受体而发挥作用。常用药物有溴隐亭、培高利特、吡贝地尔和普拉克索等。（5）单胺氧化酶B抑制剂：可阻止多巴胺降解，增加脑内多巴胺含量，常用药为司来吉米。（6）儿茶酚-氧位-甲基转移酶抑制剂：通过抑制左旋多巴在中枢的代谢，维持左旋多巴血浆浓度的稳定。该类药物单独使用有效，需与多巴丝肼或息宁等合用。代表药物有托卡朋和恩托卡朋。

单项选择题

The girls in this sixth grade class in East Palo Alto, California, all have the same access to computers as boys. But researchers say, by the time they get to high school, they are victims of what the researchers call a major new gender (性别) gap in technology. Janice Weinman of the American Association of University Women says, "Girls tend to be less comfortable than boys with the computer. They use it more for word processing rather than for problem solving, rather than to discover new ways in which to understand information."

The software company seems to think ______.
A. if girls had an equal chance of playing games, they would like computers
B. if the software was more violent, girls would be more interested
C. if the software content was changed, girls would be more interested
D. if the character were funny, girls would like them better

After re-examining a thousand studies, the American Association of University Women researchers found that girls make up only a small percentage of students in computer science classes. Girls consistently rate themselves significantly lower than boys in their ability and confidence in using computers. And they use computers less often than boys outside the classroom.An instructor of a computer lab says he’s already noticed some differences. Charles Cheadle of Cesar Chavez School says, "Boys are not so afraid they might do something that will harm the computer, whereas girls are afraid they might break it somehow."
Six years ago, the software company Purple Moon noticed that girls’ computer usage was falling behind boys. Karen Gould says, "The number one reason girls told us they don’t like computer games is not that they’re too violent, or too competitive. Girls just said they’re incredibly boring."
Purple Moon says it found what girls want, characters they can relate to and story lines relative to what’s going on in their own lives. Karen Gould of Purple Moon Software says, "What we definitely found from girls is that there is no intrinsic (固有的) reason why they wouldn’t want to play on a computer; it was just a content thing."
The sponsor of the study says it all boils down to this: the technology gender gap that separates the girls from the boys must be closed if women are to compete effectively with men in the 21st century.
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单项选择题

　　①科学知识体系内部存在一种结构。这种结构可与地球分层结构模型类比，称之为科学知识的球状结构。______。

　　②地球的内部结构从外到里，由地壳、地幔和地核组成，科学知识体系结构从外到里则由知识外壳、知识幔层和知识内核组成。

　　③知识外壳由事实性的知识组成，如海王星、电磁波、中微子这类现象的发现均属事实性发现；知识幔层由定律性知识组成，如浮力定律、自由落体定律、化学元素周期定律均属定律性知识；知识内核由原理性知识组成，即能揭露相对深刻的本质，如氧化说、进化论、相对论等原理知识。事实性知识说明“是什么”，定律性知识说明“怎么样”，原理性知识说明“为什么”。

　　④人对某一知识领域的系统认识通常遵循从事实性一定律性一原理性的发展过程，即人们的探索性思维通常是从科学知识外壳部分通过幔层而向内核逼近的。例如，在天文学史上，哥白尼的日心说首先解决了“是什么”，即确认了我们这个恒星系统中，地球、火星等行星都是围绕太阳运行的；继而，开普勒的行星运动定律描述了“怎么样”，即确立了地球等行星是按照某种特定的周期、轨道和速度围绕太阳运行的；最后，牛顿的万有引力原理探索了“为什么”，说明太阳是以某种特定的力作用于行星，从而使行星按开普勒发现的三大定律运行。

　　⑤上述过程标志着科学家对科学之谜的认识的不断深化。

　　⑥科学家则根据各自的发现的深刻性而被划分为不同的级别。这样，科学界在无形中便形成了一个声誉的金字塔结构。处在塔顶尖的是那些因为有重大原理性发现而驰名世界的科学巨星，拉瓦锡为现代科学之父，维萨留斯为现代解剖学之父。处于金字塔中部的是那些因为提出重要的定律性知识而得名的科学人物，如开普勒、哈勃、孟德尔等。相比之下，聚集在金字塔下部的通常是那些有重要事实性发现的科学家。

第6段运用的说明方法主要是（）

A．下定义、举例子

B．打比方、分类别

C．下定义、作比较

D．打比方、下定义
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