使代数式|3x-|x||4x的值为正整数的x值是( ) A.正数 B.负数 C.零 D.

题型:选择题

问题:

使代数式
|3x-|x||
4x
的值为正整数的x值是(  )
A.正数B.负数C.零D.不存在的
考点:绝对值分式的定义
题型:选择题

诊断腹腔妊娠最有力的证据是

A.胎位不正,胎儿影特别清晰

B.胎儿偏于腹腔一侧,并占据较高位置

C.子宫轮廓消失

D.胎儿骨骼与母体脊柱重叠

E.胎儿影与母体肠腔中气体影像重叠

题型:选择题

小青龙汤证的或然证原文中未出现()

A.或渴

B.或利

C.或烦

D.或噎

E.或喘

题型:选择题

①作《三角贸易路线示意图》,要求在图中填上三大洲的名称及出程、中程和归程。

②据图回答:“贩卖人类血肉”的黑奴贸易的主要路线是_____________。

③随着新航路的开辟,首先进行殖民扩张并进行“贩卖人类血肉”的黑奴贸易的国家是_____________、_____________;黑奴贸易持续了近_____________。

④从三角贸易中获益的是_____________,近代西方殖民扩张活动首先是从入侵_____________开始的。

A.亚洲

B.欧洲

C.美洲

D.非洲

题型:选择题

Feeling anxious Your mood may actually change how your dinner tastes, making the bitter and salty flavors recede, according to new research. This link between the chemical balance in your brain and your sense of taste could one day help doctors to treat depression. There are currently no on-the-spot tests for deciding which medication will work best in individual patients with this condition. Researchers hope that a test based on flavor detection could help doctors to get more prescriptions right first time.

It has long been known that people who are depressed have lower-than-usual levels of the brain chemicals serotonin or noradrenaline, or in some cases both. Many also have a blunted sense of taste, which is presumably caused by changes in brain chemistry. To unpick the relationship between the two, Lucy Donaldson and her colleagues at the University of Bristol, UK, gave 20 healthy volunteers two antidepressant drugs, and checked their sensitivity to different tastes. The drug that raised serotonin levels made people more sensitive to sweet and bitter tastes, the team reports in the Journal of Neuroscience. The other, which increased noradrenaline, enhanced recognition of bitter and sour tastes.

In healthy people, volunteers whose anxiety levels were naturally higher were less sensitive to bitter and salty tastes. "What hasn’t been done beore is to look precisely at which tastes are affected in depression," says Donaldson. Now the results are in, "we can discriminate between the chemicals and the tastes that seem to be altered," she says. Testing sensitivity to sweet and sour tastes could potentially help doctors to pick up on which chemicals are dipping, guiding them when choosing which drug to rectify the problem.

Currently, doctors rely on physical and emotional symptoms to make a best guess at an individual’s imbalance, prescribe a drug and wait about a month to check on any improvement. Good doctors have about a 60-80% success rate in selecting the right drug the first time, says psychiatrist Jan Melichar, a co-author on the paper. Are there any decent tests for prescribing drugs for depression "No. We do a best guesstimate," says Melichar. "I’m excited by this finding because in 3, 5 or 7 years we could have a simple taste test. "

Next, the team plans to perform similar tests in depressed people, and in healthy volunteers given another brain chemical called tryptophan. This chemical would lower the healthy subjects’ levels of serotonin, as actually happens in depressed patients.

The work has also generated interest from flavor houses--companies that develop chemicals for the food and drink industry--who are interested in making foods taste just as sweet with half the amount of sugar. "Theoretically there would be the possibility of enhancing your meal with drugs that affect brain chemicals so that things would taste better--you couid have a ’designer taste tablet’," Donaldson says.

The study of the link between mood and taste can help()

A. people to gain better mood

B. doctor to cure depression

C. people to increase appetite

D. researchers to get prescriptions

题型:选择题

选择供应商的总原则是:全面、具体、客观,即建立和使用一个全面的供应商综合衡量指标体系,对供应商作出全面、具体、客观的衡量。

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