X射线光子与物质发生相互作用的过程是能量传递的过程。当入射光子的能量取值不同时,发生

题型:单项选择题 共用题干题

问题:

X射线光子与物质发生相互作用的过程是能量传递的过程。当入射光子的能量取值不同时,发生的作用形式是不同的。

当入射光子能量大于物质发生核反应的阈能时,会发生()

A.相干散射

B.光电效应

C.康普顿效应

D.电子对效应

E.光核作用

考点:放射医学技术(医学高级)放射医学技术综合练习放射医学技术综合练习题库
题型:单项选择题 共用题干题

学校一间会议室,长12米,宽8米,高4米,要粉刷四壁和顶棚,扣除门窗28平方米,要粉刷的实际面积是多少?

题型:单项选择题 共用题干题

对人类基本需要各层次间的关系理解不正确的是()

A.通常先满足低层次的需要,然后再考虑较高层次的需要

B.不同层次需要不会重叠出现

C.各需要层次间可相互影响

D.个体的基本需要满足的程度和健康状况成正比

E.个体满足生理需要的方式类似

题型:单项选择题 共用题干题

人体排泄的嘌呤核苷酸分解代谢的特征性终产物是()。

A.β-丙氨酸

B.尿素

C.肌酐

D.尿酸

E.黄嘌呤

题型:单项选择题 共用题干题

部分乙型肝炎患者会出现肾小球肾炎、关节炎等肝外症状,其机制是

A.病毒使机体免疫应答能力下降所致

B.病毒变异所致

C.细胞介导的免疫病理损害

D.免疫复合物引起的病理损害

E.自身免疫反应所引起的免疫病理损害

题型:单项选择题 共用题干题

Your heart suddenly starts pounding so hard you think it’s going to leap right out of your chest. You’re sweating even though it’s cold out. You feel unsteady on your feet and generally shaky, like the world around you is spinning out of control and you can’t get a grip. Your hands and feet are numb and useless. You’re gasping for breath and feel like you’re drowning.

(41)__________Genetics may be part of the explanation; women are more prone to anxiety or depression, and a history of these mood disorders makes you more likely to have a panic attack. But unhappy life experiences may also increase women’s vulnerability.

A particularly active area of research at the moment is the effect of hormones. Women seem most susceptible to panic attacks during times of hormonal changes, such as adolescence, pregnancy, and so on. Dr. Lilian Gonsalves, psychology at the Cleveland Clinic, says some scientists think that hormonal fluctuation may upset the balance of chemicals in the brain that modulate fear and anxiety, triggering a panic attack. It feels like the fight-or-flight response gone wild with no provocation. (42)__________

Fear of another attack often makes people avoid places where an attack took place, and a small percentage of sufferers may eventually become housebound, a condition called agoraphobia. (43)__________ "We used to say that you don’t die of a panic attack, but I’ve stopped saying that," says Gonsalves. "It could be that during a panic attack you get coronary spasms or an irregular heart rate. "

(44)__________There’s no single cure that works for everyone, but generally, patients use medication, cognitive behavioral therapy or some combination of the two. Cognitive behavioral therapy teaches you a range of techniques—such as relaxation exercises—to deal with everyday anxiety and stress, lessening the chances of another attack. Many people find that drugs help control the problem until they can find a behavioral therapy that works, after which drugs may no longer be necessary. Research has also shown that regular exercise.and activities such as yoga may reduce the severity and number of attacks.

(45)__________If there is nothing wrong, then your doctor will probably refer you to a psychiatrist or psychologist who can work with you on the problem over what may be a period of several months.

It takes a while to feel completely better; generally, antidepressants start working in six to eight weeks, Gonsalves says. But many patients begin to get some relief in just two weeks, she adds. In all, about 80 percent of patients will do well. In the case of the other 20 percent, who don’t respond to treatment, doctors often find that they have missed an underlying medical condition that is behind the attacks.

[A] Suffering from frequent panic attacks also means you are at higher risk of depression, substance abuse and suicide. Some research also indicates that women who have repeated attacks are at higher risk of death.

[B] Call your doctor even if you’ve had only a single attack, because these symptoms could also signal a wide range of other problems, including thyroid and heart disease. A primary-care physician will first perform a physical exam and probably order an EKG and blood tests to rule out other possible causes of the attacks.

[C] You can be standing at a bus stop or shopping at the mall without any danger in sight, and suddenly, you feel like you’re dying. The attack is generally over in a few minutes, but sometimes symptoms—especially feeling faint and dizzy—can linger for mare than an hour.

[D] Many women report experiencing their first panic attack in late adolescence. But others have no trouble until they are around 50, when their hormone levels often vary wildly. "These are high functioning women who have never seen a psychiatrist before," says Gonsalves. "They start having hot flashes and they don’t sleep. They become acutely anxious. "

[E] If you have felt all of these come on without warning, you may have just suffered a panic attack. These frightening symptoms affect women twice as often as men, although scientists are not sure why.

[F] The cure of panic attacks often depends on the cause. If your attacks are triggered by a physical condition, they should be eliminated by treating the physical cause. If you can’t find the cause, continue looking and using the above tips to control the attacks.

[G] Because of the possible consequences of untreated panic attacks, it’s important to get help early. And fortunately, there is lot of help available.

42()

更多题库