下载APP
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】下列有关MR对比剂的叙述哪项正确（）。
A.
利用对比剂的衰减作用来达到增强效果
B.
利用对比剂本身的信号达到增强效果
C.
直接改变组织的信号强度来增加信号强度
D.
通过影响质子的弛豫时间，间接地改变组织信号强度
E.
通过改变梯度场的强度来进行增强
【单选题】关于碘对比剂的叙述，正确的是
A.
泛影葡胺属无机碘化物
B.
碘对比剂均为阳性对比剂
C.
离子型对比剂是阴性对比剂
D.
非离子对比剂不能用于心血管造影
E.
复方泛影葡胺是非碘对比剂
【单选题】关于对比剂，叙述错误的是（）。
A.
对比剂都不能入血
B.
阴性对比剂原子序数低，密度小
C.
阴性对比剂原子序数高，密度大
D.
阴性对比剂和阳性对比剂可混合使用
E.
对比剂均无毒
【单选题】Every year more than half a million American kids have drainage(排泄) tubes surgically implanted in their ears to combat persistent infections. The procedure, known as tympanostomy, may not be as (62) a...
A.
[A] feeling [C] health
B.
[B] hearing [D] memory
【单选题】Section BDirections: There are 2 passages in this section．Each passage is followed by some questions or unfinished statements．For each of them there are four choices marked A, B, C and D．You should de...
A.
could not easily be absorbed by the human body
B.
were potentially harmful to people's health
C.
were too expensive for daily consumption
D.
could not provide any cure for vitamin deficiencies