脑血管狭窄的TCD表现是 ["A.狭窄段血流速度增快","B.狭窄远端血流速度减低","C.流速曲线图形异常(充填)","D.血管杂音","E.以上均是"]
TCD常规探测大脑动脉血流信号,下列选项为血流背离探头(负向流速曲线): ①椎一基底动脉; ②大脑中动脉; ③大脑前动脉; ④大脑后动脉 ["A.①②③","B.①③","C.②④","D.④","E.①②③④"]
TCD探测大脑动脉的主要声窗是: ①颞窗; ②眼眶窗; ③枕窗; ④额上窗 ["A.①②③","B.①③","C.②④","D.④","E.①②③④"]
隐睾大多位于 ["A.腹腔","B.腹膜后","C.腹股沟","D.阴茎根部","E.大腿内侧"]
试比较下列钢材的焊接性。
试说明下列加工方法的主运动和进给运动:
1)车端面
2)车床钻孔
3)钻床钻孔
4)铣床铣平面
5)外圆磨床磨外圆