题型:单项选择题 A1/A2型题 彩色血流频移大于1/2PRF(脉冲重复频率)时出现折返,这称为()A.Nyquist(内奎斯特)极限B.傅立叶变换C.运动目标显示器(MTI)D.自相关技术E.彩色血流显像的滤波 查看答案
题型:选择题 I met Li Lei hospital last Sunday. He was ill hospital then.A.in the, in theB.in, in theC.in the, inD.in, in 查看答案