C6150车床控制电路中有()行程开关。 ["A、6个","B、3个","C、4个","D、5个"]
X连锁低丙种球蛋白血症的特点是() ["仅男性发病","感染程度较轻","多见于青壮年","新生儿手足搐搦","T细胞功能异常"]
美国第一份刊登广告的报纸是()。 ["《宾夕法尼亚日报》","《波士顿新闻通讯》","《民众杂志》","《华盛顿邮报》"]
药材大叶海藻的原植物是() ["A.独行菜","B.播娘蒿","C.海蒿子","D.羊栖菜","E.杠柳"]
(2009)计算机网络是一个复合系统,共同遵守的规则称为网络协议,网络协议主要由:() ["语句、语义和同步三个要素构成","语法、语句和同步三个要素构成","语法、语义和同步三个要素构成","语句、语义和异步三个要素构成"]
导线在弹性限度内受外力作用时,其应力与相应变形的比例系数称()。