题型:问答题 简答题 脊髓空洞症的下列哪些表述是正确的()A.是一种缓慢进行性脊髓变性疾病B.脊髓内空洞形成是其病理特征C.节段性分离性感觉障碍是早期特征性体征D.空洞常起自一侧颈膨大后角基底部E.不发生肌萎缩和皮肤关节营养障碍 查看答案
题型:问答题 简答题 The locking pin that joins the parts of a detachable link is held in position by().A.a tack weldB.the self-locking characteristics of its taperC.a cotter pinD.a lead plug 查看答案