多旋翼飞行器的飞控硬件尽量安装在() ["飞行器前部","飞行器底部","飞行器中心"]
孕18周后USG可发现哪些先天性心脏畸形() ["三尖瓣下移畸形","心内膜垫缺损","左心内膜纤维化","室间隔缺损","单心室、右室或左室发育不全"]
部分多轴飞行器螺旋桨加有外框,其主要作用是() ["提高螺旋桨效率","增加外形的美观","防止磕碰提高安全性"]
"羊水过多"常出现的并发症是() ["消化系统畸形","呼吸系统畸形","循环系统畸形","泌尿系统畸形","神经系统畸形"]
演示脊柱压痛、叩击痛的检查方法。
演示浅感觉的检查病因。