什么叫喷管?喷管分为哪两种基本类型?
液化气船舶不包括以下哪项:() ["A、LNG船","B、VLCC","C、LPG船","D、液化天然气船"]
WCDMA中,上行数据通过()发送 ["DPDCH,","DPDCH,","HARQ,","HSDPA."]
下列哪项不属于油船按作业货种分类:() ["A、原油船","B、液化气船","C、通用型油船","D、成品油船"]
主要对心血管系统有毒性的药物是() ["川乌","黄药子","蟾酥","苦杏仁","马钱子"]
涡轮落压比的定义?双转子发动机在什么转速下高压涡轮落压比不变?为什么?