upper nut上螺母upperadj.较高的；上面的；上部的n.鞋帮；上铺n.兴奋剂；令人兴奋的经历upper and lower level-jet高低空急流upper steam cylinder gasket上汽缸垫密片upper communication antenna上部通信天线upper limit of flammability可燃性上限upper point of accumulation最大聚点Upper urinary track calculi上尿路结石upper level signaling point高电平信号点Upper Bayanharashan Subgroup上巴颜喀拉山亚群upper gastrointestinal tract上消化道, 上胃肠道Upper lumbar disc herniation高位腰椎间盘移位突出症