单选题早期胃癌多发生在

单选题男性，20岁，工人，用力打苍蝇时致右肱骨上端骨折，此时应首先考虑是A．肱骨大结节撕脱骨折B．肱骨外科颈骨折C．肱骨解剖颈骨折D．病理骨折E．疲劳骨折

单选题"My own feelings went from disbelief to excitement to downright fear," says Carl Hergenrother, 23, an Arizona undergraduate who verified a large asteroid barreling toward Earth with a 230em telescope atop nearby Kitt Peak. "It was scary, because there was the possibility that we were confirming the demise of some city somewhere, or some state or small country." Well, not quite. Early last week, his celestial interloper whizzed by Earth, missing the planet by 450620 km--a hairbreadth in astronomical terms. Perhaps half a kilometer across, it was the largest object ever observed to pass that close to Earth. Duncan Steel, an Australian astronomer, has calculated that if the asteroid had struck Earth, it would have hit at some 93450 km/h. The resulting explosion, scientists estimate, would have been in the 3000-to-12000-megaton range. That, says astronomer Eugene Shoemaker, a pioneer asteroid and comet hunter, "is like taking all of the U.S. and Soviet nuclear weapons, putting them in one pile and blowing them all up." And what if one them is found to be on a collision course with Earth? Scientists at the national laboratories at Livermore, California, and Los Alamos, New Mexico, have devised a number of ingenious plans that, given enough warning time, could protect Earth from a threatening NEO. Their defensive weapons of choice include long-distance missiles with conventional or, more likely, nuclear warheads that could be used either to nudge an asteroid into a safe orbit or blast it to smithereens. Many people-including some astronomers--are understandably nervous about putting a standby squadron of nuclear tipped missiles in place. Hence the latest strategy, which in some cases would obviate the need for a nuclear defense: propelling a fusillade of cannonball-size steel spheres at an approaching asteroid. In a high-velocity encounter with a speeding NEO, explains Gregory Canavan, a senior scientist at Los Alamos, "the kinetic energy of the balls would change into heat energy and blow the thing apart." Some astronomers oppose any immediate defensive preparations, citing the high costs and low odds of a large object's striking Earth in the coming decades. But at the very least, Shoemaker contends, NEO detection should be accelerated. "There's this thing cal4ed the 'giggle factor' in Congress," he says, "people in Congress and also at the top level in NASA still don't take it seriously. But we should move ahead. It's a matter of prudence." The world, however, still seems largely unconcerned with the danger posed by large bodies hurtling in from space, despite the spectacle two years ago of Comet Shoemaker-Levy 9 riddling the planet Jupiter with mammoth explosions. It remains to be seen whether last week's record near-miss has changed any minds.

单选题慢性肾衰竭最常见的死亡原因是

单选题区别血尿和血红蛋白尿的主要方法是

单选题下列符合休克代偿期血压变化的是

单选题直肠肛管周围脓肿最常见的病因是

单选题A．高钾血症B．低钾血症C．代谢性酸中毒D．低钙血症

单选题治疗早期胃癌的有效方法是

单选题关于破伤风的叙述，下列哪项是错误的?

单选题女性，58岁，诊断为急性坏疽性阑尾炎伴弥漫性腹膜炎入院，行阑尾切除术。术后第5天腹胀、腹痛、发热，体温39℃，大便4～6次／日，呈水样。肛门有下坠感，腹部有轻压痛，未触及肿块。首先应考虑的并发症是

单选题诊断原发性肝癌的特异性指标是

单选题A．疝内容物为小肠B．疝内容物为大网膜C．疝内容物为Meckle憩室D．疝内容物为多个小肠肠袢E．疝内容物为部分小肠壁

单选题留置导尿管＞3天后，细菌尿的发生率是

单选题肠套叠好发于

单选题A．乳头血性溢液B．乳头黄绿色或浆液性溢液C．两者均有D．两者均无

单选题胃大部切除术后上腹饱胀，呕吐食物胆汁最可能为（ ）

单选题肛裂最常见于膝胸位A．12点处B．3点处C．6点处D．9点处E．3点和6点处

单选题原发性肝癌的肝内播散主要经

单选题A、腰穿显示血性脑脊液的B、典型的中间清醒期C、熊猫眼征及脑脊液鼻漏D、CT和MR无改变的脑外伤E、外伤后即表现为深度昏迷