单选题心肺复苏心脏按摩时，按压与放松时间之比应为( )(2002年)

单选题男，35岁，胃大部切除术后3小时，恶心、呕吐，其最常见原因是

单选题乳腺癌患者皮肤出现“橘皮样”改变，是因为

单选题确诊为右肾盂输尿管连接部狭窄，其最佳的治疗方案是

单选题肾癌常见症状为血尿、肿块和疼痛。肾癌还可有不典型的肾外表现，下列哪一项不是肾癌的肾外表现

单选题肛瘘行挂线疗法的最大优点是（ ）

单选题A bite of a cookie containing peanuts could cause the airway to constrict fatally. Sharing a toy with another child who had earlier eaten a peanut butter and jelly sandwich could raise a case of hives. A peanut butter cup dropped in a Halloween bag could contaminate the rest of the treats, posing an unknown risk. These are the scenarios that "make your bone marrow turn cold" according to L. Val Giddings, vice president for food and agriculture of the Biotechnology Industry Organization. Besides representing the policy interests of food biotech companies in Washington, D. C., Giddings is the father of a four-year-old boy with a severe peanut allergy. Peanuts are only one of the most allergenic foods; estimates of the number of people who experience a reaction to the beans hover around 2 percent of the population. Giddings says that peanuts are only one of several foods that biotechnologists are altering genetically in an attempt to eliminate the proteins that do great harm to some people's immune systems. Although soy allergies do not usually cause life-threatening reactions, the scientists are also targeting soybeans, which can be found in two thirds of all manufactured food, making the supermarket a minefield for people allergic to soy. Biotechnologists are focusing on wheat, too, and might soon expand their research to the rest of the "big eight" allergy-inducing foods: tree nuts, milk, eggs, shellfish and fish. Last September, for example, Anthony J. Kinney, a crop genetics researcher at DuPont Experimental Station in Wilmington, Del., and his colleagues reported using a technique called RNA interference (RNAi) to silence the genes that encode p34, a protein responsible for causing 65 percent of all soybean allergies. RNAi exploits the mechanism that cells use to protect themselves against foreign genetic material; it causes a cell to destroy RNA transcribed from a given gene, effectively turning off the gene. Whether the public will accept food genetically modified to be low-allergen is still unknown. Courtney Chabot Dreyer, a spokesperson for Pioneer Hi-Bred International, a subsidiary of DuPont, says that the company will conduct studies to determine whether a promising market exists for low allergen soy before developing the seeds for sale to farmers. She estimates that Pioneer Hi-Bred is seven years away from commercializing the altered soybeans. Doug Gurian-Sherman, scientific director of the biotechnology project at the Center for Science in the Public Interest—a group that has advocated enhanced Food and Drug Administration oversight for genetically modified foods—comments that his organization would not oppose low-allergen foods if they prove to be safe. But he wonders about "identity preservation" a term used in the food industry to describe the deliberate separation of genetically engineered and no nengineered products. A batch of nonengineered peanuts or soybeans might contaminate machinery reserved for low-allergen versions, he suggests, reducing the benefit of the gene-altered food. Such issues of identity preservation could make low-allergen genetically modified foods too costly to produce, Chabot Dreyer admits. But, she says, "it's still too early to see if that's true. /

单选题肾、输尿管结石手术治疗指征

单选题肛裂主要症状是

单选题下列关于直肠癌的叙述，错误的是( )(2007年)

单选题下列哪项症状不是输血所致的过敏反应A．发热B．面色潮红，皮肤瘙痒C．荨麻疹，血管神经性水肿D．支气管痉挛E．过敏性休克

单选题患者，男性，40岁，1个月前行左肾切开取石术，现左腰痛伴畏寒、高热，腰无法伸直，尿液检查：蛋白少量，白细胞少许。应首先考虑

单选题患者，男，75岁。7天前因胆囊多发小结石行腹腔镜胆囊切除术，近2日来发现巩膜黄染。

单选题A．酒窝征 B．橘皮征C．卫星结节 D．乳头凹陷

单选题下列骨折中，最不稳定的是( )(2003年)

单选题静脉全麻药物中，不宜应用于青光眼患者手术中的是

单选题早期胃癌多发生在

单选题男性，46岁，高处坠落，头部着地，检查示寰枢椎骨折脱位，并出现呼吸困难时，最先采取的措施是

单选题心肺复苏胸外心脏按压的频率为

单选题患者，男，35岁，左腰部受伤后出现腰痛。体检：血压125/90mmHg。P80次/分，左肾区叩痛（+）。腹膜刺激征（一）。尿常规检查：RB5～10/HP。该患者最可能的诊断是