单选题头面部污染性伤口清创缝合的时限最长为( )(1989年)

单选题下列哪项不是骨折功能复位的标准?

单选题临床上器官移植术后最主要的抗急性排斥反应的药物是

单选题成人心脏瓣膜病最常见的原因是（ ）

单选题一位术后贫血合并有心功能不全的老年病人，输入以下何种血细胞制品最恰当A．浓缩红细胞B．洗涤红细胞C．冰冻红细胞D．少含白细胞红细胞E．库存全血

单选题小胃癌是指

单选题幼儿肠梗阻多见于（ ）

单选题关于动脉栓塞的特点，下列哪项不恰当

单选题怀疑前列腺癌，为明确诊断，需做下列哪项检查

单选题体外冲击波碎石时，应用抗生素的原则下列哪项是不对的

单选题嵌顿性疝手法复位后，护士应特别注意观察（ ）

单选题甲亢术后最危急的并发症是

单选题A．棘突表面或棘突间B．腰段骶棘肌中外侧缘C．髂脊内下方D．髂脊外1／3E．髂脊内1／3

单选题A．神经根型颈椎病B．脊髓型颈椎病C．交感神经型颈椎病D．椎动脉型颈椎病

单选题肝包虫病临床上最常用的治疗方法为

单选题肠套叠好发于

单选题肠内营养的适应证不包括

单选题胸外心脏挤压，恰当操作时，动脉压可达

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. /

单选题乳腺癌患者皮肤出现“橘皮样”改变，是因为