单选题纤维蛋白降解产物的主要作用是 A.抑制纤溶 B.抗凝血 C.促进纤维蛋白单体聚合 D.抑制血小板聚集

单选题由下蹲位突然起立时发生晕厥的主要原因是( )(2010年)

单选题下述关于动脉粥样硬化的描述中，哪一项是不恰当的

单选题 前列腺癌血行转移首先转移到：（ ） A、骨 B、肝 C、肾上腺 D、脑 E、胃

单选题 下列哪种心肌细胞4期自动去极速度最大 A、 窦房结细胞 B、 心房肌细胞 C、 房室交界细胞 D、 浦肯野细胞 E、 心室肌细胞

单选题发热激活物的主要作用是

单选题下列关于使呼吸道管径变小的因素，不正确的是

单选题同HLA－B27基因相关的自身免疫病是

单选题关于毛细血管特点的描述，错误的是 A．血流速度慢 B．血流阻力大 C．总横截面积大 D．管壁通透性高

单选题下列愈合属于完全再生的是

单选题迷走神经节后纤维兴奋引起胃幽门部胃泌素分泌的神经递质是

单选题The richest man in America stepped to the podium and declared war on the nation's school systems. High schools had become "obsolete" and were "limiting—even ruining—the lives of millions of Americans every year. " The situation had become "almost shameful. " Bill Gates, prep-school grad and college dropout, had come before the National Governors Association seeking converts to his plan to do something about it—a plan he would back with $ 2 billion of his own cash. Gates's speech, in February 2005, was a signature moment in what has become a decade-long campaign to improve test scores and graduation rates, waged by a loose alliance of wealthy CEOs who arrived with no particular background in education policy—a fact that has led critics to dismiss them as "the billionaire boys' club. " Their bets on poor urban schools have been as big as their egos and their bank accounts. Has this big money made the big impact that they—as well as teachers, administrators, parents, and students—hoped for? The results, though mixed, are dispiriting proof that money alone can't repair the desperate state of urban education. For all the millions spent on reforms, nine of the 10 school districts studied substantially trailed their state's proficiency and graduation rates—often by 10 points or more. That's not to say that the urban districts didn't make gains. The good news is many did improve and at a rate faster than their states' 60 percent of the time—proof that the billionaires made some solid bets. But those spikes up weren't enough to erase the deep gulf between poor, inner-city schools, where the big givers focused, and their suburban and rural counterparts. "A lot of things we do don't work out," admitted Broad, a product of Detroit public schools and Michigan State who made a fortune in home building and financial services: "But we can take the criticism. " The confidence that marked Gates's landmark speech to the governors' association in 2005 has given way to humility. The billionaires have not retreated. But they have retooled, and learned a valuable lesson about their limitations. "It's so hard in this country to spread good practice. When we started funding, we hoped it would spread more readily," acknowledges Vicki Phillips, the director of K-12 education at the Bill ＆ Melinda Gates Foundation. "What we learned is that the only things that spread well in school are kids' viruses. " The business titans entered the education arena convinced that America's schools would benefit greatly from the tools of the boardroom. They sought to boost incentives for improving performance, deploy new technologies, and back innovators willing to shatter old orthodoxies. They pressed to close schools that were failing, and sought to launch new, smaller ones. They sent principals to boot camp. Battling the long-term worry that the best and brightest passed up the classroom for more lucrative professions, they opened their checkbooks to boost teacher pay. It was an impressive amount of industry. And in some places, it has worked out—but with unanticipated complications.

单选题可代谢合成黑色素的氨基酸是

单选题促进Lac操纵子转录的条件是必需存在

单选题DIC时最易发生的血栓是

单选题条件反射的特征是( ) A．种族遗传 B．先天获得 C．数量较少 D．个体在后天生活中形成的 E．易变性小

单选题慢性肾小球肾炎典型的尿的改变是______

单选题红色血栓可见于( )(1997年)

单选题子宫颈糜烂，组织活检报告为鳞状上皮化生，提示病变为

单选题肾上腺皮质功能不足的患者，排出水分的能力大为减弱，可出现“水中毒”，补充下列哪种激素可缓解症状( ) A．胰岛素 B．糖皮质激素 C．醛固酮 D．肾上腺素 E．胰高血糖素