单选题临床上治疗舒张期心力衰竭，下列不正确的是

单选题男性，52岁，风湿性心脏病史多年。近一周活动后出现心悸，胸闷明显，伴气促。检查：血压140／50mmHg，心率100次／分，第一心音减弱，第二心音稍增强。胸骨左缘2、3肋间3／6级叹气样杂音，X线见心影扩大，以左室大为主，双肺淤血征，超声心动图提示风湿性主动脉瓣关闭不全(重度)。

单选题急性重型肝炎的特点是

单选题Internet advertising is booming. The industry has gone from $ 9.6 billion in revenue in 2001 to $ 27 billion this year, according to Piper Jaffray, an investment bank. And it is still early days. The internet accounts for only 5% of total spending on advertising, but that figure is expected to reach at least 20% in the next few years. The single largest category within this flourishing industry, accounting for nearly half of all spending, is "pay-per-click" advertising, which is used by firms both large and small to promote their wares. The benefits of the pay-per-click approach over traditional advertising (television, radio, print and billboards are obvious. Since advertisers pay only to reach the small subset who actually respond to an advertisement, the quality of the leads generated is very high, and advertisers are prepared to pay accordingly. The price: per click varies from $ 0.10 to as much as $ 30, depending on the keyword, though the average is around $ 0.50. Google made most of its $ 6.1 billion in revenue last year from pay-per-click advertising. But as pay-per-click advertising has grown into a huge industry, concern has mounted over so-called "click fraud"--bogus clicks that do not come from genuinely interested customers. It takes two main forms. If you click repeatedly on the advertisements on your own website, or get other people or machines to do so on your behalf, you can generate a stream of bogus commissions. Click fraud can also be used by one company against another: clicking on a rival firm's advertisements can saddle it with a huge bill. Bogus clicks are thought to account for around 10% of all click traffic, though nobody knows for sure. A few months ago Mr. Gross pioneered an alternative to the pay-per-click model. In February, Snap, a search engine backed by Mr. Gross, launched "pay-per-action" (PPA), a new model in which advertisers pay only if a click on an ad is followed by an action such as a purchase or a download. Might this put an end to click fraud? Don't bet on it, says Mike Zeman at Starcom, an advertising agency. Payper-action will be a niche, he predicts, since converting a click into an action depends on a variety of factors such as the ease of use of the advertiser's website. Google and its peers will be reluctant to be so dependent on factors outside their control. But Mr. Tobaccowala thinks pay-per-action could become a real alternative to pay-per-click. As bigger companies spend more on internet advertising; they will demand more accountability and a wider range of options, he says. At the very least, that means clamping down on click fraud; but it also presents an opportunity for entrepreneurs to invent new models that are less vulnerable to abuse.

单选题梅毒传染性最大的分期是

单选题关于肺泡表面活性物质的描述，哪一项是不正确的( )(1991年)

单选题A．持续性腹痛B．疼痛-排便-缓解C．进食-疼痛-缓解D．疼痛-进食-缓解

单选题A、慢支 B、支气管哮喘 C、肺TB D、支气管扩张 E、肺癌

单选题为防止第108题病例患者病情进一步发展，下列哪项措施不合适

单选题A．胃液酸度升高 B．胃液酸度正常或减少 C．胃液酸度常减少 D．胃液酸度明显升高 E．胃液酸度明显减少 (1992年)

单选题男性，31岁，因发作性高血压伴头痛、心悸入院，血压最高时210／140mmHg，诊断为嗜铬细胞瘤，宜选择下列哪种药物做术前准备

单选题A．抗Sm抗体B．抗SSB抗体C．抗rRNP抗体D．抗磷脂抗体

单选题男性患者，63岁，间断双膝关节疼1年，加重2个月，下楼时疼痛明显，走平地时疼痛不明显，休息后疼痛可缓解，查双膝轻度肿胀，浮髌试验(＋)，可触及摩擦感。首选的检查为

单选题急性轻型肝炎的病变特点是

单选题支气管哮喘的肺功能异常，主要表现在( )(1995年)

单选题下列有关β受体阻滞剂的说法正确的是

单选题在肝硬化肝细胞坏死的病变中，可以完全经过再生修复的是

单选题关于急进型高血压的叙述，错误的是

单选题肺部X线片结果为“蝴蝶翼”征，提示

单选题下列关于嗜铬细胞瘤产生的多种肽类激素，其中引起腹泻的是