单选题In a democratic society citizens are encouraged to form their own opinions on candidates for public office, taxes, constitutional amendments, environmental concerns, foreign policy, and other issues. The opinions held by any population are shaped and manipulated by several factors: individual circumstances, the mass media, special-interest groups, and opinion leaders. Wealthy people tend to think differently on social issues from poor people. Factory workers probably do not share the same views as white-collar, nonunion workers. Women employed outside their homes sometimes have perspectives different from those of full-time homemakers. In these and other ways individual status shapes one's view of current events. The mass media, especially television, are powerful influences on the way people think and act. Government officials note how mail from the public tends to "follow the headlines. " Whatever is featured in newspapers and magazines and on television attracts enough attention that people begin to inform themselves and to express opinions. The mass media have also created larger audiences for government and a wider range of public issues than existed before. Prior to television and the national editions of newspapers, issues and candidates tended to remain localized. In Great Britain and West Germany, for example, elections to the national legislatures were usually viewed by voters as local contests. Today's elections are seen as struggles between party leaders and programs. In the United States radio and television have been beneficial to the presidency. Since the days of Franklin D. Roosevelt and his "fireside chats," presidents have appealed directly to a national audience over the heads of Congress to advocate their programs. Special-interest groups spend vast sums annually trying to influence public opinion. Public utilities, for instance, tried to sway public opinion in favor of nuclear power plants. Opposed to them were citizens' organizations that lobbied to halt the use of nuclear power. During the 1960s the American Medical Association conducted an unsuccessful advertising campaign designed to prevent the passage of Medicare. Opinion leaders are usually such prominent public figures as politicians, show-business personalities, and celebrity athletes. The opinions of these individuals, whether informed and intelligent or not, carry weight with some segments of the population. Some individuals, such as Nobel Prize winners, are suddenly thrust into public view by the media. By quickly reaching a large audience, their views gain a hearing and are perhaps influential in shaping views on complex issues.

单选题与神经细胞动作电位去极化有关的主要离子是( ) A．K+ B．Cl- C．Ca2+ D．Na+ E．Mg2+

单选题结核性腹膜炎的病变性质通常属于

单选题下列哪期接受心室额外刺激后，可出现期前收缩和代偿间歇

单选题下列属于系统性自身免疫病的是

单选题 关于急性期反应蛋白，错误的是 A、主要由单核细胞合成 B、正常时血中含量很少 C、炎症、感染、发热时明显增加 D、种类很多 E、功能相当广泛

单选题A.入睡时B.午夜C.清晨D.上午

单选题A．蛋白质B．甘油三酯C．葡萄糖D．胆固醇

单选题糖皮质激素本身没有缩血管效应，但能加强去甲肾上腺素的缩血管作用，这称为( ) A．协同作用 B．致敏作用 C．增强作用 D．允许作用 E．辅助作用

单选题关于糖类的吸收，下列叙述哪项是错误的( ) A．糖类是以单糖的形式吸收的 B．果糖的吸收速率快于乳糖和葡萄糖 C．单糖的吸收是耗能的主动过程 D．需要载体蛋白参与 E．与Na+的吸收相耦联

单选题 孕期16—18周时需为胎儿作细胞遗传学检查，可用 ( ) A、B型超声扫描 B、X线检查 C、绒毛取样 D、羊膜穿刺 E、胎儿镜检查

单选题心室肌的后负荷是指( )(1991年)

单选题 A.Na+、Cl- B.K+、Cl- C.葡萄糖 D.白蛋白

单选题 下列哪一项关于附睾发育异常的描述是错误的？（ ） A、附睾发育异常临床上较常见 B、一般临床症状明显 C、可造成不育 D、发生原因可能是在胚胎发育过程中内分泌功能失调 E、可能是因为睾酮水平低下所致

单选题下列选项中，符合肿瘤的异质性概念的是

单选题平静呼气末肺的容量是( ) A．残气量 B．补吸气量与残气量之和 C．功能残气量 D．补呼气量与潮气量之和

单选题采用简便方法测定BMR，必须测定的数据是( ) A．非蛋白呼吸商 B．一定时间内的CO2产生量 C．食物的热价 D．食物的氧热价 E．一定时间内的耗O2量

单选题风湿性心肌炎病理诊断的主要依据为

单选题下列凝血因子中，需要维生素K参与其合成的是

单选题精子获能发生于( )(2006年)