单选题Increasingly, historians are blaming diseases imported from the Old World for the great disparity between the native population of America in 1492--new estimates of which jump as high as 100 million, or approximately one-sixth of the human race at that time--and the few million full-blooded Native Americans alive at the end of the nineteenth century. There is no doubt that chronic disease was an important factor in the sharp decline, and it is highly probable that the greatest killer was epidemic disease, especially as manifested in virgin-soil epidemics. Virgin-soil epidemics are those in which the populations at risk have had no previous contact with the diseases that strike them and are therefore immunologically almost defenseless. That virgin-soil epidemics were important in American history is strongly indicated by evidence that a number of dangerous maladies--smallpox, measles, malaria, yellow fever, and undoubtedly several more--were unknown in the pre-Columbian New World. The effects of their sudden introduction are demonstrated in the early chronicles of America, which contain reports of horrible epidemics and steep population declines, confirmed in many cases by quantitative analyzes of Spanish tribute records and other sources. The evidence provided by the documents of British and French colonies is not as definitive because the conquerors of those areas did not establish permanent settlements and began to keep continuous records until the seventeenth century, by which time the worst epidemics had probably already taken place. Furthermore, the British tended to drive the native populations away, rather than to enslave them as the Spaniards did, so that the epidemics of British America occurred beyond the range of colonists' direct observation. Even so, the surviving records of North America do contain references to deadly epidemics among the native population. In 1616--1619 an epidemic, possibly of pneumonic plague, swept coastal New England, killing as many as nine out of ten, During the 1630's smallpox, the disease most fatal to the Native American people, eliminated half the population of the Huron and Iroquois confederations. In the 1820's fever ruined the people of the Columbia River area, killing eight out of ten of them. Unfortunately, the documentation of these and other epidemics is slight and frequently unreliable, and it is necessary to supplement what little we do know with evidence from recent epidemics among Native Americans. For example, in 1952 an outbreak of measles among the Native American inhabitants of Ungava Bay, Quebec, affected 99 percent of the population and killed 7 percent, even though some had the benefit of modern medicine. Cases such as this demonstrate that even diseases that are not normally fatal can have destroying consequences when they strike an immunologically defenseless community.

单选题平均利润进一步模糊了资本主义剥削关系的实质是因为 A．利润被视为可变资本的产物 B．利润被视为不变资本的产物 C．所有部门所获得的剩余价值和利润在量上相等D．各部门按预付资本所得的利润在量上相等

单选题突然昏倒，牙关紧闭，不省人事，苔白，脉迟，治宜选用

单选题孕妇忌用的药物是( )(2002年第31题)

单选题酸枣仁的药物组成不包括

单选题银翘散和桑菊饮的组成药物中含有

单选题A．防风通胜散B．五积散C．石膏汤D．大柴胡汤

单选题A．升麻B．柴胡C．两者均有D．两者均无(1996年第111，112题)

单选题一贯煎的药物组成不包含

单选题患者证见骨蒸盗汗，心烦易怒，消渴多食，遗精尿赤，足膝热痛，舌红少苔，脉细数。治宜选用的方剂是

单选题银翘散与桑菊饮功用的主要区别是：

单选题当归补血汤是一首具有以下哪种作用的方剂： A．气血双补 B．补气生血 C．益气养血D．补气活血E．以上都不是

单选题葛根黄芩黄连汤中，葛根的正确用法是

单选题脘腹痞满胀痛，赤白痢疾，里急后重，或大便秘结，舌苔黄腻，脉沉实，治宜选用何方

单选题Social-networking sites offer users easy ways to present idealized images of themselves, even if those ideals don't always square with their real-world personalities. Psychology researcher Soraya Mehdizadeh has discovered a way to poke through the offline-online curtain: she has used Faeebook to predict a person's level of narcissism and self-esteem. Mehdizadeh, who conducted the study as an undergraduate at Toronto's York University, gained access to the Faeebook accounts of 100 college students and measured activities like photo sharing, wall postings and status updates; she also studied how frequently users logged on and how often they remained online during each session. Her findings were published recently in Cyberpsyehology, Behavior and Social Networking. After measuring each subject using the Narcissism Personality Inventory and Rosenberg Self-Esteem Scale, Mehdizadeh, who graduated from York this past spring, discovered narcissists and people with lower self-esteem were more likely to spend more than an hour a day on Facebook and were more prone to post self-promo-tional photos ( striking a pose or using Photoshop, for example). Narcissists were also more likely to showcase themselves through status updates (using phrases like "I'm so glamorous I bleed glitter") and wall activity (posting self-serving links like " My Celebrity Look-alikes" ). Self-esteem and narcissism are often interrelated but don't always go hand in hand. Some psychologists believe that narcissists--those who have a pervasive pattern of grandiosity, a need for admiration, as well as a lack of sympathy--unconsciously inflate their sense of self-importance as a defense against feeling inadequate. Not enough empirical research has been produced to confirm that link, although Mehdizadeh's study seems to support it. Because narcissists have less capacity to sustain intimate or long-term relationships, Mehdizadeh thinks that they would be more drawn to the online world of virtual friends and emotionally detached communication. Although it seems that Facebook can be used by narcissists to fuel their inflated egos, Mehdizadeh stops short of proclaiming that excessive time spent on Faeebook can turn regular users into narcissists. She also notes that social-networking sites might ultimately be found to have positive effects when used by people with low self-esteem or depression. "If individuals with lower self-esteem are more prone to using Facebook," she says, "the question becomes, ' Can Facebook help raise self- esteem by allowing patients to talk to each other and help each other in a socially interactive environment?' I don't think it's necessarily a bad thing that people with low self-esteem use Facebook. /

单选题桑叶、杏仁、沙参象、贝香、豉栀皮、梨皮，以上是哪个方剂的药物组成

单选题三仁汤的配伍特点是宣上、畅中、渗下，三焦分消，气畅湿行，暑解热清．三焦通畅，诸症自除。其中体现畅中的是哪味药物

单选题夏季，发热头痛，恶寒无汗，口渴而赤，胸闷不舒，舌苔白腻，脉浮而数者，治疗常用

单选题以下哪项不是甘露消毒丹的组成药物

单选题凉膈散中可引火下行、通泻三焦的药物是