首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   16926篇
  免费   494篇
  国内免费   3篇
管理学   2530篇
民族学   103篇
人才学   10篇
人口学   1627篇
丛书文集   99篇
教育普及   1篇
理论方法论   1673篇
现状及发展   1篇
综合类   185篇
社会学   8279篇
统计学   2915篇
  2023年   107篇
  2021年   98篇
  2020年   266篇
  2019年   374篇
  2018年   430篇
  2017年   538篇
  2016年   467篇
  2015年   314篇
  2014年   391篇
  2013年   2842篇
  2012年   582篇
  2011年   534篇
  2010年   429篇
  2009年   389篇
  2008年   454篇
  2007年   470篇
  2006年   426篇
  2005年   455篇
  2004年   413篇
  2003年   371篇
  2002年   396篇
  2001年   388篇
  2000年   419篇
  1999年   377篇
  1998年   285篇
  1997年   267篇
  1996年   251篇
  1995年   241篇
  1994年   235篇
  1993年   235篇
  1992年   257篇
  1991年   205篇
  1990年   201篇
  1989年   236篇
  1988年   214篇
  1987年   184篇
  1986年   194篇
  1985年   221篇
  1984年   228篇
  1983年   205篇
  1982年   177篇
  1981年   151篇
  1980年   150篇
  1979年   179篇
  1978年   120篇
  1977年   117篇
  1976年   132篇
  1975年   102篇
  1974年   113篇
  1973年   93篇
排序方式: 共有10000条查询结果,搜索用时 757 毫秒
341.
As one of a suite of natural science galleries in the National Museum of Scotland, Animal Senses presents a comprehensive overview of how animals have evolved senses as they have adapted to different ecological niches in order to find food or avoid predation. Using different sensory channels, they also have evolved means of communication to attract mates, deter rivals, and remain hidden from predators and prey. Some of the most extraordinary examples of evolution are those which mimic the appearance of another unrelated species or some feature of the environment such as a thorn on a bush or a piece of coral. New taxidermy and models, engaging text presented hierarchically, and fun interactives were developed specifically for this gallery in order to present an up-to-date review of senses and communication. However, its real strength is the wide array of real specimens and life-size models which allow visitors to see what these animals really look like and how big they are, experiences which cannot be emulated by books or electronic media. By taking a thematic approach, we have created an unrivalled opportunity to compare animals from different taxonomic groups to see how they have solved the problems of life by evolving similar structures or completely different ones in order to find food, avoid being eaten, navigate, find mates and deceive rivals and predators.  相似文献   
342.
343.
According to cultural theorist Pierre Bourdieu, social class is defined by the interplay and operation of various forms of capital, within the set of durable and objective relations in which the classed subject is located. Informed by Bourdieu's understanding of social class, this article details the empirical dimensions of upper‐middle‐class familial involvement at the Valley View Swim and Tennis Club. An institution prefigured on the practice and development of important physical skills, Valley View represents a site for the complex interplay of capitals (economic, social, cultural, and physical) complicit in the preservation and reproduction of members' upper‐middle‐class habitus, and corresponding elevated and privileged social status. Specifically, we discuss the findings of ethnographic fieldwork focused on the acquisition, transmission, and conversion of economic, social, cultural, and physical capital in and through member families' club involvement. We argue that Valley View operates as a distinctive cultural field, wherein embodied techniques and expressions of class‐based power and privilege contribute to the reproduction of social class differences, boundaries, and hierarchies, in such a way as to render them natural, and largely unacknowledged, effects of being.  相似文献   
344.
Among policymakers, a common perception surrounding the effects of cash transfer programmes, particularly unconditional programmes targeted to families with children, is that they induce increased fertility. We evaluate the Zambian Child Grant Programme, a government unconditional cash transfer targeted to families with a child under the age of 5 and examine impacts on fertility and household composition. The evaluation was a cluster randomized control trial, with data collected over 4 years from 2010 to 2014. Our results indicate that there are no programme impacts on overall fertility. Our results contribute to a small evidence base demonstrating that there are no unintended incentives related to fertility due to cash transfers.  相似文献   
345.
Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features—a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines—one with a free-spins feature or similar bonus feature and one without. Participants then completed a testing phase where they could freely switch between the two machines. In Experiment 1, participants did not prefer the machine with a simple free-spins feature. In Experiment 2 the free-spins feature incorporated additional elements such as sounds, animations, and an increased win frequency; participants preferred to gamble on this machine. The Experiment 3 “bonus feature” machine resembled the free spins machine in Experiment 2 except spins were not free; participants showed a clear preference for this machine also. These findings indicate that (1) free-spins features have a major influence over machine choice and (2) the “freeness” of the free-spins bonus features is not an important driver of preference, contrary to self-report and interview research with gamblers.  相似文献   
346.
347.
We experimentally compare fast and slow decisions in a series of experiments on financial risk taking in three countries involving over 1700 subjects. To manipulate fast and slow decisions, subjects were randomly allocated to responding within 7 seconds (time pressure) or waiting for at least 7 or 20 seconds (time delay) before responding. To control for different effects of time pressure and time delay on measurement noise, we estimate separate parameters for noise and risk preferences within a random utility framework. We find that time pressure increases risk aversion for gains and risk taking for losses compared to time delay, implying that time pressure increases the reflection effect of Prospect Theory. The results for gains are weaker and less robust than the results for losses. We find no significant difference between time pressure and time delay for loss aversion (tested in only one of the experiments). Time delay also leads to less measurement noise than time pressure and unconstrained decisions, and appears to be an effective way of decreasing noise in experiments.  相似文献   
348.
Since third sector research emerged as a full-fledged interdisciplinary academic field during the late 1980s, a separation has usually been maintained—in common with many other social science disciplines—between communities of researchers who are primarily concerned with the study of the third sector in rich Western countries and those who work on the third sector in the so-called developing world. Whilst internationally focused researchers tend to use the language of ‘non-governmental organizations’, those in domestic settings usually prefer the terms ‘non-profit organization’ or ‘voluntary organization’, even though both subsectors share common principles and are equally internally diverse in terms of organisations and activities. Whilst there has long been common-sense logic to distinguishing between wealthier and poorer regions of the world based on differences in the scale of human need, the ‘developed’ versus ‘developing’ category can also be criticised as being rather simplistic and unhelpfully ideological. As the categories of ‘developing’ and ‘developed’ countries become less clear-cut, and global interconnectedness between third sectors and their ideas grows, this paper argues that we need to reconsider the value of maintaining these parallel worlds of research, and instead develop a more unified approach.  相似文献   
349.
350.
The use of thimerosal preservative in childhood vaccines has been largely eliminated over the past decade in the United States because vaccines have been reformulated in single‐dose vials that do not require preservative. An exception is the inactivated influenza vaccines, which are formulated in both multidose vials requiring preservative and preservative‐free single‐dose vials. As part of an ongoing evaluation by USFDA of the safety of biologics throughout their lifecycle, the infant body burden of mercury following scheduled exposures to thimerosal preservative in inactivated influenza vaccines in the United States was estimated and compared to the infant body burden of mercury following daily exposures to dietary methylmercury at the reference dose established by the USEPA. Body burdens were estimated using kinetic parameters derived from experiments conducted in infant monkeys that were exposed episodically to thimerosal or MeHg at identical doses. We found that the body burden of mercury (AUC) in infants (including low birth weight) over the first 4.5 years of life following yearly exposures to thimerosal was two orders of magnitude lower than that estimated for exposures to the lowest regulatory threshold for MeHg over the same time period. In addition, peak body burdens of mercury following episodic exposures to thimerosal in this worst‐case analysis did not exceed the corresponding safe body burden of mercury from methylmercury at any time, even for low‐birth‐weight infants. Our pharmacokinetic analysis supports the acknowledged safety of thimerosal when used as a preservative at current levels in certain multidose infant vaccines in the United States.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号