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   3132篇
  免费   96篇
  国内免费   1篇
管理学   488篇
民族学   15篇
人才学   1篇
人口学   250篇
丛书文集   25篇
理论方法论   337篇
综合类   23篇
社会学   1687篇
统计学   403篇
  2023年   18篇
  2021年   12篇
  2020年   37篇
  2019年   54篇
  2018年   68篇
  2017年   78篇
  2016年   78篇
  2015年   52篇
  2014年   67篇
  2013年   524篇
  2012年   95篇
  2011年   84篇
  2010年   78篇
  2009年   83篇
  2008年   98篇
  2007年   100篇
  2006年   100篇
  2005年   103篇
  2004年   101篇
  2003年   102篇
  2002年   110篇
  2001年   61篇
  2000年   54篇
  1999年   65篇
  1998年   53篇
  1997年   64篇
  1996年   70篇
  1995年   41篇
  1994年   48篇
  1993年   47篇
  1992年   44篇
  1991年   48篇
  1990年   45篇
  1989年   37篇
  1988年   32篇
  1987年   33篇
  1986年   21篇
  1985年   25篇
  1984年   42篇
  1983年   39篇
  1982年   35篇
  1981年   46篇
  1980年   31篇
  1979年   24篇
  1978年   23篇
  1977年   30篇
  1976年   29篇
  1975年   17篇
  1974年   11篇
  1973年   21篇
排序方式: 共有3229条查询结果,搜索用时 875 毫秒
111.

There have been few studies investigating the relationship between the built environment and the status of bird distributions in small island tropical urban areas. We present a study investigating the relationship between bird species richness, abundance and assemblage to the built environment in Suva, Fiji. Field surveys were taken at 54 randomly selected sites throughout the city, stratified by three building density classes and the central business district (CBD). At each site bird counts were recorded, along with environmental data such as average building height, within a 150 m radius. Land-use information was obtained from screen digitized high-resolution satellite imagery within the same radius. Distance to undeveloped patches of land within the urban area was calculated using a GIS. Analysis of the effects of the built environment was carried out for all species, and for exotic and native species separately. Abundance of exotics was significantly higher in the central business district (CBD) than all other urban density classes, and significantly higher than natives in all other density classes. We found a negative relationship between native species richness and distance to undeveloped patches, but no relationship for exotics. Species assemblage was not related to urban density class. We conclude that the status of native and exotic bird species in Suva is similar to what has been found in urban areas in temperate climates, and conservation efforts should focus on minimizing the amount of heavily urbanized “core areas” and protecting undeveloped areas of forested vegetation to improve bird biodiversity in small tropical islands cities.

  相似文献   
112.

High population growth in the tropics is driving urbanisation, removing diverse natural ecosystems. This is causing native species to suffer while introduced synanthropes flourish. City planners are developing urban greenspace networks, in part trying to address this issue. Architects contribute to these greenspace networks by designing elevated and ground level green spaces on large-scale buildings. However, little evidence is available on whether building green spaces support native fauna. This is true for birds in tropical Singapore that support important ecosystem services and have existence value. Therefore, in this study, we conducted bird surveys and statistical analyses to determine, if and how vegetation on three building green space types (ground gardens, roof gardens and green walls) have a positive impact on native or introduced bird species. We found that elevated greenery (roof gardens and green walls) on large-scale buildings supported a higher richness of birds and abundance of urban native birds than control roofs and walls without vegetation. Ground gardens supported similar levels of native species as roof gardens but also a larger proportion of generalist synanthropes. However, we found no tropical forest habitat specialists across any space type. Therefore, we recommend roof gardens and ground gardens as a potential space for urban natives outside of a less competitive ground-level urban environment. Our study also found certain building design elements (height of elevated space, presence of specific plants) supported different species groups. Therefore, we suggest that these ecological requirements for different species groups are considered when designing a building’s green space.

  相似文献   
113.
Intercollegiate athletics represent an industry prone to challenges of work addiction and life balance. Work addiction and life balance domains in male and female intercollegiate athletic coaches and administrators (N = 245) were examined using multiple regression analysis. Higher levels of stress/anxiety, sleep disturbance, and career satisfaction and lower levels of quality of relationships and friendships were the strongest predictors of work addiction. Counseling focused on reducing the negative aspects of work addiction, while maintaining job performance, may benefit this population.  相似文献   
114.
Environmental scanning activities of over 400 top management subunits in 108 European manufacturing firms provided the data base for this research. Four traits (constructs) of scanning using three methods (interest, frequency, and time) were examined. A confirmatory factor analysis approach to multitrait-multimethod (MTMM) data was employed. Verification of the reliability as well as convergent and discriminant validity of the scanning scales are reported and discussed. The viability of confirmatory factor analysis in providing a precise analysis of partitioning variance according to trait, method, and error is demonstrated.  相似文献   
115.
This paper addresses the questions of market penetration and locational conflict in a franchise system of distribution. The models developed provide a means to evaluate alternative scenarios and the effects of various franchise policies. It is shown that the market penetration and location goals of the members of a franchise system coincide only under a very limited set of circumstances.  相似文献   
116.
This article focuses on the contributions and, importantly, the limitations of subjective wellbeing (happiness/satisfaction) measures as indicators of broad population wellbeing and societal functioning. The popular practice of comparing happiness among countries gives a skewed view of how well their people are faring. Charting trends over time in happiness and mental health gives contradictory pictures of population wellbeing; even the responses to different questions within the same survey can yield very different findings. Asking people about their own lives and about social conditions produces contrasting results. These issues challenge the orthodox model of human development, which places Western liberal democracies at its leading edge. According to an alternative, psychosocial-dynamics, model, some, at least, may be societies in decline. Reconciling these views is no simple matter.  相似文献   
117.
Criminologists have long reported the existence of racial disparity in the criminal justice system, but the important question is why. While some argue that observed differences are a consequence of more criminal behavior among minorities, the weight of the evidence indicates that this is but a partial explanation. In this paper, we study data from a sample of juveniles to examine how racial differences in early police contact, and important social environments—family, school, and neighborhoods—affect later contact and arrests, controlling for self-reported delinquency. We find that early (in middle school) contact with police is an important predictor of later (high school) arrests. Also we found that, in addition to being male and living in a low-income family, children who have parents who have a history of arrest, who have experienced school disciplinary actions, who have delinquent peers, and who are in networks with deviant adults are more likely to have problems with law enforcement. These factors help to explain racial differences in police contacts and arrests.  相似文献   
118.
Abstract

Robert Cox developed a potent approach to studying world orders that is premised on the capacities of a special intellectual, the critical theorist, to discern social structures and the possibilities for their radical change in the future. While acknowledging the ethical appeal of adopting this intellectual persona, in this paper we are concerned with the style of historiography that it requires. In particular, we argue that the imperative to discover and foster the beginnings of social change leads to a version of philosophical history that will likely produce systematic anachronism. This is not uncommon in the discipline of International Relations, but in the case of Cox it stands in tension with some of his avowed intellectual sources, especially the work of Giambattista Vico, and with the aim of providing critical historical perspective on the present. We argue that Vico stands as an example of an alternative historical-empirical line of research that would better serve Coxian ambitions.  相似文献   
119.
Research suggests the relationship between pleasure and condom use during penile–vaginal intercourse (PVI) is associated with relationship status. This online study examined pleasure ratings and condom use at last PVI, stratifying by partner type, among a national sample of Canadian university students. Participants were 715 undergraduates (60.7% women, 39.3% men) who reported on their most recent sexual experience. Condom use decreased with level of relationship commitment, whereas ratings of pleasure increased. Overall, participants were more likely to rate their most recent PVI as Very pleasurable when condoms were not used compared to when condoms were used. However, when stratified by partner type, these differences largely disappeared. For women, with one exception, there were no differences in pleasure between PVI with and without condoms across most partner-type categories. Women in committed dating relationships were more likely to report their last PVI as very pleasurable if condoms were not used than women in these same relationships who had used condoms. Across relationship categories, men who did and did not use condoms did not differ in terms of their pleasure ratings. The results of this study suggest relationship context should be taken into account when assessing condom use experiences.  相似文献   
120.
In response surface methodology, one is usually interested in estimating the optimal conditions based on a small number of experimental runs which are designed to optimally sample the experimental space. Typically, regression models are constructed from the experimental data and interrogated in order to provide a point estimate of the independent variable settings predicted to optimize the response. Unfortunately, these point estimates are rarely accompanied with uncertainty intervals. Though classical frequentist confidence intervals can be constructed for unconstrained quadratic models, higher order, constrained or nonlinear models are often encountered in practice. Existing techniques for constructing uncertainty estimates in such situations have not been implemented widely, due in part to the need to set adjustable parameters or because of limited or difficult applicability to constrained or nonlinear problems. To address these limitations a Bayesian method of determining credible intervals for response surface optima was developed. The approach shows good coverage probabilities on two test problems, is straightforward to implement and is readily applicable to the kind of constrained and/or nonlinear problems that frequently appear in practice.  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