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   2160篇
  免费   27篇
  国内免费   19篇
管理学   328篇
民族学   14篇
人口学   417篇
丛书文集   12篇
理论方法论   102篇
综合类   180篇
社会学   864篇
统计学   289篇
  2023年   8篇
  2022年   5篇
  2021年   14篇
  2020年   15篇
  2019年   26篇
  2018年   40篇
  2017年   73篇
  2016年   112篇
  2015年   31篇
  2014年   24篇
  2013年   102篇
  2012年   222篇
  2011年   156篇
  2010年   45篇
  2009年   24篇
  2008年   29篇
  2007年   19篇
  2006年   25篇
  2005年   565篇
  2004年   287篇
  2003年   155篇
  2002年   45篇
  2001年   83篇
  2000年   35篇
  1999年   5篇
  1998年   8篇
  1997年   3篇
  1995年   2篇
  1993年   3篇
  1992年   2篇
  1991年   9篇
  1989年   3篇
  1988年   1篇
  1986年   1篇
  1985年   3篇
  1984年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1976年   2篇
  1975年   3篇
  1973年   2篇
  1972年   1篇
  1971年   1篇
  1968年   3篇
  1966年   1篇
  1964年   1篇
排序方式: 共有2206条查询结果,搜索用时 15 毫秒
71.
This paper investigates the relationships of the choice of philanthropic strategy with board capital (diversity and networks), board activities (board processes, internal board committees, and board effectiveness), and CEO leadership. Using a sample of 110 Italian foundations, the research shows that board processes have the strongest positive association with an evolved strategic approach to philanthropic institutional grant-giving, while board diversity and strong CEO leadership are associated with the strategic approach only under certain conditions. In particular, good governance processes (e.g., training the board, self-evaluation of trustees, setting the stage for effective board and committee meetings, implementing control software, and steering meetings to improve the board’s analysis) are positively associated with evolved strategic approaches to philanthropy (e.g., signaling other funders for the best grantees, improving the performance of grant recipients, and advancing selected social fields’ state of knowledge and practice).  相似文献   
72.
The purpose of this paper is focused on investigating empirically how Tunisian Auditors perceive their status regarding fraud fighting issue. In this respect, a set of auditor-associated mental representations will be expressed in terms of their respective roles as relevant governance models (legal versus ethical ones), via the cognitive mapping technique. The findings reveal that corporate governance can be globally depicted within these particular representations, indicating the supremacy of the legal governance approach over the ethical one with regard to the Tunisian case. .  相似文献   
73.
New construction methods of the regular A-optimal design matrices with elements −1, 0, 1 are presented, under assumption of nonhomogeneity of variance error. The presented constructions are based on the incidence matrices of the balanced bipartite weighing designs.  相似文献   
74.
While nature is widely acknowledged to contribute to people’s well-being, nature based well-being indicators at city-level appear to be underprovided. This study aims at filling this gap by introducing a novel indicator based on the proximity of city-residents to nature that is of high-amenity. High-amenity nature is operationalized by combining unique systematic data on people’s perceptions of what are the locations of attractive natural areas with data on natural land cover. The proposed indicator departs from the usual assumption of equal well-being from any nature, as it approximates the ‘actual’ subjective quality of nature near people’s homes in a spatially explicit way. Such indicator is used to rank 148 ‘cities’ in the Netherlands, Denmark, and Germany. International comparability of the indicator is enhanced by the use of a definition of cities as functional urban areas (FUAs), which are consistently identified across countries. Results demonstrate that the average ‘nearness’ of FUA populations to high amenity nature varies widely across the observed FUAs. A key finding, that complements insights from existing city-level indicators, is that while populations of FUAs with higher population densities may live relatively far from nature in general, they also live, on average, closer to high-amenity nature than inhabitants of lower density FUAs. Our results may stimulate policy-debates on how to combine urban agglomeration with access to natural amenities in order to account for people’s wellbeing.  相似文献   
75.
Urbanization and other land cover changes have been particularly detrimental to wetlands throughout the planet. One wetland specialist that may be sensitive to land cover changes surrounding wetlands is the round-tailed muskrat (Neofiber alleni; hereafter RTM). The RTM is a wetland obligate rodent that appears to have declined over the last half century and is a species of concern in Florida, where it is a near endemic. To determine if urbanization or other land cover influenced the distribution of RTMs we took a multi-scaled approach to examine the occurrence of RTMs and their associated vegetation in North-Central Florida. We detected RTMs on 19 of 72 sample plots and used a Classification And Regression Tree (CART) to determine that dogfennel (Eupatorium capillifolium) was negatively associated with RTMs and maidencane (Panicum hemitomon) was positively associated with their occurrence on sampling plots. Examining the influence of landscape composition for 2 km surrounding our plots we found that RTM occurrence was negatively related to urban land cover. Further, we found that dogfennel increased and maidencane decreased as urbanization increased in the surrounding landscape. Our research suggests that conservation of RTMs and their associated vegetation should focus on limiting urban sprawl at least within 2 km of wetlands.  相似文献   
76.
Does urbanization affect key life-history traits in native organisms? Some studies show that urban areas reduce diversity in certain taxa, but there is little insight into how these environments affect physiological and ecological traits. Urban areas have distinct physical structure and ecological processes compared to original habitats. The environmental changes associated with urban areas can influence the costs and benefits of different traits and behaviors of local organisms. Some of these effects have been explored in groups such as birds, but we might expect stronger effects in animals with reduced mobility, such as amphibians. Importantly, the effects of urban habitats on amphibians have not been explored, in spite that these are the most threatened vertebrate group in the world. Here, we compared three main traits related to the fitness of amphibians in urban and natural habitats: body size, body condition and immune response. To test the generality of our results, we assessed adult males of four amphibian species. We found that the body size was larger in urban environment populations in three of four studied species, while the body condition was better in the urban populations of two aquatic newt species. Finally, we found no effect of urbanization on the immune response of individuals of any species. In conclusion, we show that different species of amphibians may be affected differently by anthropogenic habitat alteration depending on their specific ecology.  相似文献   
77.
A desirable function for terrestrial urban ecosystems is the mitigation of nitrogen (N) pollution associated with cities and suburbs. To assist in maximizing this function, identifying locations of sources and sinks of N in the urban environment is crucial to inform management strategies. Lawns are an extensive land cover in urbanized landscapes, and in general, they have demonstrated the capacity to function as a sink for N inputs. How N is cycled by lawns, however, is likely not uniform across the physical heterogeneity or management activities that exist in lawns. We investigated the influence of heterogeneity in light availability on N cycling in lawns that were irrigated but not fertilized. Light availability is affected by tree canopy and built structures and is, therefore, heterogeneous both within individual lawns and among lawns. Light is expected to control N retention and loss through effects on primary productivity. We experimentally examined N regulation over one calendar year by measuring net primary production (NPP), N retention using an isotopic tracer, and N leaching in existing unfertilized lawns under heterogeneous light conditions. We used a budgetary approach to estimate gaseous N loss which we assume is primarily via denitrification. Light functioned as a limiting resource for primary productivity. From low to high light conditions, annual NPP increased 177 to 430 g C?m?2?y?1 and retention of N isotope tracer increased from 50 to 65% as a result of increased retention in plants. Nitrate leaching losses were low overall and were not affected by light levels. Light availability regulated the fate of N inputs and unfertilized lawns may function as substantial sinks for reactive N through storage in the terrestrial system and N loss by denitrification. However, whether or not denitrification is generally an N sink will depend on the ratio of non-reactive (i.e., N2) to reactive (i.e., N2O, NO) denitrification products. Overall, we find that effective strategies for managing N sources and sinks in cities will likely need to consider light availability, particularly in systems receiving water subsidies via irrigation.  相似文献   
78.
The role of urban expansion on bee diversity is poorly understood, but it may play an important role in restructuring pollinator diversity observed in rural regions at the urban perimeter. We studied bee communities in two habitats essential for pollinators (residential gardens and semi-natural areas) at 42 sites situated at the edge of greater Montreal, Canada. Bee species richness, abundance and functional diversity all increased with urbanization in both habitat types, but gardens and semi-natural areas supported distinct bee communities with unique responses to urbanization in terms of species turnover. Compared to semi-natural sites, residential gardens supported bees that foraged from a greater number but a lower proportion of available plant species. Bees did not discriminate between exotic and indigenous plant species in either gardens or semi-natural sites and were attracted to flowers in either habitat irrespective of their origins. Protecting semi-natural ruderal areas and providing residential garden habitats for pollinators are both effective means of promoting regional bee diversity in urbanizing regions.  相似文献   
79.
In a recent article from the Annals of Applied Statistics, Cox discussed the main phases of applied statistical research ranging from clarifying study objectives to final data analysis and interpreting results. As an incidental remark to these main phases, we advocate that beyond cleaning and preprocessing the data, it is a good practice to audit the data to determine if they can be trusted at all. A case study based on Ghanaian Official Fishery Statistics is used to illustrate this need, with Benford's law being the tool used to carrying out the data audit. Supplementary materials for this article are available online.  相似文献   
80.
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