全文获取类型
收费全文 | 1177篇 |
免费 | 53篇 |
专业分类
管理学 | 165篇 |
民族学 | 5篇 |
人口学 | 89篇 |
丛书文集 | 6篇 |
理论方法论 | 165篇 |
综合类 | 7篇 |
社会学 | 697篇 |
统计学 | 96篇 |
出版年
2023年 | 6篇 |
2022年 | 9篇 |
2021年 | 8篇 |
2020年 | 25篇 |
2019年 | 27篇 |
2018年 | 44篇 |
2017年 | 53篇 |
2016年 | 44篇 |
2015年 | 31篇 |
2014年 | 40篇 |
2013年 | 206篇 |
2012年 | 38篇 |
2011年 | 42篇 |
2010年 | 47篇 |
2009年 | 35篇 |
2008年 | 43篇 |
2007年 | 55篇 |
2006年 | 40篇 |
2005年 | 41篇 |
2004年 | 34篇 |
2003年 | 34篇 |
2002年 | 40篇 |
2001年 | 21篇 |
2000年 | 22篇 |
1999年 | 21篇 |
1998年 | 16篇 |
1997年 | 10篇 |
1996年 | 13篇 |
1995年 | 11篇 |
1994年 | 14篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 13篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 5篇 |
1974年 | 6篇 |
排序方式: 共有1230条查询结果,搜索用时 70 毫秒
551.
552.
553.
Stephen William Reaney Harrison Brian L. Cypher Samantha Bremner-Harrison Christine L. Van Horn Job 《Urban Ecosystems》2011,14(2):303-311
An urban population of Endangered San Joaquin kit foxes (Vulpes macrotis mutica) has persisted in the city of Bakersfield, (Kern County, California), for several decades. Urban kit foxes may play an important
role in future range wide recovery efforts for the species. As such, a comprehensive understanding of the issues that can
influence the long-term survival of this population is essential for the development of effective management strategies. Although
urban kit foxes have been studied extensively in Bakersfield, interactions between kit foxes and other urban carnivore species
are poorly understood. Urban environments can provide a number of opportunities for species to interact in ways not usually
observed in natural habitats. Interactions between urban populations of striped skunks (Mephitis mephitis) and kit foxes were investigated at denning locations and cat feeding stations on the California State University-Bakersfield
campus, California, USA. A total of 130 individual denning sites were identified, of which 39 (30%) were used by both species.
Simultaneous den use by foxes and skunks was recorded on four occasions. Inter and intra-specific aggression was recorded
at cat feeding stations on ten separate occasions including three incidences of aggression towards kit foxes by skunks and
feral cats (Felis catus). Telemetry data and cat feeding station observations clearly show that interspecific contact does occur in urban environments. 相似文献
554.
Brian J. Johnson Kristin Munafo Laura Shappell Nellie Tsipoura Mark Robson Joan Ehrenfeld Michael V. K. Sukhdeo 《Urban Ecosystems》2012,15(3):513-531
This study investigated the impacts of urban wetlands and their adjacent residential environments on the transmission dynamics of West Nile virus (WNV) within the state of New Jersey (USA). A working hypothesis was that urban wetlands decrease the local prevalence of WNV through the dilution effect from increased bird diversity, and through relative reductions in the numbers of competent avian host and mosquito species commonly associated with WNV. Surveys of mosquito and bird communities were undertaken at six urban wetlands and their adjacent residential environments over two seasons (2009, 2010). The community compositions of both avian and mosquito species differed significantly across habitats, and over relatively short geographical distances. Residential areas contained significantly higher proportions of WNV-competent mosquito species (31.25?±?5.3?%; e.g. Culex pipiens and Culex restuans), and WNV-competent avian host species (62.8?±?2.3?%, e.g. House Sparrow and American Robin) when compared to adjacent urban wetlands (13.5?±?2.1?%; 35.4?±?2.1?% respectively). Correspondingly, WNV infection rates within local Culex spp. populations indicate that WNV was more prevalent within residential areas (28.53/1000) compared to wetlands (16.77/1000). Large urban wetlands (>100?ha) produced significantly lower weekly WNV infection rates in local Culex spp. (6.67?±?2.84/1000) compared to small (<15?ha) wetlands (22.57?±?6.23/1000). Avian species richness was also influenced by patch size. Large urban wetlands contained significantly more species than small wetland patches. These results confirm that the community compositions of mosquito and avian hosts are important drivers in WNV infections, and that the ecological conditions that favor transmission are more strongly associated with urban residential environments than with adjacent urban wetlands. 相似文献
555.
Brian Blanton Kendra Dresback Brian Colle Randy Kolar Humberto Vergara Yang Hong Nicholas Leonardo Rachel Davidson Linda Nozick Tricia Wachtendorf 《Risk analysis》2020,40(1):117-133
Hurricane track and intensity can change rapidly in unexpected ways, thus making predictions of hurricanes and related hazards uncertain. This inherent uncertainty often translates into suboptimal decision-making outcomes, such as unnecessary evacuation. Representing this uncertainty is thus critical in evacuation planning and related activities. We describe a physics-based hazard modeling approach that (1) dynamically accounts for the physical interactions among hazard components and (2) captures hurricane evolution uncertainty using an ensemble method. This loosely coupled model system provides a framework for probabilistic water inundation and wind speed levels for a new, risk-based approach to evacuation modeling, described in a companion article in this issue. It combines the Weather Research and Forecasting (WRF) meteorological model, the Coupled Routing and Excess STorage (CREST) hydrologic model, and the ADvanced CIRCulation (ADCIRC) storm surge, tide, and wind-wave model to compute inundation levels and wind speeds for an ensemble of hurricane predictions. Perturbations to WRF's initial and boundary conditions and different model physics/parameterizations generate an ensemble of storm solutions, which are then used to drive the coupled hydrologic + hydrodynamic models. Hurricane Isabel (2003) is used as a case study to illustrate the ensemble-based approach. The inundation, river runoff, and wind hazard results are strongly dependent on the accuracy of the mesoscale meteorological simulations, which improves with decreasing lead time to hurricane landfall. The ensemble envelope brackets the observed behavior while providing “best-case” and “worst-case” scenarios for the subsequent risk-based evacuation model. 相似文献
556.
557.
Brian Gran 《Sociology Compass》2008,2(5):1462-1490
Across the world, political leaders and policy experts frequently use the labels ‘public’ and ‘private’ to organize social policies. A line seemingly separates public from private efforts, with social policies publicly organized in some countries and privately organized in others. According to this perspective, a public social policy is undertaken by government or deals with a public matter. When a social policy is private, non‐public actors and institutions, like employers, undertake it or it deals with a private matter, like body control. This article examines whether public or private approaches to managing social policies are currently emphasized in European countries. I begin by defining social policy and then provide an overview of the public–private dichotomy in managing social policy. I review predominant typological frameworks of public–private organization of social policies and examine three welfare social policies and three social policies dealing with body control by comparing public–private organization of these six policy areas across 21 European countries. I conclude by discussing the limited diversity of public–private organizations of social policies in Europe. 相似文献
558.
Mary H. Sailors PhD Andrew S. Jackson PED Brian K. McFarlin PhD Ian Turpin MEd Kenneth J. Ellis PhD John P. Foreyt PhD 《Journal of American college health : J of ACH》2013,61(1):13-20
Abstract Objective: The Training Interventions and Genetics of Exercise Response (TIGER) study is an exercise program designed to introduce sedentary college students to regular physical activity and to identify genetic factors that influence response to exercise. Participants: A multiracial/ethnic cohort (N = 1,567; 39% male), age 18 to 35 years, participated in the study. Methods: Subjects underwent 30 weeks of exercise training, 3 days/week, for 40 minutes at 65% to 85% of age- and gender-predicted maximum heart rate reserve. Multiple measures of body size/composition, heart rate, and blood pressure were obtained. Results: A total of 1,567 participants, (39% male), age 18 to 35 years, participated in the TIGER study. The prevalence of overweight/obesity in participants was 48.0%/19.3% in non-Hispanic Whites, 55.3%/24.2% in Hispanic Whites, 54.9%/25.4% in African Americans, and 38.3%/11.3% in Asians. Average within-semester retention was 68%, but overall retention (30 weeks, 2 semesters) was 20%. Conclusions: The TIGER study represents an efficacious strategy for introducing college-aged individuals to regular aerobic exercise. 相似文献
559.
Brian Burgoon Janice Fine Wade Jacoby Daniel Tichenor 《The International migration review》2010,44(4):933-973
Does immigration hamper union organizing in the United States? The prevailing literature strongly suggests that it does and for two reasons: first, immigrants increase the labor pool and diminish union influence over the labor market. And second, immigrants may be harder to organize than native workers. In this dominant view, unions are well served to restrict immigration and have always done so. But how, then, to explain the fact that American labor has long been deeply divided over the response to immigration? Drawing on new archival research and interviews, this paper uncovers a neglected side of American labor history in which many union leaders have extended solidarity to immigrants and sought to organize them. Moreover, analysis of time series data on immigration and union density corroborates the implicit theory of this alternate account of labor history: immigration has, in fact, no statistically significant effect – either positive or negative – on union density over time. Depending on specific conditions and strategies, unions can and have been successful in organizing during periods of high immigration. 相似文献
560.
David G. Butler John A. Eccleston Brian R. Cullis 《Australian & New Zealand Journal of Statistics》2008,50(4):295-307
The design of large‐scale field trials where the residuals are correlated has been of recent interest, in large part because of advances in statistical and computational methods of analysis. The construction of designs for correlated data has typically used A‐optimality and is computationally intensive. This involves calculating the inverse of the information matrix for treatments under the supervision of an optimization strategy that explores the design space. We propose an approximation to A‐optimality, using nearest‐neighbour balance, that is less computationally demanding and can achieve at least 95% efficiency relative to A‐optimality in many practical situations. 相似文献