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   379篇
  免费   15篇
管理学   51篇
民族学   2篇
人口学   23篇
丛书文集   3篇
理论方法论   63篇
综合类   2篇
社会学   228篇
统计学   22篇
  2023年   5篇
  2021年   4篇
  2020年   7篇
  2019年   10篇
  2018年   10篇
  2017年   13篇
  2016年   10篇
  2015年   13篇
  2014年   14篇
  2013年   74篇
  2012年   12篇
  2011年   9篇
  2010年   8篇
  2009年   7篇
  2008年   13篇
  2007年   11篇
  2006年   13篇
  2005年   13篇
  2004年   9篇
  2003年   12篇
  2002年   10篇
  2001年   6篇
  2000年   5篇
  1999年   6篇
  1998年   4篇
  1997年   3篇
  1996年   7篇
  1995年   8篇
  1994年   3篇
  1993年   4篇
  1992年   4篇
  1991年   3篇
  1990年   5篇
  1989年   6篇
  1987年   3篇
  1986年   3篇
  1985年   3篇
  1984年   8篇
  1983年   3篇
  1981年   3篇
  1980年   3篇
  1979年   5篇
  1976年   4篇
  1974年   2篇
  1973年   1篇
  1972年   1篇
  1971年   3篇
  1970年   1篇
  1969年   2篇
  1968年   1篇
排序方式: 共有394条查询结果,搜索用时 15 毫秒
21.
The U.S. Department of Energy has estimated that over 50 GW of offshore wind power will be required for the United States to generate 20% of its electricity from wind. Developers are actively planning offshore wind farms along the U.S. Atlantic and Gulf coasts and several leases have been signed for offshore sites. These planned projects are in areas that are sometimes struck by hurricanes. We present a method to estimate the catastrophe risk to offshore wind power using simulated hurricanes. Using this method, we estimate the fraction of offshore wind power simultaneously offline and the cumulative damage in a region. In Texas, the most vulnerable region we studied, 10% of offshore wind power could be offline simultaneously because of hurricane damage with a 100‐year return period and 6% could be destroyed in any 10‐year period. We also estimate the risks to single wind farms in four representative locations; we find the risks are significant but lower than those estimated in previously published results. Much of the hurricane risk to offshore wind turbines can be mitigated by designing turbines for higher maximum wind speeds, ensuring that turbine nacelles can turn quickly to track the wind direction even when grid power is lost, and building in areas with lower risk.  相似文献   
22.
This article looks at the ability of a relatively new technique, hybrid artificial neural networks (ANNs), to predict Japanese banking and firm failures. These models are compared with traditional statistical techniques and conventional ANN models. The results suggest that hybrid neural networks outperform all other models in predicting failure for one year prior to the event. This suggests that for researchers, policymakers, and others interested in early warning systems, the hybrid network may be a useful tool for predicting banking and firm failures.  相似文献   
23.
Of America's counties, 76% are rural, comprising 83% of U.S. land and 25% of the American population. Yet most child welfare programs are designed to fit the needs of urban and suburban families. This article reviews the unique needs and assets of rural children and families in Texas. It presents recommendations from a focus group for overcoming the inappropriate transfer of urban models to rural communities.  相似文献   
24.
Characterizing all possible chemical mixtures in drinking water is a potentially overwhelming project, and the task of assessing each mixture's net toxicity even more daunting. We propose that analyzing occurrence information on mixtures in drinking water may help to narrow the priorities and inform the approaches taken by researchers in mixture toxicology. To illustrate the utility of environmental data for refining the mixtures problem, we use a recent compilation of national ground-water-quality data to examine proposed U.S. Environmental Protection Agency (EPA) and Agency for Toxic Substances and Disease Registry (ATSDR) models of noncancer mixture toxicity. We use data on the occurrence of binary and ternary mixtures of arsenic, cadmium, and manganese to parameterize an additive model and compute hazard index scores for each drinking-water source in the data set. We also use partially parameterized interaction models to perform a bounding analysis estimating the interaction potential of several binary and ternary mixtures for which the toxicological literature is limited. From these results, we estimate a relative value of additional toxicological information for each mixture. For example, we find that according to the U.S. EPA's interaction model, the levels of arsenic and cadmium found in U.S. drinking water are unlikely to have synergistic cardiovascular effects, but the same mixture's potential for synergistic neurological effects merits further study. Similar analysis could in future be used to prioritize toxicological studies based on their potential to reduce scientific and regulatory uncertainty. Environmental data may also provide a means to explore the implications of alternative risk models for the toxicity and interaction of complex mixtures.  相似文献   
25.
The purpose of this study was to examine the influence of peer modeling on sexually impositional behavior in the laboratory. Male participants with and without a self‐reported history of sexually aggressive behavior viewed video clips depicting nonaggressive and sexually aggressive behavior and then chose one of the clips to show to a female confederate. Half of the participants were first exposed to a male confederate who showed the sexually aggressive video clip to a female confederate. The other half of the participants were exposed to a male confederate who showed a nonaggressive video clip to a female confederate. Exposure to a male confederate who showed a sexually aggressive video clip to a female was associated with participants' choosing to engage in this same behavior. A self‐reported history of sexually aggressive behavior was also associated with participants' showing the sexually aggressive video clip in spite of believing the effect on the female viewer would be negative.  相似文献   
26.
Cet article s'inscrit dans la lignée des études sur les dimensions culturelles de la cohabitation entre générations en examinant de près le comportement des jeunes adultes canadiens qui retournent vivre chez leurs parents. Nous explorons les rapports mutuels entre la famille et la diversité culturelle, entre le capital financier et le capital social, et entre le rythme et les mécanismes de transitions précoces qui se manifestent au cours d'une vie. Les modéles de hasards proportionnels sont appliqués à un sous‐échantillon de 2 549 jeunes adultes, àgés de 19 á 34 ans, en tenant compte des données de l'Enquete sociale générale, cycle 10, de 1995. L'une des principales conclusions tirées ici indique que les jeunes qui sont de langue maternelle anglaise sont beaucoup plus susceptibles de retourner chez leurs parents après un premier départ que ceux dont la langue maternelle est le français ou une autre langue. Les autres variables qui entrent en jeu sont le niveau d'education du père, le nombre de frères et de soeurs, le sexe, l'âge au moment du depart de la maison et la raison de ce départ. L'article aborde aussi les questions des responsabilités et des rôles des parents autour de la cinquantaine, et de la socialisation au sein de la famille au cours de la vie. This article offers a focussed examination of variation in home‐returning behaviour among Canadian young adults. Framed within the life course perspective, we explore the interrelationships among family and cultural diversity, financial and social capital, and the timing and pathways of early transitions. Proportional hazards analyses are performed on a subsample of 2,549 young adults aged 19–34, using data from the 1995 General Social Survey, Cycle 10. A major finding is that those whose mother tongue is English are significantly more likely to return to the parental home than those with French or “other” mother tongues. Other variables include: father's education, number of siblings, gender, age at home‐leaving, and initial reason for home‐leaving. Implications for midlife parental roles and responsibilities, and for family socialization are discussed.  相似文献   
27.
28.
Building on prior research characterizing organizational effectiveness as a social construction, this article identifies the perceived attributes of effective transnational nongovernmental organizations (NGOs) and the leadership values associated with higher reputations for organizational effectiveness. Results are based on an in‐depth, mixed‐method interview study of 152 NGO leaders located in the United States and representing all major sectors of organizational activity. Among the twenty‐nine attributes that leaders identified in peer organizations that they regarded as particularly effective, leaders stressed instantiation of sound principles or strategy, a grassroots approach, large organizational size and resources, being collaborative, singleness of focus, campaigning abilities, funding and fundraising prowess, global scope, and quality people. Furthermore, statistical analysis reveals that NGOs with leaders who value similarities with peer organizations, grassroots approaches, diversity of strategies, dedication, professionalism, and distributed organizational structures have significantly higher reputations for effectiveness.  相似文献   
29.
Communication about risks offers a voluntary approach to reducing exposure to pollutants. Its adequacy depends on its impact on behavior. Estimating those impacts first requires characterizing current activities and their associated risk levels, and then predicting the effectiveness of risk-reduction strategies. Characterizing the risks from chemical consumer products requires knowledge of both the physical and the behavioral processes that influence exposures. This article presents an integrated approach that combines consumer interviews, users' beliefs and behaviors, and quantitative exposure modeling. This model was demonstrated in the context of consumer exposure to a methylene chloride-based paint stripper, showing how it could be used to evaluate current levels of risk and predict the effectiveness of proposed voluntary risk-reduction strategies.  相似文献   
30.
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