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   1465篇
  免费   138篇
  国内免费   15篇
管理学   119篇
民族学   5篇
人口学   19篇
丛书文集   88篇
理论方法论   125篇
综合类   638篇
社会学   85篇
统计学   539篇
  2024年   3篇
  2023年   10篇
  2022年   19篇
  2021年   25篇
  2020年   24篇
  2019年   69篇
  2018年   58篇
  2017年   39篇
  2016年   51篇
  2015年   59篇
  2014年   65篇
  2013年   132篇
  2012年   88篇
  2011年   104篇
  2010年   81篇
  2009年   114篇
  2008年   104篇
  2007年   93篇
  2006年   66篇
  2005年   40篇
  2004年   43篇
  2003年   36篇
  2002年   36篇
  2001年   38篇
  2000年   18篇
  1999年   20篇
  1998年   14篇
  1997年   16篇
  1996年   10篇
  1995年   10篇
  1994年   17篇
  1993年   5篇
  1992年   6篇
  1991年   4篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1987年   3篇
  1986年   3篇
  1985年   8篇
  1984年   21篇
  1983年   12篇
  1982年   15篇
  1981年   6篇
  1980年   10篇
  1979年   4篇
  1978年   12篇
  1977年   1篇
排序方式: 共有1618条查询结果,搜索用时 31 毫秒
231.
Adverse childhood experiences might have long-lasting effects on decisions under uncertainty in adult life. Merging the European Survey on Health, Ageing and Retirement with data on conflict events during the Second World War, and relying on region-by-cohort variation in war exposure, we show that warfare exposure during childhood is associated with lower financial risk taking in later life. Individuals who experienced war episodes as children hold less – and are less likely to hold – stocks, but are more likely to hold life insurance, compared to non-exposed individuals. Effects are robust to the inclusion of potential mediating factors, and are tested for nonlinearity and heterogeneity. Moreover, we provide evidence of hedonic adaptation to war, as high and low intensity of war exposure have comparable long-term effects. We also document that war exposure in childhood increases sensitivity to financial uncertainty since exposed-to-war individuals are less likely to hold stocks after periods of high volatility. Finally, we shed light on the most likely mechanism in the relationship between war exposure and financial risk taking – i.e., enhanced sensitivity to uncertainty – and we show that preferences, and not beliefs, channel this relationship.  相似文献   
232.
《Risk analysis》2018,38(10):2029-2040
The Chippewa Ottawa Resource Authority monitors fish contaminants in Anishinaabe (Great Lake Native American) tribal fisheries. This article updates previously reported trends in two persistent bioaccumulative toxic (PBT) substances that are the primary contributors to consumption advisory limits for these fish: methylmercury (MeHg) and polychlorinated biphenyls (PCBs). Also, we report, for the first time, an analysis of nutritional benefit bioindicators and metrics in these same Upper Great Lakes fish harvests: selenium (Se) and omega‐3 fatty acids (PUFA‐3s). A novel risk/benefit quantification originally presented by Ginsberg et al. is reported here to characterize the tradeoffs between fatty acid benefits and toxic MeHg health outcomes. We also report a Se benefit metric to characterize the possible protective value against MeHg neurotoxicity based on Ralston et al. Congruent with Anishinaabe cultural motivations to consume fish from their ancestral fisheries, nutritional content was high in locally caught fish and, in some respects, superior to farmed/store‐bought fish. These Great Lakes fish still contained levels of PBTs that require careful education and guidance for consumers. However, the contaminant trends suggest that these fish need not be abandoned as important (both culturally and nutritionally) food sources for the Anishinaabe who harvested them.  相似文献   
233.
Generalized additive models provide a way of circumventing curse of dimension in a wide range of nonparametric regression problem. In this paper, we present a multiplicative model for conditional variance functions where one can apply a generalized additive regression method. This approach extends Fan and Yao (1998) to multivariate cases with a multiplicative structure. In this approach, we use squared residuals instead of using log-transformed squared residuals. This idea gives a smaller variance than Yu (2017) when the variance of squared error is smaller than the variance of log-transformed squared error. We provide estimators based on quasi-likelihood and an iterative algorithm based on smooth backfitting for generalized additive models. We also provide some asymptotic properties of estimators and the convergence of proposed algorithm. A numerical study shows the empirical evidence of the theory.  相似文献   
234.
In the nuclear power industry, Level 3 probabilistic risk assessment (PRA) is used to estimate damage to public health and the environment if a severe accident leads to large radiological release. Current Level 3 PRA does not have an explicit inclusion of social factors and, therefore, it is not possible to perform importance ranking of social factors for risk‐informing emergency preparedness, planning, and response (EPPR). This article offers a methodology for adapting the concept of social vulnerability, commonly used in natural hazard research, in the context of a severe nuclear power plant accident. The methodology has four steps: (1) calculating a hazard‐independent social vulnerability index for the local population; (2) developing a location‐specific representation of the maximum radiological hazard estimated from current Level 3 PRA, in a geographic information system (GIS) environment; (3) developing a GIS‐based socio‐technical risk map by combining the social vulnerability index and the location‐specific radiological hazard; and (4) conducting a risk importance measure analysis to rank the criticality of social factors based on their contribution to the socio‐technical risk. The methodology is applied using results from the 2012 Surry Power Station state‐of‐the‐art reactor consequence analysis. A radiological hazard model is generated from MELCOR accident consequence code system, translated into a GIS environment, and combined with the Center for Disease Control social vulnerability index (SVI). This research creates an opportunity to explicitly consider and rank the criticality of location‐specific SVI themes based on their influence on risk, providing input for EPPR.  相似文献   
235.
A frequency domain bootstrap (FDB) is a common technique to apply Efron’s independent and identically distributed resampling technique (Efron, 1979) to periodogram ordinates – especially normalized periodogram ordinates – by using spectral density estimates. The FDB method is applicable to several classes of statistics, such as estimators of the normalized spectral mean, the autocorrelation (but not autocovariance), the normalized spectral density function, and Whittle parameters. While this FDB method has been extensively studied with respect to short-range dependent time processes, there is a dearth of research on its use with long-range dependent time processes. Therefore, we propose an FDB methodology for ratio statistics under long-range dependence, using semi- and nonparametric spectral density estimates as a normalizing factor. It is shown that the FDB approximation allows for valid distribution estimation for a broad class of stationary, long-range (or short-range) dependent linear processes, without any stringent assumptions on the distribution of the underlying process. The results of a large simulation study show that the FDB approximation using a semi- or nonparametric spectral density estimator is often robust for various values of a long-memory parameter reflecting magnitude of dependence. We apply the proposed procedure to two data examples.  相似文献   
236.
Cooperation and competition are often viewed as incompatible, antagonistic forces, thus are operationalized as two extremes on a continuum. However, they can coexist and even enable each other, thus may be operationalized as orthogonal constructs. We address this contradictory phenomenon by developing a more granular view of the cooperation–competition paradox. Building on interdisciplinary research, we develop a three-dimensional model of relational space (fairness–opportunism, sharing–control, and engagement–rivalry), providing a novel tool with which to investigate the paradoxical interplay between cooperation and competition through eight operationalizable configurations. Using fuzzy-set qualitative comparative analysis (fsQCA), we test our model by assessing how different configurations of interfirm relationships influence the short- and long-term success of a sample of 217 firms. Our findings show that only two of the eight possible relational configurations are associated with firm success, one in both the long and short term, and the other in the short term only.  相似文献   
237.
采用由金属蒸汽真空弧离子源引出的强束流Zr,Zr+C离子对H13钢进行了离子束表面处理,借助划痕仪和摩擦试验机分别测量了经表面处理的H13钢的耐磨性和摩擦系数。研究结果表明:经Zr,Zr+C离子束处理的H13钢的耐磨性有所提高,摩擦系数明显降低,采用卢瑟福背散射谱(RBS)x射线衍射分析了注入层的成分,结构及影响其耐磨性的因素。  相似文献   
238.
面对3D打印技术发展进程中日益凸显的著作权法律问题,阐释3D打印数字模型在著作权法中的法律界定及保护范围,对3D打印数字模型究竟属于何种作品进行了探讨;指出3D数字模型到3D打印物的转换应为复制,以及3D数字模型和3D打印物的著作权侵权风险问题;提出应兼顾各方利益,对3D打印的著作权保护要在私人利益与公共利益之间寻找新的平衡.  相似文献   
239.
以倾向性贸易救济为代表的贸易保护主义对世界经济造成了强烈冲击,成为全球重点治理的领域。鉴于现时期G20的显著影响力和重要地位,从整体概况、调查与被诉国别、产品类别等层面,对G20贸易救济现状与特性进行梳理和分析,并提出G20参与全球贸易协调治理的对策建议,对于完善全球治理机制,推动国际贸易可持续发展具有重要实践意义。  相似文献   
240.
In this article, we address the testing problem for additivity in nonparametric regression models. We develop a kernel‐based consistent test of a hypothesis of additivity in nonparametric regression, and establish its asymptotic distribution under a sequence of local alternatives. Compared to other existing kernel‐based tests, the proposed test is shown to effectively ameliorate the influence from estimation bias of the additive component of the nonparametric regression, and hence increase its efficiency. Most importantly, it avoids the tuning difficulties by using estimation‐based optimal criteria, while there is no direct tuning strategy for other existing kernel‐based testing methods. We discuss the usage of the new test and give numerical examples to demonstrate the practical performance of the test. The Canadian Journal of Statistics 39: 632–655; 2011. © 2011 Statistical Society of Canada  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