全文获取类型
收费全文 | 3040篇 |
免费 | 114篇 |
专业分类
管理学 | 481篇 |
民族学 | 24篇 |
人才学 | 1篇 |
人口学 | 269篇 |
丛书文集 | 27篇 |
理论方法论 | 308篇 |
综合类 | 34篇 |
社会学 | 1596篇 |
统计学 | 414篇 |
出版年
2023年 | 24篇 |
2022年 | 18篇 |
2021年 | 30篇 |
2020年 | 72篇 |
2019年 | 77篇 |
2018年 | 91篇 |
2017年 | 129篇 |
2016年 | 116篇 |
2015年 | 84篇 |
2014年 | 93篇 |
2013年 | 460篇 |
2012年 | 126篇 |
2011年 | 112篇 |
2010年 | 75篇 |
2009年 | 96篇 |
2008年 | 90篇 |
2007年 | 77篇 |
2006年 | 83篇 |
2005年 | 98篇 |
2004年 | 97篇 |
2003年 | 86篇 |
2002年 | 86篇 |
2001年 | 85篇 |
2000年 | 70篇 |
1999年 | 51篇 |
1998年 | 38篇 |
1997年 | 33篇 |
1996年 | 47篇 |
1995年 | 36篇 |
1994年 | 34篇 |
1993年 | 52篇 |
1992年 | 39篇 |
1991年 | 35篇 |
1990年 | 26篇 |
1989年 | 22篇 |
1988年 | 24篇 |
1987年 | 24篇 |
1986年 | 23篇 |
1985年 | 22篇 |
1984年 | 32篇 |
1983年 | 24篇 |
1982年 | 28篇 |
1981年 | 20篇 |
1980年 | 20篇 |
1979年 | 21篇 |
1978年 | 13篇 |
1977年 | 22篇 |
1975年 | 21篇 |
1974年 | 19篇 |
1973年 | 10篇 |
排序方式: 共有3154条查询结果,搜索用时 734 毫秒
71.
The prediction error for mixed models can have a conditional or a marginal perspective depending on the research focus. We introduce a novel conditional version of the optimism theorem for mixed models linking the conditional prediction error to covariance penalties for mixed models. Different possibilities for estimating these conditional covariance penalties are introduced. These are bootstrap methods, cross-validation, and a direct approach called Steinian. The behavior of the different estimation techniques is assessed in a simulation study for the binomial-, the t-, and the gamma distribution and for different kinds of prediction error. Furthermore, the impact of the estimation techniques on the prediction error is discussed based on an application to undernutrition in Zambia. 相似文献
72.
73.
Over the last decade the health and environmental research communities have made significant progress in collecting and improving access to genomic, toxicology, exposure, health, and disease data useful to health risk assessment. One of the barriers to applying these growing volumes of information in fields such as risk assessment is the lack of informatics tools to organize, curate, and evaluate thousands of journal publications and hundreds of databases to provide new insights on relationships among exposure, hazard, and disease burden. Many fields are developing ontologies as a way of organizing and analyzing large amounts of complex information from multiple scientific disciplines. Ontologies include a vocabulary of terms and concepts with defined logical relationships to each other. Building from the recently published exposure ontology and other relevant health and environmental ontologies, this article proposes an ontology for health risk assessment (RsO) that provides a structural framework for organizing risk assessment information and methods. The RsO is anchored by eight major concepts that were either identified by exploratory curations of the risk literature or the exposure‐ontology working group as key for describing the risk assessment domain. These concepts are: (1) stressor, (2) receptor, (3) outcome, (4) exposure event, (5) dose‐response approach, (6) dose‐response metric, (7) uncertainty, and (8) measure of risk. We illustrate the utility of these concepts for the RsO with example curations of published risk assessments for ionizing radiation, arsenic in drinking water, and persistent pollutants in salmon. 相似文献
74.
75.
Journal of Risk and Uncertainty - There are many possible connections between the value of statistical life (VSL) and behavioral economics. A list of topics includes endowment effects, risk... 相似文献
76.
Thomas Muehlenstaedt Olivier Roustant Laurent Carraro Sonja Kuhnt 《Statistics and Computing》2012,22(3):723-738
Kriging models have been widely used in computer experiments for the analysis of time-consuming computer codes. Based on kernels,
they are flexible and can be tuned to many situations. In this paper, we construct kernels that reproduce the computer code
complexity by mimicking its interaction structure. While the standard tensor-product kernel implicitly assumes that all interactions
are active, the new kernels are suited for a general interaction structure, and will take advantage of the absence of interaction
between some inputs. The methodology is twofold. First, the interaction structure is estimated from the data, using a first
initial standard Kriging model, and represented by a so-called FANOVA graph. New FANOVA-based sensitivity indices are introduced
to detect active interactions. Then this graph is used to derive the form of the kernel, and the corresponding Kriging model
is estimated by maximum likelihood. The performance of the overall procedure is illustrated by several 3-dimensional and 6-dimensional
simulated and real examples. A substantial improvement is observed when the computer code has a relatively high level of complexity. 相似文献
77.
Social Indicators Research - The registers of Dublin’s parishes in the seventeenth century provide access to aspects of civic and religious life. In the registers are records of burials,... 相似文献
78.
Thomas Zimmerfaust 《Economic inquiry》2018,56(2):1278-1295
Using data from the Major League Baseball free‐agent market, this study is the first to show that the productivity expected of the team a worker will join produces a significant, negative compensating wage differential. The younger workers in the sample drive this result, trading 25% of their wages to join teams with an expected productivity one standard deviation higher. This investment can be recouped if a reasonable increase in human capital occurs. These results are robust to contract length‐wage simultaneity and indicate that investment in human capital motivates the observed tradeoff, suggesting a new pathway through which human capital accumulation can affect wages. Reliable measures of workers' own past productivity and the productivity expected of a worker's future team provide key advantages to identifying these effects. (JEL J31, J24, M54) 相似文献
79.
Demographic change and shifting views about marine resources and the coastal environment in Downeast Maine 总被引:1,自引:0,他引:1
Connections to the sea often define the character of coastal towns. However, as migrants arrive and economic diversification occurs, views about the use of marine resources and the ocean environment can change. Using survey data from Maine, we examined whether shifting demographics affect public perceptions of marine resource uses and coastal environmental concerns. We tested resource use and environmental items against a common set of demographic, background, and place-related variables. Results indicate that the level of education and the county of residence predict Mainers?? views about different marine resource uses and ocean-related environmental issues. Political party affiliation strongly influences environmental concern but not views about the use of marine resources. Migration history, on the other hand, has little effect. Understanding community contexts as well as individual background and ideological orientations will be critical as managers attempt to balance alternative uses of marine resources and resolve coastal environmental problems. 相似文献
80.