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   139篇
  免费   7篇
管理学   29篇
人口学   10篇
理论方法论   7篇
综合类   1篇
社会学   74篇
统计学   25篇
  2023年   2篇
  2020年   9篇
  2019年   6篇
  2018年   4篇
  2017年   7篇
  2016年   4篇
  2015年   7篇
  2014年   6篇
  2013年   14篇
  2012年   8篇
  2011年   12篇
  2010年   4篇
  2009年   2篇
  2008年   8篇
  2007年   5篇
  2006年   7篇
  2005年   3篇
  2004年   4篇
  2003年   3篇
  2002年   4篇
  2001年   3篇
  2000年   3篇
  1999年   5篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1989年   1篇
  1988年   1篇
  1982年   1篇
  1974年   1篇
排序方式: 共有146条查询结果,搜索用时 296 毫秒
1.
In the context of a pilot study the effects of the educational-psychological intervention Introvision were tested with older long-term unemployed people. The project was accomplished in the time by 1.4.2010 to 31.12.2010 in co-operation between ARGE Paderborn and the research group Introvision. In the context of the project 16 employees of ARGE Paderborn participated in an advanced training to Introvision, 31 customers of ARGE Paderborn began a coaching to get introduction in Introvision and 20 have also finished. Nine customers decided to participate five individual coachings. The results show, that the offers have a high individual use for the participants. To the central changes belong improved handling of stress, decrease of social isolation, improved (self-) perception as well as a higher self-confidence and a more open co-operation between customers and employees of ARGE Paderborn. Besides four participation began a job on the first labour market and two could be connected to a honorary activity.  相似文献   
2.
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   
3.
We propose a statistical inference framework for the component-wise functional gradient descent algorithm (CFGD) under normality assumption for model errors, also known as $$L_2$$-Boosting. The CFGD is one of the most versatile tools to analyze data, because it scales well to high-dimensional data sets, allows for a very flexible definition of additive regression models and incorporates inbuilt variable selection. Due to the variable selection, we build on recent proposals for post-selection inference. However, the iterative nature of component-wise boosting, which can repeatedly select the same component to update, necessitates adaptations and extensions to existing approaches. We propose tests and confidence intervals for linear, grouped and penalized additive model components selected by $$L_2$$-Boosting. Our concepts also transfer to slow-learning algorithms more generally, and to other selection techniques which restrict the response space to more complex sets than polyhedra. We apply our framework to an additive model for sales prices of residential apartments and investigate the properties of our concepts in simulation studies.  相似文献   
4.
In recent years, the decision to outsource information systems (IS) functions has become a viable strategic alternative in managing the increasingly complex IS functions. In this study, the IS outsourcing phenomenon is conceptualized as a strategic decision in the organization. Drawing on resource-based theories, resource dependence theories, and other theories of strategic management, a discrepancy model of this decision is developed. Relationships between a number of strategy-theoretic factors and the IS outsourcing decision are hypothesized. These factors include IS resource performance discrepancies manifested in the form of gaps in information quality, IS support quality, IS cost effectiveness and financial performance, as well as the strategic orientation of the firm. Results of the study indicate that, while cost consideration and the firm's financial performance are not associated with the IS outsourcing decision, difficulties in providing good information outputs and IS support services are associated with the decision. Overall, the findings suggest that the current trend toward outsourcing represents a continuing evolution of the IS function as it attempts to fulfill its traditional mission of providing high quality information resource to the firm. When the performance of the delivered resource begins to slip in the current environment of rising expectation and technological complexity, outsourcing may become a strategic response of necessity. The paper concludes with a discussion of the implications of the results for practicing managers and suggestions for future research.  相似文献   
5.
This article studies the extent to which educational services and schooling outcomes of local children are influenced by the presence of a refugee camp in or near their community. Investigating Congolese refugees in Rwanda and relying on a mixed‐method approach, we examine schooling rates and access to school‐based feeding programmes in communities closer to and further away from three refugee camps. We conduct cohort analyses to compare the schooling outcomes of Rwandans residing at different distances from each of these camps. Our results highlight that children residing closer to the camps have better schooling outcomes and that locals residing closer to the camps have mostly positive views regarding the effects of refugees on local education. These results contribute to the literature on the effects of refugees on host communities and inform policy debates on how refugees need not be a “burden” if a long‐term vision shapes educational investments.  相似文献   
6.
7.
8.
Urban Ecosystems - Green roofs have recently gained recognition for their potential contribution to urban ecosystems by providing, among other services, habitat for plants and animals, and stepping...  相似文献   
9.
10.
There is general consensus that physical activity is important for preserving functional capacities of older adults and positively influencing quality of life. While accelerometry is widely accepted and applied to assess physical activity in studies, several problems with this method remain (e.g., low retest reliability, measurement errors). The aim of this study was to test the intra-instrumental retest reliability of a wrist-worn accelerometer in a 3-day measurement of physical activity in older adults and to compare different estimators. A sample of 123 older adults (76.5?±?5.1?years, 59?% female) wore a uniaxial accelerometer continuously for 1?week. The data were split into two repeated measurement values (week set) of 3?days each. The sum, the 80?C99th quantiles and the 80?C99th trimmed sums were built for each week set. Retest reliability was assessed for each estimator and graphically demonstrated by Bland?CAltman plots. The intraclass correlation of the retest reliability ranged from 0.22 to 0.91. Retest reliability increases when a more robust estimator than the overall sum is used. Therefore, the trimmed sum can be recommended as a conservative estimate of the physical activity level of older adults.  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