全文获取类型
收费全文 | 459篇 |
免费 | 18篇 |
专业分类
管理学 | 149篇 |
民族学 | 3篇 |
人口学 | 25篇 |
丛书文集 | 1篇 |
理论方法论 | 37篇 |
综合类 | 2篇 |
社会学 | 177篇 |
统计学 | 83篇 |
出版年
2023年 | 8篇 |
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 16篇 |
2019年 | 17篇 |
2018年 | 28篇 |
2017年 | 26篇 |
2016年 | 26篇 |
2015年 | 12篇 |
2014年 | 28篇 |
2013年 | 43篇 |
2012年 | 24篇 |
2011年 | 38篇 |
2010年 | 23篇 |
2009年 | 18篇 |
2008年 | 23篇 |
2007年 | 26篇 |
2006年 | 17篇 |
2005年 | 17篇 |
2004年 | 14篇 |
2003年 | 12篇 |
2002年 | 19篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1980年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有477条查询结果,搜索用时 312 毫秒
21.
The purpose of this study is to investigate critical decisions when planning for product rollover at a manufacturing company, and how to organise these decisions. A literature review and a case study are used to develop a decision model. The findings indicate that product rollover can be organised in a five-phase decision model. The research quality is strengthened by a structured literature review, but it can be argued that more empirical research is needed for validation. For researchers, this paper contributes with the identification of critical decisions and a model for product rollover. For practitioners, the study highlights the need to acknowledge the importance of product rollover and its role as a competitive weapon. In earlier studies, product rollover has mainly been investigated from a market perspective, so that this study contributes by investigating the issue from a manufacturing perspective. 相似文献
22.
In make-to order production, schedule reliability is very important but still not sufficiently accomplished in industrial practice by the vast majority of companies. It has been known for long that processing the orders at a workstation in the order of their operation due-dates can compensate for lateness in the arrival at the workstation within certain boundaries. The paper analyses the effectiveness of earliest operation due date (EODD) sequencing by comparing it to an optimistic theoretical boundary. The surprising result is that EODD can nearly fully exploit the theoretical potential. It should therefore be used in practice whenever schedule reliability is important, with only few exceptions. Its effectiveness though is increasing with the workstation’s WIP level and thus is in conflict with the objective to reduce WIP levels and throughput times. A simple forecasting model allows to assess the extent to which lateness can be compensated by EODD sequencing and which schedule compliance can be achieved. 相似文献
23.
Several variable selection procedures are available for continuous time-to-event data. However, if time is measured in a discrete way and therefore many ties occur models for continuous time are inadequate. We propose penalized likelihood methods that perform efficient variable selection in discrete survival modeling with explicit modeling of the heterogeneity in the population. The method is based on a combination of ridge and lasso type penalties that are tailored to the case of discrete survival. The performance is studied in simulation studies and an application to the birth of the first child. 相似文献
24.
Elisa Perrone Andreas Rappold Werner G. Müller 《Statistical Methods and Applications》2017,26(3):403-418
Optimum experimental design theory has recently been extended for parameter estimation in copula models. The use of these models allows one to gain in flexibility by considering the model parameter set split into marginal and dependence parameters. However, this separation also leads to the natural issue of estimating only a subset of all model parameters. In this work, we treat this problem with the application of the \(D_s\)-optimality to copula models. First, we provide an extension of the corresponding equivalence theory. Then, we analyze a wide range of flexible copula models to highlight the usefulness of \(D_s\)-optimality in many possible scenarios. Finally, we discuss how the usage of the introduced design criterion also relates to the more general issue of copula selection and optimal design for model discrimination. 相似文献
25.
We deal with the double sampling plans by variables proposed by Bowker and Goode (Sampling Inspection by Variables, McGraw–Hill,
New York, 1952) when the standard deviation is unknown. Using the procedure for the calculation of the OC given by Krumbholz and Rohr (Allg.
Stat. Arch. 90:233–251, 2006), we present an optimization algorithm allowing to determine the ASN Minimax plan. This plan, among all double plans satisfying
the classical two-point-condition on the OC, has the minimal ASN maximum. 相似文献
26.
Street trees planted at tree pits with impermeable pavements are exposed to a high level of both, atmospheric and edaphic stress. For many species tree physiology, optimal growth, and consequently long-term vitality may be hampered under these harsh conditions. Therefore, maintaining the vitality and promoting the ecosystem services provided by urban trees, for example aesthetic values and microclimatic benefits, it is important to establish trees with a high tolerance to stressful urban environments. Measurements of leaf gas exchange, leaf water potential, leaf surface temperature and chlorophyll-fluorescence were used for identification of specific response of Corylus corluna L., Ginkgo biloba L., Liriodendron tulipifera L., and Tilia cordata Mill. ‘Greenspire’. The summer months in 2013 with a period of heat and drought over eight weeks only interrupted by two rainy days were appropriate to access tree’s strategies to cope with low water availability. During the measurement period, the influence of high temperatures, high values of vapor pressure deficit (VPD) and low soil water availability on stomatal conductance, water-use efficiency (WUE) and leaf water potential (Ψmin, Ψmax ) was highest for Liriodendron followed by Ginkgo. These species showed high reductions in WUE in case of higher air temperatures and high values of VPD. Results indicate an avoidance strategy under increasing heat and VPD. In contrast, Corylus and Tilia followed a tolerance strategy indicated by decreasing values of Ψmin and lower reductions of WUE. In conclusion, wide species-specific variation in response to high temperatures and high VPD indicates that substantial potential exists in the selection for dry and hot urban places. 相似文献
27.
Career Engagement: Investigating Intraindividual Predictors of Weekly Fluctuations in Proactive Career Behaviors
下载免费PDF全文
![点击此处可从《The Career development quarterly》网站下载免费的PDF全文](/ch/ext_images/free.gif)
This study applied a microlevel perspective on how within‐individual differences in motivational and social‐cognitive factors affected the weekly fluctuations of engagement in proactive career behaviors among a group of 67 German university students. Career self‐efficacy beliefs, perceived career barriers, experienced social career support, positive and negative emotions, and career engagement were assessed weekly for 13 consecutive weeks. Hierarchical linear regression analyses showed that above average levels of career engagement within individuals were predicted by higher than average perceived social support and positive emotions during a given week. Conversely, within‐individual differences in self‐efficacy, barriers, and negative emotions had no effect. The results suggest that career interventions should provide boosts in social support and positive emotions. 相似文献
28.
29.
Summary: Wald statistics in generalized linear models are asymptotically 2 distributed.
The asymptotic chi–squared law of the corresponding quadratic form shows disadvantages
with respect to the approximation of the finite–sample distribution. It is shown by means
of a comprehensive simulation study that improvements can be achieved by applying
simple finite–sample size approximations to the distribution of the quadratic form in
generalized linear models. These approximations are based on a 2 distribution with an
estimated degree of freedom that generalizes an approach by Patnaik and Pearson. Simulation studies confirm that nominal level is maintained with higher accuracy compared
to the Wald statistics. 相似文献
30.