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   431篇
  免费   16篇
管理学   90篇
民族学   3篇
人才学   2篇
人口学   28篇
丛书文集   2篇
理论方法论   48篇
综合类   5篇
社会学   225篇
统计学   44篇
  2022年   3篇
  2021年   4篇
  2019年   9篇
  2018年   8篇
  2017年   9篇
  2016年   10篇
  2015年   12篇
  2014年   16篇
  2013年   50篇
  2012年   18篇
  2011年   12篇
  2010年   10篇
  2009年   8篇
  2008年   10篇
  2007年   16篇
  2006年   11篇
  2005年   15篇
  2004年   10篇
  2003年   10篇
  2002年   13篇
  2001年   8篇
  2000年   5篇
  1999年   3篇
  1998年   13篇
  1997年   11篇
  1996年   12篇
  1995年   7篇
  1994年   13篇
  1993年   10篇
  1992年   8篇
  1991年   10篇
  1990年   7篇
  1989年   5篇
  1988年   5篇
  1987年   6篇
  1986年   5篇
  1985年   7篇
  1984年   9篇
  1983年   5篇
  1982年   2篇
  1981年   6篇
  1980年   2篇
  1979年   2篇
  1978年   6篇
  1977年   9篇
  1976年   2篇
  1975年   2篇
  1974年   3篇
  1973年   3篇
  1972年   2篇
排序方式: 共有447条查询结果,搜索用时 0 毫秒
1.
Urban Ecosystems - The development of urban areas imposes challenges that wildlife must adapt to in order to persist in these new habitats. One of the greatest changes brought by urbanization has...  相似文献   
2.
The authors present three educational approaches designed to demystify the writing process and to support better writing skills among family therapists. One framework is an academic course in professional writing, another is a writing seminar for family therapy and physician trainees within a medical school setting, and the third is a 2-hour continuing education writing workshop for family therapists. Each is replicable within a variety of settings.  相似文献   
3.
4.
Fatigue is a critical issue for nurses that may lead to medical errors, degradation in performance, decreased mental acuity, and social problems. Poor sleep quality is also a contributing factor in fatigue that nurses experience. Therefore, the purpose of this study was to examine the differences in perceptions of fatigue between night-shift and day-shift nurses, as measured by scores on the Brief Fatigue Inventory (BFI) and to examine differences in sleep quality between the two groups, as measured by responses on the Pittsburgh Sleep Quality Index (PSQI). Univariate analysis of variance showed significant differences between the two groups on the BFI, with the night-shift cohort reporting higher mean scores on the BFI. Significant differences were also found between the two groups on PSQI mean scores, with the night-shift cohort reporting higher mean scores. Findings from this study suggest that night-shift nurses, compared with day-shift nurses, perceived a much higher level of fatigue and had poorer sleep quality. Further research is needed to evaluate interventions that might decrease fatigue in nurses and improve their sleep quality.  相似文献   
5.
Deterministic goal programs for employee scheduling decisions attempt to minimize expected operating costs by assigning the ideal number of employees to each feasible schedule. For each period in the planning horizon, managers must first determine the amount of labor that should be scheduled for duty. These requirements are often established with marginal analysis techniques, which use estimates for incremental labor costs and shortage expenses. Typically, each period in the planning horizon is evaluated as an independent epoch. An implicit assumption is that individual employees can be assigned to schedules with as little as a single period of work. If this assumption violates local work rules, the labor requirements parameters for the deterministic goal program may be suboptimal. As we show in this research, this well-known limitation can lead to costly staffing and scheduling errors. We propose an employee scheduling model that overcomes this limitation by integrating the labor requirements and scheduling decisions. Instead of a single, externally determined staffing goal for each period, the model uses a probability distribution for the quantity of labor required. The model is free to choose an appropriate staffing level for each period, eliminating the need for a separate goal-setting procedure. In most cases this results in better, less costly decisions. In addition, the proposed model easily accommodates both linear and nonlinear under- and overstaffing penalties. We use simple examples to demonstrate many of these advantages and to illustrate the key techniques necessary to implement our model. We also assess its performance in a study of more than 1,700 simulated stochastic employee scheduling problems.  相似文献   
6.
Despite advances in decision analysis and decision support systems, few formulaic procedures exist for undertaking problem formulation, particularly in group settings. This leaves managers with little procedural support for the important task of carefully structuring problems. In a laboratory experiment of 29 intact student teams, we contrasted two problem formulation methodologies: a structured argument approach (based on application of formal reasoning) and a group process approach (based on private idea generation prior to public sharing and evaluation of ideas). The structured argument approach took more time to use and failed to bring about more information search and equivocality reduction in group discussions. On the positive side, however, the structured argument approach led to a greater combination of both coverage of critical issues and consensus on those issues. Use of the structured argument approach also resulted in higher satisfaction with the problem definition and commitment to implementing results of the group meeting. Overall, the results reveal cost/benefit tradeoffs associated with developing argumentation-based procedures for problem formulation.  相似文献   
7.
8.
In quantitative trait linkage studies using experimental crosses, the conventional normal location-shift model or other parameterizations may be unnecessarily restrictive. We generalize the mapping problem to a genuine nonparametric setup and provide a robust estimation procedure for the situation where the underlying phenotype distributions are completely unspecified. Classical Wilcoxon–Mann–Whitney statistics are employed for point and interval estimation of QTL positions and effects.  相似文献   
9.
The effects of different sales strategies on consumer product evaluation were investigated. It was expected that direct product experience could decrease economic product valuation. Experiments 1 and 2 studied the effects of product trials and money-back guarantees on consumer willingness to pay (WTP). It appeared that WTP was significantly lower after a product trial than with a money-back guarantee or normal sale. In Experiment 3 a structural equation model showed that product trials had a positive effect on attitude toward the product. Also, a negative effect on WTP was found when the effect was measured directly, but a positive effect when the effect was measured indirectly (through attitude).  相似文献   
10.
Discriminant analysis is relevant to business decision making in a variety of contexts, such as when one decides to make or buy a specified component, fund a venture project, or hire a particular person. Potential applications in artificial intelligence, particularly in the area of pattern recognition, have further underscored the importance of the field. A recent innovation in discriminant analysis is provided by special linear programming (LP) models, which offer attractive alternatives to classical statistical approaches. The scope of application in which discriminant analysis can be advantageously employed is broadened by the flexibility to tailor parameters in the LP approaches to reflect diverse goals and by the power to explore the sensitivity of these parameters. In spite of the promise of the LP formulations, however, limitations to their effectiveness have been uncovered in certain settings. A recent advance involving a normalization construct removes some of the limitations but entails solving the LP model twice (to allow for different signs of a normalization constant) and does not yield equivalent solutions for different rotations of the problem data. This paper introduces a new model and a new class of normalizations that remedy both remaining limitations, making it possible to take advantage of the modeling capabilities of the LP formulations without the attendant shortcomings encountered by earlier investigations. Our development shows by empirical testing and illustrative analysis that the quality of solutions from LP discriminant approaches is more favorable (relative to the classical model) than previously supposed.  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