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   2376篇
  免费   187篇
  国内免费   6篇
财政金融   221篇
工业经济   157篇
计划管理   651篇
经济学   402篇
综合类   259篇
运输经济   32篇
旅游经济   52篇
贸易经济   189篇
农业经济   418篇
经济概况   188篇
  2024年   1篇
  2023年   15篇
  2022年   37篇
  2021年   52篇
  2020年   79篇
  2019年   53篇
  2018年   47篇
  2017年   75篇
  2016年   54篇
  2015年   96篇
  2014年   194篇
  2013年   262篇
  2012年   218篇
  2011年   285篇
  2010年   210篇
  2009年   155篇
  2008年   177篇
  2007年   130篇
  2006年   122篇
  2005年   98篇
  2004年   62篇
  2003年   42篇
  2002年   28篇
  2001年   18篇
  2000年   23篇
  1999年   7篇
  1998年   10篇
  1997年   5篇
  1996年   4篇
  1995年   1篇
  1994年   2篇
  1993年   3篇
  1990年   1篇
  1988年   1篇
  1985年   1篇
  1983年   1篇
排序方式: 共有2569条查询结果,搜索用时 15 毫秒
1.
为了减小传统施工安全评价方法中主观因素过大对风险评价结果的不利影响,针对水电工程施工安全事故的动态性、随机性和模糊性特点,构建水电工程施工安全评价指标体系。通过引入人工神经网络理论,并运用MATLAB辅助设计评价模型,对水电工程施工安全进行评价。应用实例说明:该评价方法具有较高的准确性和可靠性,对于水电工程施工安全评价具有一定的应用价值。  相似文献   
2.
高校扩招后,高校教学低效成为突出问题,其原因体现在教育体制存在弊端,考核评价体系不科学,教师和学生自身出现的问题。提高教学质量,重视科研到教学与科研并重,是培养学生综合能力,提高教师教学技能的重要途径。  相似文献   
3.
Birdstrikes are a major hazard to aviation; costing millions of pounds a year in damage and delays, as well as occasional hull losses and loss of life. The numbers and species of birds on and around airfields therefore need to be managed. To aid this process, airport staff often use risk assessments to identify which bird species cause the greatest risk and use the outcome to target their bird control effort. To this end, a number of national and international regulators, airports and other organisations recommend, or use, a derivation of a risk assessment process first published in 2006. This was developed using the UK Civil Aviation Authority's birdstrike database, employing data collected between 1976 and 1996. The risk assessment process relies on using the proportion of reported strikes that cause damage to the aircraft as a proxy for the likely severity of the outcome of strike incidents, so any change in the relative level of reporting of damaging and non-damaging strikes may significantly bias the results. The implementation of mandatory birdstrike reporting by the UK CAA in 2004 led to a significant increase in the number of strikes reported. If this involved a disproportionate increase in the number of non-damaging compared to damaging incidents reported, it may have impacted on the accuracy of the risk assessment process. This paper examines how differential reporting of damaging and non-damaging strikes can impact on the risk assessment process. It shows that changes in reporting practices since the original risk assessment was developed have impacted on the apparent birdstrike risk at UK airports, giving a false impression of increasing risk over the period. It makes recommendations for how the process can be better adapted to cope with such changes in the future, and how it should be modified for use in countries with different reporting regimes to that in the UK.  相似文献   
4.
Road development in mountainous forestlands can lead to naturally formed slopes being disturbed. Efficient planning methodologies can assist forest engineers in either preventing or reducing the environmental impacts of forest roads. In this study, we first prepared an inclusive landslide susceptibility map for our study area using a Bayesian model. We next designed 12 road network alternatives using PEGGER, an ArcView GIS extension. We extracted the values of these alternatives from the susceptibility map to evaluate their environmental feasibility. We also evaluated the alternatives from an economic perspective using a model for conducting cost estimates of the forest roads. Our results show that this approach is useful for identifying the alternative that meets environmental and economic goals. The policy implications of this study suggest that if the development of road networks in mountainous areas is an important forestry goal, mechanisms should be aimed primarily at controlling slope instability.  相似文献   
5.
Indian apparel retail industry is on a complete transformation journey and trying to evolve as an organized industry. It is very common to find the disruption factors in every business and the ways to mitigate and manage them is of current research interest. The paper discusses the selective risks associated with the apparel retail supply chains in India by structural analysis of the controllable risks that are identified. The work also reveals the use of Interpretative Structural Modeling (ISM) to establish the interdependencies between these risks spread across various supply chain functions of retail industry. The relationships are established based on expert opinions using Delphi technique followed by ISM modeling technique and Fuzzy MICMAC analysis. It also classifies the risk factors based on their driving and dependence power. ISM is proved to be a useful tool to help understand the impact of risks at stages of retail supply chain. Globalization, labor issues and security and safety of resources turns out to be the strong drivers of other supply chain uncertainties. The domino effect of these risks leads to financial crises for the organization.The paper also proposes a new model for the Risk Priority Number (RPN) calculation using ISM and Fuzzy MICMAC methodology for the applications in retail and various other domain risk studies. The sample size of experts is small and to remove the biasness of opinion, the model can be further validated using Structural Equation Modeling (SEM) in the future. The outcome would help practicing managers to analyze and to take actions for managing the factors by improving the bottom line of the organization by proper utilization of resources.  相似文献   
6.
In relative performance evaluation systems, appraisers may choose to adopt stricter or laxer evaluation criteria. When laxer (vs. stricter) criteria are used, higher absolute performance evaluations become easier (vs. harder) to achieve. Thus, each appraisee's absolute performance feedback and the mean of the distribution of absolute performance feedback are shifted upward (vs. downward). Yet, relative performance remains constant. When evaluation outcomes depend solely on relative performance, can the adoption of laxer (vs. stricter) criteria—leading to higher absolute performance feedback but no change in relative performance—influence appraisees’ satisfaction with performance? Despite the ubiquity of such systems in organizations, research has not addressed this question. This article points to an important gap between practitioners’ beliefs and research findings. We show that while most appraisers believe that higher absolute performance feedback will automatically result in more satisfaction with performance, the opposite may also happen. Specifically, we find that appraisees with a stronger (vs. weaker) chronic or contextual need to engage in social comparison are more satisfied with lower (vs. higher) absolute performance feedback. Overall, we demonstrate why and how feedback interventions in relative performance evaluation systems may backfire, and suggest a set of practical guidelines for maximizing appraisees’ satisfaction with performance in such systems. © 2015 Wiley Periodicals, Inc.  相似文献   
7.
近年来,环境严重污染,资源的枯竭,发展新能源是大势所趋。太阳能作为新能源发展的重点,这几年飞速的发展。但太阳能具有不稳定性、利用的高成本性等问题,使得太阳能发电存在着一定的风险。立足于太阳能发电项目投资建设中出现的问题,构建指标体系对太阳能发电项目风险进行分析识别,提出控制太阳能发电项目风险的对策建议。对投资太阳能发电项目风险控制具有重要意义。  相似文献   
8.
Landscape is defined by the European Landscape Convention as “an area perceived by people, whose character is the result of the action and interaction of natural and/or human factors”. Many efforts have been devoted in addressing the core concepts on which this definition roots: perception and interaction of men and nature, but when coming to large (continental) scale assessments, the latter prevail on the former.This paper aims at presenting a framework for a measurable landscape awareness indicator as a key link to the public demand for a specific type of landscape: the agricultural landscape. This is a necessary effort to complement more physically based assessments, which include as well the impact of human activities on landscapes.The analysis is carried out at different levels of governance: EU and regional, using an example from the Alentejo region in Portugal and EU wide databases, and addresses conceptual and practical questions: what type of societal landscape awareness can be monitored and by whom (e.g., individuals, specific social groups, society as a whole); what are the landscape dimensions that should be assessed; what are the limitations imposed by data-related constraints. By applying the methodology to build composite indicators to map landscape societal awareness, the paper shows the regional and local meaning of indicator approaches developed at European level, presents developments for downscaling to regional level, while introducing the social component to support sound policy development for European rural landscapes.  相似文献   
9.
Though most landscape ecologists have integrated scaling issues in their works, these issues are often disregarded in landscape perception and preference studies. Researchers base their studies on a predefined single scale to assess the landscape, and they pay little attention to the scale specificity of their analysis and recommendations. We reconsidered three landscape assessment studies from our research unit in light of scaling issues. In addition to the scale of the assessed landscape, researchers should address the scale of the landscape surrogate that is submitted for assessment, including the spatial references of the people surveyed and the target level of application of the results. Indeed, many of the landscape assessment methods mix different landscape notions and scales. Therefore, we recommend the cautious use of these assessments, the integration of qualitative insights in addition tithe scoring and paying attention to the perception scale, as defined by Fairclough (2006).  相似文献   
10.
In this study, ten bioenergy crop rotations (corn, corn-stover, sorghum, soybean, corn-soybean, corn-soybean-canola, corn-stover-soybean, miscanthus, switchgrass, and sorghum-soybean) were selected based on local stakeholder (economically motivated) and regulator (environmentally motivated) preferences. These crops were implemented on diverse landscapes (agricultural, marginal, and agricultural plus marginal lands) one at time for 17 years using a SWAT model of the Saginaw River Watershed in Michigan. The bioenergy crops were evaluated based on 100 percent, 50 percent, and zero percent weight assigned to both stakeholders’ and regulators’ preferences using analytic hierarchy process (AHP), an optimization and decision-making technique that aims to satisfy multiple conflicting objectives. The corn-soybean-canola rotation was selected in all landscapes based on economic benefits (stakeholders’ preferences). Meanwhile, perennial grasses (miscanthus and switchgrass) were selected based on environmental benefits (regulators’ preferences), because they maintain permanent cover, require fewer inputs than traditional row crops, and are less management intensive. When implementing bioenergy crops on marginal lands, pollution generation greatly increased at the field level, indicating that these lands are likely not viable for bioenergy crop production to meet potential future renewable energy demand.  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