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   59091篇
  免费   1858篇
  国内免费   772篇
财政金融   4454篇
工业经济   2666篇
计划管理   14137篇
经济学   9587篇
综合类   10133篇
运输经济   565篇
旅游经济   1271篇
贸易经济   7729篇
农业经济   3931篇
经济概况   7248篇
  2024年   76篇
  2023年   715篇
  2022年   903篇
  2021年   1517篇
  2020年   1853篇
  2019年   1264篇
  2018年   1135篇
  2017年   1236篇
  2016年   1325篇
  2015年   1541篇
  2014年   4343篇
  2013年   5288篇
  2012年   5076篇
  2011年   6253篇
  2010年   4652篇
  2009年   3800篇
  2008年   3914篇
  2007年   3370篇
  2006年   3336篇
  2005年   2436篇
  2004年   1709篇
  2003年   1518篇
  2002年   1059篇
  2001年   982篇
  2000年   674篇
  1999年   408篇
  1998年   208篇
  1997年   179篇
  1996年   149篇
  1995年   112篇
  1994年   100篇
  1993年   72篇
  1992年   61篇
  1991年   51篇
  1990年   33篇
  1989年   20篇
  1988年   27篇
  1987年   6篇
  1986年   6篇
  1985年   73篇
  1984年   80篇
  1983年   53篇
  1982年   44篇
  1981年   18篇
  1980年   17篇
  1979年   16篇
  1978年   6篇
  1977年   6篇
  1973年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
This study evaluates a wide range of machine learning techniques such as deep learning, boosting, and support vector regression to predict the collection rate of more than 65,000 defaulted consumer credits from the telecommunications sector that were bought by a German third-party company. Weighted performance measures were defined based on the value of exposure at default for comparing collection rate models. The approach proposed in this paper is useful for a third-party company in managing the risk of a portfolio of defaulted credit that it purchases. The main finding is that one of the machine learning models we investigate, the deep learning model, performs significantly better out-of-sample than all other methods that can be used by an acquirer of defaulted credits based on weighted-performance measures. By using unweighted performance measures, deep learning and boosting perform similarly. Moreover, we find that using a training set with a larger proportion of the dataset does not improve prediction accuracy significantly when deep learning is used. The general conclusion is that deep learning is a potentially performance-enhancing tool for credit risk management.  相似文献   
52.
More than 25 years after the German reunification, data show that products/brands from the eastern regions of Germany (“Neue Länder”) still do not have significant shares in the country's western part (“Alte Länder”). To analyze potential reasons for this phenomenon, our current study replicates a previous study that investigated selected attitudes of Alte Länder consumers toward products/brands from the Neue Länder. It is shown that factors such as consumer ethnocentrism, product judgment, willingness to buy, and economic animosity continue to influence consumer behavior and as such our study offers potential explanation for the failure of Neue Länder products/brands in the western regions of Germany.  相似文献   
53.
ABSTRACT

This article recounts three stories from TEFI’s walking workshop in Nepal: the construction of a road through what was once a trekking path; a dance-floor encounter at a Himalayan party; and the arrival of one participant, fatigued by jet lag and disoriented by the new surroundings. These stories of confusion, discomfort and fear are linked by one common theme: the potential of uncertainty to foster deep reflection and nuanced conclusions. The premise that uncertainty is to be valued and even cultivated has been explored in educational theory, spiritual traditions, and research on transformative learning. These sources affirm the role of uncertainty in the process of knowledge creation. However, accepting this role can be challenging for educators because it requires they assume a new identity, one which they may perceive as being at odds with their status as “teacher” the identity of learner. One way for the educator to address this challenge may be through recounting their own stories of uncertainty. Stories of being immersed in unfamiliar situations that challenge, confuse and even frighten – stories, in other words of being a tourist – can foster reflection on an intellectual, emotional and spiritual level, engaging the “whole” person, and thus initiating the educator/learner’s transformative journey.  相似文献   
54.
以长春市为研究对象,基于未来经济处于新常态的发展态势,构建包含水资源、社会、经济、生态环境4个子系统的评价指标体系,并确定各指标的评价等级标准;基于模糊数学理论以及层次分析法构建包括目标层、准则层、指标层的3层模糊综合评价模型,以2015年为现状水平年,应用模型对长春市水资源开发利用潜力进行综合评价。结果表明:长春市水资源开发利用程度处于中等偏上水平,各辖区水资源开发利用规模不平衡,可通过产业结构调整提高全市用水效率,为经济持续增长提供保障。  相似文献   
55.
The paper explores the emergence of street-level public service integration in eight cities, in five countries using a new framework: services-as-a-system to explore new public governances in health and social care integration. Data is analysed from eight cities in six countries (Australia, Canada, The Netherlands, Spain, UK, and USA) gathered in over 100 semi-structured interviews with key agents. We show that whilst culture and context shape the form and processes of governances there are underlying processual drivers of new public governances, in particular where users are involved in the co-design and co-production of integrated services.  相似文献   
56.
We model market integration in the Middle East and Africa by analyzing price dispersion and testing the law of one price (LOP) on highly-comparable actual local retail prices of 135 goods and services across 23 countries in the region over the period of 1990–2016. Second-generation panel estimators are applied to four price benchmarks: Regional average, South Africa, China, and US prices. Cross-regional price dispersion diminishes considerably over time up to 2008, particularly for non-tradeables around China price. The test of LOP indicates the percentage of convergent prices is highest in China price benchmark, followed by US, South Africa, and regional average benchmarks. Direct estimation of the convergence speed confirms this order. Overall, the results show evidence of increasing market integration in Middle East and Africa but it appears to be driven by global forces and, especially, the rise of China as a new economic power. The results show that some emerging market economies, such as China, can step up and promote integration while traditional economic powerhouses, such as the USA and UK, disengage from international economic relations.  相似文献   
57.
ABSTRACT

Natural language query systems over RDF data need to rely on the semantic relations in query. First, we propose the new crowdsourcing model that used to produce semantic relations dataset. The model not only inherits completeness of the iterative model and accuracy of the parallel model, but also saves human resources. Second, we mine the rules of semantic relation recognition from the correlations between dependency structures and semantic relations. Third, we propose an algorithm of semantic relation recognition for natural language query over RDF data, and experiments demonstrate that it can recognize more semantic relations than existing methods.  相似文献   
58.
郑爽  李国良  李铁 《科技和产业》2021,21(6):233-236
针对工程招标投标领域存在的突出问题,昆明市近几年在工程招标投标监管方面进行了许多新的探索.从昆明市招标投标监管机构设置、标前监管、标中监管、标后监管4个角度对昆明市工程招标投标监管现状进行分析,并对工程招标投标监管领域的一些新趋势进行探讨,提出强化招标投标监管的建议.新技术为招标投标监管提供了新工具,需要进一步探索新技术在招标投标监管领域的应用.  相似文献   
59.
60.
零售业自营与联营之争由来已久,在当前供给侧结构性改革、完善促进消费体制机制以及零售业寻求创新发展的背景下,有必要对这一问题展开进一步的理论探讨。文章结合马克思流通经济理论指出,自营和联营的本质区别在于是商业资本还是产业资本承担商品流通职能,自营和联营并不是非此即彼的互斥关系,但如果零售业完全倚重其中一种模式并在全社会推向极端,则需要反思商业资本和产业资本是否各得其所和高效分工。在中国流通体制变革中,虽然联营模式在特定历史时期帮助众多零售企业渡过生存危机并推进内资零售快速扩张,但发展至今,已呈现零售业普遍联营的情况,使零售业整体面临着制约创新发展的新问题。数字经济为零售业回归自营提供了有利契机,零售企业应充分利用新技术摆脱联营制的路径依赖,依托数字化开展深度自营并全面提升流通效率。  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