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   5531篇
  免费   233篇
  国内免费   60篇
财政金融   390篇
工业经济   297篇
计划管理   1000篇
经济学   1225篇
综合类   530篇
运输经济   80篇
旅游经济   209篇
贸易经济   602篇
农业经济   947篇
经济概况   543篇
信息产业经济   1篇
  2024年   9篇
  2023年   98篇
  2022年   67篇
  2021年   132篇
  2020年   238篇
  2019年   190篇
  2018年   181篇
  2017年   217篇
  2016年   212篇
  2015年   175篇
  2014年   344篇
  2013年   549篇
  2012年   359篇
  2011年   456篇
  2010年   350篇
  2009年   323篇
  2008年   339篇
  2007年   292篇
  2006年   279篇
  2005年   193篇
  2004年   180篇
  2003年   130篇
  2002年   103篇
  2001年   90篇
  2000年   59篇
  1999年   49篇
  1998年   33篇
  1997年   43篇
  1996年   33篇
  1995年   20篇
  1994年   17篇
  1993年   9篇
  1992年   11篇
  1991年   5篇
  1990年   2篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   4篇
  1985年   8篇
  1984年   7篇
  1983年   9篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
排序方式: 共有5824条查询结果,搜索用时 31 毫秒
951.
In this paper we use world cycling records to study the pattern of technological development of the track bicycle. We find that there is a strong evidence of ‘contagious’ effects among cycling records which in turn provides indirect evidence of ‘contagious’ effects among technological innovations. Interestingly, the ‘contagiousness’ of records is not a salient characteristic of track and field competitions where, arguably, technology plays a smaller role.  相似文献   
952.

Measures of multifactor productivity growth in natural resource industries are misleading without accounting for the effects on the environment. This paper introduces environmental effects into an output-oriented Malmquist index of multifactor productivity growth in order to evaluate growth in productivity and technical efficiency for Korean purse seine vessels fishing for tuna in the Western and Central Pacific Ocean.  相似文献   
953.
This paper aims at providing a comprehensive empirical appraisal of the nature, extent and sources of variety in innovation in industry across Europe. The results presented in the empirical section of this paper are based on a unique database (SIEPI) containing data drawn by the second Community Innovation Survey (CIS2) for 10 countries, 22 manufacturing sectors and three firm-size classes. This database has allowed us to look beyond the sectoral aggregate statistics provided by Eurostat and explore in detail the differences in innovation processes both within and across European countries and manufacturing industries. Further, the SIEPI database has been used to identify the determinants of the variety in innovation across Europe. In particular, the analysis focuses on the relative importance of sector-specific, context-specific and firm-size factors in driving firms’ innovative behaviours and performances.  相似文献   
954.
We propose a general theory of innovation that illustrates the relative benefits of performing process versus product R&D when firm size is endogenous. A firm's size, scope, and R&D portfolio are shown to reflect the same underlying characteristic of the firm, namely manufacturing efficiency. We demonstrate that efficient firms become larger, have greater scope, and perform more of both process and product R&D. In light of decreasing returns to R&D, this implies small firms obtain more product innovations per dollar of R&D than large firms, which is consistent with evidence we present that small firms are more innovative than large firms as they obtain more patent counts and citations per dollar of R&D.  相似文献   
955.
One of the key features of our economies consists of the coexistence of different technologies supplying similar products and services. We often observe that an old technology is improved when a new one appears; behind this process of improvement often lies an intentional research activity. There thus begins a competition between the two technologies whose performances are improved via R&D. We focus our attention on this competition process and supply a formal model, based on the optimization of R&D expenditure of both technologies, which can describe the dynamics of the delayed overtaking of the new technology over the old one.  相似文献   
956.
The impact of technological change upon gross investment has been relatively ignored. Building upon the foundations of the analysis of technological diffusion, an empirical model of gross investment is constructed that takes due account of technological change. This model is then tested upon a panel data set covering 185 UK firms over the period from 1984 to 1992. The results support the hypothesis that there are significant relationships of the expected signs between firm level gross investment, indicators of technological opportunity; the price of the capital goods that embody new technology, and firm and industry characteristics. There is also evidence of lagged adjustment effects in the investment process.  相似文献   
957.
The Earth system is a complex adaptive system, characterised by non-linear change and with significant capacity for surprise. In times of systemic crisis, such as dangerous anthropogenic climate change, perverse resilience (for example the structural power of fossil fuel interests in the global economy) can threaten overall Earth system stability. Critical political economic analysis recognises climate change as a threat with significant political economic characteristics and implications. However, key dimensions of climate change as a globally coherent phenomenon, including the important implications of Earth system dynamism and non-linear change, can remain unrecognised, mischaracterised or underestimated. In contrast, resilience approaches describe social-ecological systems but neglect the significance of norms and power relations in human societies. This article builds theory by linking key concepts – hegemony and resilience – from neo-Gramscian political economic analysis and resilience approaches to social-ecological systems. Our objective is to generate a new conceptual framework to improve understanding of the role of politics in social-ecological systems. We use climate change and its mitigation to demonstrate the new framework's potential.  相似文献   
958.
从一般无形资产的研究理论出发,结合建筑施工企业的行业特点对建筑施工企业的主要无形资产进行归类,提出关于建筑施工企业无形资产与核心竞争力的关系,阐述各类无形资产的价值变动规律,为建筑施工企业提供一个更广阔的视野进行管理决策。  相似文献   
959.
针对某电力公司进行的变电站更换的工程,发现上传调度中心遥测数据异常、进出站不平衡的现象,通过对遥测数据进行采集、分析,及时排除故障,使系统恢复正常的典型实例。同时分析了相同故障的综合解决办法及防范措施。理论分析与计算验证了利用遥测数据分析运行故障的可行性,其结果为进一步潮流分析之外的应用提供了借鉴和参考。  相似文献   
960.
Abstract

National parks in Canada operate under the dual mandate of conservation and visitor use, which involves balancing ecological integrity and nature-based tourism activities. Climate-induced environmental change may increase the existing tension between conservation and visitor use as major tourism resources located in protected areas (PAs) are projected to undergo large-scale changes. This study draws upon the behavioural approach, scenario planning, and landscape visualizations to examine the relationship between climate change impacts, visitor perceptions, and visitor experience management at the Athabasca Glacier in Jasper National Park, Canada. Four tourism development scenarios defined by two management drivers (ecological integrity and visitor demand) with corresponding storylines and visualizations were developed for 2050. The visualized scenarios were presented to visitors (n?=?304) in a survey to understand potential implications on visitor satisfaction. The results suggest that park managers need to find a balance between ecological integrity and visitor use in a way that ensures commercialized tourism development is limited, educational material is prioritized, and ecological integrity is maintained. While understanding the behaviour of future tourists is complex, it is a critical component of climate change adaptation planning and decision-making processes that needs to be prioritized by policymakers and PAs managers.  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