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   3719篇
  免费   67篇
财政金融   350篇
工业经济   863篇
计划管理   647篇
经济学   945篇
综合类   107篇
运输经济   17篇
旅游经济   109篇
贸易经济   352篇
农业经济   89篇
经济概况   300篇
信息产业经济   2篇
邮电经济   5篇
  2024年   6篇
  2023年   33篇
  2022年   35篇
  2021年   52篇
  2020年   74篇
  2019年   69篇
  2018年   66篇
  2017年   94篇
  2016年   85篇
  2015年   59篇
  2014年   87篇
  2013年   207篇
  2012年   196篇
  2011年   523篇
  2010年   441篇
  2009年   342篇
  2008年   270篇
  2007年   262篇
  2006年   257篇
  2005年   230篇
  2004年   98篇
  2003年   71篇
  2002年   86篇
  2001年   29篇
  2000年   31篇
  1999年   14篇
  1998年   22篇
  1997年   4篇
  1996年   7篇
  1995年   8篇
  1994年   2篇
  1993年   7篇
  1992年   1篇
  1991年   4篇
  1990年   3篇
  1986年   2篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1979年   1篇
  1945年   2篇
排序方式: 共有3786条查询结果,搜索用时 0 毫秒
141.
The UK government published a weighted score card approach in 2003 to analyse the performance of Probation Boards in England and Wales. However, there has not been a thorough analysis of whether non-parametric methods could provide more advanced options for analysing performance than the standard Weighted Score Card approach – a variant of the Balanced Score Card. Our results show there is considerable divergence in the ranks of Probation Boards from that of the WSC when we include the input variable ‘resource expenditure’ within a DEA model, calling into question recent policy initiatives to increase efficiency in the national probation service.  相似文献   
142.
143.
144.
145.
This paper investigates whether volatility futures prices per se can be forecasted by studying the fast-growing VIX futures market. To this end, alternative model specifications are employed. Point and interval out-of-sample forecasts are constructed and evaluated under various statistical metrics. Next, the economic significance of the forecasts obtained is also assessed by performing trading strategies. Only weak evidence of statistically predictable patterns in the evolution of volatility futures prices is found. No trading strategy yields economically significant profits. Hence, the hypothesis that the VIX volatility futures market is informationally efficient cannot be rejected.  相似文献   
146.
This paper reports the results of the NN3 competition, which is a replication of the M3 competition with an extension of the competition towards neural network (NN) and computational intelligence (CI) methods, in order to assess what progress has been made in the 10 years since the M3 competition. Two masked subsets of the M3 monthly industry data, containing 111 and 11 empirical time series respectively, were chosen, controlling for multiple data conditions of time series length (short/long), data patterns (seasonal/non-seasonal) and forecasting horizons (short/medium/long). The relative forecasting accuracy was assessed using the metrics from the M3, together with later extensions of scaled measures, and non-parametric statistical tests. The NN3 competition attracted 59 submissions from NN, CI and statistics, making it the largest CI competition on time series data. Its main findings include: (a) only one NN outperformed the damped trend using the sMAPE, but more contenders outperformed the AutomatANN of the M3; (b) ensembles of CI approaches performed very well, better than combinations of statistical methods; (c) a novel, complex statistical method outperformed all statistical and CI benchmarks; and (d) for the most difficult subset of short and seasonal series, a methodology employing echo state neural networks outperformed all others. The NN3 results highlight the ability of NN to handle complex data, including short and seasonal time series, beyond prior expectations, and thus identify multiple avenues for future research.  相似文献   
147.
148.
本文通过对过西县烈马峪生态经济模式所作的分析,指出环境系统和生物系统相关关系有着正面效应和负面效应两方面表现。要光大正面效应,抑制负面效应。为此,要树立正确的指导思想,谋划适应社会主义市场经济的新思路,调整产业结构,实施整体联动,进行综合治理。  相似文献   
149.
在文献回顾的基础上确定理论模型,采用问卷调查数据,实证研究了员工的内心生活水平对其创造力的影响,并探讨了建言行为在两者间的中介作用。研究结果表明:内心生活对员工的创造力和建言行为均有显著的正向影响;建言行为在内心生活与员工创造力间的关系中起完全中介作用。  相似文献   
150.
Porter's industry forces framework is an important tool for external analysis of firms, but its qualitative nature presents numerous limitations to be used in investment analysis. This study introduces a quantitative perspective of the framework using financial information proxies. This allows investors to gauge the external factors quantitatively and to gain enhanced framework usability. In order to test its validity, the correlation movements of our quantitative perspective have been analysed. For demonstration of enhanced usability, our quantitative perspective, alongside machine learning models, was used to predict business performances. The empirical results indicate that our quantitative perspective of the framework corroborates with its original definition and that it exhibits enhanced usability than the original framework.  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