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   2766篇
  免费   139篇
  国内免费   104篇
电工技术   120篇
技术理论   1篇
综合类   892篇
化学工业   211篇
金属工艺   24篇
机械仪表   44篇
建筑科学   333篇
矿业工程   125篇
能源动力   86篇
轻工业   237篇
水利工程   78篇
石油天然气   51篇
武器工业   5篇
无线电   86篇
一般工业技术   99篇
冶金工业   238篇
原子能技术   8篇
自动化技术   371篇
  2024年   4篇
  2023年   20篇
  2022年   58篇
  2021年   75篇
  2020年   81篇
  2019年   57篇
  2018年   50篇
  2017年   47篇
  2016年   85篇
  2015年   68篇
  2014年   161篇
  2013年   175篇
  2012年   161篇
  2011年   186篇
  2010年   174篇
  2009年   240篇
  2008年   135篇
  2007年   174篇
  2006年   167篇
  2005年   120篇
  2004年   175篇
  2003年   118篇
  2002年   80篇
  2001年   89篇
  2000年   63篇
  1999年   46篇
  1998年   43篇
  1997年   28篇
  1996年   13篇
  1995年   17篇
  1994年   12篇
  1993年   7篇
  1992年   5篇
  1991年   6篇
  1988年   7篇
  1987年   4篇
  1986年   4篇
  1985年   7篇
  1984年   3篇
  1982年   3篇
  1981年   3篇
  1980年   3篇
  1975年   3篇
  1974年   2篇
  1966年   2篇
  1965年   2篇
  1963年   3篇
  1961年   2篇
  1960年   2篇
  1957年   2篇
排序方式: 共有3009条查询结果,搜索用时 265 毫秒
81.
Managerial decision-making processes often involve data of the time nature and need to understand complex temporal associations among events. Extending classical association rule mining approaches in consideration of time in order to obtain temporal information/knowledge is deemed important for decision support, which is nowadays one of the key issues in business intelligence. This paper presents the notion of multi-temporal patterns with four different temporal predicates, namely before, during, equal and overlap, and discusses a number of related properties, based on which a mining algorithm is designed. This enables us to effectively discover multi-temporal patterns in large-scale temporal databases by reducing the database scan in the generation of candidate patterns. The proposed approach is then applied to stock markets, aimed at exploring possible associative movements between the stock markets of Chinese mainland and Hong Kong so as to provide helpful knowledge for investment decisions.  相似文献   
82.
政府门户网站是地方各级政府单位通过互联网方式对外展示政府形象,实现政府信息对外公开的重要渠道。财政部门作为政府的一个重要的综合经济管理部门,其网站建设与管理在财政工作中发挥着重要的作用。该文以廊坊市财政网站从建设到管理实践过程为例,系统论述了财政网站建设的重要性,并详细总结了该网站建成后的一系列成效。  相似文献   
83.
高岩 《控制与决策》2016,31(9):1720-1722

利用非光滑分析, 讨论线性控制系统多面体区域的生存性判别. 对于有界多面体(利用有限点集的凸包来表示), 其生存性判别只需检验其在极点处是否满足生存性条件, 去掉了以往对输入集合为多面体的要求, 这种生存性判别方法简便易行. 最后利用所给出的生存性条件讨论了生存性设计.

  相似文献   
84.
This research joins the growing body of literature that advocates for the use of information and communication technology (ICT) in local governance more particularly in public financial management. Using a case study in Bohol, a province in the Philippines, this paper discusses the impact of ICT on local revenue generation by analyzing both quantitative and qualitative data from 15 municipalities which used e-taxation. This paper argues that the use of ICT can make possible more transparent and accountable revenue generation systems to benefit both government and taxpayers. However, these results are differentiated depending on the level of political leadership, the nature of articulation of the demand for ICT use, the ratio of benefit against cost, and the availability of technical skills and resources at the sub-national level. It is within this context that an eco-system analysis is argued to be useful in analyzing how ICT can be adopted, scaled, and used by sub-national governments to achieve better governance.  相似文献   
85.
Financial time series prediction is regarded as one of the most challenging job because of its inherent complexity, and the hybrid forecasting model incorporating autoregressive integrated moving average and support vector machine (SVM) has been implemented widely to deal with the both linear and nonlinear patterns in time series data. However, the SVM model does not take into consideration the time correlation knowledge between different data points in time series, which impacts the learning efficiency of the SVM in real application. To overcome this restriction, this paper proposes the Taylor Expansion Forecasting model as an alternative to the SVM and develops a novel hybrid methodology via combining autoregressive integrated moving average and Taylor Expansion Forecasting to exploit the comprehensive forecasting capacity to the financial time series data with noise. Both theoretical proof and empirical results obtained on several commodity future prices demonstrate that the proposed hybrid model improves greatly the forecasting accuracy.  相似文献   
86.
针对TB级的大规模金融对账文件的近似比对问题,本文深入分析了金融对账文件的特点,以提升比对速度作为研究目标,提出了一种多层次的近似比对模型-UpCompare模型.UpCompare模型以多进程为扩展基础,采用哈希索引建立映射表结合快速致胜策略为核心算法.测试结果表明,运用UpCompare模型,我国银行卡清算系统的每日清算文件近似比对效率提升了5倍以上.  相似文献   
87.
随着市场竞争日趋激烈,成本控制对企业的重要性日益增加.财务报销系统是企业成本支出的重要窗口,对控制企业成本起着关键性的作用.传统的财务报销管理软件侧重于业务处理,对报销支出的管控较弱,而且各级管理者在审批报销单据时常常因为缺乏相关信息而只能走过场式审批.本文目标是通过构建财务报销单据智能审批系统,为审批人提供审批决策支持,从而提高审批效率和审批质量,降低企业成本.本文对财务报销单据智能审批系统的基本功能和应用流程进行了详细介绍.  相似文献   
88.
The main goal of this paper is to show how relatively minor modifications of well-known algorithms (in particular, back propagation) can dramatically increase the performance of an artificial neural network (ANN) for time series prediction. We denote our proposed sets of modifications as the 'self-momentum', 'Freud' and 'Jung' rules. In our opinion, they provide an example of an alternative approach to the design of learning strategies for ANNs, one that focuses on basic mathematical conceptualization rather than on formalism and demonstration. The complexity of actual prediction problems makes it necessary to experiment with modelling possibilities whose inherent mathematical properties are often not well understood yet. The problem of time series prediction in stock markets is a case in point. It is well known that asset price dynamics in financial markets are difficult to trace, let alone to predict with an operationally interesting degree of accuracy. We therefore take financial prediction as a meaningful test bed for the validation of our techniques. We discuss in some detail both the theoretical underpinnings of the technique and our case study about financial prediction, finding encouraging evidence that supports the theoretical and operational viability of our new ANN specifications. Ours is clearly only a preliminary step. Further developments of ANN architectures with more and more sophisticated 'learning to learn' characteristics are now under study and test.  相似文献   
89.
财务软件在经历多年发展之后,决策支持软件(DSS)的引入使财务软件应用达到了一个新的高度。本文通过分析决策支持软件(DSS)的现状与发展,并以实际的软件对比阐述了智能财务软件的发展方向。  相似文献   
90.
Financial forecasting is an example of a signal processing problem which is challenging due to small sample sizes, high noise, non-stationarity, and non-linearity. Neural networks have been very successful in a number of signal processing applications. We discuss fundamental limitations and inherent difficulties when using neural networks for the processing of high noise, small sample size signals. We introduce a new intelligent signal processing method which addresses the difficulties. The method proposed uses conversion into a symbolic representation with a self-organizing map, and grammatical inference with recurrent neural networks. We apply the method to the prediction of daily foreign exchange rates, addressing difficulties with non-stationarity, overfitting, and unequal a priori class probabilities, and we find significant predictability in comprehensive experiments covering 5 different foreign exchange rates. The method correctly predicts the directionof change for the next day with an error rate of 47.1%. The error rate reduces to around 40% when rejecting examples where the system has low confidence in its prediction. We show that the symbolic representation aids the extraction of symbolic knowledge from the trained recurrent neural networks in the form of deterministic finite state automata. These automata explain the operation of the system and are often relatively simple. Automata rules related to well known behavior such as tr end following and mean reversal are extracted.  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