全文获取类型
收费全文 | 1207篇 |
免费 | 196篇 |
国内免费 | 109篇 |
专业分类
电工技术 | 99篇 |
综合类 | 165篇 |
化学工业 | 84篇 |
金属工艺 | 6篇 |
机械仪表 | 66篇 |
建筑科学 | 60篇 |
矿业工程 | 21篇 |
能源动力 | 19篇 |
轻工业 | 25篇 |
水利工程 | 23篇 |
石油天然气 | 10篇 |
武器工业 | 25篇 |
无线电 | 121篇 |
一般工业技术 | 158篇 |
冶金工业 | 147篇 |
原子能技术 | 11篇 |
自动化技术 | 472篇 |
出版年
2024年 | 8篇 |
2023年 | 20篇 |
2022年 | 29篇 |
2021年 | 45篇 |
2020年 | 56篇 |
2019年 | 51篇 |
2018年 | 40篇 |
2017年 | 45篇 |
2016年 | 41篇 |
2015年 | 50篇 |
2014年 | 74篇 |
2013年 | 126篇 |
2012年 | 71篇 |
2011年 | 100篇 |
2010年 | 69篇 |
2009年 | 96篇 |
2008年 | 77篇 |
2007年 | 75篇 |
2006年 | 74篇 |
2005年 | 69篇 |
2004年 | 56篇 |
2003年 | 38篇 |
2002年 | 36篇 |
2001年 | 22篇 |
2000年 | 19篇 |
1999年 | 22篇 |
1998年 | 15篇 |
1997年 | 9篇 |
1996年 | 10篇 |
1995年 | 11篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 3篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 2篇 |
1981年 | 3篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1965年 | 1篇 |
1962年 | 1篇 |
1959年 | 1篇 |
1958年 | 1篇 |
1957年 | 2篇 |
1955年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有1512条查询结果,搜索用时 15 毫秒
1.
1 IntroductionThestickingpointofassociationrulealgorithmsdependsoneffectivelyfindingallcorrelationpatternsthatsatisfyvaluerequirementinthemagnanimityofdata.Butthealgorithmsalsobringanegativeef fect:thenumberofassociationrulesisverylarge.Alsoinformation… 相似文献
2.
One of the most frequently cited reasons for conducting a meta-analysis is the increase in statistical power that it affords a reviewer. This article demonstrates that fixed-effects meta-analysis increases statistical power by reducing the standard error of the weighted average effect size (T?.) and, in so doing, shrinks the confidence interval around T?.. Small confidence intervals make it more likely for reviewers to detect nonzero population effects, thereby increasing statistical power. Smaller confidence intervals also represent increased precision of the estimated population effect size. Computational examples are provided for 3 effect-size indices: d (standardized mean difference), Pearson's r, and odds ratios. Random-effects meta-analyses also may show increased statistical power and a smaller standard error of the weighted average effect size. However, the authors demonstrate that increasing the number of studies in a random-effects meta-analysis does not always increase statistical power. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Marcela Brugnach Andrew Tagg Florian Keil Wim J. de Lange 《Water Resources Management》2007,21(7):1075-1090
The use of computer models offers a general and flexible framework that can help to deal with some of the complexities and
difficulties associated with the development of water management plans as prescribed by the Water Framework Directive. However,
despite the advantages modelling presents, the integration of information derived from models into policy is far away from
being trivial or the norm. Part of the difficulties of this integration is rooted in the lack of confidence policy makers
have on the incorporation of modelling information into policy formulation. In this paper we examine the reasons for this
apparent lack of confidence and explore how some tools, presently in use, address this problem. We conclude that public confidence
in models is highly dependent on the way uncertainties are addressed and suggest possible directions of action to improve
the current situation. Four real case studies illustrate how computer models have been used in The Netherlands for carrying
out management plans at regional and national scale. We suggest that the solution to integrate modelling information into
policy formulation lies on both the modelling and the policy-making communities. 相似文献
4.
5.
O. L. Perevozchikova V. G. Tul'chinskii A. V. Kharchenko 《Cybernetics and Systems Analysis》2003,39(4):501-508
A statistical learning model is considered within the framework of the theory of uniform convergence of frequencies of errors in the case where the convergence is violated as a result of increasing the informativeness of training examples. Drawbacks of nonconstructive refinements of Vapnik-Chervonenkis estimates based on an assumption on the distribution law of violations are shown. A new approach to obtaining constructive estimates for mass data sets is proposed. 相似文献
6.
To acquire maximum information on the geometrical errors of industrially made surfaces at a minimum cost, a method for estimating conditional probabilities of a random signal (Bayesian prediction) is applied to three-dimensional metrology. First, a surface is interpolated between data acquired on a coordinate measuring machine (CMM). Then, for a given probability, limit surfaces are computed that bind a region of space containing the known data and the most probable interpolation of the missing data of the surface. These bounds can be treated as the surface; their points can be considered as if they were actual CMM data when fitting a tolerance zone or a datum feature to the data. For Bayesian prediction, the basic hypotheses on the signal are stationarity, ergodicity, and gaussian density. Deviations from these hypotheses and their consequences on the prediction are taken into account and corrections are proposed. 相似文献
7.
本文以单项工程为研究对象,以隧洞工程为例,研究了单项工程施工所需用的时间。文中以施工单位所具有的资源,结合施工工作环境、作业空间为约束条件,以费用最小为目标函数,建立了优化模型。由资源的工作性能指标,利用模糊数学原理,对资源间的匹配程度作了定量分析,并进一步推出了不同匹配程度的资源对作业时间的影响的计算式。并从影响各工序完工时间的因素的随机性出发,利用数理统计理论,由各工序的细分活动的规律推出了各工序的完工需用时间的概率表达式,解决了工期与置信度间的关系。最后结合工程实例,求出了一定置信度下,不同资源供应时的最优工期。 相似文献
8.
Murphy Philip N.; Bentall Richard P.; Ryley Lisa D.; Ralley Richard 《Canadian Metallurgical Quarterly》2003,17(2):167
Admission scores from a model comprising 3 motivation factors concerning the cessation of heroin use and a confidence scale concerning postdischarge abstinence were tested for their ability to predict postdischarge outcomes in patients beginning inpatient opiate detoxification. Statistically significant prediction of abstinence from heroin 30 days after discharge and the number of heroin-free days in the 3 months following admission was based on the confidence scale and a factor concerned with externally imposed constraints on continued heroin use. The single-scale confidence measure made the largest contribution to each prediction, indicating that such scales may be potentially useful outcome predictors for postdischarge abstinence. External constraints on heroin use may not provide a basis for success in this treatment modality. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
基于可变大小模板的改进图像修复算法 总被引:1,自引:0,他引:1
Criminisi等人提出的基于模板的图像修复算法是该领域最重要的贡献之一。在保持Criminisi基本算法框架不变的基础上,本文提出了一些改进思想。主要贡献是设计了基于可变大小模板的块匹配程序以使模板搜索更准确灵活。此外,对信度更新方式进行了修正,并结合局部搜索以提高算法的综合性能。实验结果证实了改进的有效性。 相似文献
10.
林丰 《广东水利电力职业技术学院学报》2021,19(1)
广州既是改革开放的前沿阵地,也是岭南文化的传播和发展中心。分析广州近年来在文化建设方面的实践经验,特别是在推动岭南文化、广府文化创造性转化和创新性发展方面的经验,对于进一步贯彻落实习近平总书记关于文化自信建设的重要论述精神,扎实推进文化建设具有重要作用。 相似文献