全文获取类型
收费全文 | 81959篇 |
免费 | 6777篇 |
国内免费 | 3776篇 |
专业分类
电工技术 | 4596篇 |
技术理论 | 2篇 |
综合类 | 5247篇 |
化学工业 | 13300篇 |
金属工艺 | 5025篇 |
机械仪表 | 5115篇 |
建筑科学 | 5796篇 |
矿业工程 | 2273篇 |
能源动力 | 1851篇 |
轻工业 | 5236篇 |
水利工程 | 1857篇 |
石油天然气 | 4608篇 |
武器工业 | 719篇 |
无线电 | 8783篇 |
一般工业技术 | 11549篇 |
冶金工业 | 4879篇 |
原子能技术 | 1629篇 |
自动化技术 | 10047篇 |
出版年
2024年 | 316篇 |
2023年 | 1200篇 |
2022年 | 2467篇 |
2021年 | 3325篇 |
2020年 | 2571篇 |
2019年 | 2113篇 |
2018年 | 2298篇 |
2017年 | 2726篇 |
2016年 | 2500篇 |
2015年 | 3390篇 |
2014年 | 4125篇 |
2013年 | 4974篇 |
2012年 | 5163篇 |
2011年 | 5626篇 |
2010年 | 4885篇 |
2009年 | 4799篇 |
2008年 | 4650篇 |
2007年 | 4197篇 |
2006年 | 3804篇 |
2005年 | 3068篇 |
2004年 | 2142篇 |
2003年 | 1909篇 |
2002年 | 2060篇 |
2001年 | 1890篇 |
2000年 | 1389篇 |
1999年 | 1216篇 |
1998年 | 941篇 |
1997年 | 811篇 |
1996年 | 777篇 |
1995年 | 691篇 |
1994年 | 577篇 |
1993年 | 496篇 |
1992年 | 413篇 |
1991年 | 403篇 |
1990年 | 351篇 |
1989年 | 360篇 |
1988年 | 321篇 |
1986年 | 301篇 |
1985年 | 290篇 |
1984年 | 302篇 |
1983年 | 294篇 |
1979年 | 293篇 |
1978年 | 362篇 |
1977年 | 336篇 |
1976年 | 351篇 |
1975年 | 331篇 |
1974年 | 396篇 |
1973年 | 373篇 |
1972年 | 361篇 |
1971年 | 332篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Data mining extracts implicit, previously unknown, and potentially useful information from databases. Many approaches have been proposed to extract information, and one of the most important ones is finding association rules. Although a large amount of research has been devoted to this subject, none of it finds association rules from directed acyclic graph (DAG) data. Without such a mining method, the hidden knowledge, if any, cannot be discovered from the databases storing DAG data such as family genealogy profiles, product structures, XML documents, task precedence relations, and course structures. In this article, we define a new kind of association rule in DAG databases called the predecessor–successor rule, where a node x is a predecessor of another node y if we can find a path in DAG where x appears before y. The predecessor–successor rules enable us to observe how the characteristics of the predecessors influence the successors. An approach containing four stages is proposed to discover the predecessor–successor rules. © 2006 Wiley Periodicals, Inc. Int J Int Syst 21: 621–637, 2006. 相似文献
2.
Known examples of the positive influence of electrohydroimpulse treatment on the quality of weld joints of various steels, particularly including an increase in their long-term and cyclic strength and also corrosion resistance, are analyzed. It is shown that in this case there is a reduction in residual macro- and micro-stresses and also a change in the parameters of the dislocation structure of the joint metal in the direction of stabilization of it.Translated from Problemy Prochnosti, No. 4, pp. 119–123, April, 1996. 相似文献
3.
心电地图仪中工频干扰的一种滤除方法 总被引:1,自引:0,他引:1
在心电地图仪中记录到的体表心电信号往往由于电磁的影响而引进工频干扰.基于体表心电信号中工频干扰的特点,作者提出了一种滤除工频干扰的方法,即就单独—胸导联信号通过提高频谱的分辨率来估计工频干扰的频率;基于最小均方误差准则来估计各导联信号中工频干扰的幅度和相位。文中还给出了该算法的流程图和滤波性能分析。模拟结果表明了该算法的有效性。应用该算法对心电地图仪中的工频干扰进行对消,取得了满意的结果。 相似文献
4.
Liang Y.C. Wenjiang Zeng Pick Hong Ong Zhaoxia Gao Jun Cai Balasubramanian N. 《Electron Device Letters, IEEE》2002,23(12):700-703
In this letter, a concise process technology is proposed for the first time to enable the fabrication of good quality three-dimensional (3-D) suspended radio frequency (RF) micro-inductors on bulk silicon, without utilizing the lithography process on sidewall and trench-bottom patterning. Samples were fabricated to demonstrate the applicability of the proposed process technology. 相似文献
5.
Tsu-Hua Ai Jiann-Fuh Chen Tsorng-Juu Liang 《Industrial Electronics, IEEE Transactions on》2002,49(3):595-597
To overcome the problem of unequal switching loss in power switches, in conventional hybrid pulse width modulation (HPWM) full-bridge inverters, a random switching method for HPWM full-bridge inverters is proposed. The proposed method equalizes switching losses of the four switches, while also providing good output performance 相似文献
6.
Improving signal prediction performance of neural networks through multiresolution learning approach. 总被引:1,自引:0,他引:1
Yao Liang Xu Liang 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2006,36(2):341-352
In this paper, we extend the original work on multiresolution learning for neural networks, and present new developments on the multiresolution learning paradigm. The contributions of this paper include: (1) proposing a new concept and method of adjustable neural activation functions in multiresolution learning to improve neural network learning efficacy and generalization performance for signal predictions; (2) providing new insightful explanations for the multiresolution learning paradigm from a multiresolution optimization perspective; (3) exploring underlying ideas why the multiresolution learning scheme associated with adjustable activation functions would be more appropriate for the multiresolution learning paradigm; and (4) providing rigorous validations to evaluate the multiresolution learning paradigm with adjustable activation functions and comparing it with the schemes of multiresolution learning with fixed activation functions and traditional learning. This paper presents systematically new analytical and experimental results on the multiresolution learning approach for training an individual neural network model, demonstrates our integral solution on neural network learning efficacy, and illustrates the significant improvements on neural networks' generalization performance and robustness for nonlinear signal predictions. 相似文献
7.
8.
L. B. Getsov A. Ya. Madorskii N. N. Mozzhukhina A. G. Tereshchenko E. E. Yushchenkov 《Strength of Materials》1989,21(1):92-98
Leningrad. Translated from Problemy Prochnosti, No. 1, pp. 71–76, January, 1989. 相似文献
9.
V. Ya. Sakulin V. P. Migal’ A. P. Margishvili V. V. Bulin 《Refractories and Industrial Ceramics》2008,49(5):354-358
A range of refractories is presented for handling steel outside a furnace, which are produced by the Borovichi Refractories
Corporation. The refractory characteristics and working features are given.
Translated from Novye Ogneupory, No. 9, pp. 29–35, September, 2008. 相似文献
10.
L. M. Aksel’rod V. I. Rumyantsev N. Yu. Korableva N. V. Belykh Ya. G. Dyatlova 《Refractories and Industrial Ceramics》2008,49(2):116-119
Technology is developed for preparing refractory components made of partially stabilized zirconium dioxide using an isostatic
compaction press. Technology is provided for manufacturing dispensing nozzles using combined and separately stabilized zirconium
dioxide, and also indices of the refractories obtained and imported materials are compared.
__________
Translated from Novye Ogneupory, No. 3, pp. 127–131, March 2008. 相似文献