全文获取类型
收费全文 | 12317篇 |
免费 | 2015篇 |
国内免费 | 1166篇 |
专业分类
电工技术 | 1388篇 |
综合类 | 1146篇 |
化学工业 | 2236篇 |
金属工艺 | 444篇 |
机械仪表 | 978篇 |
建筑科学 | 219篇 |
矿业工程 | 188篇 |
能源动力 | 747篇 |
轻工业 | 156篇 |
水利工程 | 182篇 |
石油天然气 | 459篇 |
武器工业 | 350篇 |
无线电 | 1433篇 |
一般工业技术 | 1574篇 |
冶金工业 | 314篇 |
原子能技术 | 98篇 |
自动化技术 | 3586篇 |
出版年
2024年 | 115篇 |
2023年 | 309篇 |
2022年 | 504篇 |
2021年 | 505篇 |
2020年 | 630篇 |
2019年 | 515篇 |
2018年 | 477篇 |
2017年 | 596篇 |
2016年 | 633篇 |
2015年 | 636篇 |
2014年 | 770篇 |
2013年 | 876篇 |
2012年 | 926篇 |
2011年 | 1027篇 |
2010年 | 715篇 |
2009年 | 776篇 |
2008年 | 648篇 |
2007年 | 773篇 |
2006年 | 650篇 |
2005年 | 509篇 |
2004年 | 398篇 |
2003年 | 400篇 |
2002年 | 330篇 |
2001年 | 261篇 |
2000年 | 260篇 |
1999年 | 185篇 |
1998年 | 182篇 |
1997年 | 152篇 |
1996年 | 129篇 |
1995年 | 102篇 |
1994年 | 109篇 |
1993年 | 57篇 |
1992年 | 77篇 |
1991年 | 50篇 |
1990年 | 43篇 |
1989年 | 32篇 |
1988年 | 23篇 |
1987年 | 24篇 |
1986年 | 16篇 |
1985年 | 13篇 |
1984年 | 20篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
21.
Yvon Maday Frédéric Magoulès 《Computer Methods in Applied Mechanics and Engineering》2007,196(8):1541-1553
In this paper an original variant of the Schwarz domain decomposition method is introduced for heterogeneous media. This method uses new optimized interface conditions specially designed to take into account the heterogeneity between the sub-domains on each sides of the interfaces. Numerical experiments illustrate the dependency of the proposed method with respect to several parameters, and confirm the robustness and efficiency of this method based on such optimized interface conditions. Several mesh partitions taking into account multiple cross points are considered in these experiments. 相似文献
22.
A method of processing complex signals in passive multi-element antenna arrays based on an analysis of the natural values of the correlation matrix of the signal is considered. By means of the method it is possible to substantially increase the output signal-to-noise ratio. An iterational process by means of which optimal estimators of both the signal and the amplitude-phase distribution may be obtained, is proposed. Theoretical estimators of the efficiency of the method are given. It is proved that, in terms of the efficiency, the approach considered in the article comes close to the technique of matched filtration. Results of statistical modeling that confirm the statistical results are presented. 相似文献
23.
B. E. Rytsar 《Cybernetics and Systems Analysis》2007,43(2):192-207
The paper considers the set-theoretical approach to the joint decomposition of systems of Boolean functions of variables specified
in different representation forms. The approach is based on the method of q-partitions of conjuncterms and concept of decomposition
clones. Theorems on joint decomposition of a system of full and partial functions are formulated. The approach is illustrated
by examples.
Parts I and II of this article are published in No. 5 (2001) and No. 1 (2002).
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 39–58, March–April 2007. 相似文献
24.
From the principle of of the Domain Decomposition Method (DDM), we analyse the 2nd-order linear elliptic partial differential problems and link the Separated-Layers Algorithm (SLA) with DDM. The mathematical properties of SLA and numerical example are presented to obtain satisfactory computation results. For general linear differential ones, also are the structure of SLA and its characteristics discussed. 相似文献
25.
Jean-Christophe Autrique 《Computers & Structures》2007,85(9):518-525
This work is devoted to a study of a conjugated infinite element method for Helmholtz problems in exterior domains. A formulation of this method with Lagrange multipliers defined on (semi-)infinite space is presented and analyzed in a domain decomposition context. The implementation aspects of this method in a parallel industrial acoustic software (SYSNOISE) are described in details. Numerical results show the computational efficiency of this method on acoustic scattering problems. 相似文献
26.
文章介绍了大系统分解协调理论,建立了串联、并联库群水库防洪优化调度模型.以澧水流域并联系统为例进行了优化调度计算,并以常规调度方案成果进行了分析比较论证. 相似文献
27.
28.
An Operator-integration-factor splitting method for time-dependent problems: Application to incompressible fluid flow 总被引:1,自引:1,他引:0
In this paper we present a simple, general methodology for the generation of high-order operator decomposition (splitting) techniques for the solution of time-dependent problems arising in ordinary and partial differential equations. The new approach exploits operator integration factors to reduce multiple-operator equations to an associated series of single-operator initial-value subproblems. Two illustrations of the procedure are presented: the first, a second-order method in time applied to velocity-pressure decoupling in the incompressible Stokes problem; the second, a third-order method in time applied to convection-Stokes decoupling in the incompressible Navier-Stokes equations. Critical open questions are briefly described. 相似文献
29.
煤矿监控图像增强算法的分析与实现 总被引:1,自引:0,他引:1
针对煤矿井下粉尘多、光照差的恶劣环境使得矿井监控图像偏暗、对比度低、视觉效果差的特点,提出了一种基于小波变换和模糊理论的图像增强算法。该算法选择小波变换为工具分解图像,应用新的模糊隶属度和增强算子对高频信息进行模糊处理,利用直方图均衡化对低频信息进行处理,最后对图像进行重构。处理结果较好地增强了图像细节信息,从整体上改善了图像效果。 相似文献
30.
为了提高水印的鲁棒性和减小对应版权信息的大小,本文提出了一种基于Arnold变换、DWT和SVD的零水印算法。该算法将载体图像进行DWT变换,对低频子带进行分块SVD;比较置乱后的最大奇异值的大小,若大于则对应位为1,否则为0;将结果与预处理过的水印做异或运算,得密钥矩阵。该矩阵为检测水印提供密钥。实验证明,本算法对图像压缩、滤波、模糊、噪声及脏图具有良好的鲁棒性。 相似文献