全文获取类型
收费全文 | 24758篇 |
免费 | 2948篇 |
国内免费 | 1987篇 |
专业分类
电工技术 | 2247篇 |
技术理论 | 7篇 |
综合类 | 3448篇 |
化学工业 | 808篇 |
金属工艺 | 234篇 |
机械仪表 | 1179篇 |
建筑科学 | 8316篇 |
矿业工程 | 374篇 |
能源动力 | 358篇 |
轻工业 | 711篇 |
水利工程 | 273篇 |
石油天然气 | 444篇 |
武器工业 | 246篇 |
无线电 | 2616篇 |
一般工业技术 | 1540篇 |
冶金工业 | 255篇 |
原子能技术 | 198篇 |
自动化技术 | 6439篇 |
出版年
2024年 | 89篇 |
2023年 | 306篇 |
2022年 | 654篇 |
2021年 | 722篇 |
2020年 | 695篇 |
2019年 | 583篇 |
2018年 | 581篇 |
2017年 | 714篇 |
2016年 | 866篇 |
2015年 | 999篇 |
2014年 | 1790篇 |
2013年 | 1465篇 |
2012年 | 1982篇 |
2011年 | 2136篇 |
2010年 | 1839篇 |
2009年 | 1788篇 |
2008年 | 1792篇 |
2007年 | 1938篇 |
2006年 | 1667篇 |
2005年 | 1317篇 |
2004年 | 1038篇 |
2003年 | 853篇 |
2002年 | 667篇 |
2001年 | 586篇 |
2000年 | 533篇 |
1999年 | 419篇 |
1998年 | 303篇 |
1997年 | 222篇 |
1996年 | 199篇 |
1995年 | 188篇 |
1994年 | 149篇 |
1993年 | 115篇 |
1992年 | 120篇 |
1991年 | 63篇 |
1990年 | 54篇 |
1989年 | 53篇 |
1988年 | 47篇 |
1987年 | 27篇 |
1986年 | 23篇 |
1985年 | 15篇 |
1984年 | 10篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 9篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1959年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
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
72.
Markovian and semi-Markovian random processes are used to analyze the problem of optimal search for signals in a multichannel
communication system with arbitrarily distributed random outputs. The search efficiency factor is found in explicit form based
on state space merging, and a mathematical programming problem is set up to find a numerical suboptimal solution.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 144–150, May–June 2007. 相似文献
73.
Ambedkar Dukkipati 《Information Sciences》2007,177(24):5707-5714
The measure-theoretic definition of Kullback-Leibler relative-entropy (or simply KL-entropy) plays a basic role in defining various classical information measures on general spaces. Entropy, mutual information and conditional forms of entropy can be expressed in terms of KL-entropy and hence properties of their measure-theoretic analogs will follow from those of measure-theoretic KL-entropy. These measure-theoretic definitions are key to extending the ergodic theorems of information theory to non-discrete cases. A fundamental theorem in this respect is the Gelfand-Yaglom-Perez (GYP) Theorem [M.S. Pinsker, Information and Information Stability of Random Variables and Process, 1960, Holden-Day, San Francisco, CA (English ed., 1964, translated and edited by Amiel Feinstein), Theorem. 2.4.2] which states that measure-theoretic relative-entropy equals the supremum of relative-entropies over all measurable partitions. This paper states and proves the GYP-theorem for Rényi relative-entropy of order greater than one. Consequently, the result can be easily extended to Tsallis relative-entropy. 相似文献
74.
CIE TC8‐01 has adopted a new color appearance model: CIECAM021 replaces the CIECAM97s.2 The new model consists of a number of refinements and simplifications of the CIECAM97s color appearance model. This article describes further tests to the robustness of the forward and reverse modes. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 99–106, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20087 相似文献
75.
介绍了法西斯大厦的基本情况,通过对朱赛普·特拉尼的代表作法西斯大厦的空间结构、承重结构、围护结构、立面结构的分析,以使人们更深刻地理解特拉尼的建筑思想,探索其积极的现实意义。 相似文献
76.
An Efficient Code-Based Voxel-Traversing Algorithm 总被引:3,自引:1,他引:2
The paper considers an efficient approach to traversing a uniformly-subdivided space pierced by a line segment. A voxel, as the basic constituent element of the uniformly subdivided space, is restricted to having the form of a cube. The algorithm works in two steps. In the first step, the so-called Bresenham voxels are identified and, by comparing their position codes, their type of connectivity is determined. To achieve the required connectivity between neighbouring voxels, the second step of the algorithm is applied to find the missing voxels. In this way, the algorithm efficiently switches between face-, edge- and vertex-connectivity. Although the algorithm works with oating-point precision, it is extremely computationally efficient, and tests of speed compared with the Müller, Cleary & Wyvill, Amanatides & Woo, and Zemčik algorithms are described. 相似文献
77.
阮芙英 《纺织高校基础科学学报》1995,8(1):91-95
现代光学和通讯理论由于引入了傅里叶变换的方法,使计算光学系统和通讯系统的物像的对应关系简洁、清晰。该文用傅氏变换计算长为2a、照度为A的均匀缝光源在观察面上的光强分布为I(x)=│E(x)│^2=AA^2a^2(sin2πfa/2πfa)此方法也可运用于矩形孔、圆孔等。 相似文献
78.
Automated techniques for satellite imagery navigation and co-location are especially required for environmental monitoring activities intensively using satellite data. In this work are presented the results obtained after 2 years of operational use of the Subpixel Automatic Navigation of AVHRR (SANA) scheme. An automatic method for accuracy assessment of satellite navigation techniques, which permits a preliminary evaluation of their performances, dealing with a large collection of test images is also proposed. The navigation accuracy assessment, performed by using a selection of small islands as reference points, is discussed.Results achieved over more than 400 Advanced Very-High-Resolution Radiometer (AVHRR) scenes confirm that the SANA scheme is a very accurate one (computed mean navigation error is generally about one AVHRR pixel). Furthermore, because of its high processing speed, it can be considered a suitable tool for intensive satellite data processing in multitemporal analyses, especially required for environmental studies as well as for operational monitoring purposes. 相似文献
79.
In this paper we show that finding solutions of a system of multivariate polynomial equalities and inequalities in the max algebra is equivalent to solving an Extended Linear Complementarity Problem. This allows us to find all solutions of such a system of multivariate polynomial equalities and inequalities and provides a geometrical insight in the structure of the solution set. We also demonstrate that this enables us to solve many important problems in the max algebra and the max-min-plus algebra such as matrix decompositions, construction of matrices with a given characteristic polynomial, state space transformations and the (minimal) state space realization problem.Research assistant with the N.F.W.O. (Belgian National Fund for Scientific Research).Senior research associate with the N.F.W.O. 相似文献
80.
Aleksej G. Voloboj 《Computer Graphics Forum》1993,12(5):289-296
The paper describes the colour approximation problem and the method of dynamic palette construction is suggested for its solution. The method uses the graphic display palette based on the computed true colour of the individual picture. Some aspects of human colour perception are considered. Two metrics in colour space are introduced to estimate closeness of the suggested colour approximation. The method was applied to visualize 3D scenes generated by ray tracing. 相似文献