全文获取类型
收费全文 | 6944篇 |
免费 | 403篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 98篇 |
综合类 | 28篇 |
化学工业 | 1978篇 |
金属工艺 | 183篇 |
机械仪表 | 154篇 |
建筑科学 | 416篇 |
矿业工程 | 39篇 |
能源动力 | 243篇 |
轻工业 | 464篇 |
水利工程 | 42篇 |
石油天然气 | 6篇 |
无线电 | 602篇 |
一般工业技术 | 1480篇 |
冶金工业 | 281篇 |
原子能技术 | 38篇 |
自动化技术 | 1301篇 |
出版年
2024年 | 14篇 |
2023年 | 101篇 |
2022年 | 152篇 |
2021年 | 268篇 |
2020年 | 187篇 |
2019年 | 191篇 |
2018年 | 190篇 |
2017年 | 186篇 |
2016年 | 282篇 |
2015年 | 299篇 |
2014年 | 349篇 |
2013年 | 505篇 |
2012年 | 472篇 |
2011年 | 626篇 |
2010年 | 411篇 |
2009年 | 417篇 |
2008年 | 402篇 |
2007年 | 354篇 |
2006年 | 275篇 |
2005年 | 246篇 |
2004年 | 189篇 |
2003年 | 149篇 |
2002年 | 149篇 |
2001年 | 74篇 |
2000年 | 100篇 |
1999年 | 92篇 |
1998年 | 84篇 |
1997年 | 83篇 |
1996年 | 86篇 |
1995年 | 56篇 |
1994年 | 46篇 |
1993年 | 48篇 |
1992年 | 46篇 |
1991年 | 33篇 |
1990年 | 20篇 |
1989年 | 12篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 13篇 |
1985年 | 15篇 |
1984年 | 8篇 |
1983年 | 8篇 |
1981年 | 6篇 |
1980年 | 9篇 |
1975年 | 4篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1961年 | 4篇 |
1960年 | 6篇 |
1959年 | 4篇 |
排序方式: 共有7353条查询结果,搜索用时 9 毫秒
21.
22.
A Chebyshev collocation strategy is introduced for the subdivision of cuboids into cuboidal subdomains (elements). These elements are conforming, which means that the approximation to the solution isC
0 continuous at all points across their interfaces. 相似文献
23.
Andreas Klenk Andreas Beck-Greinwald Hannes Angst Georg Carle 《Service Oriented Computing and Applications》2012,6(4):321-335
Inter-domain collaborations suffer not only from technological obstacles that hinder interoperability, but also from diverting business objectives of the involved domains. Today, hand-crafted contracts define the terms and conditions for service interactions. Electronic negotiation can serve as the enabler of dynamic interdomain collaborations by providing a large degree of freedom for the automation of agreement formation and electronic contracting. Negotiation by electronic means has been an area of intensive research for many years now. However, most effort was put on the determination of prices and neglected that real-world agreements also consist of complex dependencies of interdependent obligations. In this paper we present agreement negotiation as a tool to establish ad hoc services collaborations. Our novel protocol allows for the discovery of complex agreement options and for the formation of multi-party agreements. The protocol works through an iterative exchange of requirements and offers. A major benefit over existing bilateral negotiation protocols is that our protocol is capable of discovering potential collaborations between different parties. It will leave each negotiating party with a complete agreement document after a successful negotiation. This comprehensive agreement document defines the interdependent obligations between all parties and is well suited for E-Contracting. 相似文献
24.
Asim Muhammad Nabeel Ghani Muhammad Usman Ibrahim Muhammad Ali Mahmood Waqar Dengel Andreas Ahmed Sheraz 《Neural computing & applications》2021,33(11):5437-5469
Neural Computing and Applications - In order to provide benchmark performance for Urdu text document classification, the contribution of this paper is manifold. First, it provides a publicly... 相似文献
25.
Patrick Heymans Quentin Boucher Andreas Classen Arnaud Bourdoux Laurent Demonceau 《International Journal on Software Tools for Technology Transfer (STTT)》2012,14(5):553-566
Software product line engineering seeks to systematise reuse when developing families of similar software systems so as to minimise development time, cost and defects. To realise variability at the code level, product line methods classically advocate usage of inheritance, components, frameworks, aspects or generative techniques. However, these might require unaffordable paradigm shifts for developers if the software was not thought at the outset as a product line. Furthermore, these techniques can be conflicting with a company’s coding practices or external regulations. These concerns were the motivation for the industry–university collaboration described in this paper in which we developed a minimally intrusive coding technique based on tags. The approach was complemented with traceability from code to feature diagrams which were exploited for automated configuration. It is supported by a toolchain and is now in use in the partner company for the development of flight-grade satellite communication software libraries. 相似文献
26.
After initial necking of tensile polymer samples the deformation front moves along the gauge length at a stress which is smaller than the yield stress. The still undeformed parts of the sample are therefore subjected to conditions which favour deformation by a creep mechanism. If the extension rate is right, secondary necking becomes possible. Boundary conditions are discussed. 相似文献
27.
In the present investigation it has been shown exemplarily for an austenite microstructure containing carbonitrides that the specific restraining force of a grain boundary due to the distribution of precipitates can be described by a modified Orowan's law, so that the grain boundary movement is considered to be analogous to the dislocation movement. This is achieved by using a modified restraining force Fr (corresponding to the cubic geometry of the particles), a detailed thermodynamic analysis of the precipitates (in this case, carbonitrides) and selected relation for the interparticle spacing La. The specific restraining force and the interparticle spacing depend on temperature within the austenite range. Each temperature is attached to a couple (Fr/La). The plot Fr against shows straight lines for each steel and from their average slope, a shear module G' of grain boundaries, which is about 64300 N·cm?2, is obtained. Hence, it is possible to describe the specific restraining force of a grain boundary with the help of Orowan's law or as it is conventionally done by using Zener's modell. At a critical temperature T*, which is different for each steel, the specific restraining force is equal to the driving force of the grain boundary. The corresponding values of La are also different for each steel and the steel which is the most resistant to grain coarsening is allowed to have the greatest value of La which still retains the capacity of impeding grain coarsening. 相似文献
28.
Andreas Guete 《电子技术应用》2014,(3)
正早在20世纪90年代,触摸板就已作为笔记本电脑的用户接口出现了。今天,触摸板已大规模替代轨迹球和操控手柄。触摸技术已经升级到了电容式触摸传感,并且其功能已囊括多点触摸。尽管在过去的20年里触摸板技术有了长足的发展,但由于安装条件有限,并且触摸板需要大约5 mm~7 mm的厚度,这些仍然限制 相似文献
29.
Andreas Lübbert 《化学,工程师,技术》1990,62(6):474-483
Trends in the use of real-time computers for research and development in industrial chemistry. Computers are integral parts of the complex equipment of chemical production plants. They are tools for computer aided process control. In production plants as well as in research and development laboratories, dedicated computer systems are used more and more. E. g., nearly all measuring devices will be controlled by their own microprocessors in the near future. In chemical engineering, however, the most significant developments are taking place in the software domain. The main trend in applications-software developments is the enhanced importance of the support of the plant operators by means of improved user interfaces. Within the research and development field, the software must be more flexibly adaptable to changes in the process equipment and due to changing control algorithms than in production plants. Moreover, efforts are being made to improve control by exploiting as much as possible a priori knowledge on the system in question. A current development in this direction, which will become stronger with time, is known under the heading ?expert systems”?, in which heuristic know-how of operators is made available and usable in process computers to improve control. 相似文献
30.
Jet bundle formulation of infinite-dimensional port-Hamiltonian systems using differential operators
We consider infinite-dimensional port-Hamiltonian systems described on jet bundles. Based on a power balance relation we introduce the port-Hamiltonian system representation using differential operators regarding the structural mapping, the dissipation mapping and the input mapping. In contrast to the well-known representation on the basis of the underlying Stokes–Dirac structure our approach is not necessarily based on using energy-variables which leads to a different port-Hamiltonian representation of the analyzed partial differential equations. The presented constructions will be specialized to mechanical systems to which class also the presented examples belong. 相似文献