全文获取类型
收费全文 | 17302篇 |
免费 | 518篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 236篇 |
综合类 | 23篇 |
化学工业 | 2391篇 |
金属工艺 | 520篇 |
机械仪表 | 190篇 |
建筑科学 | 614篇 |
矿业工程 | 98篇 |
能源动力 | 306篇 |
轻工业 | 594篇 |
水利工程 | 50篇 |
石油天然气 | 20篇 |
武器工业 | 1篇 |
无线电 | 939篇 |
一般工业技术 | 1801篇 |
冶金工业 | 499篇 |
原子能技术 | 131篇 |
自动化技术 | 9415篇 |
出版年
2024年 | 15篇 |
2023年 | 117篇 |
2022年 | 208篇 |
2021年 | 329篇 |
2020年 | 199篇 |
2019年 | 210篇 |
2018年 | 231篇 |
2017年 | 267篇 |
2016年 | 351篇 |
2015年 | 294篇 |
2014年 | 581篇 |
2013年 | 759篇 |
2012年 | 1287篇 |
2011年 | 2976篇 |
2010年 | 1595篇 |
2009年 | 1410篇 |
2008年 | 1140篇 |
2007年 | 992篇 |
2006年 | 816篇 |
2005年 | 866篇 |
2004年 | 765篇 |
2003年 | 756篇 |
2002年 | 434篇 |
2001年 | 102篇 |
2000年 | 96篇 |
1999年 | 114篇 |
1998年 | 123篇 |
1997年 | 95篇 |
1996年 | 86篇 |
1995年 | 51篇 |
1994年 | 59篇 |
1993年 | 37篇 |
1992年 | 47篇 |
1991年 | 26篇 |
1990年 | 39篇 |
1989年 | 23篇 |
1988年 | 28篇 |
1987年 | 27篇 |
1986年 | 23篇 |
1985年 | 20篇 |
1984年 | 29篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 15篇 |
1980年 | 20篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 26篇 |
1975年 | 13篇 |
1969年 | 11篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
Adaptive motion control using neural network approximations 总被引:1,自引:0,他引:1
In this paper, we present a new adaptive technique for tracking control of mechanical systems in the presence of friction and periodic disturbances. Radial Basis Functions (RBFs) are used to compensate for the effects of nonlinearly occurring parameters in the friction and periodic disturbance model. Theoretical analysis, such as stability and transient performance, is provided. Furthermore, the performance of the adaptive RBF controller and its non-adaptive counterpart are compared. 相似文献
23.
24.
Roland Gabriel Jürgen Kunz Lars Schwarze Peter Fettke Christian Scheer Franz Lehner Konrad Walser Thomas Deelmann 《WIRTSCHAFTSINFORMATIK》2006,48(3):218-222
Ohne Zusammenfassung 相似文献
25.
Christian P. Romero Jonathan I. Avila Edgardo Cisternas Guerau B. Cabrera Alejandro L. Cabrera Kristiaan Temst Margriet J. Van Bael 《Journal of Materials Science》2007,42(18):7667-7672
Hydrogen desorption curves were obtained from a sample composed of a square arrangement of Co dots with average diameter of
4.4 μm, separated by a distance of 11.6 μm. A macroscopic sample of Co dots grown on a 2.5 × 2.5 cm Si substrate was made
by standard lithographic techniques and used in these experiments. Thermal programmed desorption (TPD) was performed under
ultra-high vacuum conditions. Hydrogen TPD curves were obtained from a 1 × 1 cm Co dots samples displaying a maximum of intensity
at 425 K. Hydrogen TPD curve was also obtained from 1 cm× 1 cm samples of Co films and Co foils for comparison. The hydrogen
TPD curves have decreasing intensity from the Co foils to the Co dots and finally to the Co films. This indicates that there
are more sites for hydrogen adsorption on the Co dots than in the Co films. This is a surprising result because there is approximately
8.7 times less Co atoms exposed in the Co dots that in the Co film sample. A desorption energy of 27 kcal/mol was obtained
for the Co dots suggesting that hydrogen is adsorbed on an hcp hollow site of the Co dot crystalline structure. 相似文献
26.
Christian Ligoure Michel Cloitre Christille Le Chatelier Fabrice Monti 《Polymer》2005,46(17):6402-6410
A remarkable correlation exists between the degree of expansion of polyurethane foams and the structure of the reacting premixes. Polyurethane foams obtained from reacting premixes containing microemulsions are highly expanded. The expansion rate is proportional to the volume fraction of microemulsion in the premix. The stability of premixes with and without microemulsion is completely different suggesting distinct creaming mechanisms. We apply this idea to synthesize polyurethane foams from microemulsions successfully. This approach can be used to rationalize the design of polyurethane formulations leading to highly expanded foams. 相似文献
27.
Cherng-Min MaAuthor Vitae 《Pattern recognition》2003,36(8):1775-1782
Generally, a reduction operation (e.g., thinning and shrinking) on 3D binary images can be represented as a set of reduction templates where every object voxel of the image satisfying any template is turned to a background voxel. Generally, it is rather difficult, error-prone and time-consuming for verifying the topological soundness of a 3D parallel reduction operation. This paper proposes sufficient conditions of time complexity O(n) for verifying the topological soundness of 3D parallel 6-subiteration reduction operations of n templates where such a kind of 3D reduction operations is performed alternatively from the six orthogonal directions to turn object voxels to background voxels. By such sufficient conditions, the topology soundness of a 3D 6-subiteration parallel reduction operation can be verified by checking each and every of its templates. 相似文献
28.
In this paper, we present a control methodology for a class of discrete time nonlinear systems that depend on a possibly exogenous scheduling variable. This class of systems consists of an interpolation of nonlinear dynamic equations in strict feedback form, and it may represent systems with a time-varying nonlinear structure. Moreover, this class of systems is able to represent some cases of gain scheduling control, Takagi-Sugeno fuzzy systems, as well as input-output realizations of nonlinear systems which are approximated via localized linearizations. We present two control theorems, one using what we call a “global” approach (akin to traditional backstepping), and a “local” approach, our main result, where backstepping is again used but the control law is an interpolation of local control terms. An aircraft wing rock regulation problem with varying angle of attack is used to illustrate and compare the two approaches. 相似文献
29.
30.
Shawn Hu Author Vitae Author Vitae 《Automatica》2007,43(7):1243-1248
This paper is concerned with stability analysis of discrete-time networked control systems over a communication channel subject to packet loss whose behavior is modeled by an i.i.d Bernoulli process with a packet dropping probability bounded by a constant. A necessary and sufficient condition for stability is obtained. A packet dropping margin is introduced as a measure of stability robustness of a system against packet dropping, and a formula for it is derived. A design method is proposed for achieving a large margin subject to a constraint that the system has a set of prescribed nominal closed-loop poles. 相似文献