全文获取类型
收费全文 | 3029篇 |
免费 | 179篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 93篇 |
综合类 | 4篇 |
化学工业 | 722篇 |
金属工艺 | 62篇 |
机械仪表 | 104篇 |
建筑科学 | 102篇 |
矿业工程 | 8篇 |
能源动力 | 122篇 |
轻工业 | 501篇 |
水利工程 | 16篇 |
石油天然气 | 14篇 |
无线电 | 186篇 |
一般工业技术 | 776篇 |
冶金工业 | 24篇 |
原子能技术 | 10篇 |
自动化技术 | 465篇 |
出版年
2023年 | 24篇 |
2022年 | 20篇 |
2021年 | 67篇 |
2020年 | 58篇 |
2019年 | 69篇 |
2018年 | 120篇 |
2017年 | 112篇 |
2016年 | 142篇 |
2015年 | 101篇 |
2014年 | 149篇 |
2013年 | 335篇 |
2012年 | 211篇 |
2011年 | 226篇 |
2010年 | 188篇 |
2009年 | 133篇 |
2008年 | 141篇 |
2007年 | 123篇 |
2006年 | 95篇 |
2005年 | 54篇 |
2004年 | 32篇 |
2003年 | 51篇 |
2002年 | 38篇 |
2001年 | 31篇 |
2000年 | 36篇 |
1999年 | 30篇 |
1998年 | 22篇 |
1997年 | 15篇 |
1996年 | 26篇 |
1995年 | 20篇 |
1994年 | 29篇 |
1993年 | 23篇 |
1992年 | 23篇 |
1991年 | 20篇 |
1990年 | 20篇 |
1989年 | 17篇 |
1988年 | 13篇 |
1985年 | 33篇 |
1984年 | 35篇 |
1983年 | 28篇 |
1982年 | 24篇 |
1981年 | 36篇 |
1980年 | 32篇 |
1979年 | 25篇 |
1978年 | 24篇 |
1977年 | 18篇 |
1976年 | 20篇 |
1975年 | 13篇 |
1974年 | 11篇 |
1973年 | 14篇 |
1972年 | 14篇 |
排序方式: 共有3209条查询结果,搜索用时 15 毫秒
41.
42.
Oxidation of formic acid at a high surface area supported platinum modified by foreign metal adatoms
The anodic oxidation of formic acid was studied on platinum distributed in the form of small particles in a porous substrate modified by metal adatoms deposited at underpotentials. The rate of the reaction was greatly enhanced on the commercial catalyst Powercat 3000 (PC 3000). The hydrogen adsorption and the underpotential deposition of several metals at PC 3000 were shown to be dissimilar to that at smooth polycrystalline Pt. Steady-state and long-term experiments were performed to determine the stability of this electrode. 相似文献
43.
This paper presents the concept of decomposition as applied to the control synthesis of multivariable mechanical systems, in which the coupling among the subsystems can be very strong. The system class considered contains subsystems with powered degrees of freedom, as well as subsystems without their own actuators. Global control is introduced to diminish the influence of coupling on the stability of the whole system. The procedure is illustrated by simulation of two examples, one in robotics, the other in biomechanics. 相似文献
44.
Survey of Intelligent Control Techniques for Humanoid Robots 总被引:8,自引:0,他引:8
This paper focusses on the application of intelligent control techniques (neural networks, fuzzy logic and genetic algorithms) and their hybrid forms (neuro-fuzzy networks, neuro-genetic and fuzzy-genetic algorithms) in the area of humanoid robotic systems. It represents an attempt to cover the basic principles and concepts of intelligent control in humanoid robotics, with an outline of a number of recent algorithms used in advanced control of humanoid robots. Overall, this survey covers a broad selection of examples that will serve to demonstrate the advantages and disadvantages of the application of intelligent control techniques. 相似文献
45.
In this paper we present an electromagnetism (EM) metaheuristic for solving NP hard Maximum Betweenness Problem (MBP). A new encoding scheme with appropriate objective functions is implemented. Specific representation of the individuals enables the EM operators to explore the searching space in a way that achieves high quality solutions. An effective 1-swap based local search procedure improved by the specific caching technique is performed on each EM point. The algorithm is tested both on real and artificial instances from the literature. Experimental results show that the proposed EM approach achieves all previously known optimal solutions, except one, and achieves the best-known solutions or outperforms other approaches on all large-scale instances, except two. Provided statistical analysis indicates that the EM approach is significantly better than other approaches. 相似文献
46.
Branko Mitrović 《Nexus Network Journal》2013,15(1):51-62
Nelson Goodman’s highly influential book Languages of Art argued that that all visual experience is merely a cultural construct. In presenting his thesis Goodman relied on a series of geometrical arguments intended to show that the geometrical construction of perspective does not rely on the geometry of light rays. In this article I analyze the geometrical validity of Goodman’s arguments. 相似文献
47.
48.
This paper deals with modelling and performance of adjustable speed drives (ASDs) subjected to voltage disturbances in electric supply. The aim of this study was to develop appropriate models of typical ASD and investigate their sensitivity to voltage disturbances under various practical modes of operation and control. Accordingly, scalar controlled open and closed loop volts–hertz (V–Hz) and vector controlled closed loop ASDs are modelled in PSCAD/EMTDC environment, and their performance in the presence of voltage disturbances is investigated under typical operating and loading conditions. 相似文献
49.
The proposed procedure is implemented without breaking the loop with the controller in operation, by activating a cascade of band-pass filters in series with a relay in the inner loop and a notch filter in the outer loop. A highly accurate estimate of the critical point of a process Gp(s) is obtained in the presence of measurement noise and load disturbance. The effectiveness of the proposed procedure is illustrated using a test batch consisting of stable, integrating and unstable processes, including dead-time. 相似文献
50.