全文获取类型
收费全文 | 96422篇 |
免费 | 13465篇 |
国内免费 | 9599篇 |
专业分类
电工技术 | 15199篇 |
技术理论 | 9篇 |
综合类 | 11298篇 |
化学工业 | 3384篇 |
金属工艺 | 1856篇 |
机械仪表 | 4937篇 |
建筑科学 | 3927篇 |
矿业工程 | 2532篇 |
能源动力 | 2047篇 |
轻工业 | 1356篇 |
水利工程 | 1948篇 |
石油天然气 | 1755篇 |
武器工业 | 964篇 |
无线电 | 20373篇 |
一般工业技术 | 3916篇 |
冶金工业 | 1602篇 |
原子能技术 | 252篇 |
自动化技术 | 42131篇 |
出版年
2024年 | 848篇 |
2023年 | 2179篇 |
2022年 | 4107篇 |
2021年 | 4464篇 |
2020年 | 4504篇 |
2019年 | 3202篇 |
2018年 | 2659篇 |
2017年 | 3108篇 |
2016年 | 3241篇 |
2015年 | 3732篇 |
2014年 | 6439篇 |
2013年 | 5611篇 |
2012年 | 7327篇 |
2011年 | 7560篇 |
2010年 | 5861篇 |
2009年 | 6185篇 |
2008年 | 6453篇 |
2007年 | 7222篇 |
2006年 | 6035篇 |
2005年 | 5399篇 |
2004年 | 4502篇 |
2003年 | 3992篇 |
2002年 | 3115篇 |
2001年 | 2652篇 |
2000年 | 2126篇 |
1999年 | 1741篇 |
1998年 | 1239篇 |
1997年 | 1006篇 |
1996年 | 815篇 |
1995年 | 617篇 |
1994年 | 466篇 |
1993年 | 309篇 |
1992年 | 197篇 |
1991年 | 132篇 |
1990年 | 100篇 |
1989年 | 91篇 |
1988年 | 57篇 |
1987年 | 29篇 |
1986年 | 29篇 |
1985年 | 33篇 |
1984年 | 19篇 |
1983年 | 21篇 |
1982年 | 27篇 |
1981年 | 7篇 |
1980年 | 3篇 |
1979年 | 8篇 |
1978年 | 2篇 |
1975年 | 2篇 |
1959年 | 4篇 |
1951年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Evolution of the capillary network in a reactive powder concrete during hydration process 总被引:7,自引:0,他引:7
V. Morin F. Cohen-Tenoudji A. Feylessoufi P. Richard 《Cement and Concrete Research》2002,32(12):1907-1914
Ultrasonic waves in echographic mode, combined with autogenous shrinkage measurements, were used to study the evolution of the capillary network of reactive powder concrete (RPC) from the time after the mixing. Two characteristic porous classes have been identified: the first, between 10 and 20 nm, begins when the material reaches its solid hyperstatic state, and the second about 1 or 2 nm. The first class is associated with the porous space between the C-S-H hydrate clusters and the second with the internal porosity of the hydrate. The evolution of the active capillary radius as a function of the degree of hydration allows us to understand the strong interaction between the capillary network size and the chemical activity given by the dissipated calorimetric power curve. Indeed, the maximum point of the chemical activity marks the transition of the first class of pores to the second one. Finally, measurements of electrical conductivity through RPC samples show that after the maximum of the dissipated power, the curve of this electrical conductivity presents the same evolution as the capillary radius. As the electrical conductivity clearly depends on the evolution of the capillary network, the similarity between the results confirms our analysis in pore classes. 相似文献
42.
43.
F. L. Lewis 《Journal of Intelligent and Robotic Systems》2007,48(4):513-523
This is an outline of research in neural networks for feedback control done since the mid 1990s at the Automation and Robotics
Research Institute (ARRI) of The University of Texas at Arlington (UTA). It shows how the developments of Intelligent Control
Systems based on neural networks have followed three main generations. This statement provides a short, broad-brush perspective
on the development of intelligent neural feedback controllers. 相似文献
44.
In this study forecast of Turkey's net electricity energy consumption on sectoral basis until 2020 is explored. Artificial neural networks (ANN) is preferred as forecasting tool. The reasons behind choosing ANN are the ability of ANN to forecast future values of more than one variable at the same time and to model the nonlinear relation in the data structure. Founded forecast results by ANN are compared with official forecasts. 相似文献
45.
以网络计划在银山前区转炉、连铸壬程中的应用实例,论述了施工网络计划执行过程中,跟踪、调整、优化、实施的重要性。 相似文献
46.
号码是一种有限的资源,虽然企业专网的号码资源比较丰富,但也不能毫无规律随意编制,否则会为将来发展带来意想不到的麻烦,本文叙述了号码编制必须遵循的一些原则,希望对专网的管理人员有一些帮助。 相似文献
47.
48.
49.
Yurak Son Takuya Kamano Takashi Yasuno Takayuki Suzuki Hironobu Harada 《Electrical Engineering in Japan》2006,155(1):35-43
This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environments. The CPGs act as the flexible oscillators of the joints and adjust joint angles to required values. The CPGs are interconnected with each other and sets of their coupling parameters are adjusted by a genetic algorithm so that the quadruped robot can realize stable and adequate gait patterns. Generation of gait patterns results in the formation of the CPG networks suitable for the formation of not only a straight walking pattern but also of rotating gait patterns. Experimental results demonstrate that the proposed CPG networks are effective for the automatic adjustment of the adaptive gait patterns for the tested quadruped robot under various environments. Furthermore, the target tracking control based on image processing is achieved by combining the general gait patterns. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 155(1): 35–43, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20225 相似文献
50.
冶金坑内矿多级机站通风系统设计 总被引:2,自引:0,他引:2
本文简要论述了冶金坑内矿多级机站通风系统设计的基本原则及计算方法,并给出一个设计实例。 相似文献