全文获取类型
收费全文 | 3167篇 |
免费 | 248篇 |
国内免费 | 54篇 |
专业分类
电工技术 | 124篇 |
综合类 | 143篇 |
化学工业 | 556篇 |
金属工艺 | 94篇 |
机械仪表 | 114篇 |
建筑科学 | 230篇 |
矿业工程 | 32篇 |
能源动力 | 125篇 |
轻工业 | 212篇 |
水利工程 | 37篇 |
石油天然气 | 136篇 |
武器工业 | 12篇 |
无线电 | 426篇 |
一般工业技术 | 520篇 |
冶金工业 | 206篇 |
原子能技术 | 39篇 |
自动化技术 | 463篇 |
出版年
2024年 | 8篇 |
2023年 | 37篇 |
2022年 | 73篇 |
2021年 | 120篇 |
2020年 | 103篇 |
2019年 | 114篇 |
2018年 | 109篇 |
2017年 | 94篇 |
2016年 | 117篇 |
2015年 | 100篇 |
2014年 | 114篇 |
2013年 | 202篇 |
2012年 | 190篇 |
2011年 | 209篇 |
2010年 | 148篇 |
2009年 | 176篇 |
2008年 | 196篇 |
2007年 | 137篇 |
2006年 | 157篇 |
2005年 | 127篇 |
2004年 | 98篇 |
2003年 | 81篇 |
2002年 | 83篇 |
2001年 | 62篇 |
2000年 | 73篇 |
1999年 | 64篇 |
1998年 | 98篇 |
1997年 | 72篇 |
1996年 | 50篇 |
1995年 | 50篇 |
1994年 | 42篇 |
1993年 | 30篇 |
1992年 | 10篇 |
1991年 | 18篇 |
1990年 | 10篇 |
1989年 | 17篇 |
1988年 | 12篇 |
1987年 | 8篇 |
1986年 | 4篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1971年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有3469条查询结果,搜索用时 0 毫秒
101.
Rong-Jong Wai Yu-Chih Huang Yi-Chang Chen You-Wei Lin 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2013,17(10):1797-1815
This study mainly focuses on the development of intelligent forecasting structures via a similar time method with historical load change rates for the hourly, daily and monthly load forecasting simultaneously based on the basic frameworks of fuzzy neural network (FNN) and particle swarm optimization (PSO). In the regulative aspect of network parameters, conventional back-propagation (BP) and PSO tuning algorithms are used, and varied learning rates are designed in the sense of discrete-time Lyapunov stability theory. The performance comparisons of different intelligent forecasting structures including neural network (NN) structure with BP tuning algorithm (NN-BP), FNN structure with BP tuning algorithm (FNN-BP), FNN structure with BP tuning algorithm and varied learning rates (FNN-BP-V), FNN structure with PSO tuning algorithm (FNN-PSO) and newly-designed adaptive PSO (APSO) structure are verified by numerical simulations. In order to verify the effectiveness of the superior APSO forecasting structure in practical energy-saving load regulation, the load forecasting during every 15 min is also given, and its result is used to manipulate the scheduled unloading control of a real case in Taiwan campus. 相似文献
102.
Hong-Hsu Yen Steven S. W. Lee Florence G. H. Yap 《The Journal of supercomputing》2012,62(3):1119-1138
Multicast routing in wireless networks that possess the wireless multicast advantage could significantly reduce the power and energy consumption. However, this kind of multicast routing that only addresses the transmission radius coverage might not be able to meet the bandwidth requirement of the users. As a result, additional transmissions are required to incur more energy consumption and carbon dioxide emissions that make existing algorithms not applicable to bandwidth constrained applications. In this paper, for the first time, we address the bandwidth aware minimum power multicast routing problem in wireless networks where the objective function is to minimize the total power consumption subject to the users?? bandwidth requirements. This problem is a challenging cross-layer design problem that requires seamless and sophisticated integrated design in the network layer (multicast routing) and physical layer (bandwidth-aware wireless transmission and power control). We first formulate this problem as a mixed integer linear programming problem and then propose a Lagrangian relaxation based algorithm to solve this problem. Numerical results demonstrate that the proposed approach is a sound green networking algorithm that outperforms the existing power efficient multicast routing approaches under all tested cases, especially in large bandwidth request, fine radius granularity, large group size and sparse network. 相似文献
103.
104.
精密校准源是基于二极管检波方式的峰值功率分析仪进行功率测量时的溯源标准,因此要求具有很高的功率准确度。本文针对影响精密校准源功率输出准确度的误差进行了分析,通过对这些误差的修正,使校准源的功率输出在大动态范围内具有了极高的准确度,应用于某峰值功率分析仪中,取得了很好的效果。 相似文献
105.
106.
The dynamic response of a sliding-mode-controlled slider-crank mechanism, which is driven by a permanent-magnet (PM) synchronous servo motor, is studied in this paper. First, a position controller is developed based on the principles of sliding-mode control. Moreover, to relax the requirement of the bound of uncertainties in the design of a sliding-mode controller, a fuzzy neural network (FNN) sliding-mode controller is investigated, in which a FNN is adopted to adjust the control gain in a switching control law on line to satisfy the sliding mode condition. In addition, to guarantee the convergence of tracking error, analytical methods based on a discrete-type Lyapunov function are proposed to determine the varied learning rates of the FNN. Numerical and experimental results show that the dynamic behaviors of the proposed controller-motor-mechanism system are robust with regard to parametric variations and external disturbances. Furthermore, compared with the sliding-mode controller, smaller control effort results and the chattering phenomenon is much reduced by the proposed FNN sliding-mode controller 相似文献
107.
108.
109.
级联双稳随机共振系统非线性滤波特性 总被引:1,自引:0,他引:1
在级联双稳随机共振理论研究的基础上,探讨了信号通过级联双稳系统后,在能量逐渐由高频向低频转移的同时,还具有非线性的低通滤波特性。对于具有不同幅值分布的各频率分量,仿真实验表明,低频幅值如果相对高频幅值较大,通过较少级数的级联双稳系统可达到较好的低通滤波效果,而对于高频幅值比低频幅值大的情况,通过较多级数的级联双稳系统也可达到满意的低通滤波效果。最后,通过一个金属切削实验说明了其工程实用性。 相似文献
110.
结合工程实例,简单阐述酸性水罐的氮封系统设计。本设计采用安全水封罐确保酸性水罐压力,通过脱臭罐排放硫化氢气体;在脱臭罐出现事故情况下则通过安全水封罐排放硫化氢气体。该流程与储运常规氮风系统流程相比,更加安全可靠,更有利于减少环境污染。 相似文献