全文获取类型
收费全文 | 840篇 |
免费 | 100篇 |
国内免费 | 72篇 |
专业分类
电工技术 | 84篇 |
综合类 | 40篇 |
化学工业 | 111篇 |
金属工艺 | 66篇 |
机械仪表 | 64篇 |
建筑科学 | 21篇 |
矿业工程 | 11篇 |
能源动力 | 28篇 |
轻工业 | 48篇 |
水利工程 | 6篇 |
石油天然气 | 13篇 |
武器工业 | 4篇 |
无线电 | 142篇 |
一般工业技术 | 59篇 |
冶金工业 | 19篇 |
原子能技术 | 31篇 |
自动化技术 | 265篇 |
出版年
2024年 | 4篇 |
2023年 | 5篇 |
2022年 | 25篇 |
2021年 | 25篇 |
2020年 | 23篇 |
2019年 | 18篇 |
2018年 | 11篇 |
2017年 | 27篇 |
2016年 | 32篇 |
2015年 | 26篇 |
2014年 | 53篇 |
2013年 | 48篇 |
2012年 | 65篇 |
2011年 | 87篇 |
2010年 | 59篇 |
2009年 | 71篇 |
2008年 | 67篇 |
2007年 | 62篇 |
2006年 | 55篇 |
2005年 | 45篇 |
2004年 | 52篇 |
2003年 | 51篇 |
2002年 | 30篇 |
2001年 | 26篇 |
2000年 | 12篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1959年 | 2篇 |
排序方式: 共有1012条查询结果,搜索用时 0 毫秒
951.
952.
具体介绍了三相脉宽调制(PWM)引擎SA866的各项功能参数及其脉宽调制原理,给出一种在变频调速应用中的实用方案。 相似文献
953.
G. Girardin G. Rimpault F. Morin J.C. Bosq P. Coddington K. Mikityuk R. Chawla 《Annals of Nuclear Energy》2008
The present paper is related to the design and neutronic characterization of the principal control assembly system for the reference large (2400 MWth) Generation IV gas-cooled fast reactor (GFR), which makes use of ceramic–ceramic (CERCER) plate-type fuel-elements with (U–Pu) carbide fuel contained within a SiC inert matrix. For the neutronic calculations, the deterministic code system ERANOS-2.0 has been used, in association with a full core model including a European fast reactor (EFR)-type pattern for the control assemblies as a starting point. More specifically, the core contains a total of 33 control (control system device: CSD) and safety (diverse safety device: DSD) assemblies implemented in three banks. In the design of the new control assembly system, particular attention was given to the heat generation within the assemblies, so that both neutronic and thermal–hydraulic constraints could be appropriately accounted for. The thermal–hydraulic calculations have been performed with the code COPERNIC, significant coolant mass flow rates being found necessary to maintain acceptable cladding temperatures of the absorber pins. 相似文献
954.
针对平面点集的最小权三角剖分问题,在实测的基础上.首先得出遗传算法和模拟退火算法的优良参数,然后在优良参数的条件下进行运行效率上的比较.所得结论为在点集规模较大时,模拟退火算法明显优于遗传算法。所得结论对于采用这两种算法解决其他问题也具有借鉴意义。 相似文献
955.
文中在分析L-PLC系统特点和自动增益AGC控制电路工作原理的基础上,设计了一种具有高信噪比、低失真和宽动态范围的自增益控制电路。着重阐明了该电路的硬件设计,并给出了重要参数的设计公式。 相似文献
956.
In recent times nanotechnology has drawn significant attention in the field of refractory research. Different nano-powders and colloidal suspensions have been utilized to improve the properties of refractory castables. Various studies have been carried out worldwide with nano scaled binders; such as, hydratable alumina (HA), colloidal alumina (CA), colloidal silica (CS), micro silica, etc.; to improve the thermo mechanical properties of refractory materials. Nano scaled additives are also being applied to reduce the energy consumption and to improve the densification process at lower temperatures. In this paper, the contributions of nanotechnology in selection of raw materials, the binders and choice of additives to improve the quality of refractory materials, and the future of nanotechnology in refractory research are reviewed. 相似文献
957.
Present status of the JT-60SA (JT-60 Super Advanced) project, implemented jointly by Europe and Japan since 2007, is described. The design of the main tokamak components was completed in late 2008, and all the scientific missions are preserved to contribute to ITER and DEMO reactors. The construction of the JT-60SA has begun with procurement activities for the superconducting magnet systems, vacuum vessel, in-vessel components and other components under the relevant procurement arrangements between the implementing agencies of JAEA (Japan Atomic Energy Agency) in Japan and Fusion for Energy in Europe. Designs and developments of the auxiliary heating systems for JT-60SA have been progressing at JAEA so as to provide the total injection power of 41 MW for 100 s. 相似文献
958.
959.
SA508-3 钢平衡相转变的热力学计算和分析 总被引:2,自引:0,他引:2
采用Thermo-Calc热力学软件计算了SA508-3钢(%:0.19C、0.01-0.22Si、1.40-1.58Mn、0.65- 0.76Ni、0.50-0.55Mo)的析出相、析出温度和各相的含量,并研究了Si和Mn-Ni-Mo含量对该钢析出相的影响。计算结果表明,SA508-3钢平衡态的析出相主要为合金渗碳体、M7C3及Mo的碳化物。Si含量变化对钢中各相析出温度和析出量无显著影响。随Mo含量降低,钢中脆性相析出减少,但对合金渗碳体析出无显著影响。SA508-3钢最佳回火温度为643-678℃。 相似文献
960.