全文获取类型
收费全文 | 2435篇 |
免费 | 281篇 |
国内免费 | 259篇 |
专业分类
电工技术 | 341篇 |
综合类 | 269篇 |
化学工业 | 519篇 |
金属工艺 | 70篇 |
机械仪表 | 157篇 |
建筑科学 | 52篇 |
矿业工程 | 51篇 |
能源动力 | 69篇 |
轻工业 | 308篇 |
水利工程 | 3篇 |
石油天然气 | 75篇 |
武器工业 | 56篇 |
无线电 | 348篇 |
一般工业技术 | 330篇 |
冶金工业 | 101篇 |
原子能技术 | 51篇 |
自动化技术 | 175篇 |
出版年
2024年 | 20篇 |
2023年 | 58篇 |
2022年 | 73篇 |
2021年 | 98篇 |
2020年 | 82篇 |
2019年 | 68篇 |
2018年 | 81篇 |
2017年 | 105篇 |
2016年 | 108篇 |
2015年 | 120篇 |
2014年 | 178篇 |
2013年 | 160篇 |
2012年 | 193篇 |
2011年 | 180篇 |
2010年 | 144篇 |
2009年 | 146篇 |
2008年 | 136篇 |
2007年 | 139篇 |
2006年 | 153篇 |
2005年 | 130篇 |
2004年 | 94篇 |
2003年 | 83篇 |
2002年 | 81篇 |
2001年 | 43篇 |
2000年 | 50篇 |
1999年 | 37篇 |
1998年 | 41篇 |
1997年 | 33篇 |
1996年 | 28篇 |
1995年 | 28篇 |
1994年 | 15篇 |
1993年 | 13篇 |
1992年 | 12篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 2篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有2975条查询结果,搜索用时 15 毫秒
11.
汽轮机凝汽器的除垢问题通常采用化学方法或物理方法,这些除垢措施有一定的局限性。介绍了一种利用高压静电除垢技术。 相似文献
12.
介绍了电熨斗底板真空静电喷涂的工作原理。说明了电晕放电在底板真空静电喷涂中的作用。分析了氟涂料微粒的带电过程及影响因素。这个工艺对产品质量提高的作用进行了分析。 相似文献
13.
14.
15.
Clifford E Felder Simone A Botti Shneior Lifson Israel Silman Joel L Sussman 《Journal of molecular graphics & modelling》1997,15(5):318-327
The electrostatic potentials for the three-dimensional structures of cholinesterases from various species were calculated, using the Delphi algorithm, on the basis of the Poisson–Boltzmann equation. We used structures for Torpedo californica and mouse acetylcholinesterase, and built homology models of the human, Bungarus fasciatus, and Drosophila melanogaster acetylcholinesterases and human butyrylcholinesterase. All these structures reveal a negative external surface potential, in the area around the entrance to the active-site gorge, that becomes more negative as the rim of the gorge is approached. Moreover, in all cases, the potential becomes increasingly more negative along the central axis running down the gorge, and is largest at the base of the gorge, near the active site. Ten key acidic residues conserved in the sequence alignments of AChE from various species, both in the surface area near the entrance of the active-site gorge and at its base, appear to be primarily responsible for these potentials. The potentials are highly correlated among the structures examined, down to sequence identities as low as 35%. This indicates that they are a conserved property of the cholinesterase family, could serve to attract the positively charged substrate into and down the gorge to the active site, and may play other roles important for cholinesterase function. 相似文献
16.
17.
建立单通道线板式湿式电除尘器机理实验台,考察烟气中主要成分(O2、H2O和粉尘)对湿式静电除尘器放电特性的影响。随着烟气成分(O2、H2O和粉尘)浓度的增加,空间静电场中负电荷密度增加,电场分布均匀性提高,抑制电晕放电,电晕电流降低;随着电压升高,烟气成分对电晕放电的抑制作用减弱。其中,烟气中O2的体积分数增加引起电晕电流下降的速率不为常数,O2体积分数小于6%时,下降速率明显减小。烟气中液相水滴附着在电晕线表面引起表面电场畸化,起晕电压降低,击穿电压提高,湿式静电除尘器的工作电压窗口增大。电晕电流与烟气中粉尘浓度呈线性相关关系,粉尘粒径越小对电晕放电的抑制作用越明显。 相似文献
18.
Fariba Zerafati Shoja Hudsa Majidian Leila Nikzad 《International Journal of Applied Ceramic Technology》2021,18(4):1174-1182
In the present work, particle arrangement and their packing in the sediment layer of zirconia suspension were studied. To evaluate the particle settling, aqueous suspensions of zirconia nanoparticles were prepared in different dispersion states. In one state, Dolapix CE64 was used as a dispersant to provide electrosteric mechanism. In another state, pH of the suspension was adjusted at 4 to provide electrostatic mechanism. The other state was the combination of dispersant and pH adjustment which resulted in the most stable suspension. First of all, the stability of all dispersion states was evaluated by zeta potential, sediment volume (SV) and height, viscosity, and packing density (PD). Then, the sediment layers of all suspensions were characterized. Incorporation of electrostatic mechanism was resulted in a main decrease in viscosity with high surface charges, while electrosteric mechanism caused lower sedimentation of particles. Fall velocities of particles/agglomerates were estimated, and the influences of dispersion states on the particles fall velocities were characterized. The microstructural observation revealed homogeneous packing of particles in the sediment layer of the stable suspension demonstrating the proper dispersion of particles. Dolapix CE64 and pH adjustment resulted in a uniform arrangement of particles without agglomeration and spherical and regular granules with a uniform shape. 相似文献
19.
介绍 4 0 0 kt/ a硫酸系统电除雾器总体结构及工艺设计参数 ,投入运行后 ,除雾效率低 ,介绍对存在问题的分析及解决过程 ,并介绍 2点成功经验 相似文献
20.
Electrostatic actuators have the advantages of light weight, flexibility, and high energy efficiency, which make them suitable for use as artificial muscles. However, a traditional electrostatic actuator cannot generate long strokes and a high force density at the same time because such actuator would excessively widen the gap between the electrodes because of its structure. This paper presents a newly developed large-scale stacked-type electrostatic actuator (LSEA) intended for use as an artificial muscle for robots. LSEA is a multi-stacked electrostatic actuator that can be linearly contracted by the application of a voltage. It has a unique structure that prevents overextension of the gap between the electrodes. It can therefore generate a large force. The spring characteristics and the relationship between the contractive force and the stroke were experimentally determined. The findings showed that LSEA prevents the overextension of the gap between the electrodes and has a high contraction ratio that is equivalent to that of a mammalian skeletal muscle. 相似文献