全文获取类型
收费全文 | 5402篇 |
免费 | 118篇 |
国内免费 | 93篇 |
学科分类
工业技术 | 5613篇 |
出版年
2024年 | 11篇 |
2023年 | 60篇 |
2022年 | 98篇 |
2021年 | 117篇 |
2020年 | 119篇 |
2019年 | 101篇 |
2018年 | 85篇 |
2017年 | 122篇 |
2016年 | 108篇 |
2015年 | 139篇 |
2014年 | 214篇 |
2013年 | 249篇 |
2012年 | 228篇 |
2011年 | 358篇 |
2010年 | 280篇 |
2009年 | 255篇 |
2008年 | 249篇 |
2007年 | 305篇 |
2006年 | 295篇 |
2005年 | 356篇 |
2004年 | 359篇 |
2003年 | 216篇 |
2002年 | 171篇 |
2001年 | 144篇 |
2000年 | 127篇 |
1999年 | 138篇 |
1998年 | 176篇 |
1997年 | 94篇 |
1996年 | 100篇 |
1995年 | 88篇 |
1994年 | 83篇 |
1993年 | 37篇 |
1992年 | 27篇 |
1991年 | 12篇 |
1990年 | 14篇 |
1989年 | 25篇 |
1988年 | 11篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有5613条查询结果,搜索用时 15 毫秒
1.
2.
Gyeong-Ho Kim 《Computer Methods in Applied Mechanics and Engineering》2008,198(2):234-244
A continuum-based modeling of coupled electrostatics-structure interactions is presented for the frequency computations of MEMS devices. The present general formulation of electrostatics accounting for free space is validated first by specializing it to one-dimensional uniform motion of conducting surfaces and comparing the resulting electrostatics to conventional lumped models. The general coupled electrostatics-structure interactions are then applied for the prediction of resonant frequencies of MEMS devices due to bias-voltage changes and temperature variations. Comparisons of predicted resonant frequencies obtained by the present coupled electrostatics-structure interaction models with experimental results available in the literature demonstrate that the proposed continuum-based interaction modeling yields high-confidence predictions of resonant frequencies of MEMS devices. 相似文献
3.
Mayank Kashyap 《Powder Technology》2008,183(3):441-453
The effect of electric field on the hydrodynamics of nanoparticles was studied in a fluidized rectangular bed, with electrodes attached to two parallel walls. It was shown that the electric field of the order of 3 times the gravity markedly decreased the bed expansion and increased the solids volume fraction of nanoparticles fluidized by air. In these experiments, a light diode assembly was utilized to infer the local solids volume fractions within a rectangular bed of 10 nm silica particles. These experimental measurements yielded a two dimensional solids volume fraction distribution within the rectangular bed. The experimental results provided some new insights into the distribution of solids within the bed. The agglomerate diameters were computed using a momentum balance with the drag given by the Ergun equation and the empirical Richardson-Zaki method. Both methods yielded agglomerate diameters of the order of 100 μm and showed dependence on the strength of the electric field. The electric field decreased the granular temperature of the nanoparticles. 相似文献
4.
本文介绍了PLC(ProgrammableLogicController)在MK9卷烟机国产化改造中的应用,并提出了最大限度的用软件取代原机硬件电路提高可靠性的一种方法。 相似文献
5.
Satoshi Takeuchi Ryo Sugihara 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1998,410(3):104-508
The longitudinal electric field of single and double Gaussian laser beams are used to accelerate electrons. The longitudinal field of the single beam is concentrated on the axis and is favourable for acceleration. A set of two beams is considered. Beams run parallel, collinearly, overlap partially and have a phase difference iπ in between. As a result, the transverse components of fields cancel each other while the longitudinal components are double-fold. In both schemes, the electrons are accelerated in lengths of the Rayleigh range, which is common to the plasma-based accelerators. 相似文献
6.
通过引进型国产300MW汽轮机在启动试运中出现的一次窜轴事故,根据计算机追忆打印的有关图表、数据分析了产生事故的原因,并提出了为防止类似事故重演应采取的措施和建议。经采取措施后该机组多次又在相同情况下启机,已安全运行。说明分析正确,措施得当,值得同类型机组借鉴。 相似文献
7.
本文首先介绍国内和日本、德国、俄罗斯等国冷轧薄钢板及镀锌薄钢板的牌号、标记识别及生产地及与我国家标准薄钢板牌号的相互之间的关系,并比较具体地介绍冷轧板的实效性、镀锌薄钢板的锌层特性等诸多方面的状况。从而帮助我们在设计、制造家电产品中,比较正确地选择合适的板材。 相似文献
8.
L. X. Che R. Q. Yang Y. Gu T. K. Xia 《The International Journal of Advanced Manufacturing Technology》2006,31(5-6):614-620
This paper presents a method of calculating the insulating safety distances for hot-line working robots at high voltage when dielectric is adulterated with conducts. Also, finite element method is adopted to calculate the electric field strength to find whether it is beyond the critical. The above methods have been applied to analyze the insulating safety of the robot for hot-line sweeping post insulators in a 220 KV substation. They have also been testified by experimentations. 相似文献
9.
This paper presents an electromechanical wheel suspension, where the upper arm of the suspension has been provided with an electric levelling and a damper actuator, both are allowed to work in a fully active mode. A control structure for the proposed suspension is described. The complex design task involving the control of the electric damper and its machine parameters is tackled by genetic optimisation. During this process, these parameters are optimised to keep the power dissipation of the electric damper as low as possible, while maintaining acceptable comfort and road-holding capabilities. The results of the evaluations carried out demonstrate that the proposed suspension can easily adopt its control parameters to obtain a better compromise of performance than that offered by passive suspensions. If the vehicle is to maintain acceptable performance during severe driving conditions, the damper has to be unrealistically large. However, if the electric damper is combined with a hydraulic damper, the size of the electric damper is significantly reduced. In addition, the design of the electric damper with the suggested control structure, including how it regenerates energy, is discussed. 相似文献
10.
The paper describes the development and evaluation of temperature compensated high elongation resistance strain gauges for use from room temperature to 250°C. These gauges could be temperature-compensated on steels with coefficient of thermal expansion α = 11 ppm/°C. Thermal output within 250°C was about 1 μm/m/°C and maximum standard deviation of 5 gauges was 34 μm/m. Strain limit was > 4% at room temperature and at 250°C. Gauge factors of different strain ranges at R.T. and at 250°C are tabulated. Some applications are stated. 相似文献