全文获取类型
收费全文 | 2165篇 |
免费 | 113篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 23篇 |
综合类 | 4篇 |
化学工业 | 555篇 |
金属工艺 | 45篇 |
机械仪表 | 51篇 |
建筑科学 | 44篇 |
矿业工程 | 7篇 |
能源动力 | 58篇 |
轻工业 | 127篇 |
水利工程 | 10篇 |
石油天然气 | 24篇 |
武器工业 | 1篇 |
无线电 | 198篇 |
一般工业技术 | 671篇 |
冶金工业 | 68篇 |
原子能技术 | 37篇 |
自动化技术 | 360篇 |
出版年
2024年 | 7篇 |
2023年 | 23篇 |
2022年 | 80篇 |
2021年 | 105篇 |
2020年 | 74篇 |
2019年 | 64篇 |
2018年 | 78篇 |
2017年 | 74篇 |
2016年 | 76篇 |
2015年 | 51篇 |
2014年 | 110篇 |
2013年 | 151篇 |
2012年 | 161篇 |
2011年 | 209篇 |
2010年 | 96篇 |
2009年 | 107篇 |
2008年 | 101篇 |
2007年 | 121篇 |
2006年 | 95篇 |
2005年 | 71篇 |
2004年 | 77篇 |
2003年 | 51篇 |
2002年 | 70篇 |
2001年 | 27篇 |
2000年 | 21篇 |
1999年 | 23篇 |
1998年 | 34篇 |
1997年 | 25篇 |
1996年 | 9篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 12篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 7篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1965年 | 1篇 |
1958年 | 2篇 |
排序方式: 共有2283条查询结果,搜索用时 15 毫秒
101.
102.
Tommy Lorenz Igor A. Baburin Jan-Ole Joswig Gotthard Seifert 《Israel journal of chemistry》2017,57(6):553-559
The present paper compares and discusses two selected misfit (layer) compounds exemplarily, namely SnS-SnS2 and LaS-TaS2. We have employed a density-functional theory-based approach to calculate structural, energetic, and electronic properties of these structures. We have put emphasis on the difference between single layers, combined double-layer systems and periodically stacked bulk structures. Especially the varying magnitudes of charge transfer between the sublayers were studied. We demonstrate how the chemical constitution of the sublayers affects the interlayer interactions: these may be a weak non-bonding van-der-Waals dominated interlayer interaction as in SnS-SnS2 and many other layered structures or a strong interaction related to a remarkable charge transfer between the layers as in LaS-TaS2. 相似文献
103.
Andrea Spaggiari Igor Spinella Eugenio Dragoni 《Journal of Materials Engineering and Performance》2011,20(4-5):489-496
Shape memory alloys (SMAs) are smart materials exploited in many applications to build actuators with high power to mass ratio. Typical SMA drawbacks are: wires show poor stroke and excessive length, helical springs have limited mechanical bandwidth and high power consumption. This study is focused on the design of a large-scale linear SMA actuator conceived to maximize the stroke while limiting the overall size and the electric consumption. This result is achieved by adopting for the actuator a telescopic multi-stage architecture and using SMA helical springs with hollow cross section to power the stages. The hollow geometry leads to reduced axial size and mass of the actuator and to enhanced working frequency while the telescopic design confers to the actuator an indexable motion, with a number of different displacements being achieved through simple on-off control strategies. An analytical thermo-electro-mechanical model is developed to optimize the device. Output stroke and force are maximized while total size and power consumption are simultaneously minimized. Finally, the optimized actuator, showing good performance from all these points of view, is designed in detail. 相似文献
104.
105.
106.
Alexey A. Roenko Vladimir V. Lukin Igor Djurović Xu Zhengguang 《Signal, Image and Video Processing》2009,3(2):157-170
A novel adaptive clipping technique for filtering a constant amplitude frequency modulated (FM) signal embedded in non-Gaussian
noise is proposed. It is based on the analysis and processing of the estimate of probability density function of a FM signal
realization. As a result, modifications of two robust estimators of FM signal amplitude are proposed. It is shown that these
estimators can be used for Gaussian and non-Gaussian heavy-tail environments. The proposed clipping technique can exploit
one or another obtained robust estimate of the signal amplitude for adaptive setting a threshold. Analysis of signal estimate
accuracy for different noise environments is carried out. Comparative analysis of the obtained methods and known approaches
based on scanning window nonlinear filtering and optimal robust L-DFT form is performed. It is demonstrated that the usage
of clipping-based technique leads to the considerable improvement of the FM signal filtering efficiency in comparison to the
aforementioned known approaches for different noise environments and a wide range of input SNR values. 相似文献
107.
Masoud Dehghan Riadh Al-Mahaidi Igor Sbarski Elham Mohammadzadeh 《The Journal of Adhesion》2015,91(6):461-480
The epoxy resin used as the bonding agent in carbon fiber-reinforced polymer (CFRP) strengthening systems was modified by the infusion of multiwalled carbon nanotubes (MWCNTs). Two types of surfactants, Triton X-100 and C12E8, were used to disperse the nanotubes in the epoxy resin employing ultrasonic mixing. Dynamic mechanical analysis and tensile tests were conducted to study the effect of the surfactant-assisted dispersion of nanotubes on the thermal and mechanical properties of epoxy composites. The morphology of the epoxy composites was interpreted using scanning electron microscopy (SEM). Moreover, the effect of surfactant treatment on the structure of nanotubes was investigated by Fourier transform infrared (FT-IR). Based on the experimental results, the tensile strength and the storage modulus of the epoxy resin were increased by 32% and 26%, respectively, by the addition of MWCNTs. This was attributed to the homogeneous dispersion of nanotubes in the epoxy resin according to the SEM images. Another reason for the enhancement in the tensile properties was the reinforced nanotube/epoxy interaction as a result of the surfactant anchoring effect which was proved by FT-IR. A moderate improvement in the glass transition temperature (T g) was recorded for the composite fabricated using Triton X-100, which was due to the restricted molecular motions in the epoxy matrix. To characterize the temperature-dependent tensile behavior of the modified epoxy composites, tensile tests were conducted at elevated temperatures. It was revealed that the MWCNT modification using surfactant substantially improves the tensile performance of the epoxy adhesive at temperatures above the T g of the neat epoxy. 相似文献
108.
109.
110.
Joseph Berry Tonio Buonassisi David A. Egger Gary Hodes Leeor Kronik Yueh‐Lin Loo Igor Lubomirsky Seth R. Marder Yitzhak Mastai Joel S. Miller David B. Mitzi Yaron Paz Andrew M. Rappe Ilan Riess Boris Rybtchinski Oscar Stafsudd Vladan Stevanovic Michael F. Toney David Zitoun Antoine Kahn David Ginley David Cahen 《Advanced materials (Deerfield Beach, Fla.)》2015,27(35):5102-5112