全文获取类型
收费全文 | 668篇 |
免费 | 25篇 |
国内免费 | 8篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 167篇 |
金属工艺 | 6篇 |
机械仪表 | 10篇 |
建筑科学 | 8篇 |
矿业工程 | 5篇 |
能源动力 | 45篇 |
轻工业 | 78篇 |
水利工程 | 5篇 |
石油天然气 | 6篇 |
无线电 | 71篇 |
一般工业技术 | 167篇 |
冶金工业 | 50篇 |
原子能技术 | 2篇 |
自动化技术 | 72篇 |
出版年
2024年 | 7篇 |
2023年 | 19篇 |
2022年 | 47篇 |
2021年 | 50篇 |
2020年 | 34篇 |
2019年 | 33篇 |
2018年 | 62篇 |
2017年 | 36篇 |
2016年 | 39篇 |
2015年 | 15篇 |
2014年 | 26篇 |
2013年 | 28篇 |
2012年 | 24篇 |
2011年 | 37篇 |
2010年 | 24篇 |
2009年 | 26篇 |
2008年 | 31篇 |
2007年 | 18篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
排序方式: 共有701条查询结果,搜索用时 0 毫秒
11.
Multiplicative speckle noise diminishes the radiometric resolution of the synthetic aperture radar (SAR) images and all the coherent images. Speckle removal adds an extra value to an automated SAR image interpretation and analysis. In this paper, dual-tree complex wavelet-transform-based Bayesian method is proposed for despeckling the SAR images. In each subband, the reflectance and noise of the logarithmically transformed wavelet coefficients are modeled using heavy-tailed Burr and zero-mean Gaussian distributions. The closed-form expression for the shape parameter of Burr distribution is derived by employing the Mellin transform. The resultant complex-free quadratic maximum a posteriori solution with suitable shrinkage function yields despeckled SAR images. Extensive experiments are carried out using real SAR images as well as simulated images. The proposed method performs well in terms of equivalent number of looks with 3.5751 dB improvement in homogeneous region1 of Pipe river SAR image, edge preservation with 0.6158 improvement, peak signal to noise ratio of 51.3305 dB, and mean structural similarity index measure of 0.9397 at 0.05 noise variance for synthetically speckled image in comparison to the existing methods and takes averagely 2.3461 times less computing time. The proposed method provides a computationally efficient better speckle reduction in homogeneous regions while still preserving the edge. 相似文献
12.
An aim of current study is to analyze the contribution of reflected longitudinal waves to wave-induced fluid flow(WIFF)in the cracked porous solid.Initially,we ... 相似文献
13.
Rajesh K. Gangwar Vinayak A. Dhumale Dimple Kumari Umesh T. Nakate S.W. Gosavi Rishi B. Sharma S.N. Kale Suwarna Datar 《Materials science & engineering. C, Materials for biological applications》2012,32(8):2659-2663
Curcumin, a natural polyphenolic compound, has astounding therapeutic applications but lacks in bioavailability mainly due to its poor solubility in water. Polyvinyl pyrrolidone (PVP) which is a proven drug carrier has been used to facilitate the conjugation of curcumin with gold nanoparticles and to improve the solubility of curcumin in water. In this conjugate diaryl heptanoid chromophore group of curcumin which is a much needed group in biomedical applications remains intact as observed from FTIR and UV–vis spectroscopy analysis. The work shows good promise for such conjugates as therapeutic-cum-imaging materials in biomedical field. 相似文献
14.
Sangita Kumari Karthikeyan Pillai Asha Sharma Ella Mihevc Amit Srivastava Albert Chan 《Particulate Science and Technology》2015,33(5):562-566
Cryogenic aerosol cleaning is a dry cleaning method used in the back end of line (BEOL) semiconductor manufacturing to remove defects from planar hydrophobic surfaces such as SiCOH and SiCxNyHz. Cryogenic aerosol cleaning is preferred over conventional wet cleaning methods as it is a non-contact cleaning method, which uses inert gases to generate sub-micrometer-sized solid aerosol particles that physically remove nanometer-sized contaminants on wafer surfaces. Particle removal mechanism involves detachment of the particles upon impact with aerosol, diffusion, and finally entrainment away from the wafer. In BEOL metal line patterning, particles on the dielectric isolation surfaces translate through the subsequent lithography and copper fill steps in to single or multiple metal line open defects that are yield killers. In this study, we show that the particle removal performance of the standard aerosol cleaning can be enhanced by pre-heating the wafer and use of a higher molecular weight inert gas, namely Ar, for aerosol generation. Both the addition of a Pre-heat step and the use of Ar as the aerosol source showed 47–52% reduction in single and multiple line opens detected through wafer electrical tests during high volume semiconductor manufacturing process. 相似文献
15.
Scaria P. Teenu Shetty Prakasha Kumari P. Preethi Kagatikar Sneha 《Journal of Applied Electrochemistry》2022,52(11):1675-1689
Journal of Applied Electrochemistry - The inhibitive action of 2-aminobenzothiazole (ABT) on the corrosion of AA6061-T6 was evaluated in 0.5 M HCl by electrochemical techniques. The... 相似文献
16.
Zirconium oxide (ZrO2) nanostructures were synthesized by hydrothermal route. Surface morphology analysis depicts the formation of the nanobars and hexagonal-shaped nanodiscs at different synthesis conditions. The structural analysis confirms that the as-synthesized ZrO2 product is of pure monoclinic phase (m-ZrO2) with crystallite size of about 25 nm. The product consists of monodispersed nanoparticles of uniform composition, high purity, and crystallinity. The Raman spectra are quantitatively analyzed and the observed peaks are attributed to various vibration modes of the m-ZrO2. The UV–vis absorption spectrum showed a strong absorption peak at about 292 nm and the estimated optical band gap was around 3.57 eV. Photoluminescence (PL) spectrum of ZrO2 nanostructure showed a strong and broad emission peak at around 410 nm at room temperature, which can be attributed to the ionized oxygen vacancy in the material. 相似文献
17.
18.
19.
Selva Nidhyanandhan S. Sindhuja R. Selva Kumari R. Shantha 《Wireless Personal Communications》2020,114(4):2909-2921
Wireless Personal Communications - Major issue in marine environment imaging is the expulsion of hazy scenes caused by natural phenomena such as absorption and scattering in underwater images. The... 相似文献