全文获取类型
收费全文 | 300篇 |
免费 | 6篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 78篇 |
金属工艺 | 3篇 |
机械仪表 | 6篇 |
建筑科学 | 2篇 |
矿业工程 | 1篇 |
能源动力 | 6篇 |
轻工业 | 4篇 |
无线电 | 47篇 |
一般工业技术 | 60篇 |
冶金工业 | 47篇 |
原子能技术 | 4篇 |
自动化技术 | 46篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 5篇 |
2019年 | 1篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 2篇 |
2015年 | 7篇 |
2014年 | 2篇 |
2013年 | 10篇 |
2012年 | 8篇 |
2011年 | 12篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 17篇 |
2007年 | 12篇 |
2006年 | 8篇 |
2005年 | 13篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 13篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 10篇 |
1994年 | 11篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 9篇 |
1986年 | 14篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 2篇 |
排序方式: 共有307条查询结果,搜索用时 31 毫秒
1.
2.
Velocity profiles for the inner and outer flow regions of annuli are proposed for the turbulent flow of drag reducing fluids. Theoretical expressions for friction factors are developed. From the shear stress equations and the velocity profiles, estimates for the entrance lengths are given. 相似文献
3.
4.
5.
Spectral Measurement of the Film-Substrate Index Difference in Proton-Exchanged LiNbO(3) Waveguides 总被引:1,自引:0,他引:1
El Hadi K Rastogi V Shenoy MR Thyagarajan K De Micheli M Ostrowsky DB 《Applied optics》1998,37(27):6463-6467
We report the spectral characterization of proton-exchanged lithium niobate (PE:LiNbO(3)) waveguides in terms of the variation of the refractive-index difference between the waveguiding layer and the substrate. The dispersion of the extraordinary refractive-index increase (deltan(e)) is measured from 405 to 1319 nm with several light sources. Two types of proton-exchanged waveguide, prepared under different conditions, are studied. These measurements should be of use in the optimization of PE:LiNbO(3) waveguides for nonlinear optical applications, particularly in second-harmonic generation in the blue-green wavelength region. 相似文献
6.
The mathematical formulation for targeting during energy allocation with carbon capture and storage (CCS) is formally developed. For operating-cost optimization with zero excess, it is shown that CCS sources may be regarded as resources with their cost taken as the increment over the non-CCS option. CCS sources along with clean-carbon resources may then be targeted by profile matching with the limiting composite to establish optimal primary cases. The limiting composite curve is itself sacrosanct and obtained by a single computation of the composite table algorithm (CTA) including only non-CCS sources. Carbon emission networks (CENs) are designed by the nearest neighbors algorithm (NNA). A cost criterion is established to determine cost-factor ranges for optimality of the primary cases, and results validated by solving linear programming (LP) and mixed integer linear programming (MILP) formulations. The methodology essentially comprises four distinct stages – targeting, network design, cost analysis, and optimization – with the first two stages not requiring any cost data. 相似文献
7.
Molecular modeling was carried out using DFT to identify the suitable displacing agent for carrying out Gd isotope separation using displacement chromatography. EDTA was identified as the best eluting agent among EDTA, malic acid and citric acid. Displacement chromatography of Gd adsorption band in cation exchange resin was performed to observe the isotope effects in the Gd ion exchange processes involving complex forming reagent – EDTA. The heavier isotope of 160Gd was found to be enriched at the front boundary of Gd adsorption band, while the lighter isotopes of 155Gd and 157Gd were enriched at the rear boundary. 相似文献
8.
Viscoelastic properties of borax loaded CMC‐g‐cl‐poly(AAm) hydrogel composites and their boron nutrient release behavior
下载免费PDF全文
![点击此处可从《应用聚合物科学杂志》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Borax (Na2B4O7, 10.5% Boron) loaded CMC‐g‐cl‐poly(AAm) hydrogel composites were prepared by in situ grafting of acrylamide on to sodium carboxymethyl cellulose in the presence of borax by free radical polymerization technique to develop slow boron (B) delivery device. The composition, morphology, and mechanical properties of synthesized composites were studied by X‐ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, texture analyser, and dynamic shear rheometer. Characterization revealed formation of borate ion ( ) from borax during polymerization reaction leading to extensive crosslinking of cellulosic chains and generation of mechanically strong composite hydrogels. Dynamic release of from the synthesized composites hydrogels followed Fickian diffusion mechanism and composites with high mechanical strength resulted in slow release of B. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43969. 相似文献
9.
This paper presents the design and implementation of Ferret, a system for locating nomadic augmented with RFID tags and visually displaying them to a user in real-time. We present a novel algorithm to infer location of tagged objects using the location of a camera and reader that observes them. We also present techniques to refine location estimates using multiple observations and a method to display and update object locations on a video camera screen. An experimental evaluation of the Ferret prototype shows that (i) Ferret can refine object locations to only 1% of the reader’s coverage region in less than 2 min with small error rate (2.22%); (ii) Ferret can detect nomadic objects with 100% accuracy when the moving distances exceed 20 cm; and (iii) Ferret is robust against different movement patterns of user’s mobility. 相似文献
10.
Separation of nickel from copper in ammoniacal/ammonium carbonate solution using ACORGA M5640 by selective stripping was carried out. The influence of equilibration time, equilibrium pH and extractant concentration on the extraction of both the metals was studied. It was found that the copper extraction equilibrium was reached in a shorter time than the nickel extraction equilibrium. Nickel extraction decreases above an equilibrium pH of 9.0, while the extraction of copper remains unaffected by the changes in the equilibrium pH range of 7–10. Co-extraction, ammonia scrubbing and the selective stripping of copper and nickel were performed for a solution containing 3 g/l each of copper and nickel and 60 g/l ammonium carbonate. The extraction and the percentage stripping of copper and nickel were almost quantitative. 相似文献