全文获取类型
收费全文 | 164篇 |
免费 | 8篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
综合类 | 1篇 |
化学工业 | 42篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 2篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 27篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 12篇 |
一般工业技术 | 39篇 |
冶金工业 | 12篇 |
原子能技术 | 1篇 |
自动化技术 | 19篇 |
出版年
2024年 | 1篇 |
2023年 | 9篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2018年 | 3篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 17篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有174条查询结果,搜索用时 2 毫秒
1.
Oxidation behavior of a 2 mol % divinylbenzene (DVB)‐crosslinked polystyrene‐supported permanganate function was investigated toward low molecular weight primary and secondary alcohols and aldehydes. The permanganate function was attached to a polystyrene support through cyclic polyoxyethylene (POE) units immobilized on the support. Contrary to the oxidations catalyzed by low molecular weight permanganate reagents, the oxidation of primary alcohol terminated in the aldehyde stage. The secondary alcohols were converted to the respective ketone and aldehyde to acid. The effect of the variable parameters similar to solvent, temperature, and reagent to substrate ratio was followed. Nonpolar cyclohexane was found to be the best solvent for the present study. Also the reactivity increased with increasing temperature. The oxidizing reagent possesses a long shelf life and could be recycled several times without reduction of capacity and mechanical stability. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3708–3717, 2003 相似文献
2.
The present study reports an eco‐friendly and rapid method for the synthesis of core–shell nanoclusters using the modified reverse micelle method. It is a green synthetic method which uses Sesbania grandiflora Linn extract which acts as a reducing and capping agent. It is observed that this method is very fast and convenient and the nanoclusters are formed with 5–10 min of the reaction time without using harsh conditions. The core–shell nanoclusters so prepared were characterised using UV–Vis spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy. Further, their effective antibacterial activity towards the gram‐positive bacteria Staphylococcus aureus was found to be due to their smaller particle size.Inspec keywords: iron compounds, copper compounds, nanoparticles, particle size, nanofabrication, nanomedicine, biomedical materials, core‐shell nanostructures, antibacterial activity, ultraviolet spectra, visible spectra, microorganisms, reduction (chemical), scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectraOther keywords: biosynthesis, γ‐Fe2 O3 ‐CuO core‐shell nanoclusters, aqueous extract, Sesbania grandiflora Linn fresh leaves, antimicrobial activity, Staphylococcus aureus strains, eco‐friendly method, modified reverse micelle method, green synthetic method, reducing agent, capping agent, UV‐visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, antibacterial activity, gram‐positive bacteria Staphylococcus aureus, particle size, time 5 min to 10 min, Fe2 O3 ‐CuO 相似文献
3.
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
4.
Influence of plasticizers and cryogenic grinding on the high‐cooling‐rate solidification behavior of PBT/PET blends 下载免费PDF全文
Anesh Manjaly Poulose Stefano Piccarolo Domenico Carbone Saeed M. Al‐Zahrani 《应用聚合物科学杂志》2016,133(10)
Two structurally different plasticizers (cyclic and linear) and the effect of cryogenic grinding on the solidification behavior at high cooling rates by a continuous cooling transformation approach of poly(butylene terephthalate)/poly(ethylene terephthalate), PBT/PET, blends are described. The solidification curve (density versus cooling rate) is confirmed as an effective tool to compare the differences in crystallization behavior under conditions mimicking processing. In comparison to the bulky cyclic plasticizer, the linear oligomeric one was found to have a more pronounced influence on the crystallization behavior. A 60/40 by weight PBT/PET blend shows a drop‐off of density at ~50 K/s. In the plasticized sample, the long‐range crystalline order appears up to a cooling rate of ~250K/s, making the blend comparable to pure PBT. Grinding the components before blending further improves crystallizability and synergy to the addition of the plasticizer. The results suggest the important role of local chain mobility in the solidification behavior at high cooling rates. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43083. 相似文献
5.
Asha Ashuo Wenjia Zou Jingjie Fu Tengkun Yang Linlin Yu Wei Liu 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2020,37(9):1481-1490
ABSTRACT Herein, we have successfully established a novel, rapid, and simple lateral-flow immunoassay based on time-resolved fluorescence and biotin-streptavidin to detect the residues of various antibiotics in milk. The fluorescence signal and sensitivity of immunochromatography were enhanced through biotinylated antibody coupled with streptavidin europium microspheres. Moreover, due to the use of a QR Code and fluorescent reader, quantitative detection and real-time data uploading can be achieved. Under the optimal conditions, the various antibiotic residues were detected in the milk samples. The results showed that the limits of detection of tylosin, lincomycin and doxycycline were 0.10, 0.06, and 0.27 ng/mL, respectively. The recoveries of the spiked milk samples were 88.9%~127%, with coefficients of variation less than 11%, and the test strip can be stored at room temperature for 12 months. This study shows that the proposed time-resolved fluorescence immunoassay is sensitive, rapid and reliable, and has the potential to be used for detection of veterinary antibiotic residues in food safety fields. 相似文献
6.
Dodecylbenzene sulfonate (DBS)‐doped polypyrrole (PPY) conducting polymer films were electrochemically deposited onto the indium‐tin‐oxide (ITO)‐coated glass plates in aqueous medium. The enzyme cholesterol oxidase (ChOx) was immobilized on these DBS–PPY films by a physical adsorption technique. These ChOx‐immobilized DBS–PPY films were characterized by ultraviolet–visible and Fourier transform infrared spectroscopy. The enzyme activity studies indicate that ~40% of ChOx leaches out from the ChOx/DBS–PPY film. The ChOx activity in the ChOx/DBS–PPY film was assayed as a function of cholesterol concentration. The results of amperometric measurements conducted on ChOx/DBS–PPY/ITO film show linearity over the range 2–8 mM of cholesterol solution. The ChOx/DBS–PPY/ITO electrodes exhibit a response time of 30 s and are stable for ~3 months at 4 °C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 3486–3491, 2001 相似文献
7.
Evaluation of antioxidant and anti-initiating activities of crude polyphenolic extracts from seedless and seeded Indian grapes 总被引:1,自引:0,他引:1
Asha G. Ramchandani Raghunathan S. Chettiyar Shrirang S. Pakhale 《Food chemistry》2010,119(1):298-305
The extracts of crude polyphenols (seeds, pulp + skin, whole) from four different cultivars of Indian grapes were used in this study. The total polyphenolic contents of grape polyphenolic extracts (GPEs) were determined and their in vitro antioxidant and anti-initiating activities evaluated. The total polyphenolic contents, expressed in terms of gallic acid/catechin/procyanidin B3 equivalents, were found to vary significantly. Antioxidant activity of GPEs, particularly the seedless variety, was evident from significant dose-dependent inhibition of lipid peroxidation and DPPH activity. GPEs and catechin inhibited the microsome-catalysed activity of cytochrome P450 isozymes (1A1, 1A2, 2B1) in a dose-dependent manner, by the decreased formation of resorufin. The inhibitory activity of GPEs on nitrite-mediated N-nitrosation of dimethylamine and N-methylaniline appears to correlate significantly with the total polyphenolic contents. Furthermore, six individual polyphenols present in GPEs were quantitated by HPLC, wherein procyanidin B3 was a major constituent. 相似文献
8.
Barium lanthanum hafnium oxide, a complex perovskite ceramic, has been synthesized as nanoparticles by a modified combustion process for the first time. The Ba, La, and Hf ions required for the formation of Ba2LaHfO5.5 were obtained in solution by dissolving in boiling nitric acid a stoichiometric mixture of BaCO3, La2O3, and HfO2 that had been heated at 1200 degrees C for 4 h. By complexing the ions with citric acid and using ammonia as fuel, it was possible to get Ba2LaHfO5.5 as nanoparticles in a single-step combustion process. The powder obtained by the present combustion process was characterized by X-ray diffraction, BET surface area analysis, differential thermal analysis, thermogravimetric analysis, infrared spectroscopy, and scanning and high-resolution transmission electron microscopy. According to the results of X-ray and electron diffraction, the powder synthesized through the combustion process showed single-phase barium lanthanum hafnium oxide. The transmission electron microscopic investigations showed a grain size of 42 nm, with a standard deviation of 8 nm. The nanoparticles of Ba2LaHfO5.5 synthesized by the present combustion technique could be sintered to > 97% of the theoretical density at a relatively low temperature of 1425 degrees C. Scanning electron microscopic studies on the sintered Ba2LaHfO5.5 samples showed that the final grain size of the sintered specimen was < 500 nm. 相似文献
9.
P. K. Poulose J. E. Morral A. J. McEvily 《Metallurgical and Materials Transactions B》1974,5(6):1393-1400
The fracture kinetics of Al-5.5 Zn-2.5 Mg alloys submersed in 3 pct NaCl-H2O solutions were varied by heat treatment. The steady state velocity, on a plot of velocity vs stress intensity, was compared
with microstructure and it was found to be inversely proportional to the volume of MgZn2 in the grain boundary. This behavior suggests that grain boundary precipitates can act as sacrificial anodes to retard intergranular
stress corrosion cracking.
Formerly Graduate Student at the University of Connecticut 相似文献
10.
This article presents a new nonlinear classifier by arranging linear classifiers in a tree structure. The proposed classifier, called the direct fractional-step linear discriminant (DF-LDA) tree, adopts a tree structure containing a DF-LDA at each node. The structure of the tree classifier evolves as the training proceeds, so there is no need to decide any parameters as a priori. Due to the many DF-LDAs arranged in the tree structure, classification performance of the proposed classifier is improved over single-shot DF-LDA. The proposed DF-LDA tree is tested on various synthetic and real datasets. Experimental results show that the proposed classifier leads to very satisfactory results in terms of classification accuracy. 相似文献