全文获取类型
收费全文 | 837篇 |
免费 | 60篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 9篇 |
综合类 | 2篇 |
化学工业 | 431篇 |
金属工艺 | 6篇 |
机械仪表 | 16篇 |
建筑科学 | 30篇 |
能源动力 | 27篇 |
轻工业 | 110篇 |
水利工程 | 10篇 |
石油天然气 | 2篇 |
无线电 | 43篇 |
一般工业技术 | 93篇 |
冶金工业 | 48篇 |
原子能技术 | 1篇 |
自动化技术 | 70篇 |
出版年
2023年 | 18篇 |
2022年 | 89篇 |
2021年 | 100篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 29篇 |
2017年 | 30篇 |
2016年 | 40篇 |
2015年 | 39篇 |
2014年 | 33篇 |
2013年 | 55篇 |
2012年 | 48篇 |
2011年 | 59篇 |
2010年 | 37篇 |
2009年 | 45篇 |
2008年 | 35篇 |
2007年 | 32篇 |
2006年 | 21篇 |
2005年 | 25篇 |
2004年 | 21篇 |
2003年 | 18篇 |
2002年 | 12篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 12篇 |
1997年 | 11篇 |
1996年 | 4篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有898条查询结果,搜索用时 31 毫秒
51.
Tsu-Tsung Andrew Li Simon RuffellMario Tucci Yves MansouliéChristian Samundsett Simona De IullisLuca Serenelli Andres Cuevas 《Solar Energy Materials & Solar Cells》2011,95(1):69-72
While sputtering has been shown to be capable of depositing aluminum oxide suitable for surface passivation, the mechanisms for this are yet to be firmly established and its potential realized. In this paper, we investigate the relationships between the oxygen in the sputtering process to the resulting composition of the deposited film and the surface passivation obtained. We find that surface passivation is not strongly dependent on the bulk composition of the film. Instead the results indicate that the interfacial silicon oxide layer that forms after annealing between the aluminum oxide film and the silicon is a much more important factor; it is this combined structure of aluminum oxide, silicon oxide and silicon that is crucial for obtaining negative charges and excellent surface passivation. 相似文献
52.
Federico Aulenta Andrea Canosa Luigi De Roma Priscilla Reale Stefania Panero Simona Rossetti Mauro Majone 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2009,84(6):864-870
BACKGROUND: A bioelectrochemical process for trichloroethene (TCE) dechlorination was developed. In this new process, a solid‐state electrode polarized to ?450 mV versus the standard hydrogen electrode (SHE), in combination with a redox mediator (i.e., methyl viologen, MV) is employed as an electron donor for the microbial reductive dechlorination of TCE. In this study we compared the performance of the process with the redox mediator immobilized at the surface of electrodes or dissolved in the bulk liquid, using both a culture highly enriched in Desulfitobacterium spp., capable of dechlorinating TCE to cis‐dichloroethene (cis‐DCE), and a culture highly enriched in Dehalococcoides spp. capable of dechlorinating cis‐DCE to ethene. RESULTS: Short‐term potentiostatic (?450 mV versus SHE) experiments showed that TCE or cis‐DCE was dechlorinated both in the presence of soluble (500 µmol L?1) and immobilized MV. However, TCE or cis‐DCE dechlorination rates with MV‐modified electrodes were remarkably lower than with soluble MV. Both cultures produced significant amounts of H2 in the presence of electrically reduced, soluble MV, whereas no H2 was produced when the mediator was immobilized at the electrode surface, regardless of the potential applied to the electrode, in the range ?425 to ?500 mV versus SHE. CONCLUSIONS: The process, operated with modified electrodes, supports the microbial dechlorination of TCE to ethene. Immobilization not only allows retention of the mediator within the system, but also increases process efficiency by preventing bioelectrochemical H2 formation. On the other hand, strategies to increase dechlorination rates with modified electrodes need to be developed. Copyright © 2009 Society of Chemical Industry 相似文献
53.
Volker John Petr Knobloch Simona B. Savescu 《Computer Methods in Applied Mechanics and Engineering》2011,200(41-44):2916-2929
Stabilized finite element methods for convection-dominated problems require the choice of appropriate stabilization parameters. From numerical analysis, often only their asymptotic values are known. This paper presents a general framework for optimizing stabilization parameters with respect to the minimization of a target functional. Exemplarily, this framework is applied to the SUPG finite element method and the minimization of a residual-based error estimator, an error indicator, and a functional including the crosswind derivative of the computed solution. Benefits of the basic approach are demonstrated by means of numerical results. 相似文献
54.
Maurício Pinheiro de Oliveira Caroline Reggiani Silva Lilia Müller Guerrini 《Journal of Coatings Technology and Research》2011,8(4):439-447
This study investigates the influence of carboxylic monomers, such as itaconic acid (IA), on the colloidal properties of the
latexes made by semi-continuous emulsion copolymerization of styrene (STy) with n-butyl acrylate (BA). A number of copolymerization runs were carried out with different IA concentrations. The effect of functional
monomer on the overall conversion, the colloidal properties of the latexes, and the distribution of the carboxylic groups
(buried, particle surface and aqueous phase) were examined. The carboxylic groups present in the latexes were analyzed using
conductimetric and potentiometric titrations. The behavior of the IA on the wet scrub resistance of highly pigmented paints
for architectural coatings was examined and correlated with the distribution of the carboxylic groups. The results obtained
showed that the properties of highly pigmented paints are greatly dependent on the amount and distribution of the carboxylic
groups. The carboxylic acid distributed in the aqueous phase has a strong influence on the wet scrub resistance and on the
characteristics of the final products. 相似文献
55.
Experimental observation of the improvement in MTF from backthinning a CMOS direct electron detector
G. McMullan A.R. Faruqi R. Henderson N. Guerrini R. Turchetta A. Jacobs G. van Hoften 《Ultramicroscopy》2009
The advantages of backthinning monolithic active pixel sensors (MAPS) based on complementary metal oxide semiconductor (CMOS) direct electron detectors for electron microscopy have been discussed previously; they include better spatial resolution (modulation transfer function or MTF) and efficiency at all spatial frequencies (detective quantum efficiency or DQE). It was suggested that a ‘thin’ CMOS detector would have the most outstanding properties [1], [2] and [3] because of a reduction in the proportion of backscattered electrons. In this paper we show, theoretically (using Monte Carlo simulations of electron trajectories) and experimentally that this is indeed the case. 相似文献
56.
Orthonasal or retronasal presentation of odorants evokes different responses. To study this phenomenon in depth, a stimulation technique has been developed that allows ortho- or retronasal presentation of chemosensory stimuli, the release of which is precisely controlled. Based on this technique studies have been conducted using psychophysical, electrophysiological, and imaging techniques. In conjunction with clinical data the results clearly suggest that there are differences in the perception of ortho- and retronasal stimuli. The basis for this phenomenon may be found in ideas by Mozell and colleagues with regard to odorant absorption across the mucosa which may determine activation of the olfactory epithelium. 相似文献
57.
58.
Surface and interface properties of functionalized polysulfones: Cell‐material interaction and antimicrobial activity
下载免费PDF全文
![点击此处可从《Polymer Engineering and Science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Quaternized polysulfones with different ionic chlorine content tested for biomedical applications were obtained by quaternization reaction of chloromethylated polysulfones with N,N‐dimethylethanolamine. The relationship between the different physical and chemical characteristics of these polymers and their biocompatible and antimicrobial properties was established for maximizing the selectivity and performance of these materials for biomedical applications. Therefore, topographic reorganization of the polysulfonic films induced by the type of nonsolvent in casting solutions of polymer significantly influences films morphology, depending on the charge density of polyelectrolytes, the hydrophilic/hydrophobic characteristics, as well as on the history of the formed films. Furthermore, the study of the adhesion of red blood cells and cohesion of platelets on the surface of quaternized polysulfone films, as well as analysis of antibacterial activity, using Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 25923 microorganisms, contribute to extending the possible applications of quaternized polysulfones as semipermeable membranes in biomedical domains. POLYM. ENG. SCI., 55:2184–2194, 2015. © 2015 Society of Plastics Engineers 相似文献
59.
60.