全文获取类型
收费全文 | 292篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 138篇 |
金属工艺 | 8篇 |
建筑科学 | 5篇 |
矿业工程 | 1篇 |
能源动力 | 25篇 |
轻工业 | 15篇 |
水利工程 | 3篇 |
石油天然气 | 12篇 |
无线电 | 1篇 |
一般工业技术 | 48篇 |
冶金工业 | 26篇 |
原子能技术 | 1篇 |
自动化技术 | 14篇 |
出版年
2023年 | 1篇 |
2022年 | 17篇 |
2021年 | 31篇 |
2020年 | 11篇 |
2019年 | 13篇 |
2018年 | 20篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 18篇 |
2012年 | 25篇 |
2011年 | 13篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 11篇 |
2003年 | 4篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有304条查询结果,搜索用时 203 毫秒
281.
The catalytic properties of transition metal oxides (Cr, Ce, and Co) supported on ZrO2 synthesized by various methods, as well as the effect of rhodium on the performance of the MxOy/ZrO2 oxide systems in NO reduction with hydrocarbons (methane, propane–butane mixture, and propene) were studied. Scanning electron microscopy, ammonia thermoprogrammed desorption (NH3-TPD), XPS, and IR spectroscopy were used to study the physicochemical indices of rhodium-promoted MxOy/ZrO2 oxide catalysts. The enhancement of the redox properties of the oxide catalysts upon the introduction of rhodium does not alter their bifunctional nature in SCR activity: these catalysts have both redox and strong acid Brønsted-sites. 相似文献
282.
Yakov S. Vygodskii Natalia A. Churochkina Tatyana A. Panova Yurii A. Fedotov 《Reactive and Functional Polymers》1996,30(1-3):241-250
The cardo polyimides and polyamides having highly nucleophilic quinuclidine groups have been synthesized with the usage of 3,3-bis(4-aminophenyl)quinuclidine as amine monomer. The latter has been obtained by the condensation of quinuclidone-3 with aniline. The characterization of such amine, including quaternization reaction, is performed. Polyimides have been derived from this monomer and various tetracarboxylic dianhydrides by one- and two-step polycyclization. Quinuclidine moieties enhance the one-step polyimide formulation leading to high molecular polymers including corresponding poly- 1,4,5,8-naphthoyleneimides even without any added catalyst. It is stated that polyamic acid formation is hindered by the side tertiary-amine-COOH salt formation. The latter reaction is eliminated by the preliminary quaternization of amine monomer. The high molecular polyamides have been prepared by low-temperature solution polycondensation of cited monomer and diacid chlorides. The obtained polymers are characterized by high thermal properties, solubility in organic solvents and represent the quite efficient catalysts for polyamic acid imidation in homo- and heterogeneous systems. 相似文献
283.
Tatyana A. Smaglichenko Alexander V. Smaglichenko Ivan Zelinka Boris Chigarev 《International Journal of Parallel, Emergent and Distributed Systems》2018,33(5):503-512
AbstractThe seismic active zone is a distributed system consisting of various subareas. To understand a state of the system during a given period of time so called ‘the linear gradient frame’ technique was developed to search the stable characteristics for subareas. The search is based on analysis of geographic components, least-squares inversion and statistical estimators of seismic data. The stable subarea includes hypocenters of earthquakes, the space-time trajectories of which are restricted by a certain domain (seismic attractor). Fractal structures obtained in south of Iceland are in an agreement with geological history. The results are promising for the geothermal exploration. 相似文献
284.
Pavlygo Tatyana M. Plomod'yalo Leonid G. Plomod'yalo Roman L. Svistun Lev. I. 《Powder Metallurgy and Metal Ceramics》2004,43(5-6):223-228
Milling of wear-resistant steel and titanium carbide powders is studied with an attrition mill rotation rate of 980 rpm. The physical and technological properties of powders and particle size are determined. Particle shape and the change in material chemical composition during milling are studied. It is established that steel powder cannot be milled to particle sizes less than 3.6 μm whereas a mixture of steel and titanium carbide can be milled to a fine state (0.3 μm). Powders with a size of about 1 μm neither flow nor are formable. Use of benzene as a milling medium makes it possible to prevent steel powder oxidation, but the carbon content in titanium carbide decreases. During milling of the main part of the charge to a fine state rather large steel particles (up to 50 μm) remain. 相似文献
285.
Merenkov Ivan Sergeevich Myshenkov Mikhail Sergeevich Zhukov Yuri Mikhailovich Sato Yohei Frolova Tatyana Sergeevna Danilov Denis Vasilevich Kasatkin Igor Alekseevich Medvedev Oleg Sergeevich Pushkarev Roman Vladimirovich Sinitsyna Olga Ivanovna Terauchi Masami Zvereva Irina Alekseevna Kosinova Marina Leonidovna Ostrikov Ken 《Nano Research》2019,12(1):91-99
Nano Research - Dimensionality and orientation of hexagonal boron nitride (h-BN) nanosheets are promising to create and control their unique properties for diverse applications. However,... 相似文献
286.
287.
288.
Ekaterina A. Kozlova Tatyana P. KorobkinaAlexander V. Vorontsov 《International Journal of Hydrogen Energy》2009
The experiments on photocatalytic hydrogen production from aqueous solution of Ce2(SO4)3 and photocatalytic oxygen production from aqueous solution of Ce(SO4)2 were carried out on the same catalyst platinized Degussa P25. Pure oxygen was shown to evolve from Ce(SO4)2 solution and pure hydrogen from Ce2(SO4)3 solution with stoichiometric formation of Ce2(SO4)3 and Ce(SO4)2, respectively. 相似文献
289.
Joseph H. Han Audrey Bowen Tatyana N. Andryushchenko Radek P. Chalupa Anne E. Miller Harsono S. Simka Kennneth C. Cadien Sadasivan Shankar 《Journal of Applied Electrochemistry》2008,38(1):1-5
This paper demonstrates the application of a modified Levich equation for chemical systems with varying viscosity. A commonly
used technique to analyze rotating disc electrode (RDE) experiments is to fit the data to the Levich equation assuming a constant
effective diffusion coefficient which may be valid for conditions where the viscosity does not vary significantly (less than
an order of magnitude). However, most diffusion coefficient models (e.g. Stokes–Einstein) show an inverse relationship with
viscosity which consequently indicates that a constant effective diffusion coefficient may result in poorer model-to-data
agreement. Here, data are presented for a series of RDE experiments for the electrodissolution of Cu in phosphoric acid, water
and glycerin based baths. Viscosity changes of greater than one order of magnitude allow for testing the assumption of a constant
effective diffusion coefficient. The collected data, as well as data published elsewhere, can be explained by a modified Levich
equation which takes into account the viscosity dependence of the diffusion coefficient. 相似文献
290.
Diana Salnikova Varvara Orekhova Andrey Grechko Antonina Starodubova Evgeny Bezsonov Tatyana Popkova Alexander Orekhov 《International journal of molecular sciences》2021,22(16)
Altered mitochondrial function is currently recognized as an important factor in atherosclerosis initiation and progression. Mitochondrial dysfunction can be caused by mitochondrial DNA (mtDNA) mutations, which can be inherited or spontaneously acquired in various organs and tissues, having more or less profound effects depending on the tissue energy status. Arterial wall cells are among the most vulnerable to mitochondrial dysfunction due to their barrier and metabolic functions. In atherosclerosis, mitochondria cause alteration of cellular metabolism and respiration and are known to produce excessive amounts of reactive oxygen species (ROS) resulting in oxidative stress. These processes are involved in vascular disease and chronic inflammation associated with atherosclerosis. Currently, the list of known mtDNA mutations associated with human pathologies is growing, and many of the identified mtDNA variants are being tested as disease markers. Alleviation of oxidative stress and inflammation appears to be promising for atherosclerosis treatment. In this review, we discuss the role of mitochondrial dysfunction in atherosclerosis development, focusing on the key cell types of the arterial wall involved in the pathological processes. Accumulation of mtDNA mutations in isolated arterial wall cells, such as endothelial cells, may contribute to the development of local inflammatory process that helps explaining the focal distribution of atherosclerotic plaques on the arterial wall surface. We also discuss antioxidant and anti-inflammatory approaches that can potentially reduce the impact of mitochondrial dysfunction. 相似文献