全文获取类型
收费全文 | 847篇 |
免费 | 122篇 |
国内免费 | 36篇 |
专业分类
电工技术 | 10篇 |
综合类 | 32篇 |
化学工业 | 288篇 |
金属工艺 | 141篇 |
机械仪表 | 12篇 |
建筑科学 | 5篇 |
矿业工程 | 26篇 |
能源动力 | 46篇 |
轻工业 | 29篇 |
石油天然气 | 8篇 |
武器工业 | 5篇 |
无线电 | 105篇 |
一般工业技术 | 157篇 |
冶金工业 | 109篇 |
原子能技术 | 8篇 |
自动化技术 | 24篇 |
出版年
2024年 | 2篇 |
2023年 | 17篇 |
2022年 | 26篇 |
2021年 | 30篇 |
2020年 | 38篇 |
2019年 | 23篇 |
2018年 | 32篇 |
2017年 | 37篇 |
2016年 | 38篇 |
2015年 | 26篇 |
2014年 | 42篇 |
2013年 | 53篇 |
2012年 | 41篇 |
2011年 | 54篇 |
2010年 | 41篇 |
2009年 | 51篇 |
2008年 | 48篇 |
2007年 | 53篇 |
2006年 | 41篇 |
2005年 | 49篇 |
2004年 | 33篇 |
2003年 | 35篇 |
2002年 | 28篇 |
2001年 | 22篇 |
2000年 | 32篇 |
1999年 | 20篇 |
1998年 | 14篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1960年 | 1篇 |
1958年 | 1篇 |
1957年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1005条查询结果,搜索用时 0 毫秒
81.
Catalytic wet air oxidation of butyric acid solutions using carbon-supported iridium catalysts 总被引:1,自引:0,他引:1
Aqueous solutions of butyric acid were treated by catalytic wet air oxidation using carbon-supported iridium catalysts in a stirred reactor. Under the operating conditions of 6.9 bar of oxygen partial pressure and 200 °C of temperature, conversions up to 52.9% after 2 h were obtained depending on the type of catalyst used. The effects of butyric acid initial concentration, loading of catalyst, oxygen partial pressure and temperature were investigated and the empirical rate law for acid conversion is presented. Oxidation intermediates such as propionic and acetic acid were identified. The heterogeneous catalyzed free-radical oxidation of butyric acid is discussed. 相似文献
82.
K.A.T. Amalka Perera S. Gaveshana Anuradha G.R. Asoka Kumara M. Lal Paranawitharana R.M. Gamini Rajapakse H.M.N. Bandara 《Electrochimica acta》2011,(11):19
Design, Development, fabrication and investigation of the I–V characteristics of the DSSC based on interconnected 15 nm SnO2 nanoparticles covered with a nano-scale thin layer of CaCO3 are described. The presence of CaCO3 has been confirmed by its characteristic XRD pattern and EDX plots. The thickness of the protective layer can be conveniently controlled by the molar ratio of SnO2:CaCO3 used in the preparation of the thin film and the optimum conditions for best performance of the DSSC are presented together with possible explanations for the variations observed when the molar ratio is changed. An optimum light-to-electricity conversion efficiency of 5.4% in the presence of a layer of CaCO3 has been obtained which is 3.2 times enhancement over the cell prepared without CaCO3. The characterization of the surface using different techniques is explained. 相似文献
83.
84.
Simple versatile processes combining plasma treatments, micro-contact printing (µCP) or ink-jet printing (IJP), and electroless deposition (ELD) have been developed to produce micrometer and sub-micrometer scale metal (Ni, Ag) patterns at the surface of polymer substrates. Plasma treatments were mainly used to graft the substrate surfaces with either nitrogen-containing functionalities on which a palladium-based catalyst can be subsequently chemisorbed (case of Ni deposition through a tin-free process in solution) or oxygen-containing functionalities on which a tin-based sensitization agent can be subsequently chemisorbed (case of Ag deposition through a redox reaction). µCP of the catalyst or of self-assembled monolayers (SAMs) as well as ink printing were used to obtain locally active or non-active areas at the polymer surfaces. The metal micro-patterns were characterized using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Surface chemical characterization was carried out by X-ray photoelectron spectroscopy (XPS). 相似文献
85.
Bis(4-dimethylamino-2-dihydroxyphenyl)squaraine (1-1 OHSQ) dyes were deposited on van der Waals surfaces of SnS2 single crystals by two methods, dipping in a dye solution and evaporation of dye solution. Dye morphologies and photosensitization properties on the same samples were studied with atomic force microscopy (AFM) and photoelectrochemical measurements. AFM experiments in air revealed two distinct morphologies of dye aggregates and photocurrent measurements on the same samples in aqueous electrolytes showed correspondingly different photocurrent spectra. Three-dimensional needle-shaped 1-1 OHSQ aggregates aligned along crystal directions and showed a broad excitation spectrum that extended into the near-IR region with a peak around 800 nm. In contrast, flat aggregates presumably consisting of monolayers of 1-1 OHSQ molecules, had a sensitization maximum around 680 nm. Both peaks were red-shifted from absorption peak of 1-1 OHSQ in bulk dichloromethane solution. Spectral differences between these dye aggregates are discussed in terms of intermolecular interactions. 相似文献
86.
稳盐对扁平卤化银微晶增感中心大小和分布的影响 总被引:1,自引:0,他引:1
稳盐对扁平卤化银微晶增感中心大小和分布的影响*胡勇军王荣琴彭必先**(中国科学院感光化学研究所,北京100101)关键词T-颗粒,增感中心大小分布,电镜法,稳盐5-甲基-7-羟基-1,3,4三氮吲哚嗪(简称稳盐TAI)作为乳剂制备过程的有机稳定剂,... 相似文献
87.
Ramon Margalef‐Català Pilar Salagre Elena Fernández Carmen Claver 《Catalysis Letters》1999,60(3):121-123
Heterogenised homogeneous catalytic hydrogenation of aldimines by removable and reusable immobilised iridium complexes on montmorillonite clay. This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
88.
89.
针对具有烟温低、氧含量高和CO浓度大等特征的固定源烟气(钢铁烧结/球团烟气和焦化烟气等)脱硝领域,CO选择性催化还原NO x (CO-SCR)技术具有良好的发展前景。Ir基贵金属催化剂因其在CO-SCR反应体系中表现出了良好的抗氧能力和较高的催化活性成为催化脱硝领域研究的热点之一。本文重点总结了单一载体、复合载体与复合活性组分三类Ir基催化剂在CO-SCR脱除NO x 中的催化性能,同时从制备条件和反应条件两大方面归纳了其对Ir基催化剂的CO-SCR脱硝性能的影响,简要阐述了Ir基催化剂表面反应机理,并对未来研究工作进行了展望,指出采用多种手段对催化剂进行改性,并通过降低Ir负载量、反应温度窗口以及提升其催化活性等方式来降低成本,为实现Ir基催化剂CO-SCR工业化应用提供借鉴。 相似文献
90.