首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1310篇
  免费   90篇
  国内免费   48篇
电工技术   9篇
综合类   75篇
化学工业   443篇
金属工艺   12篇
机械仪表   14篇
建筑科学   41篇
矿业工程   77篇
能源动力   56篇
轻工业   316篇
水利工程   2篇
石油天然气   204篇
武器工业   2篇
无线电   30篇
一般工业技术   84篇
冶金工业   36篇
原子能技术   17篇
自动化技术   30篇
  2024年   7篇
  2023年   14篇
  2022年   23篇
  2021年   34篇
  2020年   39篇
  2019年   49篇
  2018年   42篇
  2017年   45篇
  2016年   42篇
  2015年   41篇
  2014年   81篇
  2013年   82篇
  2012年   66篇
  2011年   91篇
  2010年   84篇
  2009年   68篇
  2008年   60篇
  2007年   74篇
  2006年   91篇
  2005年   74篇
  2004年   53篇
  2003年   56篇
  2002年   47篇
  2001年   29篇
  2000年   33篇
  1999年   26篇
  1998年   22篇
  1997年   9篇
  1996年   11篇
  1995年   9篇
  1994年   8篇
  1993年   7篇
  1992年   8篇
  1991年   6篇
  1990年   3篇
  1989年   3篇
  1988年   1篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
排序方式: 共有1448条查询结果,搜索用时 15 毫秒
81.
国内外冷轧宽带钢轧制油的现状及发展趋势   总被引:3,自引:1,他引:2  
胡汉国 《石油商技》2001,19(5):11-15
简要介绍了冷轧轧制油主要添加剂的类别、组成,回顾了国内轧制油的发展历程,重点介绍了润滑技术、乳化技术及清净性技术的发展动向。  相似文献   
82.
D相乳化法制备油墨清洗剂   总被引:1,自引:0,他引:1  
本文主要介绍了用D相乳化法制备一种特效油墨清洗剂,并对清洗剂性能进行了探讨,这种清洗剂主要成分由烷基酚聚氧乙烯醚、环保油溶剂、十二烷基苯磺酸钠以及水等组成。清洗剂为中性,主要用于清洗印刷操作工手上所沾油墨。这种清洗剂对人体皮肤无伤害,去油墨效果非常显著,且无毒无污染,价格低廉,制作简单,使用方便。  相似文献   
83.
We studied different methods of preparing α-tocopherol acetate (ATA) nanoparticles, which are to be used in targeting the lungs as aerosols in order to prevent cigarette smoke toxicity. Poly-(lactide) nanoparticles were prepared using nanoprecipitation and solvent evaporation techniques, which produced, respectively, too small and too large nanoparticles to be aerosolized. The emulsification-diffusion method produced 2 months stable nanoparticles with a size between (500–700 nm). Increasing ATA concentration (1–7 mg/mL) induced a decrease in the association rate (97–93%) and in the adsorbed ATA rate (7–4.5%), which was associated with variations of Zeta potentials (?27.5 to ?24.3 mV) and decrease in polymeric wall thickness and density.  相似文献   
84.
85.
Spontaneous vitrification is a phenomenon where a crystalline phase transforms to the amorphous phase on annealing at low temperatures. It has been reported to occur in several binary alloy systems. This phenomenon has been widely investigated in the Ti–Cr system through experiments as well as thermodynamic modeling. The models reported in literature suffer from several drawbacks. They are not consistent with experimental observations. These models treat this non-equilibrium process as an essentially equilibrium process albeit involving two meta-stable phases. The thermodynamics of the “spontaneous vitrification” process has been modeled using the concept of Transformation Diagrams. This method considers the thermodynamics of non-equilibrium phase transformation and does not involve assumptions of equilibrium at any stage. A significant conclusion derived from the present model is that it is the close-packed hcp structure that transforms to the amorphous phase whereas the transformation of the relatively open bcc structure to the amorphous phase is forbidden thermodynamically. These conclusions are in contrast with the predictions of the earlier models.  相似文献   
86.
Emulsions and microcapsules are typical structures in various dispersion formulations for pharmaceutical, food, personal and house care applications. Precise control over size and size distribution of emulsion droplets and microcapsules are important for effective use and delivery of active components and better product quality. Many emulsification technologies have been developed to meet different formulation and processing requirements. Among them, membrane and microfluidic emulsification as emerging technologies have the feature of being able to precisely manufacture droplets in a drop-by-drop manner to give subscribed sizes and size distributions with lower energy consumption. This paper reviews fundamental sciences and engineering aspects of emulsification, membrane and microfluidic emulsification technologies and their use for precision manufacture of emulsions for intensified processing. Generic application examples are given for single and double emulsions and microcapsules with different structure features.  相似文献   
87.
A phaser-based processing technique was adopted in an UWB over fiber system employing SOA. The target is to simultaneously reduce the ASE noise impact and nonlinear effects inherent to optical amplification. Experimental results prove the effectiveness of chirping in terms of cross correlation and bit error rate.  相似文献   
88.
本文用变分累积展开(VCE)方法对六态矢量Potts模型的相结构和相变性质进行了研究。在引进单变分参数情况下,系统的自由能,内能,比热和自发磁化强度被计算到四阶近似;在双变分参数情况下,上述物理量被计算到二阶近似。结果表明,系统存在三相结构,在较低温度下发生的是连续相变,而在较高温度下发生的是一级相变。得出的相变位置和用蒙特卡罗(MC)数值模拟方法给出的结果相一致,体现了用VCE方法处理Potts模型的有效性。比用MC方法的优越性在于,用VCE方法能体现出序参量和内能在一级相变时发生突变的情况。  相似文献   
89.
Our objective is spoken-language classification for helpdesk call routing using a scanning understanding and intelligent-system techniques. In particular, we examine simple recurrent networks, support-vector machines and finite-state transducers for their potential in this spoken-language-classification task and we describe an approach to classification of recorded operator-assistance telephone utterances. The main contribution of the paper is a comparison of a variety of techniques in the domain of call routing. Support-vector machines and transducers are shown to have some potential for spoken-language classification, but the performance of the neural networks indicates that a simple recurrent network performs best for helpdesk call routing. Sheila Garfield received a BSc (Hons) in computing from the University of Sunderland in 2000 where, as part of her programme of study, she completed a project associated with aphasic language processing. She received her PhD from the same university, in 2004, for a programme of work connected with hybrid intelligent systems and spoken-language processing. In her PhD thesis, she collaborated with British Telecom and suggested a novel hybrid system for call routing. Her research interests are natural language processing, hybrid systems, intelligent systems. Stefan Wermter holds the Chair in Intelligent Systems and is leading the Intelligent Systems Division at the University of Sunderland, UK. His research interests are intelligent systems, neural networks, cognitive neuroscience, hybrid systems, language processing and learning robots. He has a diploma from the University of Dortmund, Germany, an MSc from the University of Massachusetts, USA, and a PhD in habilitation from the University of Hamburg, Germany, all in Computer Science. He was a Research Scientist at Berkeley, CA, before joining the University of Sunderland. Professor Wermter has written edited, or contributed to 8 books and published about 80 articles on this research area.  相似文献   
90.
膜乳化过程研究进展   总被引:4,自引:0,他引:4  
简要综述了膜乳化过程的机理、操作参数的影响和乳液性质等.操作参数包括膜材料、膜孔径及孔隙率、连续相速率、跨膜压差、乳化剂等.通过控制合适的操作参数,可制备出具有所需尺寸的单分散乳液.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号