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   1056篇
  免费   48篇
电工技术   10篇
综合类   1篇
化学工业   284篇
金属工艺   33篇
机械仪表   49篇
建筑科学   57篇
矿业工程   1篇
能源动力   35篇
轻工业   56篇
水利工程   7篇
石油天然气   1篇
无线电   67篇
一般工业技术   214篇
冶金工业   79篇
原子能技术   4篇
自动化技术   206篇
  2023年   17篇
  2022年   15篇
  2021年   49篇
  2020年   37篇
  2019年   47篇
  2018年   33篇
  2017年   18篇
  2016年   36篇
  2015年   37篇
  2014年   41篇
  2013年   61篇
  2012年   70篇
  2011年   88篇
  2010年   64篇
  2009年   51篇
  2008年   45篇
  2007年   62篇
  2006年   41篇
  2005年   38篇
  2004年   24篇
  2003年   14篇
  2002年   26篇
  2001年   11篇
  2000年   13篇
  1999年   9篇
  1998年   31篇
  1997年   19篇
  1996年   12篇
  1995年   17篇
  1994年   7篇
  1993年   7篇
  1992年   5篇
  1991年   2篇
  1990年   5篇
  1989年   3篇
  1988年   8篇
  1987年   6篇
  1986年   4篇
  1985年   5篇
  1983年   3篇
  1981年   3篇
  1980年   2篇
  1977年   2篇
  1976年   3篇
  1972年   1篇
  1971年   1篇
  1969年   2篇
  1967年   2篇
  1966年   1篇
  1965年   1篇
排序方式: 共有1104条查询结果,搜索用时 15 毫秒
921.
The microstructural evolution of Cr-Si1?x -Ge x (0 < x < 15 at. pct) alloys was studied (in annealed state). The quasi-isothermal section of the ternary diagram was assessed by quantitative EPMA analysis. Morphology, phase formation, chemical distribution, and indentation hardness of the alloys were investigated as a function of Ge/Si ratio. The microstructure of all studied alloys consisted of Crss solid solution and A15 Cr3X intermetallic phases. Substitution of Si by Ge strongly altered the microstructure by transforming the morphology from a lamellar eutectic Cr-Cr3Si system toward a peritectic one with dispersed Crss phase in A15 matrix. EPMA chemical distribution maps and X-ray diffraction results prove the mutual solubility of Si and Ge in A15 phase by forming Cr3(Si,Ge) as a complex A15 structure with Cr3(Si1?x Ge x ) composition. Precipitates of the intermetallic phase within the Crss phase was observed in Ge-alloyed samples. Indentation hardness results showed that upon Si-Ge substitution the hardness of both phases was reduced. However, Si substitution by Ge had a stronger influence on the hardness of the solid solution phase than on the intermetallic phase.  相似文献   
922.
A kit formulation has been developed for convenient, routine compounding of (111)In-labeled In(III)-DTPA-Folate, an investigational radiopharmaceutical for targeting tumor-associated folate receptors. The kit consists of the DTPA-Folate conjugate in sodium citrate solution, from which [(111)In]In-DTPA-Folate can be rapidly and reliably compounded by the addition of aqueous [(111)In]In(III)-chloride.  相似文献   
923.
924.
The proposed hybrid process represents a new application of a magnetic field which directly influences a classical press filtration. The new technology offers high potential in the field of magnetic pigment production and iron oxide processing as well as bio-separation with functionalized magnetic particles. Especially in the field of fine-scale particulate product systems high specific cake resistances result in slow cake building and dewatering kinetics, which leads to economic inefficiency.Experimental and theoretical investigations show that the magnetic field has strong influence on cake building. Two major effects were observed: (I) In inhomogeneous magnetic fields magnetic particles experience a magnetic force counter directed to the pressure force, that results in slow down of cake formation; (II) Interparticle magnetic forces lead to structured cake formation.This gives on one hand the possibility to uncouple fluid and magnetic particle motion to force a cake built-up in designated location of the filter chamber. The result is a big increase of the overall filtrate mass flow and therefore an improvement of filtration kinetics. On the other hand due to the particle's magnetization including the formation of an attracting north and south-pole chainlike agglomerates can be observed. This leads to a “structured” cake building and therefore higher permeability.This work will show the effect of a superposed magnetic field on press filtration of ferromagnetic iron oxide particles (Fe3O4) in a lab-scale filter press.  相似文献   
925.
This paper describes a flexible MOS transistor layout generator which draws optimal layouts whatever the W and L dimensions. The drawing methodology is based on the use of small elementary parts, called bricks, which are placed side by side inside a user-specified boundary. The generated transistors may allow diffusion merging along whichever sides the user wishes and may have a global rectilinear shape. The internal structure of these cells may also be chosen by the designer so that it is well suited to his application. Transistors developed using this generator have been tested, and have been used to build a simple operational amplifier.  相似文献   
926.
927.
928.
929.
This paper describes a system architecture, which enables the automatic semantic annotation and adaptation of multimedia content in context-aware content sharing environments. The discussed architecture is the result of research done in the EU FP6 IST INTERMEDIA project. Generating a common vision on user-centric multimedia services in shared content environments to provide users with content personalized to their user preferences and usage environment is one of the objectives of the project. The work presented in this paper describes how media formats with their related metadata are automatically annotated and dynamically adapted. Based on the architecture, a full-featured demonstrator is built.  相似文献   
930.
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