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   518篇
  免费   21篇
  国内免费   4篇
电工技术   12篇
综合类   1篇
化学工业   107篇
金属工艺   17篇
机械仪表   49篇
建筑科学   14篇
能源动力   45篇
轻工业   26篇
水利工程   2篇
石油天然气   1篇
无线电   46篇
一般工业技术   157篇
冶金工业   8篇
原子能技术   6篇
自动化技术   52篇
  2024年   3篇
  2023年   16篇
  2022年   28篇
  2021年   30篇
  2020年   20篇
  2019年   32篇
  2018年   37篇
  2017年   30篇
  2016年   31篇
  2015年   21篇
  2014年   16篇
  2013年   48篇
  2012年   36篇
  2011年   39篇
  2010年   16篇
  2009年   17篇
  2008年   23篇
  2007年   17篇
  2006年   21篇
  2005年   5篇
  2004年   11篇
  2003年   9篇
  2002年   10篇
  2001年   6篇
  2000年   1篇
  1999年   7篇
  1998年   6篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   2篇
  1992年   1篇
排序方式: 共有543条查询结果,搜索用时 15 毫秒
21.
22.
Highly transparent Aluminum oxynitride (AlON) body has been produced using aqueous slip casting technique. High‐purity alumina and AlN were used as raw materials for the synthesis of single‐phase AlON powder. As‐synthesized AlON powder was surface modified to enable the AlON powders resistant to hydrolysis in water during aqueous slip casting. High solid loaded aqueous AlON slip was prepared for casting followed by drying and sintering to produce transparent AlON. Phase formation and stability was characterized by XRD, pH, and viscosity measurements. AlON powders before and after surface treatments were characterized. Sintered transparent AlON samples were characterized for their mechanical, microstructural, and optical properties. Sintered and polished AlON produced in this study has shown inline transparency up to 80% between 0.22 and 6 μm wavelength region.  相似文献   
23.
A library of 3,4‐(methylenedioxy)aniline‐derived semicarbazones was designed, synthesized, and evaluated as monoamine oxidase (MAO) and acetylcholinesterase (AChE) inhibitors for the treatment of neurodegenerative diseases. Most of the new compounds selectively inhibited MAO‐B and AChE, with IC50 values in the micro‐ or nanomolar ranges. Compound 16 , 1‐(2,6‐dichlorobenzylidene)‐4‐(benzo[1,3]dioxol‐5‐yl)semicarbazide presented a balanced multifunctional profile of MAO‐A (IC50=4.52±0.032 μm ), MAO‐B (IC50=0.059±0.002 μm ), and AChE (IC50=0.0087±0.0002 μm ) inhibition without neurotoxicity. Kinetic studies revealed that compound 16 exhibits competitive and reversible inhibition against MAO‐A and MAO‐B, and mixed‐type inhibition against AChE. Molecular docking studies further revealed insight into the possible interactions within the enzyme–inhibitor complexes. The most active compounds were found to interact with the enzymes through hydrogen bonding and hydrophobic interactions. Additionally, in silico molecular properties and ADME properties of the synthesized compounds were calculated to explore their drug‐like characteristics.  相似文献   
24.
25.
Energy demand is the hot topic of all developing and developed countries. Energy demand has been increasing day by day at a high rate. So, it is necessary to find an alternative solution that is eco-friendly. Biodiesel can be the alternative solution for this problem. The main purpose of this paper is to test the engine performance and emission parameters of a diesel engine using pure cinnamon oil blended with diesel and using cerium oxide as a catalyst. The parameters measured are brake power, brake thermal efficiency, specific fuel conception, CO2, CO, NOx and HC.  相似文献   
26.
Arunkumar  S.  Kumar  A. Senthil 《SILICON》2022,14(5):1959-1967
Silicon - The hybrid metal matrix composite is developed through stir casting process. In theAl7075 aluminium matrix material, two different combination of reinforcements are used to make hybrid...  相似文献   
27.
Vasanthi  P.  Selvan  S. Senthil 《SILICON》2022,14(1):127-133
Silicon - In this research, multi response Taguchi-grey relational approach was employed to optimize the mixing parameters in cement mortar preparation. The main aim of this present investigation...  相似文献   
28.
The accuracy of the thermodynamic properties prediction from the different Equation of state (EOS) varies upon the range of temperature and pressure. Despite the variety of EOS available, there is no de facto for selecting an EOS for particular computational modeling. The EOS model recently developed by Kumar and Kim (K-K EOS) determines more accurately the thermodynamic properties of CO2 than earlier models. In this present study, K-K EOS is successfully implemented in the computational analysis of compressible supercritical CO2 flow (S-CO2) in the thermodynamic region near and away from the vapour-liquid critical point. Computational results of SCO2 flow with the real gas properties predicted with the K-K EOS is compared with Span and Wagner (SW EOS) and ideal EOS.  相似文献   
29.
Iranian Polymer Journal - Poly(vinyl alcohol) (PVA) nanocomposites incorporated with ZnO nanofiller were prepared and examined to study the influence of nanofiller on their properties. All the...  相似文献   
30.
Gas diffusion layer (GDL) is subjected to compressive stress at high temperature along with polymer electrolyte membrane in the fabrication process and in assembling the fuel cell stacks. Compressive stress decreases the thickness of GDL, electrical conductivity, permeability, and affects the pores. Carbon cloth based GDL withstands higher strain level when compared to carbon paper and the pore structure is also disrupted to a greater extent in cloth based GDL. In the present paper, we have addressed the effects of stress on pore structure of cloth based GDL. An optimum GDL must offer low mass transport resistance in an operating PEM fuel cell. The pore size analysis of pristine GDL and GDLs pressed at different pressure levels (200, 600 & 1000 kg cm−2) and their characteristics are evaluated using capillary flow porometry. The compressive stress affects the three types of pores in GDL called bubble point pore, mean flow pore and smallest pore. The change in electrical resistance, wetting behavior and surface morphology is also examined as a function of compressive stress. The fuel cell performances using these GDLs pressed at different compressive stresses are also evaluated and presented. The highest PEMFC performance is achieved at a compressive stress of 200 kg cm−2, which could be attributed to the combined effect of reduced ohmic resistance and optimized pore structure. The order of increasing performance in terms of current density is observed to be j200 > jPristine > j600 > j1000 at 0.15 V. The thicknesses and pore sizes of custom made GDL for optimum fuel cell performance are recommended.  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