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   119篇
  免费   6篇
电工技术   2篇
化学工业   38篇
金属工艺   2篇
机械仪表   3篇
能源动力   3篇
轻工业   9篇
无线电   5篇
一般工业技术   27篇
冶金工业   13篇
原子能技术   6篇
自动化技术   17篇
  2024年   1篇
  2023年   1篇
  2022年   4篇
  2021年   2篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2017年   4篇
  2016年   5篇
  2015年   5篇
  2014年   1篇
  2013年   10篇
  2012年   6篇
  2011年   11篇
  2010年   6篇
  2009年   3篇
  2008年   4篇
  2007年   6篇
  2006年   5篇
  2004年   3篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   2篇
  1999年   2篇
  1998年   3篇
  1996年   4篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1990年   2篇
  1989年   2篇
  1988年   4篇
  1987年   5篇
  1985年   2篇
  1984年   2篇
  1980年   1篇
排序方式: 共有125条查询结果,搜索用时 31 毫秒
1.
2.
An increase in scintillation of up to 17% has been observed application of low electric fields (<6 kV/cm) for 1H, 4He, 18O and 36Ar ions of energy 1-35 MeV/u. This increase occurs at a field much lower than that required for the proportional region (106 V/cm). The observed phenomenon is attributed to the recovery of quenching in the high excitation density region of the particle track by the external field  相似文献   
3.
The effects of vitamin B6 (B6) deficiency on cytokine levels and proportions of lymphocyte subsets in BALB/c mice were investigated. The proportion of lymphocytes from the thymus and spleen of mice given no B6, that were CD4+ CD8- T cells, was larger than in mice given B6, and the ratio of CD8+ to CD4+ T cells in the thymus of mice given no B6 was lower. The concentrations of interleukin-5 and -10 in spleen cells stimulated in vitro with concanavalin A were significantly higher in the mice with B6 deficiency, as was their plasma corticosterone concentrations. These results suggested that B6 is necessary to maintain cytokine levels and lymphoid function in the thymus and spleen of mice.  相似文献   
4.
Application development productivity is becoming an increasingly important issue in the MIS department. Unfortunately, dramatic improvements in hardware performance have not been matched with corresponding advances in software development, even though there have been significant investments in productivity tools. This article identifies a range of productivity tools and presents results from a survey of MIS managers that reveals which specific tools are being used and their relative importance to software development productivity.  相似文献   
5.
The goal in global illumination solutions for dynamic environments is to update a scene based on past scenes. For this difficult problem, current state of the art solutions are either not applicable, or unduly complex, when there are large changes in the illumination of unbounded number of objects. Such changes may be caused by the appearance of unexpected (at modeling time), irregular light sources.

We define a subset of dynamic environments in which new light sources may be user introduced, and implement solutions that complement existing schemes.  相似文献   

6.
The aim of the present work is to compute feed-paths and hot-spots by combining level-set-method based sharp interface and feed-path model. The model is based on the solution of energy and level-set equations in solid and liquid, with Stefan condition on the interface. The energy and level-set equation are discretized using finite-volume and finite-difference method, respectively. Feed-path is computed by tracking mass-less particles along the liquid-solid interface during solidification using combined Eulerian-Lagrangian framework. The proposed model is benchmarked on six test cases, where temperature contours and solidification time are compared with a finite-element-method based commercial software. The capability to predict the temporal evolution of interface and to identify multiple hot-spots is validated with an industrial aluminum-alloy lug casting. The numerical as well as experimental validations demonstrate the effectiveness of level-set-method for feed-path calculation.  相似文献   
7.
8.
Doke  Suhas D.  Patel  C. M.  Lad  V. N. 《SILICON》2022,14(3):913-922
Silicon - Abundant applications of silica nanoparticles (SiNPs) have motivated many research groups for silica nanoparticles synthesis with tuned properties. Here we show the formation of SiNPs...  相似文献   
9.
As part of a comprehensive effort to predict the development of caking in granular materials, a mathematical model is introduced to model simultaneous heat and moisture transfer with phase change in porous media when undergoing temperature oscillations/cycling. The resulting model partial differential equations were solved using finite-volume procedures in the context of the PHYSICA framework and then applied to the analysis of sugar in storage. The influence of temperature on absorption/desorption and diffusion coefficients is coupled into the transport equations. The temperature profile, the depth of penetration of the temperature oscillation into the bulk solid, and the solids moisture content distribution were first calculated, and these proved to be in good agreement with experimental data. Then, the influence of temperature oscillation on absolute humidity, moisture concentration, and moisture migration for different parameters and boundary conditions was examined. As expected, the results show that moisture near boundary regions responds faster than farther away from them with surface temperature changes. The moisture absorption and desorption in materials occurs mainly near boundary regions (where interactions with the environment are more pronounced). Small amounts of solids moisture content, driven by both temperature and vapour concentration gradients, migrate between boundary and center with oscillating temperature.  相似文献   
10.
引言 在蜂窝电话、PDA和便携式GPS等由电池供电的便携式产品中,高度集成的LT3491可为驱动背光照明电路组成简单和紧凑的解决方案。该器件具有内部补偿电路、LED开路保护功能、一个32V电源开关和一个32V肖特基二极管,而其封装却是纤巧的SC70。  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