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   221篇
  免费   8篇
电工技术   2篇
综合类   2篇
化学工业   43篇
金属工艺   1篇
机械仪表   3篇
建筑科学   2篇
能源动力   4篇
轻工业   11篇
无线电   43篇
一般工业技术   35篇
冶金工业   39篇
原子能技术   16篇
自动化技术   28篇
  2022年   3篇
  2021年   1篇
  2020年   2篇
  2019年   3篇
  2018年   3篇
  2017年   6篇
  2016年   5篇
  2015年   2篇
  2014年   3篇
  2013年   9篇
  2012年   18篇
  2011年   9篇
  2010年   13篇
  2009年   14篇
  2008年   11篇
  2007年   12篇
  2006年   8篇
  2005年   8篇
  2004年   6篇
  2003年   5篇
  2002年   12篇
  2001年   5篇
  2000年   7篇
  1999年   1篇
  1998年   14篇
  1997年   8篇
  1996年   7篇
  1995年   6篇
  1994年   3篇
  1993年   2篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1989年   3篇
  1988年   2篇
  1985年   2篇
  1984年   3篇
  1983年   2篇
  1981年   3篇
  1979年   1篇
  1977年   1篇
排序方式: 共有229条查询结果,搜索用时 31 毫秒
1.
This paper addresses the impact of device macromodels on the accuracy of signal integrity and performance predictions for critical digital interconnecting systems. It exploits nonlinear parametric models for both single-ended and differential devices, including the effects of power supply fluctuations and receiver bit detection. The analysis demonstrates that the use of well-designed macromodels dramatically speeds up the simulation as well it preserves timing accuracy even for long bit sequences.  相似文献   
2.
3.
This paper addresses adaptive radar detection of distributed targets in noise plus interference assumed to belong to a known or unknown subspace of the observables. At the design stage we resort to either the GLRT or the so-called two-step GLRT-based design procedure and assume that a set of noise-only data is available (the so-called secondary data). Detection algorithms have been derived modeling noise vectors, corresponding to different range cells, as independent, zero-mean, complex normal ones, sharing either the same covariance matrix (homogeneous environment) or the same covariance matrix up to possibly different (mean) power levels between primary data, i.e., range cells under test, and secondary ones (partially homogeneous environment). The performance assessment has been conducted by Monte Carlo simulation, also in comparison to previously proposed detection algorithms, and confirms the effectiveness of the newly proposed ones  相似文献   
4.
Ten different strains of unicellular microalgae have been used in the bioconversion of progesterone. Regio and stereoselective reduction and hydroxylation of the title compound were induced. A 9,10-seco derivative was obtained in high yield by using Scenedesmus quadricauda.  相似文献   
5.
The raising countries asking for desalination plants are 0.011:0 normally in trouble for the period of time between taking over of the plant and the first two years of operation.During this period it is very useful to use proper consultants to supervise plant operation and train operating, maintenance and management personnel.In the present paper appropriate schemes of cooperation are outlined togheter with a particullary idea about plant operation control.  相似文献   
6.
Experiences of acid cleaning and passivation treatments of copper alloy tubes are described. The suitability of corrosion monitoring to follow each step of such operation is demonstrated.  相似文献   
7.
Uncoupled thermomechanical transient analyses have been carried out to investigate the behavior of IFMIF-EVEDA lithium test loop bayonet backplate target assembly under two selected start-up transient operational scenarios. The first transient scenario considered foresees that the target assembly, starting from the initial uniform temperature of 50 °C, is heated up uniquely by convective heat transfer with lithium, flowing from inlet to outlet nozzle at its reference nominal temperature and pressure, until its nominal steady state thermal field distribution is reached. The second transient scenario foresees, more realistically, that the target assembly, starting from the uniform temperature of 50 °C, is initially warmed-up by electric heaters mounted onto its main accessible surfaces and, subsequently, by convective heat transfer with lithium reference flow, until nominal steady state conditions are reached. Heaters have been supposed to operate in an on/off stepwise mode, resulting to be alternatively switched on and off in order to allow the target assembly thermal field to grow up minimizing thermal gradients. To this purpose, a parametric analysis has been performed to realistically assess, for each electric heater, its heat flux and duty-cycle. Numerical results obtained are presented and critically discussed.  相似文献   
8.
Sustainable intensification (SI) has been proposed as a solution to meeting the challenge of feeding a growing global population under increasing land pressure. This paper explores the level of ambivalence felt towards SI and towards experts promoting SI based solutions to meet food security. A web-based experiment was conducted with 600 respondents who had varying degrees of knowledge about food security issues. We found a diversity of public ambivalence towards sustainable intensification and a high level of felt ambivalence towards experts promoting SI as a solution to global food security. High levels of ambivalence towards experts seemed to influence how messages on global food security were accepted. Moreover, within the respondents here sustainable consumption and greater equity ranked higher than production based sustainable intensification solutions. This paper represents the first application of the psychological construct of ambivalence applied to the topic of sustainable intensification and we argue this helps to localise the debate around SI as it offers the opportunity to capture or disentangle responses towards food security issues.  相似文献   
9.
10.
The ITER diagnostic Upper Port Plug (UPP) is a water-cooled stainless steel structure aimed to integrate within vacuum vessel the plasma diagnostic systems, shielding them from neutron and photon irradiation. Due to the very intense heat loads expected, a proper cooling circuit has been designed to ensure an adequate UPP cooling with an acceptable thermal rise and an unduly high pumping power and to perform its draining and drying procedure by injection of pressurized nitrogen.A theoretical research activity has been launched at the Department of Nuclear Engineering of the University of Palermo aiming to investigate the hydraulic behaviour of the UPP Trapezoid Section cooling circuit under steady state conditions and during its draining and drying transient procedure. The research activity has been performed following a theoretical-computational approach and adopting the RELAP5 thermal-hydraulic system code.The Trapezoid Section cooling circuit characteristic functions have been derived under steady state conditions at various coolant temperatures for both the coolant flow paths at the present under consideration for this circuit. The distributions of coolant mass flow rates along the channels of the cooling circuit have been calculated too. Results show that the flow path characterized by right plate inlet has improved hydraulic performances.The transient behaviour of the Trapezoid Section cooling circuit has been investigated during the draining and drying operational transient procedure, considering realistic operative scenarios, for both the coolant flow paths at the present under consideration for the cooling circuit. In particular, it has been found out that the recently proposed flow path seems to allow the complete draining of the Trapezoid Section circuit, eliminating the need for the drying procedure.  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