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   366篇
  免费   17篇
  国内免费   2篇
电工技术   13篇
化学工业   95篇
金属工艺   6篇
机械仪表   6篇
建筑科学   5篇
矿业工程   3篇
能源动力   14篇
轻工业   22篇
水利工程   1篇
石油天然气   2篇
无线电   84篇
一般工业技术   64篇
冶金工业   26篇
原子能技术   1篇
自动化技术   43篇
  2023年   3篇
  2022年   10篇
  2021年   19篇
  2020年   8篇
  2019年   15篇
  2018年   20篇
  2017年   16篇
  2016年   9篇
  2015年   8篇
  2014年   11篇
  2013年   22篇
  2012年   15篇
  2011年   12篇
  2010年   8篇
  2009年   26篇
  2008年   11篇
  2007年   9篇
  2006年   10篇
  2005年   6篇
  2004年   8篇
  2003年   10篇
  2002年   7篇
  2001年   4篇
  2000年   3篇
  1999年   6篇
  1998年   12篇
  1997年   6篇
  1996年   4篇
  1995年   8篇
  1994年   3篇
  1993年   3篇
  1992年   6篇
  1991年   2篇
  1990年   6篇
  1989年   2篇
  1987年   2篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   3篇
  1981年   5篇
  1980年   2篇
  1979年   6篇
  1978年   7篇
  1977年   3篇
  1976年   2篇
  1975年   5篇
  1974年   2篇
  1970年   1篇
  1969年   1篇
排序方式: 共有385条查询结果,搜索用时 15 毫秒
31.
Stasinski  R. Nandi  A.K. 《Electronics letters》1992,28(18):1680-1681
The possibility and the construction of a number of fast algorithms for the two-dimensional masking of small mask sizes is clearly demonstrated. These are based on nesting and represent extension of the ideas of Stasinski (1990). Moreover, the authors explain how to make the optimal choice of the algorithm depending on the computational machine available.<>  相似文献   
32.
A dual-input ideal differentiator network design with a single resistor-controlled time constant and high-gain operational amplifier (OA) devices is described. At high frequencies, the network becomes functionally nonideal and its quality factor (Q) degrades because of the frequency-dependent gain of the OA. A suitable Q-compensation design that yields a 1:|A|2 order of Q improvement at higher frequencies is proposed. The network exhibits high-frequency deemphasis characteristics due to the OA-poles which would suppress the high-frequency noise components  相似文献   
33.
In this paper, an experimental mixed reality using a multimodal approach is introduced which lets users play characters in interactive narratives as though acting on a stage. Users interact with characters through speech, attitude, and gesture, enhancing their immersion in the virtual world. This system provides a small-scale but complete integration of multimodal communication in interactive storytelling. It uses a narrative's semantic context to focus multimodal input processing-that is, the system interprets users' acting (the multimodal input) in the mixed reality stage in terms of narrative functions representing users' contributions to the unfolding plot.  相似文献   
34.
This paper introduces two algorithms for analog and digital modulations recognition. The first algorithm utilizes the decision-theoretic approach in which a set of decision criteria for identifying different types of modulations is developed. In the second algorithm the artificial neural network (ANN) is used as a new approach for the modulation recognition process. Computer simulations of different types of band-limited analog and digitally modulated signals corrupted by band-limited Gaussian noise sequences have been carried out to measure the performance of the developed algorithms. In the decision-theoretic algorithm it is found that the overall success rate is over 94% at the signal-to-noise ratio (SNR) of 15 dB, while in the ANN algorithm the overall success rate is over 96% at the SNR of 15 dB  相似文献   
35.
Interaction of prion peptide HuPrP106-126 with nucleic acid   总被引:1,自引:0,他引:1  
Synthetic prion peptide PrP106-126 has been used as a model to understand prion diseases. The conformation of the peptide depends on the environmental conditions and it forms amyloid in vitro. The potential of this prion peptide to interact with nucleic acids has been studied using a fluorescent labelled nucleic acid by kinetic and equilibrium methods. A decrease in the fluorescence of the labelled DNA induced by the peptide with time is observed which is pH, ionic strength and temperature dependent. The activation energy of the reactions is approximately 100 kJ mol-1. Lysine tripeptide and spermidine, carrying the same number of positive charges as the prion peptide, do not show an appreciable effect on the DNA. The binding constant between the prion peptide and DNA has a value of > 10(6) M-1 in phosphate buffer, pH 8 which is of the same order of magnitude as the binding of a retroviral protein, p10, with model nucleic acids. It is tempting to speculate that this interaction might play a role in the prion diseases.  相似文献   
36.
本文介绍了南京奥林匹克体育中心灯光控制系统的工程设计与实施,并着重介绍了电流检测以及全中文监控软件在灯光控制系统中的应胜.  相似文献   
37.
The synthesis of dibenzylamine from benzylamine and benzyl alcohol in the presence of a phosphoric acid catalyst has been carried out under pressure. Very high pressure has no beneficial effect on the synthesis of dibenzylamine. Under optimum conditions (473K, 3.10×106Nm?2; residence period 2h; benzylamine to benzyl alcohol mol. ratio, 1:2 and benzylamine to catalyst mol. ratio, 1:0.2174), the conversion of benzylamine to dibenzylamine was 88.50%.  相似文献   
38.
A systematic and extensive approach incorporating in vitro and in vivo experimentation to treat chronic osteomyelitis in animal model were made using antibiotic loaded special bioactive glass porous scaffolds. After thorough characterization for porosity, distribution, surface charge, a novel drug composite were infiltrated by using vacuum infiltration and freeze-drying method which was subsequently analyzed by SEM-EDAX and studied for in vitro drug elution in PBS and SBF. Osteomyelitis in rabbit was induced by inoculation of Staphylococcus aureus and optimum drug-scaffold were checked for its efficacy over control and parenteral treated animals in terms of histopathology, radiology, in vivo drug concentration in bone and serum and implant-bone interface by SEM. It was optimized that 60P samples with 60-65% porosity (bimodal distribution of macro- to micropore) with average pore size ~60 μm and higher interconnectivity, moderately high antibiotic adsorption efficiency (~49%) was ideal. Results after 42 days showed antibiotic released higher than MIC against S. aureus compared to parenteral treatment (2 injections a day for 6 weeks). In vivo drug pharmacokinetics and SEM on bone-defect interface proved superiority of CFS loaded porous bioactive glass implants over parenteral group based on infection eradication and new bone formation.  相似文献   
39.
High-power synchronous motor drives are usually fed from naturally commutated cycloconverters. The output voltage of the cycloconverter contains interharmonics/subharmonics which affect the power quality and restrict the allowable frequency range. Further, a practical circulating current-free cycloconverter usually gives rise to stator current discontinuities. The present paper deals with a simulation method to study the performance of a cycloconverter-fed synchronous motor drive in the presence of interharmonics/subharmonics taking into account the discontinuities in the output current as well as the effect of ripple in the output current on the input current of the cycloconverter. Interharmonics in output phase voltage, output phase current, input supply current, and the field current are estimated and verified with experimental results on a laboratory prototype. The significant oscillating torque components due to these interharmonics are identified in a typical case. The simulation results are useful in power quality studies for such drives and in devising methods for suppression of these interharmonics/subharmonics.  相似文献   
40.
Herrmann  F. Nandi  A.K. 《Electronics letters》1998,34(23):2208-2210
Super-exponential blind equalisation methods offer a significant improvement over conventional techniques. The authors propose a new technique, the novel modified eigenvector approach (mEVA), and compare it with the eigenvector approach (EVA). It appears that the mEVA has the same performance as the EVA, but with with significantly reduced computation  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