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   211篇
  免费   6篇
电工技术   5篇
化学工业   91篇
金属工艺   4篇
机械仪表   6篇
建筑科学   3篇
能源动力   5篇
轻工业   3篇
水利工程   3篇
石油天然气   13篇
无线电   10篇
一般工业技术   44篇
冶金工业   11篇
原子能技术   9篇
自动化技术   10篇
  2023年   2篇
  2022年   10篇
  2021年   17篇
  2020年   8篇
  2019年   4篇
  2018年   6篇
  2017年   10篇
  2016年   3篇
  2015年   4篇
  2014年   9篇
  2013年   9篇
  2012年   10篇
  2011年   13篇
  2010年   4篇
  2009年   3篇
  2008年   9篇
  2007年   11篇
  2006年   1篇
  2005年   7篇
  2004年   6篇
  2003年   3篇
  2002年   3篇
  2001年   4篇
  2000年   4篇
  1999年   1篇
  1998年   8篇
  1997年   1篇
  1994年   1篇
  1993年   3篇
  1991年   1篇
  1987年   3篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   8篇
  1975年   2篇
  1974年   3篇
  1973年   3篇
  1972年   2篇
  1971年   5篇
  1970年   2篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1966年   1篇
排序方式: 共有217条查询结果,搜索用时 15 毫秒
1.
Moveable bubble flow control is an efficient technique to avoid deadlock for torus networks. However, it does not take into consideration the load balance feature. Therefore, this leads to inefficient resources utilization. Moreover, packets may be discarded due to the congestion of a network area. On the other hand, there are other algorithms that consider load balancing such as rHALB (r hop adaptive load-balanced)routing technique. Nonetheless, rHALB detects deadlock using the timeout threshold. This concept of deadlock detection may give incorrect responses in case the traffic is high. Therefore, packets are dropped although there is no deadlock. At the end, this affects the whole performance of the network. This paper proposes a new routing algorithm for tori interconnection networks, namely, the LBMBS (load-balanced moveable bubble scheme). LBMBS integrates both concepts of moveable bubble and rHALB in order to provide at the end a load-balanced efficient deadlock-free algorithm. The protocol details are given and compared against other routing algorithms in the literature.  相似文献   
2.
Phase formation in the SrF2–LaF3 system was studied at temperatures ranging from 300°C to 450°C using nitrate flux. The solubility of LaF3 in SrF2 decreases with decreasing temperature. The equilibrium width of the solid solution region Sr1−xLaxF2+x at 400°C, it is 44.6 ± 0.4 mol% LaF3 (x = 0.446), at 350°C — 38.3 ± 0.7 mol% LaF3 (x = 0.383), and decreases almost to zero at 300°C.  相似文献   
3.
4.
This study explores younger and older adults learning of MS Publisher functionalities from a multimedia tutorial. Twenty younger and twenty three older adults assigned to a redundant (experimental) or non-redundant (control) condition were taught how to create a greeting card, while the results of their learning were assessed with immediate and delayed performance measures. While younger learners benefited from a non-redundant condition, older learners exhibited an opposite trend. Redundant condition was beneficial for their performance efficiency on a set of a transfer tasks, and their troubleshooting performance during the delayed session. From a cognitive load perspective, using a redundant text along with an audio narration overloads learner’s working memory by placing more strain on the visual pathway and not providing any additional cognitive advantage. From an environmental support standpoint and decreased processing resources view of cognitive aging, providing additional representational support helps reducing the task demands for older adults and results in better learning. The results have cognitive and practical implications for the design of multimedia learning environments for older adults.  相似文献   
5.
New efficient method is suggested for estimating the domain of phase variables in linear nonautonomous systems; the method is based on involving extremal Lyapunov functions.  相似文献   
6.
Molybdenum octahedral clusters, when incorporated into an appropriate polymer matrix, are considered as promising agents for a range of biological applications. This work describes the one‐pot synthesis, morphology and cellular toxicity of nano‐sized polystyrene beads doped with luminescent cluster complexes [{Mo6X8}(NO3)6]2? (X = Cl, Br or I). Specifically, the particles were obtained by free radical dispersion copolymerisation of styrene and methacrylic acid or 4‐vinylpyridine in the presence of the cluster complexes. The effects of the cluster loading in the reaction mixture on both the content of the final material and number‐average molar mass of the copolymers were evaluated. © 2017 Society of Chemical Industry  相似文献   
7.
Solid, liquid, and gaseous products of the pyrolytic decomposition of coal are studied. Analysis of the gas composition shows that most gas is formed at 600–900°C. The calorific value of the gas is greatest at 500°C, on account of the high concentration of methane and heavy hydrocarbons. The results for the liquid products show that, with increase in temperature, the yield of phenols decreases, while the concentration of polycyclic aromatic hydrocarbons increases.  相似文献   
8.
The ice surface softening by friction is investigated considering the additive non-correlated fluctuations of the shear strain and stress, and the temperature. The premelting is construed by the Kelvin–Voigt equation for shear strain and by the relaxation equations of Landau–Khalatnikov type for shear stress and temperature. Taking into account the noises in these equations, the Langevin and Fokker–Planck equations are derived. Their analysis is based on the investigation of extrema of the distribution function, i.e., steady-state values of the shear strain using the Stratonovich interpretation. The phase diagrams are constructed, where the noises intensities and thermostat temperature determine the regions of ice, softened ice and their mixture (stick–slip rubbing). We present that domain of ice friction is bounded by relatively small background sliding block temperatures and fluctuation intensities of the stress and temperature. The ice film softens with growth of the stress noise intensity even at small thermostat temperatures. The friction force time series for all rubbing modes are calculated and compared with experimentally observed ones.  相似文献   
9.
Novel series of poly (CL–co–Pluronic) polymers were successfully synthesized in situ by ring-opening polymerization (ROP) of ε-caprolactam (ε-CL). The copolymerization was activated by new type macroactivators (MAs) based on hydroxyl-terminated poly (ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) [PEO-PPO-PEO] triblock copolymers, known under the trade name Pluronic®. Toluene-2,4-diisocyanate (TDI) was used to obtain the isocyanate-terminated Pluronic prepolymers. The corresponding MAs were synthesized in situ with an N-carbamoyllactam structure. As an initiator of the copolymerization processes was used sodium lactamate (NaCL). To confirm the influence over the copolymerization process, microstructure, composition and molecular weight of the polymeric products two new types MAs based on Pluronic (P123 and F68) have been varied from 2 to 10 wt.% (vs. the monomer ε-CL). The structure of the both Pluronic based macroactivators (MAs) and accordingly obtained two series poly (CL-co-Pluronic) polymers were confirmed by 1H NMR and FT-IR analyses. Additionally, the structure, molecular weight, physicomechanical behavior, thermal stability and morphology of the new synthesized poly (CL–co–Pluronic) polymers have been investigated by Differential Scanning Calorimetry (DSC), Wide-Angle X-ray Diffraction (WAXD), Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) analysis.  相似文献   
10.
The development of the instrumentation and control system for the PGU-410 power unit at the Krasnodar cogeneration station is discussed. Problems encountered in designing the process control system of a complex facility are considered, in particular, the need to integrate local control systems. Special attention is paid to the importance of setting up a united control area at such facilities.  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