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   22865篇
  免费   2514篇
  国内免费   1714篇
电工技术   3296篇
技术理论   4篇
综合类   2386篇
化学工业   883篇
金属工艺   544篇
机械仪表   1630篇
建筑科学   2155篇
矿业工程   480篇
能源动力   893篇
轻工业   577篇
水利工程   348篇
石油天然气   482篇
武器工业   228篇
无线电   2818篇
一般工业技术   1503篇
冶金工业   582篇
原子能技术   109篇
自动化技术   8175篇
  2024年   197篇
  2023年   484篇
  2022年   742篇
  2021年   895篇
  2020年   878篇
  2019年   729篇
  2018年   640篇
  2017年   861篇
  2016年   913篇
  2015年   997篇
  2014年   1702篇
  2013年   1399篇
  2012年   1605篇
  2011年   1716篇
  2010年   1398篇
  2009年   1448篇
  2008年   1410篇
  2007年   1447篇
  2006年   1395篇
  2005年   1140篇
  2004年   937篇
  2003年   838篇
  2002年   648篇
  2001年   489篇
  2000年   433篇
  1999年   290篇
  1998年   249篇
  1997年   176篇
  1996年   158篇
  1995年   137篇
  1994年   121篇
  1993年   115篇
  1992年   90篇
  1991年   46篇
  1990年   52篇
  1989年   54篇
  1988年   49篇
  1987年   31篇
  1986年   32篇
  1985年   19篇
  1984年   34篇
  1983年   14篇
  1982年   20篇
  1981年   16篇
  1980年   14篇
  1979年   12篇
  1978年   3篇
  1977年   7篇
  1972年   2篇
  1962年   3篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
一种遗传-梯度混合算法   总被引:3,自引:0,他引:3  
本文提出一种函数全局优化的遗传-梯度混合算法。该算法由选择、交叉和诱导变异算子组成。通过对自适应滤波和前向神经网络权值训练两个典型问题的数字仿真,表明该算法是一种快速有效的全局优化算法。  相似文献   
52.
基于文[1]提出的求解组合最优化问题的Boltzmann&Darwin混合寻优策略,本文进一步分析研究了Boltzmann&Darwin混合寻优策略非时齐情形下的收敛特性,包括全局收敛性和收敛速度。结果表明,Boltzmann&Darwin混合寻优策略的收敛特性优于模拟退火(sim-ulated annealing)方法的收敛特性。  相似文献   
53.
The exploration for a geothermal resource on Ascension Island utilized a strategy that initially employed geologic mapping. On the basis of this, subsurface faults were mapped using an aeromagnetic survey. The faults were then explored using electrical resistivity surveys to define areas of potential hydrothermal fluid up-welling. The results of all of these techniques were used to site temperature gradient holes. A deep geothermal exploration well was then drilled in the area with highest heat flow adjacent to a rhyolite-to-trachyte volcanic complex.  相似文献   
54.
55.
The standard least squares (LS) estimation algorithm is modified in such a way that it becomes passive. Therefore the scope of application of the LS algorithm is extended to those adaptive schemes whose convergence proof is based on passivity. The passive version of LS is presented in both continuous and discrete time.  相似文献   
56.
In this paper, an adaptive line spectral pair filter is derived from an adaptive lattice filter. A least-mean-square(LMS) type adaptive algorithm used to calculate directly the line spectral pair(LSP) coefficients on a stage-by-stage basis is presented. Experimental results show that the algorithm has higher convergence rate and lower misadjustment as compared with the other algorithms. The LSP coefficients calculated by the algorithm have been used to carry out speech linear predictive synthesis, resulting in better results than PARCOR coefficients.  相似文献   
57.
Summary Algorithms for mutual exclusion that adapt to the current degree of contention are developed. Afilter and a leader election algorithm form the basic building blocks. The algorithms achieve system response times that are independent of the total number of processes and governed instead by the current degree of contention. The final algorithm achieves a constant amortized system response time. Manhoi Choy was born in 1967 in Hong Kong. He received his B.Sc. in Electrical and Electronic Engineerings from the University of Hong Kong in 1989, and his M.Sc. in Computer Science from the University of California at Santa Barbara in 1991. Currently, he is working on his Ph.D. in Computer Science at the University of California at Santa Barbara. His research interests are in the areas of parallel and distributed systems, and distributed algorithms. Ambuj K. Singh is an Assistant Professor in the Department of Computer Science at the University of California, Santa Barbara. He received a Ph.D. in Computer Science from the University of Texas at Austin in 1989, an M.S. in Computer Science from Iowa State University in 1984, and a B.Tech. from the Indian Institute of Technology at Kharagpur in 1982. His research interests are in the areas of adaptive resource allocation, concurrent program development, and distributed shared memory.A preliminary version of the paper appeared in the 12th Annual ACM Symposium on Principles of Distributed ComputingWork supported in part by NSF grants CCR-9008628 and CCR-9223094  相似文献   
58.
试论就业形势与战略   总被引:5,自引:1,他引:4  
论述了就业的特殊重要性、目前我国就业形势的极端严重性,以及所应当采取的战略和措施。  相似文献   
59.
针对日益激烈的市场竞争,探讨了引发大规模商战的原因,建立了两企业集团间的商战模型,并分析了模型的均衡点,同时在此基础上建立了多个企业集团问商战模型,分析了模型的稳定性,最后根据模型的结论给出了企业间避免恶性商战的相关建议与对策。  相似文献   
60.
The certainty equivalence approach to adaptive control is commonly used with two types of identifiers: passivity-based identifiers and swapping identifiers. The “passive” (also known as “observer-based”) approach is the prevalent identification technique in existing results on adaptive control for PDEs but has so far not been used in boundary control problems. The swapping approach, prevalent in finite-dimensional adaptive control is employed here for the first time in adaptive control of PDEs. For a class of unstable parabolic PDEs we prove a separation principle result for both the passive and swapping identifiers combined with the backstepping boundary controllers. The result is applicable in any dimension. For physical reasons we restrict our attention to dimensions no higher than three. The results of the paper are illustrated by simulations.  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