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   2726篇
  免费   202篇
  国内免费   2篇
电工技术   27篇
综合类   14篇
化学工业   851篇
金属工艺   29篇
机械仪表   46篇
建筑科学   119篇
矿业工程   5篇
能源动力   65篇
轻工业   553篇
水利工程   24篇
石油天然气   13篇
武器工业   1篇
无线电   184篇
一般工业技术   434篇
冶金工业   226篇
原子能技术   16篇
自动化技术   323篇
  2024年   4篇
  2023年   47篇
  2022年   124篇
  2021年   160篇
  2020年   47篇
  2019年   69篇
  2018年   80篇
  2017年   85篇
  2016年   101篇
  2015年   96篇
  2014年   120篇
  2013年   198篇
  2012年   167篇
  2011年   226篇
  2010年   157篇
  2009年   142篇
  2008年   143篇
  2007年   113篇
  2006年   94篇
  2005年   92篇
  2004年   83篇
  2003年   66篇
  2002年   65篇
  2001年   26篇
  2000年   28篇
  1999年   33篇
  1998年   40篇
  1997年   44篇
  1996年   28篇
  1995年   29篇
  1994年   19篇
  1993年   19篇
  1992年   8篇
  1991年   15篇
  1990年   12篇
  1989年   11篇
  1988年   12篇
  1987年   8篇
  1986年   7篇
  1985年   12篇
  1984年   7篇
  1983年   7篇
  1982年   16篇
  1981年   6篇
  1979年   4篇
  1978年   10篇
  1977年   4篇
  1976年   13篇
  1975年   5篇
  1973年   5篇
排序方式: 共有2930条查询结果,搜索用时 31 毫秒
41.
Natural rubber vulcanizates of two formulations, with sulfur/N-cyclohexyl-2-benzothiazolesulfenamide (CBS) and tetramethylthiuram disulfide (TMTD), respectively, were analyzed by pyrolysis gas chromatography. A sulfur-selective flame-photometric detector was utilized. The main pyrolysis products were identified as CS2 and some thiophenes. The yields of the pyrolysis products from the two types of rubber were very different. The yields also varied with the curing time of the rubbers.  相似文献   
42.
43.
The performance of 0.5% Ru/Al2O3 for the deep oxidation of trichloroethene (1000–2500 ppmV, WHSV = 55 h−1) in air was studied in this work. Experiments were carried out both at dry and wet (20,000 ppmV of H2O) conditions. Catalytic performance was studied in terms of activity and selectivity for the different reaction products (CO2, HCl, Cl2, C2Cl4, CCl4 and CHCl3). Both the activity and the selectivity for total combustion are higher than other catalysts suggested in the literature for this process (especially Pd and Pt).The main organic by-products are CCl4 and CHCl3, whereas in all the other catalysts tested in the literature, tetrachloroethene is the main organic by-product. This fact suggests that the mechanism of the combustion reaction, involving a double-bond scission, is essentially specific for this catalyst.Kinetic data was fit to a pseudo-first order kinetic expression, providing fairly good fit.  相似文献   
44.
45.
In this paper, we consider the problem of robust stability and stabilization for networked control systems (NCS) with uncertain/nonlinear dynamics AUTHOR: Please check that authors and their affiliations are correct. in which the network‐induced delays are time‐varying and bounded. Based on some recent achievements, a relatively simple Lyapunov–Krasovskii functional is proposed to derive sufficient conditions both for analysis and synthesis of NCS in the form of LMIs depending on the delay bounds. The effectiveness of the proposed method is illustrated by several benchmark examples available in the literature. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
46.
47.
Most of the literature on innovation management highlights the fundamental role played by people in the innovation process and the need to fully develop the creative and innovative potential of organizations' members. This article offers the result of extensive research carried out among some of the most innovative companies in the Basque Country, a highly innovative region located in the north of Spain. It draws interesting conclusions about how these innovative companies combine strong leadership, human resource practices, and an organizational culture that enhances innovation capabilities among the company's employees. More specifically, it answers questions such as the following: Are human resources policies, leadership, and innovation culture implemented equally in Basque innovative companies? Do companies make the same effort in deploying these elements or routines and practices related to them? Can we see a pattern in the use of these elements among innovative firms? © 2012 Wiley Periodicals, Inc.  相似文献   
48.
In this work, a review and comprehensive evaluation of heuristics and metaheuristics for the m-machine flowshop scheduling problem with the objective of minimising total tardiness is presented. Published reviews about this objective usually deal with a single machine or parallel machines and no recent methods are compared. Moreover, the existing reviews do not use the same benchmark of instances and the results are difficult to reproduce and generalise. We have implemented a total of 40 different heuristics and metaheuristics and we have analysed their performance under the same benchmark of instances in order to make a global and fair comparison. In this comparison, we study from the classical priority rules to the most recent tabu search, simulated annealing and genetic algorithms. In the evaluations we use the experimental design approach and careful statistical analyses to validate the effectiveness of the different methods tested. The results allow us to clearly identify the state-of-the-art methods.  相似文献   
49.
50.
Fault tolerance in the interconnection network of large clusters of PCs is an issue of growing importance, since their increasing size also increases the failure probability. The fat-tree topology is usually used in these machines since it has become very popular among high-speed interconnect manufacturers. This paper proposes a new distributed fault-tolerant routing methodology for fat trees. Unlike other previous proposals, it does not require additional network hardware, and its memory requirements, switch hardware, and routing delay scales up with the network size. Indeed, it nullifies only the strictly necessary paths, allowing adaptive routing through the healthy paths. The methodology is based on enhancing the interval routing scheme with exclusion intervals. Exclusion intervals are associated to each switch output port and represent the nodes that are unreachable from this port after a fault. We propose a methodology to identify the links where the exclusion intervals must be updated after a fault, the values to write on them, and a very efficient mechanism to distribute the required information through the network without stopping the system activity. Our methodology can tolerate a high number of network failures with a low degradation in performance. Moreover, it can achieve zero packet losing during the updating period.  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