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   187652篇
  免费   19180篇
  国内免费   6049篇
电工技术   12088篇
技术理论   18篇
综合类   11776篇
化学工业   30111篇
金属工艺   10290篇
机械仪表   11927篇
建筑科学   13966篇
矿业工程   5577篇
能源动力   5768篇
轻工业   13156篇
水利工程   3369篇
石油天然气   10839篇
武器工业   1408篇
无线电   23271篇
一般工业技术   23396篇
冶金工业   8993篇
原子能技术   2129篇
自动化技术   24799篇
  2025年   166篇
  2024年   4520篇
  2023年   4168篇
  2022年   6612篇
  2021年   8960篇
  2020年   7289篇
  2019年   5868篇
  2018年   5921篇
  2017年   6614篇
  2016年   6096篇
  2015年   7808篇
  2014年   9597篇
  2013年   11372篇
  2012年   12286篇
  2011年   12958篇
  2010年   11057篇
  2009年   10450篇
  2008年   9988篇
  2007年   9226篇
  2006年   9380篇
  2005年   8044篇
  2004年   5365篇
  2003年   4536篇
  2002年   4058篇
  2001年   3630篇
  2000年   3552篇
  1999年   4170篇
  1998年   3478篇
  1997年   2962篇
  1996年   2775篇
  1995年   2254篇
  1994年   1820篇
  1993年   1320篇
  1992年   1060篇
  1991年   799篇
  1990年   582篇
  1989年   483篇
  1988年   379篇
  1987年   268篇
  1986年   223篇
  1985年   137篇
  1984年   123篇
  1983年   97篇
  1982年   93篇
  1981年   69篇
  1980年   67篇
  1979年   32篇
  1978年   31篇
  1977年   28篇
  1976年   36篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
电厂锅炉水冷壁清焦检测工作一直是个难题,目前国内外尚无更好的解决办法。多功能金属表面清焦检测机具为电厂锅炉水冷壁的清焦检测工作提供了智能化手段,使水冷壁的检测清焦自动化,较好地解决了这一难题。另外,它亦可广泛应用于船体检测、储油气罐及给排水、油管道的检测、疏通堵塞等领域。  相似文献   
102.
The first measurement of a turnover rate with respect to surface intermediate concentration in a high pressure heterogeneous catalytic reaction is reported. By using infrared-visible sum frequency generation to study the hydrogenation of ethylene on Pt(111), it was found that the surface concentration of -bonded ethylene, the key reaction intermediate, represented approximately 4% of a monolayer. Thus the absolute turnover rate per surface adsorbed ethylene molecule is 25 times faster than the rate measured per platinum atom. To explain these results, we propose a model of weakly adsorbed ethylene intermediates reacting on atop sites.  相似文献   
103.
The non-fragile dynamic output feedback H controller design problem is investigated. The controller to be designed is assumed to be with additive gain variations. A two-step procedure is proposed to develop sufficient conditions for the non-fragile H controller design by employing the structured vertex separator. A comparison between the proposed and the existing controller design methods is provided, and a numerical example is carried out to support the theoretical findings.  相似文献   
104.
105.
In order to improve decision-making efficiency about emergency event, this paper proposes a novel concept, i.e., Agile-Delphi Method, which is an integration of agile decision and Delphi Method implicating that the decision-makers instantly deliver, respond, treat, and utilize information via Delphi process while conducting group decision-making about emergency event. The paper details the mechanism of group decision-making about emergency event based on network technology and Agile-Delphi Method. Finally, the paper conducts an empiric analysis taking the “111 event”, i.e., the liquid ammonia spill event happened on November 1, 2006 in a phosphorus chemical company in China, as an example.  相似文献   
106.
The twisted cube is an important variant of the most popular hypercube network for parallel processing. In this paper, we consider the problem of embedding multi-dimensional meshes into twisted cubes in a systematic way. We present a recursive method for embedding a family of disjoint multi-dimensional meshes into a twisted cube with dilation 1 and expansion 1. We also prove that a single multi-dimensional mesh can be embedded into a twisted cube with dilation 2 and expansion 1. Our work extends some previously known results.  相似文献   
107.
In recent years, several techniques have been proposed to simulate the gaze effect of the Human Visual System (HVS). It is believed that this effect is due to the foveation filtering. Current techniques to simulate the foveation filtering in computer graphics are either slow or suffer from artifacts and limitations. In this paper, we present a new approach of foveation filtering based on the Mipmap Pyramid of the current view by considering the relationship between the Gaussian kernel and Mipmap level. Due to the nonlinear Mipmap interpolation under the Bilateral Filtering scheme, we are able to simulate the foveation filtering more naturally and efficiently than in previous work. Moreover, a detail enhancement method based on the Cornsweet illusion is proposed to augment the gazing effect. We demonstrate our new approach with a variety of examples and provide comparisons with recent approaches.  相似文献   
108.
109.
110.
This paper presents an improved ant colony optimization algorithm (IACO) for solving mobile agent routing problem. The ants cooperate using an indirect form of communication mediated by pheromone trails of scent and find the best solution to their tasks guided by both information (exploitation) which has been acquired and search (exploration) of the new route. Therefore the premature convergence probability of the system is lower. The IACO can solve successfully the mobile agent routing problem, and this method has some excellent properties of robustness, self-adaptation, parallelism, and positive feedback process owing to introducing the genetic operator into this algorithm and modifying the global updating rules. The experimental results have demonstrated that IACO has much higher convergence speed than that of genetic algorithm (GA), simulated annealing (SA), and basic ant colony algorithm, and can jump over the region of the local minimum, and escape from the trap of a local minimum successfully and achieve the best solutions. Therefore the quality of the solution is improved, and the whole system robustness is enhanced. The algorithm has been successfully integrated into our simulated humanoid robot system which won the fourth place of RoboCup2008 World Competition. The results of the proposed algorithm are found to be satisfactory.  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