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   90590篇
  免费   8703篇
  国内免费   4833篇
电工技术   6075篇
技术理论   4篇
综合类   6542篇
化学工业   14209篇
金属工艺   5161篇
机械仪表   6219篇
建筑科学   8049篇
矿业工程   2693篇
能源动力   2446篇
轻工业   6657篇
水利工程   1913篇
石油天然气   4428篇
武器工业   843篇
无线电   11184篇
一般工业技术   10174篇
冶金工业   3860篇
原子能技术   1097篇
自动化技术   12572篇
  2024年   442篇
  2023年   1684篇
  2022年   3217篇
  2021年   4325篇
  2020年   3234篇
  2019年   2591篇
  2018年   2725篇
  2017年   3202篇
  2016年   2875篇
  2015年   4006篇
  2014年   4996篇
  2013年   5869篇
  2012年   6356篇
  2011年   6965篇
  2010年   6224篇
  2009年   6007篇
  2008年   5769篇
  2007年   5196篇
  2006年   4840篇
  2005年   3972篇
  2004年   2581篇
  2003年   2174篇
  2002年   2083篇
  2001年   1890篇
  2000年   1640篇
  1999年   1664篇
  1998年   1277篇
  1997年   1123篇
  1996年   1078篇
  1995年   928篇
  1994年   753篇
  1993年   560篇
  1992年   394篇
  1991年   327篇
  1990年   229篇
  1989年   198篇
  1988年   159篇
  1987年   102篇
  1986年   86篇
  1985年   55篇
  1984年   36篇
  1983年   41篇
  1982年   32篇
  1981年   24篇
  1980年   31篇
  1979年   21篇
  1962年   42篇
  1961年   39篇
  1960年   16篇
  1951年   9篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
基于蚁群算法的网格资源发现模型研究   总被引:1,自引:0,他引:1  
本文通过对传统的网格资源发现存在的问题进行分析,针对其不足,引入蚁群算法,提出基于蚁群算法的网格资源发现模型(AA_GRRM),设计并分析AA_GRRM的体系结构,并对其关键模块分析设计,以提高网格资源发现效率。  相似文献   
102.
Distance-between-vehicle-measurement is the only factor in traditional car rear-end alarm system. To address the above problem, this paper proposes an alarming model based on multi-agent systems (MAS) and driving behavior. It consists of four different types of agents that can either work alone or collaborate through a communications protocol on the basis of the extended KQML. The rear-end alarming algorithm applies the Bayes decision theory to calculate the probability of collision and prevent its occurrence real-time. The learning algorithm of driving behavior based on ensemble artificial neural network (ANN) and the decision procedure based on Bayes’ theory are also described in this paper. Both autonomy and reliability are enhanced in the proposed system. The effectiveness and robustness of the model have been confirmed by the simulated experiments.  相似文献   
103.
Partner selection is a major issue in the formation of a virtual enterprise. In practice, in the partner selection process, the information about the candidates and their performances are incomplete and uncertain. Vague sets theory is one of the methods used to deal with uncertain information. In this paper, a new method based on vague sets is proposed to deal with the partner selection problem in the formation of a virtual enterprise while the factors of satisfaction degree, due date, cost and the precedence of tasks are taken into account. On the basis of the agreement index of satisfaction degree, the formulated partner selection problems are interpreted so as to maximize the minimum agreement index. To solve the problem, an improved particle swarm optimization (PSO) algorithm is proposed. Finally, the simulation of a numerical example demonstrates that the method is effective.  相似文献   
104.
In this paper, we consider the following nonlinear fractional three-point boundary value problem
  相似文献   
105.
Understanding the TCP congestion control mechanism from a global optimization point of view is not only important in its own right, but also crucial to the design of other transport layer traffic control protocols with provable properties. In this paper, we derive a global utility function and the corresponding optimal control law, known as TCP control law, which maximizes the global utility. The TCP control law captures the essential behaviors of TCP, including slow start, congestion avoidance, and the binary nature of congestion feedback in TCP. We find that the utility function of TCP is linear in the slow start phase and is proportional to the additive increase rate and approaches the well-known logarithm function as the data rate becomes large in the congestion avoidance phase. We also find that understanding the slow start phase with a fixed threshold is critical to the design of new transport layer control protocols to enable quality of service features. Finally, as an application, we design a Minimum Rate Guaranteed (MRG) traffic control law that shares the same utility function as the TCP control law. Our simulation study of the MRG control law indicates that it is indeed TCP friendly and can provide minimum rate guarantee as long as the percentage of network resource consumed by the MRG flows is moderately small.  相似文献   
106.
Since color recording and color representing abilities of various media are very different, color information is often lost or misrepresented in the process of image transmission and reproduction. A Color Management System (CMS) based on iCAM color appearance model is presented in this paper. It can be used either in computer operation system software or application software for obtaining color consistency across different software applications, imaging devices, imaging media and viewing conditions.  相似文献   
107.
In this paper, we consider finite-time control problems for linear multi-agent systems subject to exogenous constant disturbances and impulses. Some sufficient conditions are obtained to ensure the finite-time boundedness of the multi-agent systems, which could be then reduced to a feasibility problem involving linear matrix inequalities. Numerical examples are given to illustrate the results.  相似文献   
108.
109.
Hu  Changhui  Lu  Xiaobo  Ye  Mengjun  Zeng  Weili  Du  Yijun 《Multimedia Tools and Applications》2017,76(24):26523-26550
Multimedia Tools and Applications - The extended sparse representation classifier (ESRC) is one of the state-of-the-art solutions for single sample face recognition, but it performs...  相似文献   
110.
多元分析法在沉淀滴定中的应用   总被引:1,自引:0,他引:1  
将多元分析法应用于沉淀滴定之中 ,提出固定电位的方法 ,建立了沉淀滴定中各组分浓度与体积之间关系的数学模型 ,对卤素和硫氰酸盐混合体系进行了测定。  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