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   347648篇
  免费   41511篇
  国内免费   17208篇
电工技术   32641篇
技术理论   32篇
综合类   29146篇
化学工业   31435篇
金属工艺   12848篇
机械仪表   28513篇
建筑科学   52343篇
矿业工程   9496篇
能源动力   23356篇
轻工业   18496篇
水利工程   7575篇
石油天然气   11057篇
武器工业   3534篇
无线电   25456篇
一般工业技术   34417篇
冶金工业   13360篇
原子能技术   2653篇
自动化技术   70009篇
  2025年   139篇
  2024年   9431篇
  2023年   9760篇
  2022年   13078篇
  2021年   14383篇
  2020年   14670篇
  2019年   12145篇
  2018年   10376篇
  2017年   11957篇
  2016年   13187篇
  2015年   13444篇
  2014年   23786篇
  2013年   21269篇
  2012年   25160篇
  2011年   26215篇
  2010年   20465篇
  2009年   20901篇
  2008年   18797篇
  2007年   21710篇
  2006年   17987篇
  2005年   15171篇
  2004年   12383篇
  2003年   10911篇
  2002年   8996篇
  2001年   7499篇
  2000年   6196篇
  1999年   4824篇
  1998年   3936篇
  1997年   3247篇
  1996年   2772篇
  1995年   2184篇
  1994年   1790篇
  1993年   1363篇
  1992年   1082篇
  1991年   882篇
  1990年   673篇
  1989年   600篇
  1988年   448篇
  1987年   328篇
  1986年   244篇
  1985年   254篇
  1984年   280篇
  1983年   184篇
  1982年   212篇
  1981年   95篇
  1980年   137篇
  1979年   83篇
  1964年   52篇
  1963年   50篇
  1959年   51篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
This article deals with the issue of input-to-state stabilization for recurrent neural networks with delay and external disturbance. The goal is to design a suitable weight-learning law to make the considered network input-to-state stable with a predefined -gain. Based on the solution of linear matrix inequalities, two schemes for the desired learning law are presented via using decay-rate-dependent and decay-rate-independent Lyapunov functionals, respectively. It is shown that, in the absence of external disturbance, the proposed learning law also guarantees the exponential stability of the network. To illustrate the applicability of the present weight-learning law, two numerical examples with simulations are given.  相似文献   
2.
ABSTRACT

In recent years, the exploration of a practical strategy for novel energetic molecules with high energy and low sensitivity is very desirable but highly challenging. Novel ionic energetic molecules have attracted much attention in this area due to their prominent advantages including low sensitivities, high thermal stability, and excellent energy performances. Herein, five different ionic energetic molecules based on new monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties with enhanced oxygen balance have been synthesized, characterized and evaluated as potential high-energy materials. Thermal stability, sensitivities and energy output test were measured and studied in detail. The heats of formation and energetic parameters were calculated by using Gaussian 09 suite of programs and EXPLO 5 code. The results suggest that all as-prepared new molecules exhibit good thermal stability with high decomposition temperature (3, 231°C; 5, 160°C; 6, 185°C; 7, 180°C; 8, 213°C), and relative low sensitivity (IS > 20 J, FS = 324 N). Inheriting the significant oxygen content of monovalent and divalent 4-oxyl-3,5-dinitropyrazolate moieties, they also possess good energy properties (v D = 8238 ~ 9208 m s?1, P = 26.8 ~ 36.7 GPa, V o = 481.8 ~ 959.4 L kg?1), which make them competitive high-energy materials.  相似文献   
3.
Recently, the applications of Blockchain technology have begun to revolutionise different aspects of supply chain (SC) management. Among others, Blockchain is a platform to execute the smart contracts in the SC as transactions. We develop and test a new model for smart contract design in the SC with multiple logistics service providers and show that this problem can be presented as a multi-processor flexible flow shop scheduling. A distinctive feature of our approach is that the execution of physical operations is modelled inside the start and completion of cyber information services. We name this modelling concept ‘virtual operation’. The constructed model and the developed experimental environment constitute an event-driven dynamic approach to task and service composition when designing the smart contract. Our approach is also of value when considering the contract execution stage. The use of state control variables in our model allows for operations status updates in the Blockchain that in turn, feeds automated information feedbacks, disruption detection and control of contract execution. The latter launches the re-scheduling procedure, comprehensively combining planning and adaptation decisions within a unified methodological framework of dynamic control theory. The modelling complex developed can be used to design and control smart contracts in the SC.  相似文献   
4.
In the network environment, the single time-triggered scheme wastes limited bandwidth resources due to all the sampled data are transmitted to the networks, and the single event-triggered scheme may increase system error because of ignoring factors such as changes in network utilization. To reduce the design conservatism, this paper is concerned with the hybrid-triggered L1 fault detection filter design for a class of nonlinear networked control systems (NCSs) described by Takagi–Sugeno (T-S) fuzzy model. Taking the effects of time-triggered scheme and event-triggered scheme into consideration simultaneously, we construct a fuzzy fault detection system. New results on stability and L1 performance are proposed for fuzzy fault detection system by exploiting the Lyapunov–Krasovskii functional and by means of the integral inequality method. Specially, attention is focused on the design of fault detection filter that guarantees a prescribed L1 noise attenuation level . Finally, two examples are presented to demonstrate the effectiveness of the proposed method.  相似文献   
5.
6.
在楼房爆破拆除中,根据待拆楼房的围围环境,采用了沿楼房对角线方向定向倾倒拆除的方案,并取得了成功。文中介绍了爆破方案、布孔方法及具体的爆破参数。  相似文献   
7.
清洁生产     
阐述清洁生产的重要性,清洁生产的概念、方法以及清洁生产的全过程。  相似文献   
8.
在高层建筑深基坑挡土支护中,用锚杆拉结钻孔灌注桩作挡土墙是近年来应用的主要方法之一。以烟台龙睛大厦深基坑挡土支护为例,介绍了用锚杆拉结的钻孔灌注桩设计方法。  相似文献   
9.
根据资料,分析了西部传统牧区生产和生活用能源消费的数量和结构特点,得出农牧区传统能源中畜粪、秸秆和煤炭一直是最主要的能源,能源使用呈现明显的地域特征,新能源和清洁能源使用量少、比例小等特点,总结出该区能源利用的典型特征,并对这一区域农村能源的未来发展趋势做了预测.  相似文献   
10.
对ZKB2460型振动脱水筛的工作原理、结构设计进行了阐述,对动力学方程及工作参 数等进行了设计计算,并进行了运转测试和工业应用。  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