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   107425篇
  免费   18715篇
  国内免费   3145篇
电工技术   4639篇
技术理论   5篇
综合类   4592篇
化学工业   28227篇
金属工艺   4352篇
机械仪表   5175篇
建筑科学   6876篇
矿业工程   2376篇
能源动力   2677篇
轻工业   11240篇
水利工程   1489篇
石油天然气   4382篇
武器工业   575篇
无线电   14835篇
一般工业技术   19353篇
冶金工业   3895篇
原子能技术   712篇
自动化技术   13885篇
  2024年   393篇
  2023年   1253篇
  2022年   2063篇
  2021年   3090篇
  2020年   3575篇
  2019年   4955篇
  2018年   5096篇
  2017年   5638篇
  2016年   5853篇
  2015年   6578篇
  2014年   7089篇
  2013年   8802篇
  2012年   7012篇
  2011年   7108篇
  2010年   6593篇
  2009年   6288篇
  2008年   5641篇
  2007年   5421篇
  2006年   5551篇
  2005年   4653篇
  2004年   3608篇
  2003年   3285篇
  2002年   3009篇
  2001年   2684篇
  2000年   2777篇
  1999年   2305篇
  1998年   1650篇
  1997年   1384篇
  1996年   1252篇
  1995年   1036篇
  1994年   904篇
  1993年   615篇
  1992年   474篇
  1991年   415篇
  1990年   291篇
  1989年   233篇
  1988年   197篇
  1987年   137篇
  1986年   108篇
  1985年   63篇
  1984年   35篇
  1983年   25篇
  1982年   29篇
  1981年   19篇
  1980年   25篇
  1979年   10篇
  1978年   8篇
  1977年   6篇
  1976年   14篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
Based on the optimal fusion estimation algorithm weighted by scalars in the linear minimum variance sense, a distributed optimal fusion Kalman filter weighted by scalars is presented for discrete‐time stochastic singular systems with multiple sensors and correlated noises. A cross‐covariance matrix of filtering errors between any two sensors is derived. When the noise statistical information is unknown, a distributed identification approach is presented based on correlation functions and the weighted average method. Further, a distributed self‐tuning fusion filter is given, which includes two stage fusions where the first‐stage fusion is used to identify the noise covariance and the second‐stage fusion is used to obtain the fusion state filter. A simulation verifies the effectiveness of the proposed algorithm. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   
72.
结合小城镇发展的现实情况,介绍了小城镇规划与发展关联的不足,并对小城镇的规划要点进行了探讨,以期在小城镇规划的理论与实践建设中抛砖引玉。  相似文献   
73.
钛的应用及前景展望   总被引:1,自引:0,他引:1  
从传统应用及新兴应用两方面对钛的应用进行了综述,并对钛的应用前景进行了展望。  相似文献   
74.
He and Grigoryan (Quality and Reliability Engineering International 2002; 18 :343–355) formulated the design of a double‐sampling (DS) s control chart as an optimization problem and solved it with a genetic algorithm. They concluded that the DS s control charts can be a more economically preferable alternative in detecting small shifts than traditional s control charts. We explain that, since they only considered the average sample size when the process is in control, their conclusion is questionable. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
75.
76.
In this note, a generalized Bezoutian matrix with respect to a polynomial sequence of interpolatory type is introduced. The operator representation relative to a pair of dual bases and the generalized Barnett-type factorization formula are derived. An intertwining relation and a Bezoutian reduction to a block diagonal form by congruence via a generalized Vandermonde matrix are presented. Fujiwara-Hermite and Routh-Hurwitz criteria in terms of this generalized Bezout matrix are obtained.  相似文献   
77.
Discovering unknown adverse drug reactions (ADRs) in postmarketing surveillance as early as possible is highly desirable. Nevertheless, current postmarketing surveillance methods largely rely on spontaneous reports that suffer from serious underreporting, latency, and inconsistent reporting. Thus these methods are not ideal for rapidly identifying rare ADRs. The multiagent systems paradigm is an emerging and effective approach to tackling distributed problems, especially when data sources and knowledge are geographically located in different places and coordination and collaboration are necessary for decision making. In this article, we propose an active, multiagent framework for early detection of ADRs by utilizing electronic patient data distributed across many different sources and locations. In this framework, intelligent agents assist a team of experts based on the well‐known human decision‐making model called Recognition‐Primed Decision (RPD). We generalize the RPD model to a fuzzy RPD model and utilize fuzzy logic technology to not only represent, interpret, and compute imprecise and subjective cues that are commonly encountered in the ADR problem but also to retrieve prior experiences by evaluating the extent of matching between the current situation and a past experience. We describe our preliminary multiagent system design and illustrate its potential benefits for assisting expert teams in early detection of previously unknown ADRs. © 2007 Wiley Periodicals, Inc. Int J Int Syst 22: 827–845, 2007.  相似文献   
78.
中兴宽带线路测试技术及功能介绍   总被引:1,自引:0,他引:1  
宽带线路测试是中兴通讯ZXDSL综合宽带运维系统的核心功能,在DSL业务提供过程中主要应用在开通前的预测试、线路测试、开通后的例测试以及故障时的在线测试。对其测试技术和功能作了介绍。  相似文献   
79.
胡幼平 《湖南电力》2003,23(3):41-43
对湘潭电厂存在已久的胶球清洗装置收球率低的问题进行了深入探讨,结合电厂对胶球清洗系统的改造、试验过程,分析并提出了影响胶球清洗装置清洗效果及收球率的诸多原因及其解决方法。  相似文献   
80.
A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na+‐saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm?3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face‐to‐face interactions of platelets and effectively entrapped TiO2 particles in band‐type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO2 particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry  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