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   180777篇
  免费   15837篇
  国内免费   8548篇
电工技术   11514篇
技术理论   13篇
综合类   11744篇
化学工业   29555篇
金属工艺   10129篇
机械仪表   11317篇
建筑科学   13843篇
矿业工程   5502篇
能源动力   5337篇
轻工业   12557篇
水利工程   3315篇
石油天然气   10838篇
武器工业   1418篇
无线电   21640篇
一般工业技术   21685篇
冶金工业   8826篇
原子能技术   1942篇
自动化技术   23987篇
  2024年   917篇
  2023年   3453篇
  2022年   6412篇
  2021年   8599篇
  2020年   6467篇
  2019年   5101篇
  2018年   5790篇
  2017年   6471篇
  2016年   5759篇
  2015年   7661篇
  2014年   9497篇
  2013年   11341篇
  2012年   12358篇
  2011年   12981篇
  2010年   11087篇
  2009年   10458篇
  2008年   9993篇
  2007年   9197篇
  2006年   9380篇
  2005年   8014篇
  2004年   5346篇
  2003年   4512篇
  2002年   4050篇
  2001年   3637篇
  2000年   3569篇
  1999年   4189篇
  1998年   3471篇
  1997年   2950篇
  1996年   2757篇
  1995年   2219篇
  1994年   1809篇
  1993年   1300篇
  1992年   1050篇
  1991年   786篇
  1990年   570篇
  1989年   468篇
  1988年   369篇
  1987年   254篇
  1986年   209篇
  1985年   131篇
  1984年   116篇
  1983年   86篇
  1982年   86篇
  1981年   69篇
  1980年   62篇
  1979年   29篇
  1978年   25篇
  1977年   24篇
  1976年   26篇
  1975年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
大门小品建筑属多项目综合性工程。本文作者从管理者的角度 ,通过对公司大门及附属工程施工质量控制的总结 ,说明了质量控制应贯穿于工程施工的全过程  相似文献   
92.
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   
93.
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   
94.
详细介绍了 宏蜂窝传播模 型校正的基本操作流程 结果分析及注意事项 对工程 ,人员了解和开展模型校正工作有一定的指导作用 。  相似文献   
95.
IPv6和基于IPv6的网络设计   总被引:2,自引:0,他引:2  
对IPv6协议的主要内容进行了简要介绍,并针对IPv6的特点对基于IPv6的网络设计进行了探讨。  相似文献   
96.
97.
98.
Similarity retrieval of iconic image database   总被引:3,自引:0,他引:3  
The perception of spatial relationships among objects in a picture is one of the important selection criteria to discriminate and retrieve the images in an iconic image database system. The data structure called 2D string, proposed by Chang et al., is adopted to represent symbolic pictures. The 2D string preserves the objects' spatial knowledge embedded in images. Since spatial relationship is a fuzzy concept, the capability of similarity retrieval for the retrieval by subpicture is essential. In this paper, similarity measure based on 2D string longest common subsequence is defined. The algorithm for similarity retrieval is also proposed. Similarity retrieval provides the iconic image database with the distinguishing function different from a conventional database.  相似文献   
99.
Field experiments were conducted at a Class B biosolids land application site in central Arizona to measure, model, and source-track the off-site transport of aerosols emitted when biosolids were disk-incorporated into soils. Real-time PM10 monitoring provided time-resolved aerosol information sufficient for verifying both off-site concentration and off-site exposure time model results. Under the conditions considered and at a distance of 165?m from the aerosol source, biosolids disk-incorporation resulted in an intermittent exposure to biosolids-derived aerosol concentration between 15 and 40?μg/m3 and an inhalable biosolids dose between 2 and 8?μg. Transport modeling predicted that these doses will decrease with increasing wind speed. In addition, three DNA sequence-based biosolids source tracking methods were applied to aerosol samples and confirmed the presence of biosolids in aerosols at 5, 65, and 165?m from the aerosol source. Field measurements and modeling indicate that the nature of biosolids-derived aerosol exposure is a series of intermittent high concentration puffs, rather than a continuous low concentration.  相似文献   
100.
Perceptual Temporal Quality Metric for Compressed Video   总被引:2,自引:0,他引:2  
This paper presents a metric to quantify frame loss according to the impact on perceived temporal quality. This metric particularly aims at measuring the temporal quality degradation caused by both regular and irregular frame loss. Experimental results with subjective viewing demonstrate high performance on prediction of perceptual temporal quality.  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