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   7612篇
  免费   1238篇
  国内免费   821篇
电工技术   126篇
综合类   717篇
化学工业   97篇
金属工艺   64篇
机械仪表   386篇
建筑科学   107篇
矿业工程   39篇
能源动力   23篇
轻工业   70篇
水利工程   44篇
石油天然气   25篇
武器工业   31篇
无线电   1307篇
一般工业技术   499篇
冶金工业   311篇
原子能技术   32篇
自动化技术   5793篇
  2024年   17篇
  2023年   144篇
  2022年   203篇
  2021年   211篇
  2020年   211篇
  2019年   204篇
  2018年   194篇
  2017年   241篇
  2016年   269篇
  2015年   295篇
  2014年   455篇
  2013年   484篇
  2012年   508篇
  2011年   648篇
  2010年   565篇
  2009年   551篇
  2008年   679篇
  2007年   629篇
  2006年   554篇
  2005年   491篇
  2004年   413篇
  2003年   352篇
  2002年   270篇
  2001年   232篇
  2000年   170篇
  1999年   133篇
  1998年   82篇
  1997年   70篇
  1996年   65篇
  1995年   39篇
  1994年   38篇
  1993年   26篇
  1992年   21篇
  1991年   23篇
  1990年   13篇
  1989年   16篇
  1988年   10篇
  1987年   16篇
  1986年   18篇
  1985年   14篇
  1984年   12篇
  1983年   13篇
  1982年   9篇
  1981年   9篇
  1980年   4篇
  1979年   9篇
  1978年   4篇
  1976年   7篇
  1975年   8篇
  1973年   5篇
排序方式: 共有9671条查询结果,搜索用时 18 毫秒
91.
Indirect Immunofluorescence (IIF) images are increasingly being used for the diagnosis of autoimmune diseases. However, the analysis of this kind of images has until now reached a comparatively low level of automation, if compared with other medical imaging techniques. The Special Issue on the Analysis and Recognition of Indirect Immunofluorescence Images of the Pattern Recognition journal aims at providing a comprehensive evaluation of the state of the art for the staining pattern classification problem, through the adoption of a common experimental protocol and the testing of all the methods on a publicly available dataset.  相似文献   
92.
The article analyses some surface roughness parameters of metal parts determining the ability of the surface of digital image identification, covariance functions and Wavelet’s wave theory. Expressions of covariance functions are formed using random functions, made by spreading digital image pixel arrays by columns in the form of individual vectors. The digital images used for research may vary in scale, because the frequencies of colour waves with individual pixels remain constant in the images, therefore, the image change does not influence the scale in computing covariance functions. The colour spectrum of RGB format was applied to identify the surface images of the parts. There was analysed the influence of individual RGB colour tensor components on the estimates of digital image covariance functions. The identity of digital images was evaluated by the change of correlation coefficient values in the range of RGB colours. The software was applied to compute the above process.  相似文献   
93.
目的 传统的手绘图像检索方法主要集中在检索相同类别的图像,忽略了手绘图像的细粒度特征。对此,提出了一种新的结合细粒度特征与深度卷积网络的手绘图像检索方法,既注重通过深度跨域实现整体匹配,也实现细粒度细节匹配。方法 首先构建多通道混合卷积神经网络,对手绘图像和自然图像分别进行不同的处理;其次通过在网络中加入注意力模型来获取细粒度特征;最后将粗细特征融合,进行相似性度量,得到检索结果。结果 在不同的数据库上进行实验,与传统的尺度不变特征(SIFT)、方向梯度直方图(HOG)和深度手绘模型Deep SaN(sketch-a-net)、Deep 3DS(sketch)、Deep TSN(triplet sketch net)等5种基准方法进行比较,选取了Top-1和Top-10,在鞋子数据集上,本文方法Top-1正确率提升了12%,在椅子数据集上,本文方法Top-1正确率提升了11%,Top-10提升了3%,与传统的手绘检索方法相比,本文方法得到了更高的准确率。在实验中,本文方法通过手绘图像能在第1幅检索出绝大多数的目标图像,达到了实例级别手绘检索的目的。结论 提出了一种新的手绘图像检索方法,为手绘图像和自然图像的跨域检索提供了一种新思路,进行实例级别的手绘检索,与原有的方法相比,检索精度得到明显提升,证明了本文方法的可行性。  相似文献   
94.
Abstract

The convergence of computing, communications, and traditional educational technologies enables teaching faculty and librarians to discuss, plan, create, and implement fundamentally unique strategies for providing access to people, information, and the teaching/learning process. A tripartite strategy for achieving these goals is presented. The three critical areas are: (1) Content (how to put together search strategies, look for information, process it, sift it, and organize it); (2) Process (how to use the technology to maximum benefit); and (3) Lobbying (in the areas of information policy, financial resources, and technological infrastructure). An action plan is proposed to provide both inspiration and guidance to help accomplish these goals.  相似文献   
95.
Emulsions prepared with an inert gelatin have been sensitized with sodium thiosulphate labelled with radioactive 35S. An analytical technique similar to that used by Frieser and Ranz1 has been used to measure the amounts of silver sulphide formed. The breakdown of thiosulphate has been shown to follow first order reaction kinetics at a rate proportional to the free silver ion concentration in the emulsion to the power of 0.8.  相似文献   
96.
Anisotropic blur and mis-registration frequently happen in multi-focus images due to object or camera motion. These factors severely degrade the fusion quality of multi-focus images. In this paper, we present a novel multi-scale weighted gradient-based fusion method to solve this problem. This method is based on a multi-scale structure-based focus measure that reflects the sharpness of edge and corner structures at multiple scales. This focus measure is derived based on an image structure saliency and introduced to determine the gradient weights in the proposed gradient-based fusion method for multi-focus images with a novel multi-scale approach. In particular, we focus on a two-scale scheme, i.e., a large scale and a small scale, to effectively solve the fusion problems raised by anisotropic blur and mis-registration. The large-scale structure-based focus measure is used first to attenuate the impacts of anisotropic blur and mis-registration on the focused region detection, and then the gradient weights near the boundaries of the focused regions are carefully determined by applying the small-scale focus measure. Experimental results clearly demonstrate that the proposed method outperforms the conventional fusion methods in the presence of anisotropic blur and mis-registration.  相似文献   
97.
Data fusion in information retrieval has been investigated by many researchers and a number of data fusion methods have been proposed. However, problems such as why data fusion can increase effectiveness and favorable conditions for the use of data fusion methods are poorly resolved at best. In this paper, we formally describe data fusion under a geometric framework, in which each component result returned from an information retrieval system for a given query is represented as a point in a multi-dimensional space. The Euclidean distance is the measure by which the effectiveness and similarity of search results are judged. This allows us to explain all component results and fused results using geometrical principles. In such a framework, score-based data fusion becomes a deterministic problem. Several interesting features of the centroid-based data fusion method and the linear combination method are discussed. Nevertheless, in retrieval evaluation, ranking-based measures are the most popular. Therefore, this paper investigates the relation and correlation between the Euclidean distance and several typical ranking-based measures. We indeed find that a very strong correlation exists between these. It means that the theorems and observations obtained using the Euclidean distance remain valid when ranking-based measures are used. The proposed framework enables us to have a better understanding of score-based data fusion and use score-based data fusion methods more precisely and effectively in various ways.  相似文献   
98.
99.
自动化立体仓库是一种典型的机电一体化设备,对于机电一体化专业学生理解和掌握机电一体化系统设计及维护有着极大的帮助.介绍了基于PLC的自动化立体仓库实验系统的研制,该系统由机械本体、电气系统、PLC控制系统以及组态监控系统构成.装置研发成功后,已经在课程教学、实训以及毕业设计等环节得到了应用,取得了预期的效果.  相似文献   
100.
通过实例归纳了日本建筑在继承传统意象的主要设计手法,剖析了日本现代建筑对其传统文化与建筑工艺的传承与发扬,并分析了当代日本建筑的传统精神和现代表现手法。  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