全文获取类型
收费全文 | 7612篇 |
免费 | 1238篇 |
国内免费 | 821篇 |
专业分类
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 |
出版年
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.
《Measurement》2014
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.
《国际互联网参考资料服务季刊》2013,18(1):89-103
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.
D.M. Spracklen 《成像科学杂志》2013,61(4):220-227
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