全文获取类型
收费全文 | 41789篇 |
免费 | 9043篇 |
国内免费 | 6515篇 |
专业分类
电工技术 | 1596篇 |
技术理论 | 1篇 |
综合类 | 5337篇 |
化学工业 | 930篇 |
金属工艺 | 771篇 |
机械仪表 | 3570篇 |
建筑科学 | 1187篇 |
矿业工程 | 501篇 |
能源动力 | 287篇 |
轻工业 | 1064篇 |
水利工程 | 289篇 |
石油天然气 | 438篇 |
武器工业 | 535篇 |
无线电 | 10957篇 |
一般工业技术 | 3712篇 |
冶金工业 | 553篇 |
原子能技术 | 209篇 |
自动化技术 | 25410篇 |
出版年
2024年 | 385篇 |
2023年 | 989篇 |
2022年 | 1576篇 |
2021年 | 1937篇 |
2020年 | 1862篇 |
2019年 | 1517篇 |
2018年 | 1373篇 |
2017年 | 1770篇 |
2016年 | 1933篇 |
2015年 | 2264篇 |
2014年 | 2959篇 |
2013年 | 2782篇 |
2012年 | 3565篇 |
2011年 | 3563篇 |
2010年 | 3098篇 |
2009年 | 3097篇 |
2008年 | 3301篇 |
2007年 | 3418篇 |
2006年 | 2817篇 |
2005年 | 2492篇 |
2004年 | 2009篇 |
2003年 | 1575篇 |
2002年 | 1263篇 |
2001年 | 1011篇 |
2000年 | 816篇 |
1999年 | 625篇 |
1998年 | 524篇 |
1997年 | 498篇 |
1996年 | 383篇 |
1995年 | 325篇 |
1994年 | 289篇 |
1993年 | 230篇 |
1992年 | 208篇 |
1991年 | 159篇 |
1990年 | 143篇 |
1989年 | 105篇 |
1988年 | 85篇 |
1987年 | 52篇 |
1986年 | 63篇 |
1985年 | 63篇 |
1984年 | 50篇 |
1983年 | 44篇 |
1982年 | 33篇 |
1981年 | 20篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1965年 | 5篇 |
1960年 | 5篇 |
1959年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
喷墨打印相纸及打印图像质量的分析 总被引:2,自引:1,他引:1
喷墨打印相纸随着数码相机的发展近几年在国内发展迅速。针对目前产品质量没有测量标准的现状,提出喷墨相纸的质量指标主要为4个,即白度、光泽度、油墨吸收性和防水性。给出了相应的测量方法。并指出相纸上油墨点的面积是衡量质量的第一重要指标,其次是点的圆度。另外对图像输出的质量介绍了一种科学的评价方法,即图像的逼真性分析。说明图像的打印墨点直径不应小于方形像素的对角线长,图像才能真实再现。 相似文献
42.
43.
V. Rodin Author Vitae A. Benzinou Author VitaeAuthor Vitae P. Ballet Author VitaeAuthor Vitae J. Tisseau Author VitaeAuthor Vitae 《Pattern recognition》2004,37(4):631-645
In this article, we present a parallel image processing system based on the concept of reactive agents. Our system lies in the oRis language, which allows to describe finely and simply the agents’ behaviors to detect image features. We also present a method of segmentation using a multi-agent system, and two biological applications made with oRis. The stopping of this multi-agent system is implemented through a technique issued from immunology: the apoptosis. 相似文献
44.
45.
军事和空间技术的要求促进了微光技术的发展。微光图像实时处理技术是夜技术今后发展的重要方向,本文针对微光图像与脉冲激光测距仪的数据信息实时融合与显示的方法及其实现进行了研究。给出了系统框图及工作原理,为实现探测识别、跟踪的实时性、智能化和微型化,从而为研制新一代战术侦察与火控系统提供了具体有效的技术基础。 相似文献
46.
透视图象的三维实体几何复原 总被引:1,自引:0,他引:1
昂海松 《计算机辅助设计与图形学学报》1995,7(1):17-24
对于未知透视参数的图象,如何获得较精确的原实体三维几何构形,本文推导了几个线段逆变换关系式,给出一个有效的方法,实现复杂组合体透视图象的三维重建,文中给出几个实例。 相似文献
47.
一个矢量形式的双圆弧插值算法 总被引:3,自引:1,他引:2
本文在分析数控插补最常用的双圆弧插值算法特点的基础上,将以局部坐标系中的三角运算为核心的传统双圆弧插值算法,改造成为以整体坐标系中的线性运算为核心的矢量形式的双圆弧插值算法,从而减少了计算的复杂性和程序的复杂性,提高了效率和可靠性。 相似文献
48.
Dimitrios Tzovaras Nikos Grammalidis Michael G. Strintzis 《Signal Processing: Image Communication》1998,11(3):205-230
In the present paper techniques are examined for the coding of the depth map and disparity fields for stereo or multiview image communication applications. It is assumed that both the left and right channels of the multiview image sequence are coded using block- or object-based methods. A dynamic programming algorithm is used to estimate a disparity field between each stereo image pair. Depth is then estimated and occlusions are optionally detected, based on the estimated disparity fields. Spatial interpolation techniques are examined based on the disparity/depth information and the detection of occluded regions using either stereoscopic or trinocular camera configurations. It is seen that the presence of a third camera at the transmitter site improves the estimation of disparities, the detection of occlusions and the accuracy of the resulting spatial interpolation at the receiver. Various disparity field and depth map coding techniques are then proposed and evaluated, with emphasis given to the quality of the resulting intermediate images at the receiver site. Block-based and wireframe modeling techniques are examined for the coding of isolated depth or disparity map information. Further, 2D and 3D motion compensation techniques are evaluated for the coding of sequences of depth or disparity maps. The motion fields needed may be available as a byproduct of block-based or object-based coding of the intensity images. Experimental results are given for the evaluation of the performance of the proposed coding and spatial interpolation methods. 相似文献
49.
50.
The Logarithmic Image Processing Model: Connections with Human Brightness Perception and Contrast Estimators 总被引:1,自引:0,他引:1
Jean-Charles Pinoli 《Journal of Mathematical Imaging and Vision》1997,7(4):341-358
The logarithmic image processing (LIP) model is amathematical framework based on abstract linear mathematicswhich provides a set of specific algebraic and functionaloperations that can be applied to the processing of intensityimages valued in a bounded range. The LIP model has been provedto be physically justified in the setting of transmitted lightand to be consistent with several laws and characteristics ofthe human visual system. Successful application examples havealso been reported in several image processing areas, e.g.,image enhancement, image restoration, three-dimensional imagereconstruction, edge detection and image segmentation.The aim of this article is to show that the LIP model is atractable mathematical framework for image processing which isconsistent with several laws and characteristics of humanbrightness perception. This is a survey article in the sensethat it presents (almost) previously published results in arevised, refined and self-contained form. First, an introductionto the LIP model is exposed. Emphasis will be especially placedon the initial motivation and goal, and on the scope of themodel. Then, an introductory summary of mathematicalfundamentals of the LIP model is detailed. Next, the articleaims at surveying the connections of the LIP model with severallaws and characteristics of human brightness perception, namelythe brightness scale inversion, saturation characteristic, Weber'sand Fechner's laws, and the psychophysical contrast notion. Finally,it is shown that the LIP model is a powerful and tractable framework for handling the contrast notion. This is done througha survey of several LIP-model-based contrast estimators associated with special subparts (point, pair of points,boundary, region) of intensity images, that are justified bothfrom a physical and mathematical point of view. 相似文献