全文获取类型
收费全文 | 53985篇 |
免费 | 8735篇 |
国内免费 | 5330篇 |
专业分类
电工技术 | 4749篇 |
技术理论 | 2篇 |
综合类 | 4696篇 |
化学工业 | 1908篇 |
金属工艺 | 1169篇 |
机械仪表 | 4030篇 |
建筑科学 | 2218篇 |
矿业工程 | 1093篇 |
能源动力 | 440篇 |
轻工业 | 4485篇 |
水利工程 | 502篇 |
石油天然气 | 1063篇 |
武器工业 | 803篇 |
无线电 | 11731篇 |
一般工业技术 | 3419篇 |
冶金工业 | 752篇 |
原子能技术 | 495篇 |
自动化技术 | 24495篇 |
出版年
2024年 | 550篇 |
2023年 | 1572篇 |
2022年 | 2485篇 |
2021年 | 2702篇 |
2020年 | 2641篇 |
2019年 | 2046篇 |
2018年 | 1723篇 |
2017年 | 2229篇 |
2016年 | 2385篇 |
2015年 | 2739篇 |
2014年 | 4192篇 |
2013年 | 3617篇 |
2012年 | 4488篇 |
2011年 | 4651篇 |
2010年 | 3555篇 |
2009年 | 3553篇 |
2008年 | 3570篇 |
2007年 | 3888篇 |
2006年 | 3211篇 |
2005年 | 2741篇 |
2004年 | 2026篇 |
2003年 | 1728篇 |
2002年 | 1325篇 |
2001年 | 907篇 |
2000年 | 783篇 |
1999年 | 564篇 |
1998年 | 457篇 |
1997年 | 308篇 |
1996年 | 293篇 |
1995年 | 208篇 |
1994年 | 139篇 |
1993年 | 128篇 |
1992年 | 125篇 |
1991年 | 97篇 |
1990年 | 84篇 |
1989年 | 45篇 |
1988年 | 49篇 |
1987年 | 24篇 |
1986年 | 34篇 |
1985年 | 28篇 |
1984年 | 27篇 |
1983年 | 24篇 |
1982年 | 19篇 |
1981年 | 23篇 |
1980年 | 18篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
形态学边缘检测的新算法及其应用 总被引:3,自引:0,他引:3
刘岚岚 《红外与毫米波学报》1998,17(5):386-390
提出了一种基于数学形态学的边缘检测的所算法,该算法具有简便和灵活可编程控制等优点,比原来主算法更国完善,在实际应用中有着很好的前景,并给出了实验结果。 相似文献
122.
How to study drying shrinkage microcracking in cement-based materials using optical and scanning electron microscopy? 总被引:3,自引:0,他引:3
Three different ‘destructive’ microscopy methods were tested on their ability to show drying shrinkage microcracks on a specimen cross-section. The first two were methods in which the microcracks were impregnated with a fluorescent epoxy and examined with fluorescence microscopy. In one method, the impregnation was applied before making the cross-section and in the other after making the cross-section. In the third method, the sample was kept wet constantly and examined in an environmental scanning electron microscope (ESEM). It was concluded that the method in which the dried specimen was impregnated before making the cross-section was the most reliable method to record drying shrinkage microcracks. With this method, it was possible to impregnate the complete drying shrinkage microcrack pattern in the studied cement-based materials from the surface, and there was no risk of recording microcracks introduced by sample preparation. 相似文献
123.
陈明志 《数字社区&智能家居》2006,1(12):159-160
本文对数字图像中几种具有代表性的边缘检测算子进行了理论分析,并通过VC编程实验,对各种算法进行实现,通过比较得出了各自的优缺点和适用范围。 相似文献
124.
陈希武 《中国计量学院学报》1992,(1)
本文提出并研制成补偿式光纤F-P干涉仪信号处理系统,提出了用来测量微小位移信号的三种方法及电路,即透射峰时间间隔测量法、光脉冲基波幅度测量法(精密整流法)、鉴相法。测试结果表明:时间间隔测量法,它的最大灵敏度达到0.26纳米/微秒;精密整流法,最大灵敏度为2.38纳米/伏特。 相似文献
125.
Research presented in this paper deals with the systematic examination, development, and evaluation of a novel multimodal registration approach that can perform accurately and robustly for relatively close range surveillance applications. An analysis of multimodal image registration gives insight into the limitations of assumptions made in current approaches and motivates the methodology of the developed algorithm. Using calibrated stereo imagery, we employ maximization of mutual information in sliding correspondence windows that inform a disparity voting algorithm to demonstrate successful registration of objects in color and thermal imagery. Extensive evaluation of scenes with multiple objects at different depths and levels of occlusion shows high rates of successful registration. Ground truth experiments demonstrate the utility of the disparity voting techniques for multimodal registration by yielding qualitative and quantitative results that outperform approaches that do not consider occlusions. A basic framework for multimodal stereo tracking is investigated and promising experimental studies show the viability of using registration disparity estimates as a tracking feature. 相似文献
126.
We present a new background-subtraction technique fusing contours from thermal and visible imagery for persistent object detection in urban settings. Statistical background-subtraction in the thermal domain is used to identify the initial regions-of-interest. Color and intensity information are used within these areas to obtain the corresponding regions-of-interest in the visible domain. Within each region, input and background gradient information are combined to form a Contour Saliency Map. The binary contour fragments, obtained from corresponding Contour Saliency Maps, are then fused into a single image. An A* path-constrained search along watershed boundaries of the regions-of-interest is used to complete and close any broken segments in the fused contour image. Lastly, the contour image is flood-filled to produce silhouettes. Results of our approach are evaluated quantitatively and compared with other low- and high-level fusion techniques using manually segmented data. 相似文献
127.
128.
孙伟 《中国制造业信息化》2006,35(23):85-87
多元视觉显示界面逐渐成为主要的信息显示方式。观察者经常不能探测到场景中大的变化,并且高估自己的变化探测的能力,严重削弱了信息系统的使用效率。针对这种变化盲现象进行了回顾,分析总结影响操作人员变化探测能力的因素,对信息系统的显示界面设计使用和研究具有积极的指导意义。 相似文献
129.
A fast digital Radon transform based on recursively defined digital straight lines is described, which has the sequential complexity of N2 log N additions for an N × N image. This transform can be used to evaluate the Hough transform to detect straight lines in a digital image. Whilst a parallel implementation of the Hough transform algorithm is difficult because of global memory access requirements, the fast digital Radon transform is vectorizable and therefore well suited for parallel computation. The structure of the fast algorithm is shown to be quite similar to the FFT algorithm for decimation in frequency. It is demonstrated that even for sequential computation the fast Radon transform is an attractive alternative to the classical Hough transform algorithm. 相似文献
130.
Herbert W. Franke 《The Visual computer》1988,4(1):35-39
The article points out some new possibilities for using computers as an instrument for visual art, especially stressing the mathematical method of picture synthesis. It is illustrated with results of recent computer art by Herbert W. Franke and Horst Helbig. 相似文献