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   7632篇
  免费   1401篇
  国内免费   821篇
电工技术   269篇
综合类   617篇
化学工业   919篇
金属工艺   112篇
机械仪表   358篇
建筑科学   233篇
矿业工程   104篇
能源动力   578篇
轻工业   221篇
水利工程   103篇
石油天然气   199篇
武器工业   68篇
无线电   2267篇
一般工业技术   660篇
冶金工业   167篇
原子能技术   103篇
自动化技术   2876篇
  2024年   91篇
  2023年   254篇
  2022年   365篇
  2021年   432篇
  2020年   394篇
  2019年   305篇
  2018年   280篇
  2017年   332篇
  2016年   382篇
  2015年   405篇
  2014年   566篇
  2013年   572篇
  2012年   669篇
  2011年   678篇
  2010年   524篇
  2009年   483篇
  2008年   490篇
  2007年   475篇
  2006年   421篇
  2005年   333篇
  2004年   243篇
  2003年   215篇
  2002年   154篇
  2001年   129篇
  2000年   113篇
  1999年   103篇
  1998年   86篇
  1997年   53篇
  1996年   63篇
  1995年   46篇
  1994年   26篇
  1993年   18篇
  1992年   19篇
  1991年   21篇
  1990年   17篇
  1989年   14篇
  1988年   15篇
  1987年   8篇
  1986年   6篇
  1985年   7篇
  1984年   9篇
  1983年   8篇
  1982年   6篇
  1981年   3篇
  1980年   5篇
  1976年   3篇
  1962年   1篇
  1959年   2篇
  1956年   1篇
  1951年   2篇
排序方式: 共有9854条查询结果,搜索用时 0 毫秒
51.
无线传感器网络(WSNs)具有放置方便,自组织,移动性强等特点,为了保证安全生产,可以将网络中的节点放置在煤矿井下狭长工作面上,用来对大型设备的工作情况和环境参数进行监测以提供实时信息。基于上述环境,提出了监测区域可变的覆盖算法,在B样条数学理论和Matlab工具的支持下做了算法仿真。结果表明:通常情况下覆盖度随着节点通信半径的增大而增加;合理选择第一个簇首会达到较高的覆盖度;合适的节点密度不但可以有效覆盖监测区域,还可延长网络寿命。  相似文献   
52.
基于多尺度Retinex的自适应图像增强方法   总被引:10,自引:1,他引:9  
介绍了一种基于MSR的自适应图像增强的方法,能够较好地自动处理由于云雾、雨天等天气原因和光照不足导致的景物不清、视觉质量差和对比度低的图像,提升多种类型的图像视觉质量.通过对实验的结果以及算法的普适性进行比较和分析,证明了该方法是有效的.  相似文献   
53.
实时图像增强算法改进及FPGA实现   总被引:2,自引:0,他引:2  
针对复杂背景的多目标图像,提出了一种基于直方图的实时自适应图像增强方法.该方法根据自适应直方图窗口选择高低阈值,通过灰度线性变换及灰度级等间距密度均衡进行图像增强.利用该算法增强图像视频时,采用FPGA,通过并行处理结构及流水线技术,可实时处理每秒50帧780×582×12bits的可见光图像.在处理视频的过程中,由前一帧图像的直方图信息,来增强后一帧图像.理论分析和实验结果均表明,该算法克服了直方图均衡及平台直方图均衡增强图像引起的灰度断层现象,有效地增强了图像的对比度,提高了图像质量.  相似文献   
54.
基于改进谱减法的语音增强研究   总被引:2,自引:0,他引:2  
语音增强技术是语音信号处理中的重要课题之一,谱减法是目前语音增强处理中常用的方法.针对传统谱减法残余音乐噪声过强,清音部分损失严莺的缺点,引入了一种利用语音信号的短时平均幅度差特征并结合短时平均幅度的语音检测算法,对传统的谱减法进行了改进.根据采集的真实航空噪声数据,将传统谱减法和改进的谱减法结果进行了比较分析.仿真结果表明,改进形式的谱减法可以有效降低音乐噪声,提高信噪比和町懂度,可以满足语音增强的要求.  相似文献   
55.
Mutation testing has traditionally been used as a defect injection technique to assess the effectiveness of a test suite as represented by a “mutation score.” Recently, mutation testing tools have become more efficient, and industrial usage of mutation analysis is experiencing growth. Mutation analysis entails adding or modifying test cases until the test suite is sufficient to detect as many mutants as possible and the mutation score is satisfactory. The augmented test suite resulting from mutation analysis may reveal latent faults and provides a stronger test suite to detect future errors which might be injected. Software engineers often look for guidance on how to augment their test suite using information provided by line and/or branch coverage tools. As the use of mutation analysis grows, software engineers will want to know how the emerging technique compares with and/or complements coverage analysis for guiding the augmentation of an automated test suite. Additionally, software engineers can benefit from an enhanced understanding of efficient mutation analysis techniques. To address these needs for additional information about mutation analysis, we conducted an empirical study of the use of mutation analysis on two open source projects. Our results indicate that a focused effort on increasing mutation score leads to a corresponding increase in line and branch coverage to the point that line coverage, branch coverage and mutation score reach a maximum but leave some types of code structures uncovered. Mutation analysis guides the creation of additional “common programmer error” tests beyond those written to increase line and branch coverage. We also found that 74% of our chosen set of mutation operators is useful, on average, for producing new tests. The remaining 26% of mutation operators did not produce new test cases because their mutants were immediately detected by the initial test suite, indirectly detected by test suites we added to detect other mutants, or were not able to be detected by any test.
Laurie WilliamsEmail:

Ben Smith   is a second year Ph.D. student in Computer Science at North Carolina State University working as an RA under Dr. Laurie Williams. He received his Bachelor’s degree in Computer Science in May of 2007 and he hopes to receive his doctorate in 2012. He has begun work on developing SQL Coverage Metrics as a predictive measure of the security of a web application. This fall, he will be beginning the doctoral preliminary exam and working as a Testing Manager for the NCSU CSC Senior Design Center: North Carolina State’s capstone course for Computer Science. Finally, he has designed and maintained the websites for the Center for Open Software Engineering and ESEM 2009. Laurie Williams   is an Associate Professor in the Computer Science Department of the College of Engineering at North Carolina State University. She leads the Software Engineering Reasearch group and is also the Director of the North Carolina State University Laboratory for Collaborative System Development and the Center for Open Software Engineering. She is also technical co-director of the Center for Open Software Engineering (COSE) and the area technical director of the Secure Open Systems Initiative (SOSI) at North Carolina State University. Laurie received her Ph.D. in Computer Science from the University of Utah, her MBA from Duke University, and her BS in Industrial Engineering from Lehigh University. She worked for IBM for nine years in Raleigh, NC before returning to academia. Laurie’s research interests include agile software development methodologies and practices, collaborative/pair programming, software reliability and testing, and software engineering for secure systems development.   相似文献   
56.
Aiming at the poor adaptability and robustness of existing pseudo-color methods, most of which can only deal with an 8-bit grayscale, an adaptive enhancement algorithm of high grayscale images based on priori knowledge was proposed. Firstly, aiming at the problem that the original RGB color space is not easy to adjust dynamically, the power adjustment was integrated into the constructed high-bit chromatogram, and a power adaptive adjustment function based on the brightness priority over the original grayscale image was designed. Secondly, aiming at the problems of over-exposure, under-exposure, and poor gradients in RGB space, an adaptive grayscale correction algorithm was designed according to the priori knowledge distribution of RGB perceived brightness. Finally, to guarantee the color balance of the enhanced image, a color balance correction algorithm based on CMY space was designed. To verify the effectiveness of this method, it was applied to the pseudo-color enhancement of 16-bit pipeline CR images, 14-bit infrared images, 24-bit pipeline DR weld images, 8-bit or 24-bit rail crack images, and 16-bit remote sensing images respectively. The subjective and objective experimental results show that the design method has stronger adaptability, which has obvious advantages compared with the existing advanced high grayscale image enhancement methods. The enhancement effect is more coordinated, the processing result is more in line with human visual perception, and the details and texture information of the original image can be better preserved.  相似文献   
57.
As a comprehensive integration of many new-generation information technologies, the metaverse has become a research hotspot that has attracted much attention. As a part of the metaverse, the industrial metaverse is expected to break through the constraints of space and time and promote high-quality industrial development. The industrial metaverse is human-centric, so its quality of experience (QoE) is a key topic. As one of the enabling technologies of the industrial metaverse, Mixed Reality (MR) can seamlessly integrate virtual information with the physical world and is widely regarded as an important window to the industrial metaverse. In close integration with other enabling technologies, industrial MR applications can be seen as a path toward the realization of the industrial metaverse; thus, the optimization of industrial MR applications can effectively achieve the QoE enhancement of the industrial metaverse. Based on the analysis of existing research and the characteristics of industrial scenarios, consistency, authenticity, smoothness, and comfort are identified as the factors that influence the user experience (UX) of industrial MR applications. Specific optimization methods for industrial MR applications are proposed to improve the UX with regard to these four factors. To verify the effectiveness of the proposed methods, a QoE evaluation model of the industrial metaverse based on the fuzzy analytic hierarchy process (FAHP) is established. Moreover, an industrial metaverse prototype for longwall mining that incorporates the proposed methods is developed and its QoE is evaluated. The results show that the proposed optimization methods for industrial MR applications significantly enhance the QoE in the industrial metaverse, and can provide better services for users in industrial systems, thus better serving these systems.  相似文献   
58.
This paper presents efficient and portable implementations of a powerful image enhancement process, the Symmetric Neighborhood Filter (SNF), and an image segmentation technique that makes use of the SNF and a variant of the conventional connected components algorithm which we call -Connected Components. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. The image segmentation algorithm makes use of an efficient connected components algorithm based on a novel approach for parallel merging. The algorithms have been coded in Split-C and run on a variety of platforms, including the Thinking Machines CM-5, IBM SP-1 and SP-2, Cray Research T3D, Meiko Scientific CS-2, Intel Paragon, and workstation clusters. Our experimental results are consistent with the theoretical analysis (and provide the best known execution times for segmentation, even when compared with machine-specific implementations). Our test data include difficult images from the Landsat Thematic Mapper (TM) satellite data.Also affiliated with the Department of Electrical Engineering.Also affiliated with the Department of Computer Science and the Center for Automation Research.  相似文献   
59.
提出一种柔性制造系统(FMS)的故障诊断和可用性评价方法;针对传统的随机Petri网在解决FMS故障诊断上极大受限于底层马尔科夫链规模而容易产生状态爆炸的问题,首先,将蚁群优化算法(ACO)融入随机有色网(SPN)中,提出并定义了一种能对柔性制造系统的故障进行诊断的诊断器;然后,通过马尔科夫链计算制造单元的可用性,得到FMS到诊断器的映射,从而可以得到FMS中所有可能生产过程;最后,在经典FMS可用性评价方法的基础上,引入覆盖因子,提出了一种新的对FMS生产过程进行可用性评价的方法;仿真实验显示了覆盖因子对系统可用性的影响,通过与传统方法进行比较,表明覆盖因子越大,FMS的可用性越高。  相似文献   
60.
针对PCB图像的特点对图像进行增强处理,使得图像的边缘更加突出,灰度的对比度增加,同时滤除靠近边缘的噪声,为后续图像分割时更有效的选取阈值打下良好基础。使用二阶梯度算子获得图像的增强效果,实验表明,不仅解决了边缘附近噪声去除问题,而且有效地突出了边缘信息,图像的黑白对比分明,尤其是目标图像靠近边缘部分灰度值明显高于其他的非边缘区域。  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