全文获取类型
收费全文 | 9979篇 |
免费 | 828篇 |
国内免费 | 659篇 |
专业分类
电工技术 | 199篇 |
技术理论 | 1篇 |
综合类 | 507篇 |
化学工业 | 190篇 |
金属工艺 | 1629篇 |
机械仪表 | 3314篇 |
建筑科学 | 193篇 |
矿业工程 | 185篇 |
能源动力 | 102篇 |
轻工业 | 345篇 |
水利工程 | 27篇 |
石油天然气 | 39篇 |
武器工业 | 48篇 |
无线电 | 556篇 |
一般工业技术 | 351篇 |
冶金工业 | 73篇 |
原子能技术 | 9篇 |
自动化技术 | 3698篇 |
出版年
2024年 | 28篇 |
2023年 | 186篇 |
2022年 | 318篇 |
2021年 | 345篇 |
2020年 | 307篇 |
2019年 | 212篇 |
2018年 | 193篇 |
2017年 | 260篇 |
2016年 | 324篇 |
2015年 | 405篇 |
2014年 | 583篇 |
2013年 | 572篇 |
2012年 | 832篇 |
2011年 | 893篇 |
2010年 | 563篇 |
2009年 | 561篇 |
2008年 | 478篇 |
2007年 | 666篇 |
2006年 | 636篇 |
2005年 | 516篇 |
2004年 | 437篇 |
2003年 | 409篇 |
2002年 | 357篇 |
2001年 | 252篇 |
2000年 | 221篇 |
1999年 | 204篇 |
1998年 | 154篇 |
1997年 | 131篇 |
1996年 | 104篇 |
1995年 | 86篇 |
1994年 | 49篇 |
1993年 | 47篇 |
1992年 | 33篇 |
1991年 | 21篇 |
1990年 | 16篇 |
1989年 | 16篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
核函数是SVM(Support Vector Machine,支持向量机)的重要组成部分,核函数的选取对分类效果有明显的影响。该文把混合核函数引入到变压器状态评估中。实例分析表明,混合核函数支持向量机提高了状态评估的准确率。 相似文献
32.
Haze is a poor-quality state described by the opalescent appearance of the atmosphere which reduces the visibility. It is caused by high concentrations of atmospheric air pollutants, such as dust, smoke and other particles that scatter and absorb sunlight. The poor visibility can result in the failure of multiple computer vision applications such as smart transport systems, image processing, object detection, surveillance etc. One of the major issues in the field of image processing is the restoration of images that are corrupted due to different degradations. Typically, the images or videos captured in the outside environment have low contrast, colour fade and restricted visibility due to suspended particles of the atmosphere that directly influence the image quality. This can cause difficulty in identifying the objects in the captured hazy images or frames. To address this problem, several image dehazing techniques have been developed in the literature, each of which has its own advantages and limitations, but effective image restoration remains a challenging task. In recent times, various learning (Machine learning & Deep learning) based methods greatly condensed the drawbacks of manual design of haze related features and reduces the difficulty in efficient restoration of images with less computational time and cost. The current state-of-the-art methods for haze free images, mainly from the last decade, are thoroughly examined in this survey. Moreover, this paper systematically summarizes the hardware implementations of various haze removal methods in real time. It is with the hope that this current survey acts as a reference for researchers in this scientific area and to provide a direction for future improvements based on current achievements. 相似文献
33.
34.
ZWK-100注塑机微机控制系统,是新近研制开发的具有汉字和曲线显示功能,适用于1万克及其以上大型注塑机的微机电气控制系统.本文介绍其工作过程,硬软件结构及其性能等. 相似文献
35.
针对核极限学习机高斯核函数参数选优难,影响学习机训练收敛速度和分类精度的问题,该文提出一种K插值单纯形法的核极限学习机算法。把核极限学习机的训练看作一个无约束优化问题,在训练迭代过程中,用Nelder-Mead单纯形法搜索高斯核函数的最优核参数,提高所提算法的分类精度。引入K插值为Nelder-Mead单纯形法提供合适的初值,减少单纯形法的迭代次数,提高了新算法的训练收敛效率。通过在UCI数据集上的仿真实验并与其它算法比较,新算法具有更快的收敛速度和更高的分类精度。 相似文献
36.
《Mechatronics》2023
Structure-integrated force measurement in hexapod structures or kinematics offers great potential for spatial process force control in six degrees of freedom. Although force control has been studied for many years, research questions remain unanswered, especially when regarding parallel kinematic machine tools with numerical control and integrated sensors. This contribution summarizes the technology of structure-integrated force sensing in hexapod machine tools and develops two approaches to use the measured signals for direct hybrid/parallel force control. For different use-cases, such as teach-in or synchronous force/position control with variable task frame, different approaches of set-point specification and injection of manipulated values are studied from a practical point of view. As a result of the work, the feasibility of the force control with structure-integrated sensors on a commercial CNC can be confirmed through appropriate experiments. Furthermore, the realized G-Code integration represents a practical solution for programming force-controlled machine tools in an easy and concise way from the NC programme. 相似文献
37.
胡志勇 《电子工业专用设备》2004,33(5):70-72
向模块化组装生产线方向发展正获得愈来愈多人们的关注。一条由多种“高速模块”所组成的生产线具有许多优点,将对现有的装配厂商具有很大的诱惑力。由高速柔性化贴装设备所组成的组装生产线可以超越传统的芯片射手和微细间距贴装设备。 相似文献
38.
支持向量机训练算法及其应用 总被引:2,自引:0,他引:2
支持向量机是在统计学习理论基础上提出的一种新的机器学习方法。由于其出.色尊学习性能,该技术已成为机器学习界的研究热点,并成功地应用在模式识别、时间序列预测、苛线性系统辨识、控制及其它方面。本文简要介绍了支持向量机训练算法及其应用,并且讨论了未来的发展方向。 相似文献
39.
Dengsheng Zhang Md. Monirul Islam Guojun Lu 《Journal of Visual Communication and Image Representation》2013,24(7):1087-1098
Image retrieval has lagged far behind text retrieval despite more than two decades of intensive research effort. Most of the research on image retrieval in the last two decades are on content based image retrieval or image retrieval based on low level features. Recent research in this area focuses on semantic image retrieval using automatic image annotation. Most semantic image retrieval techniques in literature, however, treat an image as a bag of features/words while ignore the structural or spatial information in the image. In this paper, we propose a structural image retrieval method based on automatic image annotation and region based inverted file. In the proposed system, regions in an image are treated the same way as keywords in a structural text document, semantic concepts are learnt from image data to label image regions as keywords and weight is assigned to each keyword according to spatial position and relationship. As the result, images are indexed and retrieved in the same way as structural document retrieval. Specifically, images are broken down to regions which are represented using colour, texture and shape features. Region features are then quantized to create visual dictionaries which are similar to monolingual dictionaries like English or Chinese dictionaries. In the next step, a semantic dictionary similar to a bilingual dictionary like the English–Chinese dictionary is learnt to mapping image regions to semantic concepts. Finally, images are then indexed and retrieved using a novel region based inverted file data structure. Results show the proposed method has significant advantage over the widely used Bayesian annotation models. 相似文献
40.
设计了用于半导体先进封装光刻设备中的高精度机器视觉对准测量系统,明确了机器视觉对准测量系统工作原理、设计指标及系统设计中需要考虑的关键技术点,同时给出了机器视觉对准测量系统关键零部件的设计,并给出了对准测量系统最终在整机上测得的性能数据。测试结果表明,所设计的机器视觉对准测量系统完全可以满足集成电路先进封装工艺需求。 相似文献