全文获取类型
收费全文 | 22917篇 |
免费 | 2416篇 |
国内免费 | 1638篇 |
专业分类
电工技术 | 892篇 |
综合类 | 2793篇 |
化学工业 | 2708篇 |
金属工艺 | 928篇 |
机械仪表 | 1713篇 |
建筑科学 | 2424篇 |
矿业工程 | 821篇 |
能源动力 | 607篇 |
轻工业 | 1139篇 |
水利工程 | 828篇 |
石油天然气 | 1436篇 |
武器工业 | 352篇 |
无线电 | 1840篇 |
一般工业技术 | 2034篇 |
冶金工业 | 1707篇 |
原子能技术 | 372篇 |
自动化技术 | 4377篇 |
出版年
2024年 | 104篇 |
2023年 | 335篇 |
2022年 | 566篇 |
2021年 | 725篇 |
2020年 | 757篇 |
2019年 | 637篇 |
2018年 | 601篇 |
2017年 | 767篇 |
2016年 | 922篇 |
2015年 | 992篇 |
2014年 | 1416篇 |
2013年 | 1317篇 |
2012年 | 1772篇 |
2011年 | 1968篇 |
2010年 | 1553篇 |
2009年 | 1552篇 |
2008年 | 1379篇 |
2007年 | 1636篇 |
2006年 | 1482篇 |
2005年 | 1216篇 |
2004年 | 1036篇 |
2003年 | 866篇 |
2002年 | 679篇 |
2001年 | 602篇 |
2000年 | 457篇 |
1999年 | 326篇 |
1998年 | 245篇 |
1997年 | 177篇 |
1996年 | 162篇 |
1995年 | 119篇 |
1994年 | 108篇 |
1993年 | 69篇 |
1992年 | 64篇 |
1991年 | 46篇 |
1990年 | 35篇 |
1989年 | 33篇 |
1988年 | 20篇 |
1986年 | 10篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1975年 | 8篇 |
1966年 | 9篇 |
1965年 | 10篇 |
1964年 | 19篇 |
1963年 | 8篇 |
1962年 | 8篇 |
1961年 | 8篇 |
1958年 | 10篇 |
1956年 | 10篇 |
1955年 | 17篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
This paper presents a novel No-Reference Video Quality Assessment (NR-VQA) model that utilizes proposed 3D steerable wavelet transform-based Natural Video Statistics (NVS) features as well as human perceptual features. Additionally, we proposed a novel two-stage regression scheme that significantly improves the overall performance of quality estimation. In the first stage, transform-based NVS and human perceptual features are separately passed through the proposed hybrid regression scheme: Support Vector Regression (SVR) followed by Polynomial curve fitting. The two visual quality scores predicted from the first stage are then used as features for the similar second stage. This predicts the final quality scores of distorted videos by achieving score level fusion. Extensive experiments were conducted using five authentic and four synthetic distortion databases. Experimental results demonstrate that the proposed method outperforms other published state-of-the-art benchmark methods on synthetic distortion databases and is among the top performers on authentic distortion databases. The source code is available at https://github.com/anishVNIT/two-stage-vqa. 相似文献
4.
《Journal of dairy science》2022,105(4):3176-3191
Milk concentrates are used in the manufacturing of dairy products such as yogurt and cheese or are processed into milk powder. Processes for the nonthermal separation of water and valuable milk ingredients are becoming increasingly widespread at farm level. The technical barriers to using farm-manufactured milk concentrate in dairies are minimal, hence the suspicion that the practice of on-farm raw milk concentration is still fairly uncommon for economic reasons. This study, therefore, set out to investigate farmers' potential willingness to adopt a raw milk concentration plant. The empirical analysis was based on discrete choice experiments with 75 German dairy farmers to identify preferences and the possible adoption of on-farm raw milk concentration. The results showed that, in particular, farmers who deemed the current milk price to be insufficient viewed on-farm concentration using membrane technology as an option for diversifying their milk sales. We found no indication that adoption would be impeded by a lack of trustworthy information on milk processing technologies or capital. 相似文献
5.
目的研究蛋类礼盒包装结构的缓冲性能。方法以蛋类尺寸为基础,建立可发性聚乙烯(expandable polyethylene. EPE)缓冲单元结构和组合结构,进行静态仿真分析和实验验证,比较结构在形状、叠合层数、组合形式等参数变化时的载荷与位移。结果结构层数变化相同时,单元结构的极限载荷从143N增加到236 N,组合结构的极限载荷从224 N增加到476 N,均呈近线性增长。结论蛋类礼盒包装中,组合结构的承载能力优于单元结构,通过单元结构的组合,可满足不同蛋类的包装要求。 相似文献
6.
7.
随着自主式水下机器人的发展,水下探测技术成为新的研究热点。然而,吸收效应和散射效应导致水下获取的图像存在雾化和色彩偏差等缺陷。降质的水下图像在一定程度上降低了水下目标识别的准确性。为了改善水下图像质量,国内外学者对水下图像处理方法进行了深入研究。因水下图像处理方法对提升水下目标识别准确性具有良好的促进作用,故其具有重要的研究与分析价值。介绍了水下成像模型,分析了水下图像视觉质量下降的原理;根据水下物理成像模型将水下图像处理方法分为水下图像增强与水下图像复原,并分别对两类方法的研究现状进行分析与归纳;最后,总结与讨论了各类方法的优缺点,并展望了未来的发展方向。 相似文献
8.
Aishwarya
Srivastava Siddhant Aggarwal Amy Apon Edward Duffy Ken Kennedy Andre Luckow Brandon Posey Marcin Ziolkowski 《Software》2020,50(6):868-898
We investigate the challenges of building an end-to-end cloud pipeline for real-time intelligent visual inspection system for use in automotive manufacturing. Current methods of visual detection in automotive assembly are highly labor intensive, and thus prone to errors. An automated process is sought that can operate within the real-time constraints of the assembly line and can reduce errors. Components of the cloud pipeline include capture of a large set of high-definition images from a camera setup at the assembly location, transfer and storage of the images as needed, execution of object detection, and notification to a human operator when a fault is detected. The end-to-end execution must complete within a fixed time frame before the next car arrives in the assembly line. In this article, we report the design, development, and experimental evaluation of the tradeoffs of performance, accuracy, and scalability for a cloud system. 相似文献
9.
As suggested by the uncanny valley hypothesis, robots that resemble humans likely elicit feelings of eeriness. Based on the psychological model of meaning maintenance, we expected that the uncanny valley experience could be mitigated through a fictional story, due to the meaning-generating function of narratives. A field experiment was conducted, in which 75 participants interacted with the humanlike robot Telenoid. Prior to the interaction, they either read a short story, a non-narrative leaflet about the robot, or they received no preliminary information. Eeriness ratings were significantly lower in the science fiction condition than in both other conditions. This effect was mediated by higher perceived human-likeness of the robot. Our findings suggest that science fiction may provide meaning for otherwise unsettling future technologies. 相似文献
10.