全文获取类型
收费全文 | 6200篇 |
免费 | 351篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 81篇 |
综合类 | 5篇 |
化学工业 | 1521篇 |
金属工艺 | 94篇 |
机械仪表 | 98篇 |
建筑科学 | 210篇 |
矿业工程 | 21篇 |
能源动力 | 252篇 |
轻工业 | 1123篇 |
水利工程 | 37篇 |
石油天然气 | 21篇 |
无线电 | 334篇 |
一般工业技术 | 989篇 |
冶金工业 | 548篇 |
原子能技术 | 34篇 |
自动化技术 | 1186篇 |
出版年
2024年 | 14篇 |
2023年 | 57篇 |
2022年 | 232篇 |
2021年 | 229篇 |
2020年 | 146篇 |
2019年 | 201篇 |
2018年 | 245篇 |
2017年 | 221篇 |
2016年 | 235篇 |
2015年 | 199篇 |
2014年 | 268篇 |
2013年 | 443篇 |
2012年 | 422篇 |
2011年 | 459篇 |
2010年 | 371篇 |
2009年 | 321篇 |
2008年 | 344篇 |
2007年 | 286篇 |
2006年 | 246篇 |
2005年 | 198篇 |
2004年 | 153篇 |
2003年 | 144篇 |
2002年 | 139篇 |
2001年 | 71篇 |
2000年 | 73篇 |
1999年 | 74篇 |
1998年 | 151篇 |
1997年 | 122篇 |
1996年 | 78篇 |
1995年 | 82篇 |
1994年 | 32篇 |
1993年 | 49篇 |
1992年 | 25篇 |
1991年 | 26篇 |
1990年 | 20篇 |
1989年 | 25篇 |
1988年 | 11篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 17篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 11篇 |
1975年 | 11篇 |
1974年 | 5篇 |
排序方式: 共有6554条查询结果,搜索用时 0 毫秒
41.
One of the leading time of flight imaging technologies for depth sensing is based on Photonic Mixer Devices (PMD). In PMD sensors each pixel samples the correlation between emitted and received light signals. Current PMD cameras compute eight correlation samples per pixel in four sequential stages to obtain depth with invariance to signal amplitude and offset variations. With motion, PMD pixels capture different depths at each stage. As a result, correlation samples are not coherent with a single depth, producing artifacts. We propose to detect and remove motion artifacts from a single frame taken by a PMD camera. The algorithm we propose is very fast, simple and can be easily included in camera hardware. We recover depth of each pixel by exploiting consistency of the correlation samples and local neighbors of the pixel. In addition, our method obtains the motion flow of occluding contours in the image from a single frame. The system has been validated in real scenes using a commercial low-cost PMD camera and high speed dynamics. In all cases our method produces accurate results and it highly reduces motion artifacts. 相似文献
42.
43.
Stephen Q. Zhou Liming Wang Xiugao Liao Georges Manuel William P. Weber 《Journal of Inorganic and Organometallic Polymers and Materials》1991,1(2):199-210
High molecular weight poly(1,1-dimethyl-1-germa-cis-pent-3-ene), poly(1,1-diphenyl-1-germa-cis-pent-3-ene), poly(1,1-dimethyl-1-sila-cis-pent-3-ene), and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) have been prepared. The thermal stability of these polymers is found to increase with their molecular weight. 相似文献
44.
Jose Ygnacio Pastor Jaime Planas Manuel Elices 《Journal of the American Ceramic Society》1993,76(11):2927-2929
A new technique that provides stable fracture tests in brittle ceramic materials at room and at high temperature is presented. This technique uses the crack mouth opening displacement signal from a laser extensometer to feed the servo control of a hydraulic testing machine. In this way it is possible to obtain—in addition to the fracture toughness—the fracture energy and the R -curve, in a single test. 相似文献
45.
Pablo Giménez Benjamín Molina Jaime Calvo-Gallego Manuel Esteve Carlos E. Palau 《Computers in Industry》2014
Sensor Web Enablement (SWE) technologies have been successfully applied to a great variety of outdoor scenarios but, in practical terms, little effort has been applied for indoor environments, and even less in the field of industrial applications. This article presents an intelligent SWE application for an indoor and industrial scenario, with the aim of improving and increasing the levels of human safety. The base low-level architecture is built on top of wireless sensor networks (WSN) connected to a Sensor Observation Service (SOS). Higher layers in the architecture include services that make real time decisions based on the collected data. Both simulation and experimental results are presented. The paper shows the viability of our approach in terms of performance, scalability, modularity and safety. 相似文献
46.
Emilio Soto Candela Mario Ortega Pérez Clemente Marín Romero David C. Pérez López Gustavo Salvador Herranz Manuel Contero Mariano Alcañiz Raya 《Multimedia Tools and Applications》2014,70(3):1837-1868
In this paper, a computer vision based interactive multi-touch tabletop system called HumanTop is introduced. HumanTop implements a stereo camera vision subsystem which allows not only an accurate fingertip tracking algorithm but also a precise touch-over-the-working surface detection method. Based on a pair of visible spectra cameras, a novel synchronization circuit makes the camera caption and the image projection independent from each other, providing the minimum basis for the development of computer vision analysis based on visible spectrum cameras without any interference coming from the projector. The assembly of both cameras and the synchronization circuit is not only capable of performing an ad-hoc version of a depth camera, but it also introduces the recognition and tracking of textured planar objects, even when contents are projected over them. On the other hand HumanTop supports the tracking of sheets of paper and ID-code markers. This set of features makes the HumanTop a comprehensive, intuitive and versatile augmented tabletop that provides multitouch interaction with projective augmented reality on any flat surface. As an example to exploit all the capabilities of HumanTop, an educational application has been developed using an augmented book as a launcher to different didactic contents. A pilot study in which 28 fifth graders participated is presented. Results about efficiency, usability/satisfaction and motivation are provided. These results suggest that HumanTop is an interesting platform for the development of educational contents. 相似文献
47.
48.
ABSTRACT Many designers and User Interface (UI) educators discuss principles to be followed when designing the functional aspects of a UI. However, many UI principles have been proposed, scattered in scientific papers and teaching books. Some principles are different, and many are somehow similar or overlapping with others. This makes it very difficult to comprehend where to pay attention to when designing a UI. In this paper, we perform a systematic literature review to first identify the most relevant authors in the domain of functional UI design principles. Focusing on the three most cited works of these authors, we extracted 257 principles. We next analyzed all these principles, unified their variants, and, considering their scientific influence, finally derived a shorter and core selection of 36 principles. This core selection provides educators and UI designers with a clear path to teach, evaluate, learn and improve the UI functional design. 相似文献
49.
Tellez Eric S. Ruiz Guillermo Chavez Edgar Graff Mario 《Pattern Analysis & Applications》2021,24(2):763-777
Pattern Analysis and Applications - Nearest neighbor search is a powerful abstraction for data access; however, data indexing is troublesome even for approximate indexes. For intrinsically... 相似文献
50.
Decision recommendations are a set of alternative options for clinical decisions (e.g., diagnosis, prognosis, treatment selection, follow-up, and prevention) that are provided to decision makers by knowledge-based Clinical Decision Support Systems (k-CDSS) as aids. We propose to follow a “reasoning over domain” approach for the generation of decision recommendations by gathering and inferring conclusions from production rules. In order to rationalize our approach, we present a specification that will sustain the logic models supported in the knowledge bases we use for persistence. We introduce first the underlying knowledge model and then the necessary extensions that will convey toward the solution of the reported needs. The starting point of our approach is the proposition of Reflexive Ontologies (RO). Here, we go a step further, proposing an extension of RO that includes the handling and reasoning that production rules provide. Our approach speeds up the recommendation generation process. 相似文献