全文获取类型
收费全文 | 5493篇 |
免费 | 166篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 79篇 |
综合类 | 5篇 |
化学工业 | 1057篇 |
金属工艺 | 114篇 |
机械仪表 | 75篇 |
建筑科学 | 315篇 |
矿业工程 | 7篇 |
能源动力 | 162篇 |
轻工业 | 371篇 |
水利工程 | 44篇 |
石油天然气 | 18篇 |
武器工业 | 1篇 |
无线电 | 374篇 |
一般工业技术 | 865篇 |
冶金工业 | 1397篇 |
原子能技术 | 50篇 |
自动化技术 | 735篇 |
出版年
2021年 | 60篇 |
2020年 | 58篇 |
2019年 | 59篇 |
2018年 | 70篇 |
2017年 | 61篇 |
2016年 | 78篇 |
2015年 | 83篇 |
2014年 | 86篇 |
2013年 | 347篇 |
2012年 | 203篇 |
2011年 | 231篇 |
2010年 | 167篇 |
2009年 | 178篇 |
2008年 | 222篇 |
2007年 | 227篇 |
2006年 | 192篇 |
2005年 | 187篇 |
2004年 | 167篇 |
2003年 | 153篇 |
2002年 | 161篇 |
2001年 | 89篇 |
2000年 | 86篇 |
1999年 | 95篇 |
1998年 | 61篇 |
1997年 | 68篇 |
1996年 | 89篇 |
1995年 | 74篇 |
1994年 | 67篇 |
1993年 | 78篇 |
1992年 | 75篇 |
1991年 | 54篇 |
1990年 | 68篇 |
1989年 | 79篇 |
1988年 | 66篇 |
1987年 | 85篇 |
1986年 | 80篇 |
1985年 | 99篇 |
1984年 | 109篇 |
1983年 | 81篇 |
1982年 | 74篇 |
1981年 | 85篇 |
1980年 | 62篇 |
1979年 | 96篇 |
1978年 | 68篇 |
1977年 | 76篇 |
1976年 | 57篇 |
1975年 | 65篇 |
1974年 | 57篇 |
1973年 | 74篇 |
1972年 | 53篇 |
排序方式: 共有5669条查询结果,搜索用时 31 毫秒
1.
2.
3.
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
4.
Meysam Heydari Gharahcheshmeh Maxwell T. Robinson Edward F. Gleason Karen K. Gleason 《Advanced functional materials》2021,31(14):2008712
Engineering the texture and nanostructure to improve the electrical conductivity of semicrystalline conjugated polymers must address the rate-limiting step for charge carrier transport. In highly face-on orientation, the charge transport between chains within a crystallite becomes rate-limiting, which is highly sensitive to the π–π stacking distance and interchain charge transfer integral. Here, face-on oriented semicrystalline poly(3,4-ethylenedioxythiophene) (PEDOT) thin films are grown via water-assisted (W-A) oxidative chemical vapor deposition (oCVD). Combining W-A with the volatile oxidant, antimony pentachloride, yields an optimized electrical conductivity of 7520 ± 240 S cm−1, a record for PEDOT thin films. Systematic control of π–π stacking distance from 3.50 Å down to 3.43 Å yields an electrical conductivity enhancement of ≈ 1140%. The highest electrical conductivity also corresponds to minimum in Urbach energy of 205 meV, indicating superior morphological order. The figure of merit for transparent conductors, σdc/σop, reaches a maximum value of 94, which is 1.9 × and 6.7 × higher than oCVD PEDOT grown without W-A and utilizing vanadium oxytrichloride and iron chloride oxidizing agents, respectively. The W-A oCVD is single-step all-dry process and provides conformal coverage, allowing direct growth on mechanical flexible, rough, and structured surfaces without the need for complex and costly transfer steps. 相似文献
5.
6.
Edward A. Chappell 《Vernacular Architecture》2018,49(1):79-98
Early-modern timber framing and associated finish vary significantly among the countless places settled by Europeans and Africans in the age of exploration. Most of these dots on maps of the western hemisphere remain essentially unstudied, as evidence for their vernacular architecture slips away. This is of more than local interest because the material offers opportunities to investigate how related populations share and alter cultural traits, and how the traits evolve in response to degrees of immigration, value of labour, environmental conditions and trade. This paper focuses on one of the dots, presenting new evidence for frame construction on the small British island of Bermuda, and addresses its role in the population’s economic evolution. 相似文献
7.
Yeon Ui Lee Kanghoon Yim Steven Edward Bopp Junxiang Zhao Zhaowei Liu 《Advanced materials (Deerfield Beach, Fla.)》2020,32(28):2002387
Hyperbolic media strengthen numerous attractive applications in optics such as super-resolution imaging, enhanced spontaneous emission, and nanoscale waveguiding. Natural hyperbolic materials exist at visible frequencies; however, implementations of these materials suffer substantial compromises resulting from the high loss in the currently available candidates. Here, the first experimental and theoretical investigation of regioregular poly(3-alkylthiophenes) (rr-P3ATs), a naturally low-loss organic hyperbolic material (OHM) in the visible frequency range, is shown. These hyperbolic properties arise from a highly ordered structure of layered electron-rich conjugated thiophene ring backbones separated by insulating alkyl side chains. The optical and electronic properties of the rr-P3AT can be tuned by controlling the degree of crystallinity and alkyl side chain length. First-principles calculations support the experimental observations, which result from the rr-P3AT's structural and optical anisotropy. Conveniently, rr-P3AT-based OHMs are facile to fabricate, flexible, and biocompatible, which may lead to tremendous new opportunities in a wide range of applications. 相似文献
8.
AbstractIndustry 4.0 aims at providing a digital representation of a production landscape, but the challenges in building, maintaining, optimizing, and evolving digital models in inter-organizational production chains have not been identified yet in a systematic manner. In this paper, various Industry 4.0 research and technical challenges are addressed, and their present scenario is discussed. Moreover, in this article, the novel concept of developing experience-based virtual models of engineering entities, process, and the factory is presented. These models of production units, processes, and procedures are accomplished by virtual engineering object (VEO), virtual engineering process (VEP), and virtual engineering factory (VEF), using the knowledge representation technique of Decisional DNA. This blend of the virtual and physical domains permits monitoring of systems and analysis of data to foresee problems before they occur, develop new opportunities, prevent downtime, and even plan for the future by using simulations. Furthermore, the proposed virtual model concept not only has the capability of Query Processing and Data Integration for Industrial Data but also real-time visualization of data stream processing. 相似文献
9.
AbstractWith the rapid progress of information technologies, cars have been made increasingly intelligent. This allows cars to act as cognitive agents, i.e., to acquire knowledge and understanding of the driving habits and behavioral characteristics of drivers (i.e., driving behavioral fingerprint) through experience. Such knowledge can be then reused to facilitate the interaction between a car and its driver, and to develop better and safer car controls. In this paper, we propose a novel approach to extract the driver’s driving behavioral fingerprints based on our conceptual framework Experience-Oriented Intelligent Things (EOIT). EOIT is a learning system that has the potential to enable Internet of Cognitive Things (IoCT) where knowledge can be extracted from experience, stored, evolved, shared, and reused aiming for cognition and thus intelligent functionality of things. By catching driving data, this approach helps cars to collect the driver’s pedal and steering operations and store them as experience; eventually, it uses obtained experience for the driver’s driving behavioral fingerprint extraction. The initial experimental implementation is presented in the paper to demonstrate our idea, and the test results show that it outperforms the Deep Learning approaches (i.e., deep fully connected neural networks and recurrent neural networks/Long Short-Term Memory networks). 相似文献
10.
Daniel Boon Loong Teh Akshaya Bansal Chou Chai Tan Boon Toh Robert Alan Jappy Tucker Gil Gerald Lasam Gammad Yanzhuang Yeo Zhendong Lei Xiang Zheng Fengyuan Yang John S. Ho Nagarjun Bolem Bing Cheng Wu Muthu Kumar Gnanasammandhan Lissa Hooi Gavin Stewart Dawe Camilo Libedinsky Wei-Yi Ong Barry Halliwell Edward Kai-Hua Chow Kah-Leong Lim Yong Zhang Brian K. Kennedy 《Advanced materials (Deerfield Beach, Fla.)》2020,32(29):2001459
Near-infrared (NIR) activatable upconversion nanoparticles (UCNPs) enable wireless-based phototherapies by converting deep-tissue-penetrating NIR to visible light. UCNPs are therefore ideal as wireless transducers for photodynamic therapy (PDT) of deep-sited tumors. However, the retention of unsequestered UCNPs in tissue with minimal options for removal limits their clinical translation. To address this shortcoming, biocompatible UCNPs implants are developed to deliver upconversion photonic properties in a flexible, optical guide design. To enhance its translatability, the UCNPs implant is constructed with an FDA-approved poly(ethylene glycol) diacrylate (PEGDA) core clad with fluorinated ethylene propylene (FEP). The emission spectrum of the UCNPs implant can be tuned to overlap with the absorption spectra of the clinically relevant photosensitizer, 5-aminolevulinic acid (5-ALA). The UCNPs implant can wirelessly transmit upconverted visible light till 8 cm in length and in a bendable manner even when implanted underneath the skin or scalp. With this system, it is demonstrated that NIR-based chronic PDT is achievable in an untethered and noninvasive manner in a mouse xenograft glioblastoma multiforme (GBM) model. It is postulated that such encapsulated UCNPs implants represent a translational shift for wireless deep-tissue phototherapy by enabling sequestration of UCNPs without compromising wireless deep-tissue light delivery. 相似文献