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   3224篇
  免费   188篇
  国内免费   16篇
电工技术   32篇
综合类   10篇
化学工业   1086篇
金属工艺   56篇
机械仪表   60篇
建筑科学   57篇
矿业工程   12篇
能源动力   146篇
轻工业   161篇
水利工程   16篇
石油天然气   12篇
武器工业   1篇
无线电   298篇
一般工业技术   816篇
冶金工业   137篇
原子能技术   51篇
自动化技术   477篇
  2023年   51篇
  2022年   172篇
  2021年   173篇
  2020年   67篇
  2019年   79篇
  2018年   100篇
  2017年   103篇
  2016年   121篇
  2015年   98篇
  2014年   169篇
  2013年   252篇
  2012年   192篇
  2011年   235篇
  2010年   169篇
  2009年   164篇
  2008年   176篇
  2007年   137篇
  2006年   103篇
  2005年   100篇
  2004年   87篇
  2003年   89篇
  2002年   97篇
  2001年   62篇
  2000年   49篇
  1999年   44篇
  1998年   26篇
  1997年   33篇
  1996年   32篇
  1995年   24篇
  1994年   27篇
  1993年   18篇
  1992年   22篇
  1991年   9篇
  1990年   21篇
  1989年   10篇
  1988年   5篇
  1987年   9篇
  1986年   5篇
  1985年   7篇
  1984年   14篇
  1983年   8篇
  1982年   7篇
  1981年   7篇
  1980年   4篇
  1979年   4篇
  1978年   4篇
  1976年   4篇
  1972年   4篇
  1971年   4篇
  1965年   3篇
排序方式: 共有3428条查询结果,搜索用时 15 毫秒
11.
12.

Augmented, mixed and virtual reality are changing the way people interact and communicate. Five dimensional communications and services, integrating information from all human senses are expected to emerge, together with holographic communications (HC), providing a truly immersive experience. HC presents a lot of challenges in terms of data gathering and transmission, demanding Artificial Intelligence empowered communication technologies such as 5G. The goal of the paper is to present a model of a context-aware holographic architecture for real time communication based on semantic knowledge extraction. This architecture will require analyzing, combining and developing methods and algorithms for: 3D human body model acquisition; semantic knowledge extraction with deep neural networks to predict human behaviour; analysis of biometric modalities; context-aware optimization of network resource allocation for the purpose of creating a multi-party, from-capturing-to-rendering HC framework. We illustrate its practical deployment in a scenario that can open new opportunities in user experience and business model innovation.

  相似文献   
13.
Although the ZigBee technology is massively deployed the performance question still remains unanswered. There is a lack of serious performance evaluations and thus this paper provides a comprehensive and unbiased study of the ZigBee PRO technology. An extensive real measurement was conducted to accomplish this task. We found out a big performance gap among ZigBee implementations even though they are compliant with the ZigBee standard. The presented results and analysis could be beneficial for many wireless sensor network developers.  相似文献   
14.
15.
Uplink power control is used in 3GPP Long Term Evolution (LTE) systems to maximize the power of the desired received signals while limiting the interference. This paper analyzes two power control mechanisms, Fractional Power Control (FPC) and Interference Based Power Control (IBPC). A way of combining them is proposed in order to find an efficient algorithm to control the transmitted Power Spectral Density (PSD) in order to compensate poor channel conditions and thus to obtain better performance in terms of cell edge throughput.  相似文献   
16.
In this paper, we address a super-resolution problem of generating a high-resolution image from low-resolution images. The proposed super-resolution method consists of three steps: image registration, singular value decomposition (SVD)-based image fusion and interpolation. The contribution of this work is two-fold. First we customize an image registration approach using Scale Invariant Feature Transform (SIFT), Belief Propagation and Random Sampling Consensus (RANSAC) for super-resolution. Second, we propose SVD-based fusion to integrate the important features from the low-resolution images. The proposed image registration and fusion steps effectively maintain the important features and greatly improve the super-resolution results. Results, for a variety of image examples, show that the proposed method successfully generates high-resolution images from low-resolution images.  相似文献   
17.
Functional optoelectronic vertical merged MOS (OVMMOS) elements with optical power supply increasing the packaging density for advanced high-speed low-voltage low-power deep-submicron ULSI are considered. Two types of new OVVMOS logical elements are proposed, analyzed and simulated. The simple reduced but adequate numerical electrical-optical model for the OVMMOS is formulated. Low-voltage low-power OVMMOS with combined channels for electrons and holes to increase integration level are simulated using two-dimensional (2D)-numerical device simulators. The problems of low light power operations and optimizations of OVMMOS elements are investigated using 2D simulators.  相似文献   
18.
This tutorial paper describes various efficient implementations (published and new unpublished) of the forward and backward modified discrete cosine transform (MDCT) in the MPEG layer III (MP3) audio coding standard developed in the time period 1990-2010, including the efficient implementation of polyphase filter banks for completeness. The efficient MDCT implementations are discussed in the context of (fast) complete analysis/synthesis MDCT filter banks in the MP3 encoder and decoder. In general, for each efficient forward/backward MDCT block transforms implementation are presented: complete formulas or sparse matrix factorizations of the algorithm, the corresponding signal flow graph for the short audio block and the total arithmetic complexity as well as the useful comments related to improving the arithmetic complexity and a possible structural simplification of the algorithm. Finally, all efficient forward/backward MDCT implementations are compared both in terms of the arithmetic complexity and structural simplicity. It is important to note that almost all presented algorithms can be also used for the 2n-length data blocks in others MPEG audio coding standards and proprietary audio compression algorithms.  相似文献   
19.
Materials with broad absorption bands are highly desirable for electromagnetic filtering and processing applications, especially if the absorption can be externally controlled. Here, a new class of broadband‐absorption materials is introduced. Namely, layered metamagnets exhibit an electromagnetic excitation continuum in the magnetic‐field‐induced mixed ferro‐ and anti­ferromagnetic phase. Employing a series of complementary experimental techniques involving neutron scattering, muon spin relaxation, specific heat, ac and dc magnetization measurements, and electron magnetic resonance, a detailed magnetic phase diagram of Cu3Bi(SeO3)2O2Br is determined and it is found that the excitations in the mixed phase extend over at least ten decades of frequency. The results, which reveal a new dynamical aspect of the mixed phase in metamagnets, open up a novel approach to controllable microwave filtering.  相似文献   
20.
The chemical quantitative composition, phase constitution, and crystal structure of doped with In lead telluride films on Si (1 0 0) or SiO2/Si (1 0 0) substrates have been studied in this work. By EPMA and atomic absorption measurements, it has been found that the concentration of In atoms yIn varied from 0.0011 to 0.045 in these deposited Pb1−yInyTe films. The results of EPMA, SEM, and X-ray diffraction (XRD) measurements show that formation of In solid solutions in lead telluride matrix revealed not only in PbTe–InTe cross-section, but in PbTe–In2Te3 pseudobinary system also. The results of XRD show that the lattice parameter aPbTe of PbTeIn/Si and PbTeIn/SiO2/Si heterostructures is described by nonmonotone function and does not obey the Vegard's law within concentration interval 0.0011yIn0.045.  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