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   12861篇
  免费   794篇
  国内免费   43篇
电工技术   170篇
综合类   15篇
化学工业   2596篇
金属工艺   470篇
机械仪表   958篇
建筑科学   233篇
矿业工程   3篇
能源动力   470篇
轻工业   1111篇
水利工程   83篇
石油天然气   13篇
无线电   2374篇
一般工业技术   2813篇
冶金工业   719篇
原子能技术   199篇
自动化技术   1471篇
  2024年   3篇
  2023年   159篇
  2022年   80篇
  2021年   437篇
  2020年   285篇
  2019年   330篇
  2018年   385篇
  2017年   436篇
  2016年   468篇
  2015年   382篇
  2014年   566篇
  2013年   848篇
  2012年   847篇
  2011年   1045篇
  2010年   755篇
  2009年   812篇
  2008年   745篇
  2007年   577篇
  2006年   506篇
  2005年   465篇
  2004年   423篇
  2003年   377篇
  2002年   386篇
  2001年   295篇
  2000年   271篇
  1999年   253篇
  1998年   367篇
  1997年   248篇
  1996年   173篇
  1995年   127篇
  1994年   115篇
  1993年   97篇
  1992年   65篇
  1991年   59篇
  1990年   54篇
  1989年   58篇
  1988年   32篇
  1987年   41篇
  1986年   19篇
  1985年   32篇
  1984年   21篇
  1983年   8篇
  1982年   8篇
  1981年   10篇
  1980年   4篇
  1979年   2篇
  1978年   4篇
  1977年   3篇
  1976年   5篇
  1973年   4篇
排序方式: 共有10000条查询结果,搜索用时 765 毫秒
21.
22.
23.
24.
International Journal of Control, Automation and Systems - In this paper, a regulation problem for a class of lower triangular nonlinear systems under unknown measurement sensitivity by output...  相似文献   
25.
26.
The majority of visualizations on the web are still stored as raster images, making them inaccessible to visually impaired users. We propose a deep‐neural‐network‐based approach that automatically recognizes key elements in a visualization, including a visualization type, graphical elements, labels, legends, and most importantly, the original data conveyed in the visualization. We leverage such extracted information to provide visually impaired people with the reading of the extracted information. Based on interviews with visually impaired users, we built a Google Chrome extension designed to work with screen reader software to automatically decode charts on a webpage using our pipeline. We compared the performance of the back‐end algorithm with existing methods and evaluated the utility using qualitative feedback from visually impaired users.  相似文献   
27.
Vegetable soup (VS), a plant-based functional food, has been used as a traditional folk medicine and is attracting attention for its ability to enhance the immune response. β-Glucan, a well-established and effective immunomodulator, has synergistic effects when used in combination with some bioactive compounds. In the present study, we aimed to evaluate the synergistic immunomodulatory effects of the combination of VS and β-glucan on macrophage-mediated immune responses. β-Glucan was demonstrated to synergistically enhance the VS-stimulated immune response, including the production of interleukin-6, tumor necrosis factor-α, and nitric oxide, mainly through the mitogen-activated protein kinase pathway in macrophages. In addition, this combination has the potential for further development in functional foods with immune-enhancing activity.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10068-021-00888-x.  相似文献   
28.
Co-browsing is an activity in which a group of users navigate their way through of a set of Web pages together for a shared purpose. Effective co-browsing among users with different device capabilities requires a shared understanding of those Web pages. This paper demonstrates the concept of shared viewpoints (SVPs), and personal viewpoints (PVPs), for co-browsing, before detailing a framework for implementing these concepts. Finally, the effectiveness of the framework is presented through a perceptual experiment.  相似文献   
29.
All-buried InP-InGaAsP ring resonators laterally coupled to bus waveguides are demonstrated. The buried configurations offer a lower built-in refractive index step along the resonator periphery, which affords enhanced optical coupling coefficients between the waveguides and reduced scattering losses caused by the resonator sidewall imperfections. Very low optical intensity attenuations of 0.4 cm/sup -1/ and coupling-limited quality factors of greater than 10/sup 5/ are observed from 200-/spl mu/m-radii ring resonators. The measured spectral linewidth is as narrow as 0.0145 nm.  相似文献   
30.
Continuously variable ferroelectric (BST on sapphire) phase shifters based on all-pass networks are presented. An all-pass network phase shifter consists of only lumped LC elements, and thus the total size of the phase shifter is kept to less than 2.2 mm /spl times/ 2.6 mm at 2.4 GHz. The tunability (C/sub max//C/sub min/) of a BST interdigital capacitor is over 2.9 with a bias voltage of 140 V. The phase shifter provides more than 121/spl deg/ phase shift with the maximum insertion loss of 1.8 dB and the worst case return loss of 12.5 dB from 2.4 GHz to 2.5 GHz. By cascading two identical phase shifters, more than 255/spl deg/ phase shift is obtained with the maximum insertion loss of 3.75 dB. The loss figure-of-merit of both the single- and double-section phase shifters is over 65/spl deg//dB from 2.4 GHz to 2.5 GHz.  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