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   828篇
  免费   51篇
  国内免费   4篇
电工技术   21篇
化学工业   229篇
金属工艺   11篇
机械仪表   25篇
建筑科学   17篇
矿业工程   1篇
能源动力   36篇
轻工业   55篇
水利工程   14篇
石油天然气   4篇
无线电   86篇
一般工业技术   192篇
冶金工业   45篇
原子能技术   7篇
自动化技术   140篇
  2024年   2篇
  2023年   20篇
  2022年   47篇
  2021年   40篇
  2020年   35篇
  2019年   43篇
  2018年   63篇
  2017年   31篇
  2016年   40篇
  2015年   26篇
  2014年   45篇
  2013年   72篇
  2012年   41篇
  2011年   60篇
  2010年   26篇
  2009年   35篇
  2008年   37篇
  2007年   24篇
  2006年   16篇
  2005年   10篇
  2004年   13篇
  2003年   8篇
  2002年   7篇
  2001年   3篇
  2000年   14篇
  1999年   6篇
  1998年   8篇
  1997年   7篇
  1996年   6篇
  1995年   4篇
  1994年   6篇
  1993年   7篇
  1992年   8篇
  1991年   7篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1987年   8篇
  1986年   2篇
  1985年   2篇
  1984年   9篇
  1982年   8篇
  1981年   5篇
  1980年   9篇
  1979年   3篇
  1978年   3篇
  1976年   2篇
  1974年   2篇
  1973年   1篇
  1970年   1篇
排序方式: 共有883条查询结果,搜索用时 0 毫秒
881.
Silicon - To overcome the fabrication complexity and achieve a better switching ratio is a major grave concern for applications in semiconductor devices. In this regards, a novel stack gate-oxide...  相似文献   
882.
Skin lesions detection and classification is a prominent issue and difficult even for extremely skilled dermatologists and pathologists. Skin disease is the most common disorder triggered by fungus, viruses, bacteria, allergies, etc. Skin diseases are most dangerous and may be the cause of serious damage. Therefore, it requires to diagnose it at an earlier stage, but the diagnosis therapy itself is complex and needs advanced laser and photonic therapy. This advance therapy involves financial burden and some other ill effects. Therefore, it must use artificial intelligence techniques to detect and diagnose it accurately at an earlier stage. Several techniques have been proposed to detect skin disease at an earlier stage but fail to get accuracy. Therefore, the primary goal of this paper is to classify, detect and provide accurate information about skin diseases. This paper deals with the same issue by proposing a high-performance Convolution neural network (CNN) to classify and detect skin disease at an earlier stage. The complete methodology is explained in different folds: firstly, the skin diseases images are pre-processed with processing techniques, and secondly, the important feature of the skin images are extracted. Thirdly, the pre-processed images are analyzed at different stages using a Deep Convolution Neural Network (DCNN). The approach proposed in this paper is simple, fast, and shows accurate results up to 98% and used to detect six different disease types.  相似文献   
883.
This research suggests a compact uniplanar multiple-input multiple-output (MIMO) with four ports for n79/n46/millimeter-wave (mm-wave) applications. The size of the quad MIMO is only 30 × 30 × 0.8 mm3. MIMO system consists of four identical Z-shaped radiators and common ground on the same plane and no decoupling structures are used for isolation. The system covers the bandwidth of 1.9 GHz (4.4–6.3 GHz) with a mid-frequency of 5.6 GHz and also covers the high-band frequencies ranging from 18 to 30 GHz with a bandwidth of 12 GHz. The suggested quad MIMO is fabricated on an FR-4 board, and the measured outcomes are well in line with the simulated results. An isolation value of −11 dB has been achieved for mid-band frequency and −24 dB has been attained for mm-wave bands. Through the value of DG = 10 dB, ECC < 0.07, TARC < −3 dB, MEG < −5 dB, and the ratio of MEG = 1 dB, uniplanar quad MIMO shows acceptable MIMO diversity performance. The entire system was evaluated for the users' hand specific absorption rate (SAR) impacts and is within the limits. After the complete analysis of the miniature quad MIMO antenna, an 8-port, and a 16-port uniplanar MIMO are simulated for smartphone-sized dielectric substrates and the performances were examined. The suggested MIMO system provides an efficient single-layer MIMO antenna to 5G smartphones with high bandwidth and low SAR. The proposed quad MIMO systems are suitable for both the sub-6 GHz band and the mm-wave band.  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