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   55046篇
  免费   5673篇
  国内免费   2924篇
电工技术   3809篇
技术理论   1篇
综合类   4065篇
化学工业   9053篇
金属工艺   3109篇
机械仪表   3118篇
建筑科学   4221篇
矿业工程   1465篇
能源动力   1788篇
轻工业   4841篇
水利工程   1073篇
石油天然气   2478篇
武器工业   580篇
无线电   6592篇
一般工业技术   6457篇
冶金工业   2315篇
原子能技术   816篇
自动化技术   7862篇
  2024年   314篇
  2023年   1121篇
  2022年   2219篇
  2021年   3086篇
  2020年   2147篇
  2019年   1802篇
  2018年   1839篇
  2017年   2043篇
  2016年   1799篇
  2015年   2558篇
  2014年   3080篇
  2013年   3656篇
  2012年   3952篇
  2011年   4202篇
  2010年   3613篇
  2009年   3527篇
  2008年   3279篇
  2007年   2898篇
  2006年   2776篇
  2005年   2383篇
  2004年   1700篇
  2003年   1452篇
  2002年   1505篇
  2001年   1195篇
  2000年   898篇
  1999年   849篇
  1998年   700篇
  1997年   564篇
  1996年   533篇
  1995年   409篇
  1994年   337篇
  1993年   233篇
  1992年   192篇
  1991年   144篇
  1990年   106篇
  1989年   88篇
  1988年   97篇
  1987年   58篇
  1986年   57篇
  1985年   28篇
  1984年   36篇
  1983年   21篇
  1982年   30篇
  1981年   15篇
  1980年   22篇
  1979年   21篇
  1976年   9篇
  1965年   5篇
  1959年   7篇
  1951年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Zhang  Man  Zhou  Yong  Liu  Bing  Zhao  Jiaqi  Yao  Rui  Shao  Zhiwen  Zhu  Hancheng  Chen  Hao 《Pattern Analysis & Applications》2023,26(2):669-677
Pattern Analysis and Applications - The designed method aims to perform image classification tasks efficiently and accurately. Different from the traditional CNN-based image classification methods,...  相似文献   
52.
Computational Visual Media - In this paper, we tackle the challenging problem of point cloud completion from the perspective of feature learning. Our key observation is that to recover the...  相似文献   
53.
Lv  Yang  Su  Donglin 《Wireless Personal Communications》2022,126(3):1965-1980
Wireless Personal Communications - With the rapid development of information technology, issues such as network security and privacy protection have attracted more and more attention. The...  相似文献   
54.
Chen  Rongxin  Wang  Zhijin  Su  Hang  Xie  Shutong  Wang  Zongyue 《The Journal of supercomputing》2022,78(4):5420-5449
The Journal of Supercomputing - The performance of XPath query is the key factor to the capacity of XML processing. It is an important way to improve the performance of XPath by making full use of...  相似文献   
55.
Zhou  Hongtao  Xia  Liang  Su  Housheng 《Neural computing & applications》2022,34(19):16463-16472
Neural Computing and Applications - A new iterative method based on the event-triggered strategy for finding a solution to a mixed equilibrium problem (MEP) is introduced in this paper. The target...  相似文献   
56.
All‐solution processed, high‐performance wearable strain sensors are demonstrated using heterostructure nanocrystal (NC) solids. By incorporating insulating artificial atoms of CdSe quantum dot NCs into metallic artificial atoms of Au NC thin film matrix, metal–insulator heterostructures are designed. This hybrid structure results in a shift close to the percolation threshold, modifying the charge transport mechanism and enhancing sensitivity in accordance with the site percolation theory. The number of electrical pathways is also manipulated by creating nanocracks to further increase its sensitivity, inspired from the bond percolation theory. The combination of the two strategies achieves gauge factor up to 5045, the highest sensitivity recorded among NC‐based strain gauges. These strain sensors show high reliability, durability, frequency stability, and negligible hysteresis. The fundamental charge transport behavior of these NC solids is investigated and the combined site and bond percolation theory is developed to illuminate the origin of their enhanced sensitivity. Finally, all NC‐based and solution‐processed strain gauge sensor arrays are fabricated, which effectively measure the motion of each finger joint, the pulse of heart rate, and the movement of vocal cords of human. This work provides a pathway for designing low‐cost and high‐performance electronic skin or wearable devices.  相似文献   
57.
The acid-catalyzed ring-opening reaction of styrene oxide was used as a probe reaction for evaluating the acidic properties of carboxylated carbocatalysts. Significant discrepancies in the initial reaction rates were normalized using the total number of carboxyl groups, and demonstrated that the average catalytic activities of the carboxyl moieties on the carbocatalysts differed. Comparisons between the apparent activation energy E a and the pre-exponential factor A, derived from Arrhenius analysis, demonstrated that A varied more significantly, and therefore had a more significant effect on the reaction rates than E a. The variation in the calculated pKa values of the carboxyl groups was attributed to the electronic effects of the nitro groups. This hypothesis was supported by the temperature programmed desorption profiles of nitrogen monoxide ions.
  相似文献   
58.
59.
60.
Flush toilets waste a significant amount of water every day due to the unavoidable adhesions between human waste and the toilet surfaces. Super-slippery surfaces can repel complex fluids and various viscoelastic solids, however, are easily broken by mechanical abrasions. Herein, the fabrication of an abrasion-resistant super-slippery flush toilet (ARSFT) is reported using a selective laser sintering 3D printing technology. Unlike traditional super-slippery surfaces with limited thicknesses which can be easily worn away, the powder-sintered strategy endows the ARSFT not only with a self-supporting 3D complex shape but also with a porous structure that can accommodate considerable lubricants for an abrasion-resistant super-slippery property. As a result, the as-prepared ARSFT remains clean after contacting with various liquids such as milk, yogurt, highly sticky honey, and starch gel mixed congee, demonstrating excellent repellence to complex fluids. Besides liquids, the ARSFT exhibits a high resistance to sticky synthetic feces. Notably, even after being abraded to 1,000 cycles of abrasion using sandpaper, the ARSFT maintains its record-breaking super-slippery capability. The concept of the 3D-printed object with a superior abrasion-resistant slippery ability will improve the development of super-slippery materials and further save water consumption in the human society.  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