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   251862篇
  免费   3219篇
  国内免费   457篇
电工技术   4451篇
综合类   274篇
化学工业   40808篇
金属工艺   9622篇
机械仪表   7657篇
建筑科学   5880篇
矿业工程   1409篇
能源动力   5375篇
轻工业   26112篇
水利工程   2559篇
石油天然气   5118篇
武器工业   32篇
无线电   26216篇
一般工业技术   46335篇
冶金工业   48044篇
原子能技术   6086篇
自动化技术   19560篇
  2021年   2270篇
  2019年   2162篇
  2018年   3680篇
  2017年   3602篇
  2016年   3904篇
  2015年   2360篇
  2014年   4124篇
  2013年   10728篇
  2012年   6545篇
  2011年   8793篇
  2010年   6944篇
  2009年   7625篇
  2008年   8040篇
  2007年   8151篇
  2006年   7231篇
  2005年   6392篇
  2004年   6090篇
  2003年   5860篇
  2002年   5919篇
  2001年   5803篇
  2000年   5612篇
  1999年   5566篇
  1998年   13416篇
  1997年   9442篇
  1996年   7265篇
  1995年   5614篇
  1994年   4971篇
  1993年   4885篇
  1992年   3803篇
  1991年   3503篇
  1990年   3718篇
  1989年   3589篇
  1988年   3422篇
  1987年   2991篇
  1986年   3034篇
  1985年   3511篇
  1984年   3314篇
  1983年   2967篇
  1982年   2799篇
  1981年   2909篇
  1980年   2797篇
  1979年   2706篇
  1978年   2724篇
  1977年   3046篇
  1976年   3948篇
  1975年   2416篇
  1974年   2280篇
  1973年   2424篇
  1972年   1999篇
  1971年   1874篇
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
1.
2.
3.
Fan  Deng-Ping  Huang  Ziling  Zheng  Peng  Liu  Hong  Qin  Xuebin  Van Gool  Luc 《国际自动化与计算杂志》2022,19(4):257-287
Machine Intelligence Research - This paper aims to conduct a comprehensive study on facial-sketch synthesis (FSS). However, due to the high cost of obtaining hand-drawn sketch datasets, there is a...  相似文献   
4.
This study presents the development and characterization of PVDF-conjugated polymer nanofiber-based systems. Five different conducting polymers (CPs) were synthesized successfully and used to create the nanofiber systems. The CPs used are polyaniline (PANI), polypyrrole (PPY), polyindole (PIN), polyanthranilic acid (PANA), and polycarbazole (PCZ). Nanofiber systems were produced utilizing the Forcespinning® technique. The nanofiber systems were developed by mechanical stretching. No electrical field or post-process poling was used in the nanofiber systems. The morphology, structure, electrochemical and piezoelectric performance was characterized. All of the nanofiber PVDF/CP systems displayed higher piezoelectric performance than the fine fiber PVDF systems. The PVDF/PPY nanofiber system displays the highest piezoelectric performance of 15.56 V. The piezoelectric performance of the PVDF/CP nanofiber systems favors potential for an attractive source of energy where highly flexible membranes could be used in power actuators, sensors and portable, and wireless devices to mention some.  相似文献   
5.
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid...  相似文献   
6.
Journal of Communications Technology and Electronics - A statistical study of the effectiveness of the non-threshold search procedure for a noise-like phase-shift keyed signal by the delay time is...  相似文献   
7.
Glass and Ceramics - Ceramic bricks based on low-melting clay and ferro-dust from self-disintegrating, low-carbon, ferrochrome slags, graded from M100 to M175, respectively, were obtained in the...  相似文献   
8.
Journal of Inorganic and Organometallic Polymers and Materials - In this work, a borosilicate glass sample (5SiO2–45B2O3–20Na2O–25CaO–5Ag2O) was added to nano-sized...  相似文献   
9.
Abnormal levels of glutathione, a cellular antioxidant, can lead to a variety of diseases. We have constructed a near-infrared ratiometric fluorescent probe to detect glutathione concentrations in biological samples. The probe consists of a coumarin donor, which is connected through a disulfide-tethered linker to a rhodamine acceptor. Under the excitation of the coumarin donor at 405 nm, the probe shows weak visible fluorescence of the coumarin donor at 470 nm and strong near-infrared fluorescence of the rhodamine acceptor at 652 nm due to efficient Forster resonance energy transfer (FRET) from the donor to the acceptor. Glutathione breaks the disulfide bond through reduction, which results in a dramatic increase in coumarin fluorescence and a corresponding decrease in rhodamine fluorescence. The probe possesses excellent cell permeability, biocompatibility, and good ratiometric fluorescence responses to glutathione and cysteine with a self-calibration capability. The probe was utilized to ratiometrically visualize glutathione concentration alterations in HeLa cells and Drosophila melanogaster larvae.  相似文献   
10.
Glass and Ceramics - An analysis of the specific mechanisms of the influence of the state of the grain structure on the thermoelectric properties (electrical resistivity and total thermal...  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