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   318251篇
  免费   34586篇
  国内免费   10763篇
电工技术   16420篇
技术理论   22篇
综合类   16069篇
化学工业   64470篇
金属工艺   15245篇
机械仪表   17833篇
建筑科学   24855篇
矿业工程   6869篇
能源动力   8903篇
轻工业   24293篇
水利工程   4954篇
石油天然气   15271篇
武器工业   1910篇
无线电   40505篇
一般工业技术   45651篇
冶金工业   15600篇
原子能技术   2865篇
自动化技术   41865篇
  2024年   962篇
  2023年   4226篇
  2022年   7940篇
  2021年   10998篇
  2020年   9154篇
  2019年   9405篇
  2018年   10059篇
  2017年   11365篇
  2016年   11131篇
  2015年   13570篇
  2014年   16839篇
  2013年   21306篇
  2012年   19665篇
  2011年   21225篇
  2010年   18735篇
  2009年   18243篇
  2008年   16988篇
  2007年   16371篇
  2006年   16733篇
  2005年   14775篇
  2004年   10376篇
  2003年   9313篇
  2002年   8518篇
  2001年   7709篇
  2000年   7993篇
  1999年   8418篇
  1998年   7448篇
  1997年   6084篇
  1996年   5534篇
  1995年   4621篇
  1994年   3897篇
  1993年   3009篇
  1992年   2291篇
  1991年   1773篇
  1990年   1385篇
  1989年   1215篇
  1988年   967篇
  1987年   646篇
  1986年   515篇
  1985年   417篇
  1984年   284篇
  1983年   239篇
  1982年   208篇
  1981年   185篇
  1980年   167篇
  1979年   127篇
  1978年   76篇
  1977年   95篇
  1976年   91篇
  1975年   53篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Feng  Wenran  Li  Zhen  Chen  Yingying  Chen  Jinyang  Lang  Haoze  Wan  Jianghong  Gao  Yan  Dong  Haitao 《Journal of Materials Science》2022,57(3):1881-1889
Journal of Materials Science - Although chalcogenide materials continue to generate considerable interest due to great potentials for various optoelectronic devices, annealing for a long time in...  相似文献   
2.
Multimedia Tools and Applications - With the advancement of technology and the spread of the COVID19 epidemic, learning can no longer only be done through face-to-face teaching. Numerous digital...  相似文献   
3.
Xiao  Zhu  Chen  Yanxun  Jiang  Hongbo  Hu  Zhenzhen  Lui  John C. S.  Min  Geyong  Dustdar  Schahram 《Wireless Networks》2022,28(7):3305-3322
Wireless Networks - Unmanned aerial vehicles (UAV) have been widely used in various fields because of their high mobility and portability. At the same time, due to the rapid development of...  相似文献   
4.
5.
6.
The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results.  相似文献   
7.
The effects of cellulose microfibres (CMFs, Average size: 100 ± 5 μm) and cellulose nanofibres (CNFs, Average size: 60 ± 3 nm) on the properties of myofibrillar protein (MP) gels from duck breast meat were studied. The results demonstrated that CMFs and CNFs were mostly connected to MP by non-covalent bonds, the diffusion and cross-linking of MP molecules was promoted, and a denser and more complete gel network was formed. With the increases of CMFs and CNFs concentration (0–10%), the hardness was increased by 13.15% and 19.78% for CMFs10% and CNFs10% gels, respectively, and the elasticity was increased by 40% and 80%, respectively. At the same concentration (0–10%), the increase in gel hardness, viscoelasticity and immobilised water content was greater in the CNFs-MP group than in the CMFs-MP group. The CNFs-MP group had a tighter gel network, and CNFs had a better potential to improve the gelation performance of MP.  相似文献   
8.
针对传统的电弧电路故障检测结果不准确的问题,设计用于电弧检测的SoC系统,并且在55nm工艺下进行流片验证。采用包含两种结构的模数转换器的片上电压源,设计了锁相环以及复位电路,精度最高可达8.67 bit。验证结果表明,本设计可提高电弧检测的准确性。  相似文献   
9.
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   
10.
The purpose of this study was to increase the water solubility and potential bioavailability of quercetin by encapsulation in whey protein isolate (WPI) based on a green, efficient pH-driven method. According to the results, the water solubility of quercetin increased by 346.9: times after loading into WPI nanoparticles. When the initial quercetin concentration was 0.25 mg mL−1 and WPI was 2% w/v, the encapsulation efficiency reached 94.1%, the Z-average diameter was 36.63 nm, and the zeta potential was −36.4 mV at pH 7.0. The fluorescence spectroscopy assay suggested the molecular complexation of quercetin and WPI at pH 12.0. X-ray diffraction assay indicated the enclosure of amorphous quercetin in WPI. Correspondingly, the bioaccessibility increased from 2.76% to 31.23% and the Caco-2 cell monolayer uptake increased from 0% to 2.12% after nanoencapsulation. This work confirmed that the pH-driven method is an effective approach to prepare WPI–quercetin nanocapsules to improve physical and potentially biological properties of quercetin.  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