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   141724篇
  免费   15039篇
  国内免费   10263篇
电工技术   11596篇
技术理论   3篇
综合类   13632篇
化学工业   19107篇
金属工艺   9736篇
机械仪表   9820篇
建筑科学   10315篇
矿业工程   5091篇
能源动力   3744篇
轻工业   13062篇
水利工程   4424篇
石油天然气   6473篇
武器工业   1875篇
无线电   15629篇
一般工业技术   13751篇
冶金工业   5962篇
原子能技术   2104篇
自动化技术   20702篇
  2024年   595篇
  2023年   2275篇
  2022年   4897篇
  2021年   6536篇
  2020年   4785篇
  2019年   3585篇
  2018年   3919篇
  2017年   4314篇
  2016年   3833篇
  2015年   5870篇
  2014年   7475篇
  2013年   8830篇
  2012年   10608篇
  2011年   11635篇
  2010年   10755篇
  2009年   10219篇
  2008年   10187篇
  2007年   10061篇
  2006年   9217篇
  2005年   7583篇
  2004年   5609篇
  2003年   3967篇
  2002年   3820篇
  2001年   3355篇
  2000年   2890篇
  1999年   2138篇
  1998年   1504篇
  1997年   1283篇
  1996年   1114篇
  1995年   914篇
  1994年   754篇
  1993年   575篇
  1992年   468篇
  1991年   311篇
  1990年   257篇
  1989年   216篇
  1988年   145篇
  1987年   105篇
  1986年   80篇
  1985年   55篇
  1984年   43篇
  1983年   38篇
  1982年   31篇
  1981年   30篇
  1980年   38篇
  1979年   21篇
  1977年   12篇
  1976年   24篇
  1959年   15篇
  1951年   16篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
张鹏  丰梦  陈伟  杨鑫  周洁  胡东林 《变压器》2021,58(9):58-62
本文中作者研究了温度对油浸式变压器绝缘纸老化水平的影响,开展了频域介电谱测试得出不同的试验温度下绝缘纸的电导率频域谱.推导了温度、电导率和相对介电常数之间的作用情况,并进行实例验证.  相似文献   
2.
3.
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   
4.
5.
Ceramic microparticles have great potentials in various fields such as materials engineering, biotechnology, microelectromechanical systems, etc. Morphology of the microparticle performs an important role on their application. To date, it remains difficult to find an effective and controllable way for fabricating nonspherical ceramic microparticles with 3D features. This work demonstrates a method that combines UV light lithography and single emulsion opaque-droplet-templated microfluidic molding to prepare the crescent-shaped ceramic microparticles. By tailoring the intensity of UV light and flow rate of fluid, the shapes of microparticles are accordingly tuned. Therefore, varieties of crescent-shaped microparticles and their variations have been fabricated. After sintering, the crescent-shaped alumina ceramic microparticles were obtained. Benefitting from the light absorption and scattering behavior of most ceramic nanoparticles, this system can serve as a general platform to produce crescent-shaped microparticles made from different materials, and hold great potentials for applications in microrobotics, structural materials in MEMS, and biotechnology.  相似文献   
6.
7.
8.
9.
10.
To investigate the effect of cooking temperature (55, 65, 75, 85 and 95 °C) on texture and flavour binding of braised sauce porcine skin (BSPS), sensory acceptance, microstructure and flavour-binding capacity were investigated during the processing of BSPS. Samples cooked at 85 and 95 °C showed better texture and aroma scores. Hardness and chewiness of BSPS were obviously improved at 85 and 95 °C than control group. Collagen structure was significantly destroyed over 85 °C. The porcine skin collagen heated at 85 and 95 °C showed relatively higher flavour-binding capacity than other samples. The improvement of texture of BSPS was mainly attributed to the degradation of collagen. Higher aroma scores of BSPS were related to intense binding abilities with aroma compounds at 85 and 95 °C. Cooking at 85 or 95 °C could be an optimal cooking temperature for BSPS.  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