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   338篇
  免费   19篇
  国内免费   4篇
电工技术   9篇
化学工业   76篇
金属工艺   15篇
机械仪表   18篇
建筑科学   8篇
能源动力   13篇
轻工业   22篇
水利工程   2篇
石油天然气   2篇
无线电   41篇
一般工业技术   42篇
冶金工业   55篇
原子能技术   4篇
自动化技术   54篇
  2024年   4篇
  2023年   7篇
  2022年   23篇
  2021年   12篇
  2020年   16篇
  2019年   15篇
  2018年   22篇
  2017年   29篇
  2016年   18篇
  2015年   12篇
  2014年   14篇
  2013年   30篇
  2012年   21篇
  2011年   14篇
  2010年   9篇
  2009年   13篇
  2008年   12篇
  2007年   11篇
  2006年   4篇
  2005年   4篇
  2004年   4篇
  2003年   2篇
  2002年   9篇
  2000年   1篇
  1999年   3篇
  1998年   4篇
  1997年   3篇
  1996年   4篇
  1995年   3篇
  1994年   2篇
  1993年   1篇
  1992年   1篇
  1991年   1篇
  1986年   2篇
  1984年   3篇
  1983年   3篇
  1982年   6篇
  1981年   6篇
  1979年   1篇
  1977年   2篇
  1976年   5篇
  1975年   1篇
  1972年   1篇
  1966年   2篇
  1965年   1篇
排序方式: 共有361条查询结果,搜索用时 15 毫秒
231.
The nanocomposite of 50/50 acrylonitrile styrene acrylate/Zn-ionomer blend uses varying weight ratios (0.5–5.0%) of multiwalled carbon nanotubes. The morphological, thermal, thermomechanical, and creep behavior along with metal adhesion were evaluated. The phase-separated surface morphology of the blend formed non-uniform microscale nanotube dispersion and resulted in nanotube network formation at 1 wt%. Lowest creep compliance and increased complex modulus were found at 1 wt% nanotube loading. The presence of weather resistant acrylonitrile styrene acrylate and carbon nanotubes made the nanocomposite excellent weather resistant.  相似文献   
232.
233.
Knowledge and Information Systems - We propose a novel collaborative filtering method for top- $$n$$ recommendation task using bicustering neighborhood approach. Our method takes advantage of local...  相似文献   
234.
The choice of a solar radiation data source is expected to have a significant impact on the predicted performance of a concentrating solar power (CSP) system and consequently on its technical and financial feasibility. In the present study, an attempt has been made to analyse the effect of choice of various solar radiation data sources on the predicted performance of a CSP system at 13 different locations in 5 different climatic zones of India. It was observed that there is significant variation in the amount of annual electricity output obtained for various locations using different solar radiation data sources resulting in variations in levelised cost of electricity. For a 50-MW parabolic trough-based CSP plant located in Jaisalmer, the estimated value of annual electricity output varies from 63 to 124?GWh. For a CSP plant based on the central tower receiver technology, the corresponding range is from 106 to 145?GWh.  相似文献   
235.
236.
237.
238.
Trehalose has been used as an emollient and antioxidant in cosmetics. We aimed to explore trehalose amphiphiles as oil structuring agents for the preparation of gel-based lip balms as part of wax-free cosmetics. This article describes the synthesis of trehalose fatty acyl amphiphiles and their corresponding oleogel-based lip balms. Trehalose dialkanoates were synthesized by esterifying the two primary hydroxyls of trehalose with fatty acids (C4-C12) using a facile, regioselective lipase catalysis. The gelation potential of as-synthesized amphiphiles was evaluated in organic solvents and vegetable oils. Stable oleogels were subjected to X-ray diffraction (XRD), thermal (DSC), and rheological studies and further used for the preparation of lip balms. Trehalose dioctanoate (Tr8), trehalose didecanoate (Tr10) were found to be super gelators as their minimum gelation concentration is ≤0.2 wt%. XRD studies revealed their hexagonal columnar molecular packing while forming the fibrillar networks. Rheometry proved that the fatty acyl chain length of amphiphiles can influence the strength and flow properties of oleogels. Further rheometry (at 25, 37, and 50 °C) and DSC studies have validated that Tr8- and Tr10-based oleogels are stable for commercial applications. Tr8- and Tr10-based olive oil oleogels were used for the preparation of lip balms. The preliminary results suggested that the cumulative effect of trehalose's emolliency and vegetable oil gelling nature can be achieved with trehalose amphiphiles, specifically, Tr8 and Tr10. This study has also demonstrated that Tr8- and Tr10-based lip balms can be used as an alternative to beeswax and plant wax lip balms, indicating their huge potential to succeed as a new paradigm to formulate wax-free cosmetics.  相似文献   
239.
Biswas C  Güneş F  Duong DL  Lim SC  Jeong MS  Pribat D  Lee YH 《Nano letters》2011,11(11):4682-4687
Persistent photoconductance, a prolonged light-induced conducting behavior that lasts several hundred seconds, has been observed in semiconductors. Here we report persistent negative photoconductance and consecutive prominent persistent positive photoconductance in graphene. Unusually large yields of negative PC (34%) and positive PC (1652%) and remarkably long negative transient response time (several hours) were observed. Such high yields were reduced in multilayer graphene and were quenched under vacuum conditions. Two-dimensional metallic graphene strongly interacts with environment and/or substrate, causing this phenomenon, which is markedly different from that in three-dimensional semiconductors and nanoparticles.  相似文献   
240.
A library of imidazopyridine–oxindole conjugates was synthesised and investigated for anticancer activity against various human cancer cell lines. Some of the tested compounds, such as 10 a , 10 e , 10 f , and 10 k , exhibited promising antiproliferative activity with GI50 values ranging from 0.17 to 9.31 μM . Flow cytometric analysis showed that MCF‐7 cells treated by these compounds arrested in the G2/M phase of the cell cycle in a concentration‐dependent manner. More particularly, compound 10 f displayed a remarkable inhibitory effect on tubulin polymerisation. All the compounds depolarised mitochondrial membrane potential and caused apoptosis. These results are further supported by the decreased phosphorylation of Akt at Ser473. Studies on embryonic development revealed that the lead compounds 10 f and 10 k caused delay in the development of zebra fish embryos. Docking of compound 10 f with tubulin protein suggested that the imidazo[1,2‐a]pyridine moiety occupies the colchicine binding site of tubulin.  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