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   271篇
  免费   20篇
  国内免费   1篇
电工技术   4篇
化学工业   124篇
金属工艺   11篇
机械仪表   4篇
建筑科学   12篇
能源动力   6篇
轻工业   70篇
水利工程   1篇
石油天然气   1篇
无线电   1篇
一般工业技术   45篇
冶金工业   5篇
自动化技术   8篇
  2023年   2篇
  2022年   5篇
  2021年   11篇
  2020年   3篇
  2019年   3篇
  2018年   11篇
  2017年   4篇
  2016年   5篇
  2015年   8篇
  2014年   13篇
  2013年   10篇
  2012年   13篇
  2011年   18篇
  2010年   13篇
  2009年   20篇
  2008年   13篇
  2007年   9篇
  2006年   11篇
  2005年   13篇
  2004年   14篇
  2003年   12篇
  2002年   18篇
  2001年   6篇
  2000年   6篇
  1999年   9篇
  1998年   9篇
  1997年   6篇
  1996年   6篇
  1995年   1篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   3篇
  1990年   1篇
  1989年   2篇
  1987年   2篇
  1986年   1篇
  1983年   1篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1973年   1篇
排序方式: 共有292条查询结果,搜索用时 421 毫秒
81.
The article Nitrogen balance in paddy fields under flowing-irrigation condition, written by Makoto Saiki, Thi Phuong Mai Nguyen, Junko Shindo, Kei Nishida, was originally published Online First...  相似文献   
82.
This paper discusses the sorption of cellooligosaccharides to activated clay in concentrated sulfuric acid solution. Cellobiose was sorbed to the clay in 72% (w/w) sulfuric acid but not in water; the sorption of glucose was not observed in both solutions. Hydrolysate of filter paper cellulose after 72% sulfuric acid treatment was also sorbed to the clay, and the sorbed sugars were partly released by diluting the mixture. The sorbed sugars could also be recovered in the form of d-glucose after hot dilute acid treatment of the sugar-acid-clay suspension.  相似文献   
83.
Carbon oxidation with platinum supported catalysts   总被引:3,自引:0,他引:3  
The effect of the support oxide, Pt precursor and reactant gas composition on the catalysis of soot oxidation was investigated using carbon black as a model soot and simulated exhaust gases. The Pt precursors used were Pt(NH3)4(OH)2, H2PtCl6·6H2O, Pt(NH3)4(NO3)2, and Pt(NH3)4Cl2. The support metal oxides used were SiO2, Al2O3, and ZrO2. Pt/SiO2 prepared from Pt(NH3)4(OH)2 showed the highest carbon oxidation activity. It had much higher activity in the condition of N2+O2+H2O+NO+SO2 than without NO and SO2.  相似文献   
84.
In the previous quartz crystal microbalance measurements for 4He films adsorbed on porous gold, we have observed a competition between superfluidity and slippage: In low areal densities, the resonance frequency increases gradually below T S due to the slippage of solid layer, while at high areal densities the slippage disappears and the superfluid onset of liquid overlayer is observed at T C . In the crossover region, the slippage below T S is suddenly suppressed at T D , which is much lower than T C . In the present work, we introduced a small amount of 3He onto 4He films, and studied the competition as a function of 3He areal density ρ 3. As ρ 3 is increased, T C is monotonically lowered. In contrast, T D increases up to a certain value of ρ 3, and then turns over to decrease in parallel to T C .  相似文献   
85.
A super-hydrophobic film was successfully deposited on magnesium alloy AZ31 by the microwave plasma-enhanced chemical vapor deposition (MPECVD) process. The film surface showed a static water contact angle of more than 150°. The hydrophobicity and root mean square roughness of the film surface increased with an increase in deposition time. The anticorrosion resistance of the deposited film was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the super-hydrophobic film considerably improved the anticorrosion resistant performance of magnesium alloy AZ31. The anticorrosion mechanism of the super-hydrophobic film was also considered. Moreover, the chemical stability of the super-hydrophobic film in acidic, neutral, and alkaline aqueous solutions was investigated. The super-hydrophobic film showed high chemical stability in acidic and neutral aqueous solutions.  相似文献   
86.
87.
88.
The C-terminal catalytic domain of tobacco N-acetylglucosaminyltransferase I fused to maltose-binding protein was produced in Escherichia coli as a soluble form with significant activity. The protein was affinity-purified using amylose resin, and its enzymatic properties were investigated, including its divalent cation requirements, optimal temperature, optimal pH, and substrate specificity.  相似文献   
89.
90.
The relationship between the microstrucutural changes of L10-type ordered β′ phase and hardening behavior in as-solutionized dental Ag-Pd-Au-Cu alloys was investigated by changing the cooling rate and the solution treatment temperature. Additionally, the formation process of the β′ phase in as-solutionized Ag-Pd-Au-Cu alloy was attempted to clarify. The microstructural changes were observed by X-ray diffraction (XRD) method and transmission electron microscopy (TEM). The hardness was evaluated using a Vickers microhardness tester. The β′ phase is precipitated regardless of the cooling rate, after solution treatment at 1123 K. TEM dark field images show that the size of the β′ phase decreases and the number of β′ phase increases with an increase in the cooling rate. The Vickers hardness value increases with an increase in cooling rate. TEM dark field images show that the microstructure of β′ phase is similar when the solution treatment temperature increases from 1123 K to 1173 K. However, the Vickers hardness increases with an increase of solution treatment temperature. It is of great significance to reveal that the β′ phase precipitated in as-solutionized Ag-Pd-Au-Cu alloy is formed during cooling after high-temperature solution treatment and that the growth of the β′ phase is diffusion controlled.  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