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   143篇
  免费   8篇
电工技术   5篇
化学工业   47篇
金属工艺   3篇
机械仪表   3篇
建筑科学   7篇
能源动力   3篇
轻工业   5篇
水利工程   1篇
无线电   11篇
一般工业技术   22篇
冶金工业   19篇
自动化技术   25篇
  2023年   3篇
  2022年   8篇
  2021年   2篇
  2020年   2篇
  2019年   2篇
  2018年   5篇
  2017年   7篇
  2016年   1篇
  2015年   3篇
  2014年   8篇
  2013年   14篇
  2012年   3篇
  2011年   7篇
  2010年   9篇
  2009年   9篇
  2008年   5篇
  2007年   4篇
  2006年   4篇
  2005年   3篇
  2004年   9篇
  2003年   3篇
  2002年   3篇
  2001年   2篇
  2000年   1篇
  1999年   2篇
  1998年   4篇
  1997年   2篇
  1996年   5篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1990年   2篇
  1989年   1篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   3篇
  1979年   2篇
  1973年   1篇
  1971年   2篇
  1968年   1篇
排序方式: 共有151条查询结果,搜索用时 359 毫秒
81.
This study was carried out to evaluate the influence of the lipase‐producing yeasts, present in the brine, on the quality of table olive oil. The oily fraction of olives processed microbiologically using the β‐glucosidase‐positive, lipase‐negative yeast Candida wickerhamii 1542 showed an excellent quality, such as the typical extra‐virgin olive oil. In contrast, the quality of the oily fraction of olives debittered microbiologically with the β‐glucosidase‐ and lipase‐producing yeast Williopsis californica 1639 worsened dramatically to such a point that the acidity of the oily fraction increased more than 90%. The microbiological analysis of brines showed that the lipase‐producing yeasts are part of the natural yeast population of the brine, and when their presence is high, it can damage significantly the quality of table olives. The lipase‐producing yeast W. californica 1639 in the brine showed the maximum lipolytic activity at pH 6, while the NaCl of the brine, at the maximum concentration of 12%, inhibited lipase activity by 70%. The concentration of the polyphenols present in the brine was not able to control the lipolytic activity of W. californica 1639 during the microbiological debittering process of table olives.  相似文献   
82.
The neutral titanium(III) complex Ti(BP)3 {BP = dihydrobis(pyrazol-1-yl)borate} was synthesized by reacting TiCl3(THF)2 with an excess of the potassium salt of the ligand in THF. The compound was isolated as a green solid and characterized by elemental analysis, NMR and IR spectroscopy, Mass spectrometry and magnetic and conductivity measurements. The molecular ion was detected in the Mass spectrum. 11B NMR data suggested a distortion from the ideal octahedral geometry caused by the d1 electronic configuration of the metal centre and this hypothesis was confirmed by means of DFT calculations.  相似文献   
83.
The hydrophobic or hydrophilic properties of solid catalysts often have a crucial influence on their properties in liquid-phase catalytic reactions. Several methods to measure liquid-phase adsorption on catalytic solids are compared, and special attention is given to the liquid chromatographic method. The experimental setup and the determination of adsorption constants are discussed. Finally, adsorption data measured via the chromatographic method are used to gain insight into liquid-phase catalytic reactions, particularly oxidations with Ti zeolites.  相似文献   
84.
A successful design of peptidomimetics must come to terms with χ-space control. The incorporation of χ-space constrained amino acids into bioactive peptides renders the χ(1) and χ(2) torsional angles of pharmacophore amino acids critical for activity and selectivity as with other relevant structural features of the template. This review describes histidine analogues characterized by replacement of native α and/or β-hydrogen atoms with alkyl substituents as well as analogues with α, β-didehydro unsaturation or C(α)-C(β) cyclopropane insertion (ACC derivatives). Attention is also dedicated to the relevant field of β-aminoacid chemistry by describing the synthesis of β(2)- and β(3)-models (β-hHis). Structural modifications leading to cyclic imino derivatives such as spinacine, aza-histidine and analogues with shortening or elongation of the native side chain (nor-histidine and homo-histidine, respectively) are also described. Examples of the use of the described analogues to replace native histidine in bioactive peptides are also given.  相似文献   
85.
In automated production processes grasping devices and methods play a crucial role in the handling of many parts, components and products. This keynote paper starts with a classification of grasping phases, describes how different principles are adopted at different scales in different applications and continues explaining different releasing strategies and principles. Then the paper classifies the numerous sensors used to monitor the effectiveness of grasping (part presence, exchanged force, stick-slip transitions, etc.). Later the grasping and releasing problems in different fields (from mechanical assembly to disassembly, from aerospace to food industry, from textile to logistics) are discussed. Finally, the most recent research is reviewed in order to introduce the new trends in grasping. They provide an outlook on the future of both grippers and robotic hands in automated production processes.  相似文献   
86.
In this paper we critically review and compare experimental methods, based on the Lundstrom model, to extract the channel backscattering ratio in nano MOSFETs. Basically two experimental methods are currently used, the most common of them is based on the measurement of the saturation drain current at different temperatures. We show that this method is affected by very poor assumptions and that the extracted backscattering ratio strongly underestimates its actual value posing particular attention to the backscattering actually extracted in nano devices. The second method is based on the direct measurement of the inversion charge by CV characteristics and gets closer to the physics of the backscattering model. We show, through measurements in high mobility p-germanium devices, how the temperature-based method gives the same result of the CV-based method once that its approximations are removed. Moreover we show that the CV-based method uses a number of approximations which are partially inconsistent with the model. In particular we show, with the aid of 2D quantum corrected device simulations, that the value of the barrier lowering obtained through the CV-based method is totally inconsistent with the barrier lowering used to correct the inversion charge and that the extracted saturation inversion charge is underestimated.  相似文献   
87.
Journal of Porous Materials - Carbon monoxide releasing molecule-2 (CORM-2) exhibited protection against cardiac hypoxia reoxygenation injury (H/R). However, its poor water solubility and short...  相似文献   
88.
89.
To gain insight into how the pressure drop in monolithic silica columns is determined by the microscopic details of the pore structure, a series of well-validated computational fluid dynamics simulations has been performed on a simplified model structure, the so-called tetrahedral skeleton column. From these simulations, a direct correlation between the pressure drop and two main structural properties (skeleton thickness and column porosity) of the monolithic skeleton could be established. The correlation shows good agreement with the experimental pressure-drop data available from the literature on silica monoliths, especially when a correction for the flow-through pore size heterogeneity is made. The established correlation also yields a much more accurate representation of the relation between the flow resistance and the bed porosity than does the Kozeny-Carman model, making it much better suited for porosity optimization calculations.  相似文献   
90.
Human-robot collaboration represents a significant evolutionary step in manufacturing. A crucial point is to establish a proper task assignment to combine robot productivity with human flexibility. In this regard, this paper proposes a genetic algorithm to approach the Assembly Line Balancing Problem (ALBP) in the case of human-robot collaborative work. The aim is the minimization of: i) the assembly line cost, evaluated according to the number of workers and equipment on the line, including collaborative robots, ii) the number of skilled workers on the line, iii) the energy load variance among workers, based on their energy expenditures and thus on their physical capabilities and on the level of collaboration with robots.  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