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   281篇
  免费   16篇
  国内免费   2篇
电工技术   3篇
综合类   1篇
化学工业   57篇
金属工艺   3篇
机械仪表   3篇
建筑科学   17篇
矿业工程   6篇
能源动力   19篇
轻工业   72篇
水利工程   1篇
无线电   10篇
一般工业技术   42篇
冶金工业   21篇
原子能技术   4篇
自动化技术   40篇
  2023年   2篇
  2022年   2篇
  2021年   6篇
  2020年   5篇
  2019年   1篇
  2018年   5篇
  2017年   5篇
  2016年   10篇
  2015年   6篇
  2014年   13篇
  2013年   23篇
  2012年   19篇
  2011年   22篇
  2010年   11篇
  2009年   18篇
  2008年   13篇
  2007年   27篇
  2006年   11篇
  2005年   12篇
  2004年   5篇
  2003年   10篇
  2002年   5篇
  2001年   5篇
  2000年   5篇
  1999年   5篇
  1998年   4篇
  1997年   9篇
  1996年   1篇
  1995年   9篇
  1994年   4篇
  1993年   6篇
  1992年   1篇
  1991年   2篇
  1990年   3篇
  1989年   3篇
  1988年   1篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1983年   2篇
  1976年   1篇
  1975年   3篇
  1973年   1篇
排序方式: 共有299条查询结果,搜索用时 15 毫秒
21.
The influence of reducing and oxidizing buckwheat sourdoughs on the rheological, protein, and bread properties of buckwheat and brown rice flour was investigated. Batters and breads prepared with chemically acidified doughs, fresh pre-doughs, and fresh pre-doughs containing glutathione (3 mM) were used as controls. No significant differences were observed after the addition of reducing and oxidizing sourdoughs in all trials. Proteolysis was observed after proofing time in buckwheat and brown rice batters, respectively. Acidified doughs increased the elasticity and the gelatinization temperature of buckwheat batters. No notable microstructure changes were detected in brown rice batters. The extension of fermentation time in sourdough caused a slight decrease in bread volumes in all trials. Sourdoughs increased the bread volume and decreased the crumb hardness of buckwheat breads. In trials with brown rice flour, the addition of sourdough did not show relevant volume differences as compared to the controls, except big voids in sourdough bread crumb. Linear correlations between hardness, volume, and cells’ density were observed. However, no clear correlations among rheological parameters and bread characteristics could be detected. These results indicated that the applied strains were responsible for the leavening capacity of the yeast during the proofing time and for crumb structure in trials with buckwheat and brown rice flour. Applied sourdoughs were able to change the molecular, and bread properties of buckwheat and brown rice bread.  相似文献   
22.
In this study, old corrugated container recycled fibers were treated with polyelectrolyte multilayers consisting of biopolymer cationic starch with two degrees of substitution (DS) each in combination with one anionic starch. Pulp zeta potential, paper strength and the thin layer ellipsometry technique were applied to examine the influence of cationic starch DS on the formation of polyelectrolyte multilayers. The results indicated a significant interaction between the DS of cationic starch and the number of ionic starch layers formed. When low‐DS cationic starch was used, the pulp zeta potential and the paper strength increased significantly in assembling the first cationic layer. However, in depositing high‐DS cationic starch a greater zeta potential and a stronger influence on the paper strength were observed with a larger number of starch layers. This was confirmed by thin layer ellipsometry when a greater thickness of multilayers was achieved by employing high‐DS cationic starch to form a higher number of layers. © 2017 Society of Chemical Industry  相似文献   
23.
We investigate the localization of a camera subject to a planar motion with horizontal optical axis in the presence of known vertical landmarks. Under these assumptions, a calibrated camera can measure the distance to the viewed landmarks. We propose to replace the trilateration method by intersecting a pair of Chasles-Apollonius circles. In the case of square pixels but unknown focal length we introduce a new method to recover the camera position from one image with three vertical landmarks. To this end we consider virtual landmarks and Apollonius-like circles. We extend this method in order to deal with an unknown principal point by using four landmarks.  相似文献   
24.
25.
神经酰胺脂质体——含角质层脂质膜的脂质体   总被引:4,自引:0,他引:4  
角质层的渗透屏障大多是由饱和脂质如神经酰胺、胆固醇和游离脂肪酸组成。它是物质交换的有效阻隔并防止皮肤干燥。神经酰胺脂质体(Cerasomes)是一种脂质体,它的膜是由最重要的角质层脂质组成的。神经酰胺脂质体作为类皮肤膜的来源,它能加快受损屏障层的再生、降低皮肤刺激,并且它还提供了将角质层脂质应用于化妆品中简单而有效的途径。  相似文献   
26.
Multistandard channelisation for base stations is a big application of generalised discrete Fourier transform modulated filter banks (GDFT‐FBs) in digital communications. For technologies such as software‐defined radio and cognitive radio, nonuniform channelisers must be used if frequency bands are shared by different standards. However, GDFT‐FB‐based nonuniform channelisers can suffer from high filter orders when applied to wideband input signals. In this paper, various combinations of GDFT‐FB with the frequency response masking technique are proposed and evaluated for both uniform and nonuniform channelisation applications. Results show that the proposed techniques achieve savings in both the number of filter coefficients and the number of operations per input sample. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
27.
Methods to access natural‐product‐like macrocyclic peptides can disclose new opportunities for the exploration of this important structural class for chemical biology and drug discovery applications. Here, the scope and mechanism of a novel strategy for directing the biosynthesis of thioether‐bridged bicyclic peptides in bacterial cells was investigated. This method entails split intein‐catalyzed head‐to‐tail cyclization of a ribosomally produced precursor peptide, combined with inter‐side‐chain crosslinking through a genetically encoded cysteine‐reactive amino acid. This strategy could be successfully applied to achieve formation of structurally diverse bicyclic peptides with high efficiency and selectivity in Escherichia coli. Insights into the sequence of reactions underlying the peptide bicyclization process were gained from time‐course experiments. Finally, the potential utility of this methodology toward the discovery of macrocyclic peptides with enhanced functional properties was demonstrated through the isolation of a bicyclic peptide with sub‐micromolar affinity for streptavidin.  相似文献   
28.
In this paper, the focus is put on multi‐core branch‐and‐bound algorithms for solving large‐scale permutation‐based optimization problems. We investigate five work stealing (WS) strategies with a new data structure called integer–vector–matrix (IVM). In these strategies, each thread has a private IVM allowing the local management of a set of subproblems enumerated using a factorial system. The WS strategies differ in the way the victim thread is selected and the granularity of stolen work units (intervals of factoradics). To assess the efficiency of the private IVM‐based WS approach, the five WS strategies have been extensively experimented on the flowshop scheduling permutation problem and compared with their conventional linked‐list‐based counterparts. The obtained results demonstrate that the IVM‐based WS outperforms the linked‐list‐based one in terms of CPU time, memory usage and number of performed WS operations. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
29.
A complete and accurate model for the symmetric gas–solid turbulent round jet is accomplished using the Reynolds Averaged Navier–Stokes (RANS) equations. The two-fluid model was used to describe the averaged characteristics of the two phases, including the particle mass concentration, the turbulent kinetic energy and its dissipation in the mixture. Particle–turbulence interaction (turbulence modulation) is described by a two-way coupling model. The drag, lift and gravitation forces are incorporated into the system of equations using appropriate closure equations. A finite difference numerical scheme was used for the solution of the set of the governing equations and the results of the model were validated by comparison with data from several experiments. The influence of two types of particles, namely glass and electrocorundum, of different sizes and different loadings on the velocity and turbulence structure of the jet is examined. The computational results show the influence of the particulate phase on the velocity and turbulence structure of the jet.The significance of this study is that for the first time it presents explicitly the full RANS equations for a fluid jet with particles in an unabridged way and specifies the entire set of closure relations that are used for fluid–particle interactions including the equations for the extended kε model, the two-way particle–turbulence interactions and turbulence modulation as well as the inclusion of a lateral Saffman force.  相似文献   
30.
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