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   168篇
  免费   9篇
  国内免费   5篇
化学工业   40篇
金属工艺   3篇
机械仪表   2篇
建筑科学   4篇
能源动力   13篇
轻工业   6篇
无线电   17篇
一般工业技术   38篇
冶金工业   3篇
原子能技术   6篇
自动化技术   50篇
  2023年   4篇
  2022年   11篇
  2021年   4篇
  2020年   7篇
  2019年   8篇
  2018年   17篇
  2017年   8篇
  2016年   11篇
  2015年   8篇
  2014年   11篇
  2013年   16篇
  2012年   10篇
  2011年   5篇
  2010年   4篇
  2009年   8篇
  2008年   10篇
  2007年   3篇
  2006年   2篇
  2005年   5篇
  2004年   3篇
  2003年   7篇
  2002年   2篇
  2001年   3篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1996年   2篇
  1995年   2篇
  1994年   3篇
  1992年   1篇
  1991年   2篇
  1980年   1篇
排序方式: 共有182条查询结果,搜索用时 0 毫秒
81.
Multimedia Tools and Applications - This paper introduces a new mesh segmentation approach into semantic parts, most closely resemble those made by humans, which is based on the pixel color of the...  相似文献   
82.
We introduce a nonlocal discrete regularization framework on weighted graphs of the arbitrary topologies for image and manifold processing. The approach considers the problem as a variational one, which consists of minimizing a weighted sum of two energy terms: a regularization one that uses a discrete weighted p-Dirichlet energy and an approximation one. This is the discrete analogue of recent continuous Euclidean nonlocal regularization functionals. The proposed formulation leads to a family of simple and fast nonlinear processing methods based on the weighted p-Laplace operator, parameterized by the degree p of regularity, the graph structure and the graph weight function. These discrete processing methods provide a graph-based version of recently proposed semi-local or nonlocal processing methods used in image and mesh processing, such as the bilateral filter, the TV digital filter or the nonlocal means filter. It works with equal ease on regular 2-D and 3-D images, manifolds or any data. We illustrate the abilities of the approach by applying it to various types of images, meshes, manifolds, and data represented as graphs.  相似文献   
83.
84.
Bio‐nanocomposite films based on polyvinyl alcohol/chitosan (PVA/CS) polymeric blend and cellulose nanocrystals (CNC) were prepared by casting a homogenous and stable aqueous mixture of the three components. CNC used as nanoreinforcing agents were extracted at the nanometric scale from sugarcane bagasse via sulfuric acid hydrolysis; then they were characterized and successfully dispersed into a PVA/CS (50/50, w/w) blend to produce PVA/CS–CNC bio‐nanocomposite films at different CNC contents (0.5, 2.5, 5 wt %). Viscosity measurement of the film‐forming solutions and structural and morphological characterizations of the solid films showed that the CNC are well dispersed into PVA/CS blend forming strong interfacial interactions that provide an enhanced load transfer between polymer chains and CNC, thus improving their properties. The obtained bio‐nanocomposite films are mechanically strong and exhibit improved thermal properties. The addition of 5 wt % CNC within a PVA/CS blend increased the Young's modulus by 105%, the tensile strength by 77%, and the toughness by 68%. Herein, the utilization of Moroccan sugarcane bagasse as raw material to produce high quality CNC has been explored. Additionally, the ability of the as‐isolated CNC to reinforce polymer blends was studied, resulting in the production of the aforementioned bio‐nanocomposite films with improved properties. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42004.  相似文献   
85.
Abstract

A new sorbent, the polyethylenimine methylenephosphonic acid (PEIMPA), was synthesized from commercially available polyethylenimine. After characterization by (1H, 13C, 31P) NMR, elementary analysis, UV/VIS and FTIR, the new ion exchange polymer PEIMPA has been investigated in liquid – solid extraction of a mixture of Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II), and Zn(II) cations from a mineral residue of zinc ore dissolved in nitric acid. The selectivity of this polymer was studied as a function of pH. PEIMPA can sorb much higher amounts of Fe ion than Cd, Co, Cu, Ni, Pb, and Zn ions. The recovery of Fe(III) is almost quantitative. Because of this remarkable affinity, the PEIMPA resin has the potential for application in several fields. Further studies of the polymer are in progress.  相似文献   
86.
Cationic lipids nowadays constitute a promising alternative to recombinant viruses for gene transfer. We have recently explored the transfection potential of a new class of lipids based upon the use of aminoglycosides as cationic polar headgroups. The encouraging results obtained with a first cholesterol derivative of kanamycin A prompted us to investigate this family of vectors further, by modulating the constituent structural units of the cationic lipid. For this study, we have investigated the transfection properties of a series of new derivatives based on a kanamycin A scaffold. The results primarily confirm that aminoglycoside-based lipids are efficient vectors for gene transfection both in vitro and in vivo (mouse airways). Furthermore, a combination of transfection and physicochemical data revealed that some modifications of the constitutive subunits of kanamycin A-based vectors were associated with substantial changes in their transfection properties.  相似文献   
87.
The importance of including an electromagnetic actuator as a moving boundary on the dissipative flows of weakly conducting fluids had led to many published facts. But, nothing is known on the generalized differential quadrature analysis of magnetohydrodynamics over a Riga plate with emphasis on the case of viscous dissipation and space-dependent heat source. After deriving the simplified boundary layer equation that models the transport phenomenon, appropriate variables were used to non-dimensionalize and parameterize the partial differential equations. Thereafter, the resulting set of ordinary differential equations was solved numerically by applying a powerful differential quadrature algorithm. Based on the outcome of the simulation, it can be concluded that the viscous frictional effect can be minimized at the Riga plate either by weakening the suction process or by heightening the magnetic parameter. Moreover, the Lorentz forces have a hastening effect on the fluid motion, in the case when those magnetic causes are directed in the same sense of the developed flow.  相似文献   
88.
Three different biochemical test systems were chosen based on their solubility to study the antioxidant activity of ginger extracts. Reducing power and DPPH. scavenging activity tests were considered to produce hydrophilic environments and the H2O2 test was considered as creating a lipophilic environment. The average yields were 10.23 ± 1.02% and 0.48 ± 0.19% for oleoresin and essential oil, respectively. The content of total phenols was 67.6 ± 1.08 mg GAE/g of dry extract. In terms of EC50, in hydrophilic environment standards, it showed the highest effects compared to ginger extracts, with oleoresin presenting more activity than essential oil. In contrast, except for quercetin, essential oil showed the best scavenging activity in inhibiting H2O2 compared to all other antioxidants. The present work demonstrated that, when using reducing power, DPPH· free radical scavenging and H2O2 scavenging assays, the same ginger extracts exhibit different antioxidant activities, which were affected not only by the extract itself but also by the chemical environment (hydrophilic/lipophilic).  相似文献   
89.
Pattern Analysis and Applications - This study proposes a new approach of $$H_{infty }$$ deconvolution filtering of 2D system described by Fornasini–Marchesini model and Tchebichef moments....  相似文献   
90.
Nuclear safety analysis remains of crucial importance for both the design and the operation of nuclear reactors. Safety analysis usually entails the simulation of several selected postulated accidents, which can be divided into two main categories, namely reactivity insertion accident (RIA) and loss of flow accident (LOFA). In this paper, thermal-hydraulic simulations of fast LOFA accident were carried out on the new core configuration of the material test research reactor NUR. For this purpose, the nuclear reactor analysis PARET code was used to determine the reactor performance by calculating the reactor power, the reactivity and the temperatures of different components (fuel, clad and coolant) as a function of time. It was observed that during the transient the maximum clad temperature remained well below the critical temperature limit of 110 °C, and the maximum coolant temperature did not exceed the onset of nucleate boiling point of 120 °C. It is concluded that the reactor can be operated at full power level with sufficient safety margins with regard to such kind of transients.  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