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   80篇
  免费   3篇
化学   36篇
力学   4篇
数学   33篇
物理学   10篇
  2024年   1篇
  2023年   2篇
  2022年   3篇
  2021年   3篇
  2017年   3篇
  2016年   4篇
  2015年   2篇
  2014年   6篇
  2013年   6篇
  2012年   7篇
  2011年   4篇
  2010年   7篇
  2009年   5篇
  2008年   7篇
  2007年   5篇
  2006年   5篇
  2004年   3篇
  2003年   1篇
  2002年   1篇
  2001年   2篇
  1999年   1篇
  1998年   3篇
  1984年   1篇
  1982年   1篇
排序方式: 共有83条查询结果,搜索用时 250 毫秒
1.
Research on Chemical Intermediates - Innovative hybrid composites based on poly (4,4'-Diaminodiphenyl sulfone) (PDDS) and TiO2 nanoparticles have been synthesized. The samples have been...  相似文献   
2.
Journal of Thermal Analysis and Calorimetry - Through this paper, three-dimensional fluid flow and heat transfer of Al2O3 nanofluid within ventilated enclosures was taken into consideration....  相似文献   
3.
Clarithromycin is a very important macrolide antibiotic used to treat bacterial infections in human and veterinary medicine. This study reports the development and validation of cost-effective, simple, precise, accurate, and robust high-performance liquid chromatography (HPLC) for the determination of clarithromycin (CLA) in tablets. Reversed-phase chromatography was conducted using a standard column at 55°C with ultraviolet detection at 215 nm. A mobile phase consisting of acetonitrile –2-methyl-2-propanol –potassium phosphate buffer was used at a flow rate of 1.0 mL/min. The proposed method displayed good linearity, precision, accuracy, robustness, and specificity. The present HPLC was compared with capillary electrophoresis and bioassay methods and the results indicated that there was no significant difference between these methods. Moreover, the obtained results demonstrated the validity of the isocratic HPLC, which allows reliable quantitation of CLA in pharmaceutical samples. Thus, it can be used as a substitute alternative methodology for the routine quality control of this medicine, in situations where other methods are less accessible in the laboratory.  相似文献   
4.
5.
The Near Surface Mounted (NSM) technique has been used in recent years for the strengthening of reinforced concrete beams. It involves the insertion of strips or rods of polymers reinforced with carbon fiber (CFRP) in the groove made previously in the concrete cover of corresponding surfaces, filled with epoxy adhesive for fixation. In order to characterize the bond behavior of the laminate and rods to concrete, an experimental work of pullout-bending tests was carried out. The pullout force at the laminate and the slip at the free and loaded end were measured. The influences of the concrete strength, the strength of the bond, and bond length on the bonding behavior between the three materials concrete, epoxy adhesive and CFRP were analyzed.  相似文献   
6.
The purpose of this Note is the study of the structure and fluxional behavior of the complex [{Ru(CO)25C5H5)}3112:-CC)]+, using density functional methods. The molecular geometry of this complex will be optimized, the transition state (TS) of the fluxional process will be determined and the origin of the energy barrier will be analyzed.  相似文献   
7.
In this paper, we study fractional differential inclusions with Dirichlet boundary conditions. We prove the existence of a solution under both convexity and nonconvexity conditions on the multi-valued right-hand side. The proofs rely on nonlinear alternative Leray–Schauder type, Bressan–Colombo selection theorem and Covitz and Nadler’s fixed point theorem for multi-valued contractions. The compactness of the set solutions and relaxation results is also established. In the last section we consider the fractional boundary value problem with infinite delay.  相似文献   
8.
The temperature dependence of the electrical conductivity and thermoelectric power of liquid selenium with thallium and indium additives have been studied. Large variations appear in the electrical conductivity and thermoelectric power, where Tl and In additives favourp-type conduction.  相似文献   
9.
We classify three-dimensional Lorentz homogeneous spaces G/I having a compact manifold locally modeled on them. We prove a completeness result: any compact locally homogeneous Lorentz threefold M is isometric to a quotient of a Lorentz homogeneous space G/I by a discrete subgroup Γ of G acting properly and freely on G/I. Moreover, if I is noncompact, G/I is isometric to a Lie group L endowed with a left invariant Lorentz metric, where L is isomorphic to one of the following Lie groups:
R3, [(SL(2, R))\tilde], He is  or SOL.{\bf R}^3, \widetilde{SL(2, {\bf R})}, He\,is \,{\rm or}\, SOL.  相似文献   
10.
In this article, we investigate some classes of semilinear impulsive functional differential inclusions with infinite delay. It is assumed that the linear part is possibly neither densely defined nor it satisfies the Hille–Yosida condition on a Banach space, namely the extrapolated space. Our approach is based on the theory of extrapolation spaces combined with a recent Frigon nonlinear alternative for multivalued admissible contractions in Fréchet spaces.  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