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   219篇
  免费   8篇
  国内免费   1篇
化学   127篇
力学   9篇
数学   24篇
物理学   68篇
  2024年   1篇
  2023年   3篇
  2022年   12篇
  2021年   16篇
  2020年   13篇
  2019年   13篇
  2018年   7篇
  2017年   1篇
  2016年   11篇
  2015年   9篇
  2014年   8篇
  2013年   8篇
  2012年   14篇
  2011年   7篇
  2010年   10篇
  2009年   8篇
  2008年   9篇
  2007年   17篇
  2006年   9篇
  2005年   11篇
  2004年   7篇
  2003年   5篇
  2002年   2篇
  2001年   3篇
  2000年   1篇
  1999年   2篇
  1998年   2篇
  1996年   1篇
  1994年   2篇
  1989年   1篇
  1985年   2篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1977年   2篇
  1976年   2篇
  1974年   1篇
  1945年   1篇
  1936年   1篇
排序方式: 共有228条查询结果,搜索用时 0 毫秒
21.
JPC – Journal of Planar Chromatography – Modern TLC - Thin-layer chromatography (TLC) of fifteen amino acids was performed using silica gel and alumina impregnated with micellar...  相似文献   
22.
Iron(III) hydroxide was precipitated from the homogeneous solutions, containing variuos amounts of iron(III) nitrate, potassium sulfate, and urea, by heating at 85 °C for different periods of time (5‐30 min). The precipitated solids were either in the form of gel or dispersed particles of different shapes and sizes, depending upon the composition of the reactant mixtures. The as‐prepared solids were amorphous in nature and were formulated as Fe(OH)3.H2O. On calcinations at 800 °C for 1 h, the latter converted into crystalline compound, composed of α‐Fe2O3 (hematite). The calcined particles retained the original features of their precursors to a maximum extent.  相似文献   
23.
Kim MS  Scharf T  Haq MT  Nakagawa W  Herzig HP 《Optics letters》2011,36(19):3930-3932
We report on the fabrication and characterization of nanoscale solid immersion lenses (nano-SILs) with sizes down to a subwavelength range. Submicrometer-scale cylinders fabricated by electron-beam lithography are thermally reflowed to form a spherical shape. Subsequent soft lithography leads to nano-SILs on transparent substrates for optical characterization. The optical characterization is performed using a high-resolution interference microscope with illumination at 642 nm wavelength. The focal spots produced by the nano-SILs show both spot-size reduction and enhanced optical intensity, which are consistent with the immersion effect.  相似文献   
24.
Much effort has been devoted to the design and synthesis of polymers for use in flat panel display, solid state lighting, transistors, and photovoltaic devices. Especially, development of white light emitting polymeric materials has recently attracted much interest owing to their possible use in lighting application and backlights for flat panel displays. White emission has been obtained from polymeric molecules, small organic molecules, organometallic molecules, and phosphor-based or quantum dot-based inorganic molecules. Among materials used in white light emitting diodes, we summarize the white light emitting polymeric materials synthesized and published till December 2007. Correspondence: In Tae Kim, Department of Chemistry, Kwangwoon University, 447-1 Wolgye-Dong, Nowon-Ku, Seoul 139-701, Korea, So Ha Lee, Life Sciences Research Division, Korea Institute of Science and Technology, P.O. Box 131, Cheongryang, Seoul 130-650, Korea.  相似文献   
25.
Aequationes mathematicae - In this paper the concept of symmetrized convex stochastic processes is introduced. Some characterizations involving Hermite–Hadamard type inequalities and a...  相似文献   
26.
27.
28.
Statistical spectroscopy methods are used to calculate level densities for one-body Hamiltonians in the space of 440 single particle states. Comparisons are made with combinatorial counting and Fermi gas model. Possibilities to arrive at a more realistic level density formula including two-body effects are discussed.  相似文献   
29.
This paper studies a meshfree technique for the numerical solution of the two-dimensional reaction–diffusion Brusselator system along with Dirichlet and Neumann boundary conditions. Combination of collocation method using the radial basis functions (RBFs) with first order accurate forward difference approximation is employed for obtaining meshfree solution of the problem. Different types of RBFs are used for this purpose. The method is shown to converge to the only equilibrium point of the system. Performance of the proposed method is successfully tested in terms of various error norms. In the case of non-availability of exact solution, performance of the new method is compared with the results obtained from the existing methods [7] and [8]. The elementary stability analysis is established theoretically and is also supported by numerical results.  相似文献   
30.
Transition Metal Chemistry - A series of bidendate 5,6-dimethyl benzimidazolium-based N-heterocyclic carbene (NHC) proligands and their silver complexes were synthesized. The synthetic approaches...  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