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   1171篇
  免费   41篇
  国内免费   8篇
化学   757篇
晶体学   2篇
力学   34篇
数学   206篇
物理学   221篇
  2022年   12篇
  2021年   30篇
  2020年   20篇
  2019年   24篇
  2018年   19篇
  2017年   16篇
  2016年   47篇
  2015年   25篇
  2014年   23篇
  2013年   52篇
  2012年   58篇
  2011年   71篇
  2010年   51篇
  2009年   41篇
  2008年   52篇
  2007年   51篇
  2006年   48篇
  2005年   44篇
  2004年   36篇
  2003年   33篇
  2002年   29篇
  2001年   23篇
  2000年   17篇
  1999年   18篇
  1998年   20篇
  1997年   9篇
  1996年   14篇
  1995年   11篇
  1994年   8篇
  1993年   9篇
  1992年   10篇
  1991年   13篇
  1990年   10篇
  1988年   14篇
  1985年   10篇
  1983年   10篇
  1982年   8篇
  1981年   7篇
  1978年   9篇
  1976年   8篇
  1975年   6篇
  1973年   8篇
  1968年   6篇
  1963年   7篇
  1962年   29篇
  1961年   14篇
  1957年   7篇
  1956年   10篇
  1955年   11篇
  1954年   8篇
排序方式: 共有1220条查询结果,搜索用时 46 毫秒
1.
2.
We study the pointwise convergence problem for the inverse Fourier transform of piecewise smooth functions, i.e., whether SrD f (\bx) ? f (\bx)S_{\rho D} f (\bx) \to f (\bx) as r? ¥\rho \to \infty . r? ¥\rho \to \infty . Here for \bx,\bxi ? \Rn\bx,\bxi \in \Rn SrDf(\bmx)=\dsf1(2p)n/2\intlirD [^(f)](\bxi) e\dst iá\bmx,\bxi? d\bxi . S_{\rho D}f(\bm{x})=\dsf1{(2\pi)^{n/2}}\intli_{\rho D} \widehat{f}(\bxi) e^{\dst i\langle\bm{x},\bxi\rangle} d\bxi~. is the partial sum operator using a convex and open set DD containing the origin, and rD={ r\bxi:\bxi ? D }\rho D=\left\{ \rho \bxi:\bxi\in D \right\}.  相似文献   
3.
It is shown, that the category ℰ A (X) ofA-bundles over a topological spaceX is an additive pseudo-Abelian category for each Waelbroeck algebraA. This research was supported by Greek State Scholarship Foundation and Estonian Science Foundation grant 6205.  相似文献   
4.
This article describes a comprehensive literature review of liquid entrainment in horizontal pipes with vertical-up branches. Deficiencies in the available data and correlations were identified. The Air–water Test Loop for Advanced Thermal–hydraulic Studies (ATLATS) was constructed and entrainment onset and steady-state data were collected for a wide range of flow conditions. Using new insights gained from experimental testing, the authors developed a model for predicting the onset of entrainment and steady-state entrainment rate. Previously published correlations, along with the new model, are compared against all available data. The new model shows very good agreement with the onset data, but is not very good at predicting branch quality at high liquid flow rates.  相似文献   
5.
6.
In this paper, three new direct Mutually Orthogonal Latin Squares (MOLS) constructions are presented for 7 MOLS(24), 7 MOLS(75) and 8 MOLS(36); then using recursive methods, several new constructions for 7 and 8 MOLS are obtained. These reduce the largest value for which 7 MOLS are unknown from 780 to 570, and the largest odd value for which 8 MOLS are unknown from 1935 to 419. © 2003 Wiley Periodicals, Inc.  相似文献   
7.
Surface free energy of a solid surface gives a direct measure of intermolecular interactions at interfaces and has a strong influence on adsorption and adhesion behaviour. However few data are available for the surface free energies of electroless Ni–P based composition coatings. In this paper, the electroless Ni–P, Ni–P-surfactant, Ni–Cu–P, Ni–P–PTFE and Ni–Cu–P–PTFE composite coatings were prepared under various coating conditions. The chemical compositions, surface morphology and thickness of the coatings were measured using an energy dispersive X-ray microanalysis (EDX), a scanning electron microscope (SEM) and a digital micrometer respectively. The contact angles of water, diiodomethane and ethylene glycol on the coatings were measured automatically using dataphysics OCA-20 contact angle analyser. The surface free energy of the coatings and their components (e.g. dispersion, polar or acid/base portions) were calculated using various methods. The experimental results showed that the incorporation of surfactant or PTFE particles into Ni–P matrixes has a significant influence on the surface free energy of the coatings, while the incorporation of copper into Ni–P matrixes has no significant influence on the surface free energy of the coatings.  相似文献   
8.
We study embeddings of complex vector bundles, especially line bundles, in the complexification of the tangent bundle of a manifold. The aim is to understand implications of properties of interest in partial differential equations.

  相似文献   

9.
10.
Bounded representations of bornological algebras are considered. The left and right bornological radicals in bornological algebras are introduced. It is shown that the left (right) bornological radical of a bornological algebra A is equal to the intersection of all bornologically closed maximal regular left (respectively, right) ideals of A, and both these radicals of A and the Jacobson radical of A coincide if A is an advertive and simplicial bornological algebra (in particular, a bornological Q-algebra). Bibliography: 16 titles. Published in Zapiski Nauchnykh Seminarov POMI, Vol. 326, 2005, pp. 9–22.  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