全文获取类型
收费全文 | 567篇 |
免费 | 7篇 |
国内免费 | 4篇 |
专业分类
化学 | 414篇 |
晶体学 | 2篇 |
力学 | 19篇 |
数学 | 40篇 |
物理学 | 103篇 |
出版年
2022年 | 7篇 |
2021年 | 6篇 |
2020年 | 9篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 3篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 15篇 |
2013年 | 27篇 |
2012年 | 32篇 |
2011年 | 29篇 |
2010年 | 18篇 |
2009年 | 17篇 |
2008年 | 27篇 |
2007年 | 28篇 |
2006年 | 24篇 |
2005年 | 34篇 |
2004年 | 33篇 |
2003年 | 36篇 |
2002年 | 38篇 |
2001年 | 13篇 |
2000年 | 13篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 10篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 1篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有578条查询结果,搜索用时 31 毫秒
71.
Approximate inertial manifolds for reaction-diffusion equations in high space dimension 总被引:4,自引:0,他引:4
Martine Marion 《Journal of Dynamics and Differential Equations》1989,1(3):245-267
The concept of approximate inertial manifolds was introduced by Foiaset al. (1987) in the case of the two-dimensional Navier-Stokes equations. These manifolds are finite dimensional smooth manifolds such that the orbits enter a very thin neighborhood of the manifold after a transient time; this concept replaces the one of inertial manifold when either an inertial manifold does not exist or its existence is not known. Our aim in this paper is to prove that approximate inertial manifolds exist for reaction-diffusion equations in high space dimension by opposition with exact inertial manifolds whose existence has only been proved in low dimension and for which nonexistence results have been obtained in space dimensionn=4. 相似文献
72.
We examine in this paper some properties of Morita and Prüfer hulls of FCP and FIP extensions of rings. Dichotomy phenomena appear in the case of a quasi-local base ring. In the general case, we define relative supports that allow us to introduce the concept of direct factorization of an extension and to characterize these hulls. 相似文献
73.
A new concept of photoresponsive composites has been elaborated by intimately connecting a Photochromic Phase (PP), (H(2)DABCO)(2)(HDMA)(0.5)Na(0.75)(H(3)O)(0.75)[Mo(8)O(27)]·3H(2)O (1), with a second hybrid organic-inorganic molybdate material, (H(2)DABCO)(HDABCO)[Fe(OH)(6)Mo(6)O(18)]·4H(2)O (2) acting as an Oxidation Catalytic Phase (OCP) toward the former once photoexcited. The association of both the PP and the OCP in the composite drastically improves the bleaching process of the PP alone because of efficient electronic transfers through the OCP-PP interface without affecting significantly its photoinduced color change characteristic. Two OCP-PP composites with different PP weight percents have been obtained by associating 1 with 2. The optical properties of these composites before and after UV irradiation have been investigated by Diffuse Reflectance Spectroscopy, and the strong impact of the OCP on the fading kinetics of the PP has been clearly highlighted. 相似文献
74.
75.
B. Fornal F. Gramegna W. Meczynski G. Prete R. A. Ricci G. Viesti G. D'Erasmo L. Fiore G. Guarino A. Pantaleo I. Iori A. Moroni P. Blasi F. Lucarelli 《Zeitschrift für Physik A Hadrons and Nuclei》1987,328(2):227-232
The deep-inelastic reaction induced by 143 MeV32S on58Ni have been studied detecting projectile-like fragments (PLF) in coincidence withγ-rays in NaI(TI) scintillators. γ-ray multiplicity and anisotropy have been derived for Zplf=14, 15 as a function of energy loss and/or γ-energy. The information obtained are compared with a discrete γ-line study of the same reaction. The effect of the exit channel selection (ejectileZ, energy loss,E γ) on the γ-observables is discussed in connection with the evidence of a strong PLF γ-emission. 相似文献
76.
We introduce a new criterion, based on multipole dynamical correlations calculated within reptation quantum Monte Carlo, to discriminate between a melting versus freezing behavior in quantum clusters. This criterion is applied to small clusters of para-hydrogen molecules (both pristine and doped with a CO chromophore), for cluster sizes of around twelve molecules. This is a magic size at which para-hydrogen clusters display an icosahedral structure and a large stability. Despite the similar geometric structure of CO@(pH2)12 and (pH2)13, the first system has a rigid, crystalline, behavior; the second behaves more like a superfluid (or, possibly, a supersolid). 相似文献
77.
Duc Hanh Nguyen Frdric Hebrard Josep Duran Alfonso Polo Martine Urrutigoíty Philippe Kalck 《应用有机金属化学》2005,19(1):30-34
Three different kinds of representative monoterpenic alcohol are involved in the palladium‐catalysed cyclocarbonylation reaction. Lactone formation is shown to occur when cyclic ( 1 ), tertiary ( 3 ) and primary allylic alcohol ( 7 ) functions are reacted, in the presence of CO with [HPd(SnCl3)L2] as the active catalytic species. Good yields and selectivities can easily be reached for isopulegol ( 1 ), and dihydromyrcenol ( 3 ). However, more modest results are obtained for the functionalization of geraniol into the original lactone ( 9 ). This lactone can be largely favoured by using a basic chelating diphosphine ligand such as 1,4‐bis(diphenylphosphino)butane. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
78.
79.
Jean Devillers Martine Cornus Jean Roussel Jacques Navech Ramon Burgada 《Magnetic resonance in chemistry : MRC》1974,6(4):205-210
The influence of various factors (temperature, nature and concentration of solvent) or the utilisation of various physical methods (tickling or INDOR experiments, for example) are employed to analyse the PMR spectra of some 5-monosubstituted or 4,5-disubstituted 1,3,2-oxazaphospholane derivatives. 相似文献
80.
The position of the thermochemical surface oscillation (TCSO) model applied to the CO oxidation on supported Pt pellets is tentatively specified. 相似文献