全文获取类型
收费全文 | 490篇 |
免费 | 7篇 |
专业分类
化学 | 305篇 |
晶体学 | 6篇 |
力学 | 8篇 |
数学 | 22篇 |
物理学 | 156篇 |
出版年
2023年 | 4篇 |
2021年 | 8篇 |
2019年 | 1篇 |
2018年 | 4篇 |
2017年 | 1篇 |
2016年 | 6篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 9篇 |
2012年 | 21篇 |
2011年 | 14篇 |
2010年 | 17篇 |
2009年 | 11篇 |
2008年 | 17篇 |
2007年 | 35篇 |
2006年 | 26篇 |
2005年 | 25篇 |
2004年 | 21篇 |
2003年 | 15篇 |
2002年 | 25篇 |
2001年 | 12篇 |
2000年 | 25篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 11篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 23篇 |
1992年 | 11篇 |
1991年 | 17篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 4篇 |
1973年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有497条查询结果,搜索用时 0 毫秒
31.
32.
33.
B.?SzafranEmail author S.?Bednarek J.?Adamowski M.?B.?Tavernier E.?Anisimovas F.?M.?Peeters 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2004,28(3):373-380
Few-electron systems confined in two-dimensional parabolic quantum dots at high magnetic fields are studied by the Hartree-Fock (HF) and exact diagonalization methods. A generalized multicenter Gaussian basis is proposed in the HF method. A comparison of the HF and exact results allows us to discuss the relevance of the symmetry of the charge density distribution for the accuracy of the HF method. It is shown that the energy estimates obtained with the broken-symmetry HF wave functions become exact in the infinite magnetic-field limit. In this limit the charge density of the broken-symmetry solution can be identified with the classical charge distribution.Received: 24 October 2003, Published online: 6 January 2004PACS:
73.20.Qt Electron solids - 73.21.-b Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems 相似文献
34.
In a single condensation step, a poly-ureidophthalimide is synthesized, which folds into a chiral, helical architecture according to circular dichroism spectroscopy. 相似文献
35.
Optimized design of the optical filters inside integrated color pixels (ICPs) for complementary metal-oxide semiconductor image sensors requires analytical models. ICP optical filters consist of subwavelength patterned metal layers. We show that a one-mode model, in which subwavelength gaps in the metal layer are described in terms of single-mode waveguides, suffices to predict the salient features of measured ICP wavelength selectivity. The Airy-like transmittance formula, derived for transverse-electric polarization, predicts an angle-independent cutoff wavelength, which is in good agreement with predictions made with a two-dimensional finite-difference time-domain method. 相似文献
36.
Lagoja IM Pochet S Boudou V Little R Lescrinier E Rozenski J Herdewijn P 《The Journal of organic chemistry》2003,68(5):1867-1871
The synthesis of fully [13C/15N] labeled pyrimidine nucleosides has been achieved from 13C-glucose and labeled nucleobases. The reaction scheme leads directly to the protected nucleosides without the need for the inversion of configuration of C-3 of 13C-glucose. This was achieved by an oxitative ring-opening reaction removing the carbon with the wrong configuration. 相似文献
37.
De Proft F Vivas-Reyes R Peeters A Van Alsenoy C Geerlings P 《Journal of computational chemistry》2003,24(4):463-470
Atomic dipole moments, derived within the Hirshfeld partitioning of the molecular electron density, have been studied for compounds of the type H-X and Cl-X, for a series of functional groups X frequently encountered in organic molecules. In the case of the H-X compounds, the component of the atomic dipole moment on H along the axis connecting H with the central atom in X is found to be linearly correlated with the electronegativity of X, the hardness of X playing no significant role. In the case of the Cl-X compounds, the situation is less clear. However, evidence seems to point to the conclusion that for these compounds, also the group hardness plays an important role. 相似文献
38.
The properties of a capacitive HF discharge with growing nanoparticles are studied with the use of kinetic PIC-MCC simulation.
At the initial stage of growth, the nanoparticles are shown to be localized at the interface between the near-electrode layer
and quasi-neutral plasma, where the rate of ionization by electron impact has the maximum value. At the beginning of formation
of particles, plasma parameters change rapidly and a transition between the capacitive and spatial discharge burning modes
is observed for a certain critical size of the particles. If the growth of the dust particles continues, their distribution
over the discharge becomes more uniform and the steady-state parameters of the gas-discharge plasma hardly change.
Original Russian Text ? I.V. Shveigert, F.M. Peeters, 2007, published in Pis’ma v Zhurnal éksperimental’noĭ i Teoreticheskoĭ
Fiziki, 2007, Vol. 86, No. 9, pp. 657–661. 相似文献
39.
Bram Neirinck Lieve Van Mellaert Jan Fransaer Omer Van der Biest Jozef Ann Jef Vleugels 《Electrochemistry communications》2009,11(9):1842-1845
The possibility to use alternating current electrophoretic deposition (AC-EPD) to deposit living cells in the form of Staphylococcus aureus and Escherichia coli on stainless steel was assessed. The experimental results revealed that these bacteria can be successfully deposited on metallic surfaces from demineralized water and sucrose based solutions using asymmetric unbalanced electric fields. Cell viability of the deposited bacteria was influenced by the strain and deposition medium. 相似文献
40.
The incompressible, two-dimensional Navier-Stokes equations are solved by the finite element method (FEM) using a novel stream function/vorticity formulation. The no-slip solid walls boundary condition is applied by taking advantage of the simple implementation of natural boundary conditions in the FEM, eliminating the need for an iterative evaluation of wall vorticity formulae. In addition, with the proper choice of elements, a stable scheme is constructed allowing convergence to be achieved for all Reynolds numbers, from creeping to inviscid flow, without the traditional need for upwinding and its associated false diffusion. Solutions are presented for a variety of geometries. 相似文献