全文获取类型
收费全文 | 137篇 |
免费 | 19篇 |
国内免费 | 20篇 |
专业分类
化学 | 94篇 |
晶体学 | 2篇 |
力学 | 1篇 |
数学 | 17篇 |
物理学 | 62篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 2篇 |
2019年 | 3篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 6篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 14篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 14篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 5篇 |
1979年 | 3篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 3篇 |
1973年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 125 毫秒
41.
Simon Doherty Julian G. Knight Adam L. Bell Shireen El-Menabawey Christopher M. Vogels Andreas Decken Stephen A. Westcott 《Tetrahedron: Asymmetry》2009,20(12):1437-1444
Rhodium complexes of (R)-Me-CATPHOS and (R)-(S)-JOSIPHOS form a complementary pair of catalysts for the highly efficient asymmetric hydrogenation of a selection of (E)- and (Z)-β-aryl-β-(enamido)phosphonates, respectively, in the majority of cases giving excellent yields and ee’s in excess of 99%; the highest to be reported for this class of substrate. 相似文献
42.
43.
The TDDFT method is first applied in a series of tetra-nuclear transition metal clusters studies for nonlinear optical properties. The results indicate that the charge transfer inside the metal core [MCu3X4] (M=W, Mo; X=S, O, Cl, Se, Br) makes contribution to the optical nonlinearity. It is possible to enhance the hyperpolarizability by substituting the ligands of the clusters. 相似文献
44.
Haiwen Zhang Jennifer E. Enman Maren L. Conrad Marcy J. Manning Courtney S. Turner Susan L. Wheaton Christopher M. Vogels Stephen A. Westcott Andreas Decken Felix J. Baerlocher 《Transition Metal Chemistry》2006,31(1):13-18
Pyridinecarboxaldimines (N–N′) derived from pyridin-2-ylcarboxaldehydes and unsaturated amines add to [PdCl2(coe)]2 (coe = cis-cyclooctene) to give complexes of the type PdCl2(N–N′) in moderate yields. The palladium complexes have been investigated as substrates for hydroboration reactions and as
antifungal agents against Aspergillus niger, A. flavus, Candida albicans, and Saccharomyces cerevisiae. 相似文献
45.
This paper considers the asymptotic distribution for the horizontal displacement of a random walk in a medium represented by a two-dimensional lattice, whose transitions are to nearest-neighbor sites, are symmetric in the horizontal and vertical directions, and depend on the column currently occupied. On either side of a change-point in the medium, the transition probabilities are assumed to obey an asymptotic density condition. The displacement, when suitably normalized, converges to a diffusion process of oscillating Brownian motion type. Various special cases are discussed. 相似文献
46.
Mark Westcott 《Journal of statistical physics》1982,27(1):75-82
This paper discusses the mean-square displacement for a random walk on a two-dimensional lattice, whose transitions to nearest-neighbor sites are symmetric in the horizontal and vertical directions and depend on the column currently occupied. Under a uniform density condition for the step probabilities it is shown that the horizontal mean-square displacement aftern steps is asymptotically proportional ton, and independent of the particular column configuration. The model generalizes that of Seshadri, Lindenberg, and Shuler and the arguments are essentially probabilistic. 相似文献
47.
48.
Probability Theory and Related Fields - 相似文献
49.
Hayes Paul G. Stringer Sylvie A. M. Vogels Christopher M. Westcott Stephen A. 《Transition Metal Chemistry》2001,26(3):261-266
Addition of alkenylamines and alkenylpyridines to trans-[PdCl2(coe)]2
(1) (coe = C8H14) afforded complexes of the type trans-PdCl2L2 (where L is a nitrogen-containing ligand). Coordination of the alkenylamine or alkenylpyridine groups occurred primarily through the nitrogen atom in all cases. Addition of aminopropylvinylether (apve = H2NCH2CH2CH2OCH=CH2) to (1) gave trans-PdCl2(thmo)2
(9) (thmo = tetrahydro-2-methyl-1,3-oxazine) via an intramolecular hydroamination. 相似文献
50.
The φ meson productions in Au+Au and/or Pb+Pb collisions at AGS, SPS,
RHIC, and LHC energies have been studied systematically with a hadron and
string cascade model LUCIAE. After considering the energy dependence of the
model parameter α in string fragmentation function and adjusting it
to the experimental data of charged multiplicity to a certain extent,
the model predictions for φ meson yield, rapidity, and
transverse mass distributions are compatible with the experimental data at
AGS, SPS and RHIC energies. A calculation for Pb+Pb collisions at LHC energy
is given as well. The obtained fractional variable in string fragmentation
function shows a saturation in energy dependence. It is discussed that the
saturation of fractional variable in string fragmentation function might be a
qualitative representation of the energy dependence of nuclear transparency. 相似文献