全文获取类型
收费全文 | 93篇 |
免费 | 2篇 |
专业分类
化学 | 45篇 |
力学 | 1篇 |
数学 | 4篇 |
物理学 | 45篇 |
出版年
2021年 | 1篇 |
2019年 | 1篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2012年 | 1篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 1篇 |
2007年 | 7篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 1篇 |
1992年 | 7篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1938年 | 1篇 |
1935年 | 2篇 |
1934年 | 1篇 |
1931年 | 1篇 |
1929年 | 3篇 |
排序方式: 共有95条查询结果,搜索用时 15 毫秒
1.
Summary The kinetics of reduction of ruthenium(III) by sodium tetrahydroborate in aqueous acidic medium have been studied. The effect of variation in the concentration of substrate (RuCl3·3H2O), pH, and reductant (BH4
–1) has been studied. The activation parameters were evaluated. Based on a one-electron transfer, the mechanism involves the reduction of ruthenium(III) by hydrogen. 相似文献
2.
The proton transfer process mediated by water molecules adsorbed in an aluminosilicate framework has been studied using ab initio molecular dynamics simulations. This investigation has been carried out using a quasi-one-dimensional model simulating the mesoporous aluminosilicate channel structures. The effects of both the water loading and temperature of the system have been considered. At low coverage (one water molecule per acid site), the hydroxonium ion (H(3)O)(+) is found to be a transition state, in agreement with earlier studies on zeolites. At a higher water coverage (two water molecules per acid site), the (H(5)O(2))(+) species and the hydrogen bonded "neutral complex" structure are both found to be stable complexes at finite temperatures. The vibrational frequency spectrum is simulated by performing a Fourier transform of the velocity autocorrelation function (VAF), and the peak positions in the VAF are compared with IR measurements and zero-temperature calculations. 相似文献
3.
The kinetics of substitution of aqua ligands fromcis-[Ru(bipy)2(H2O)2]2+ ion by salicylhydroxamic acid (L) in aqueous medium has been studied spectrophotometrically at different temperatures (50–65°C).
The following rate law has been established in the pH range 4.0 to 5.8;
相似文献
4.
We use different determinantal Hartree-Fock (HF) wave functions to calculate true variational upper bounds for the ground
state energy of N spin-half fermions in volume V
0, with mass m, electric charge zero, and magnetic moment μ, interacting through magnetic dipole-dipole interaction. We find that at high
densities when the average interparticle distance r
0 becomes small compared to the magnetic length r
m ≡ 2mμ2/ħ2, a ferromagnetic state with spheroidal occupation function n
↑(), involving quadrupolar deformation, gives a lower upper bound compared to the variational energy for the uniform paramagnetic
state or for the state with dipolar deformation. This system is unstable towards infinite density collapse, but we show explicitly
that a suitable short-range repulsive (hard core) interaction of strength U
0 and range a can stop this collapse. The existence of a stable equilibrium high density ferromagnetic state with spheroidal occupation
function is possible as long as the ratio of coupling constants Γcm ≡ (U
0
a
3/μ2) is not very small compared to 1.
相似文献
5.
Gabriella Kervefors Kumar Bhaskar Pal Gergely L. Tolnai Mukul Mahanti Hakon Leffler Ulf J. Nilsson Berit Olofsson 《Helvetica chimica acta》2021,104(2):e2000220
β-Galactose derivatives have recently been reported to selectively inhibit galectin-3, and a library of O3-arylated galactosides with varying substitution patterns was designed to study such inhibitions further. The O3-arylated galactosides were synthesized using diaryliodonium salts under mild and transition metal free conditions, providing the target products in moderate to good yields. An O3-trifluoroethylated galactoside was also synthesized using iodonium salt chemistry. Azido-substituted products were subsequently transformed into the corresponding triazoles. After deprotection, a selection of galactoside derivatives were evaluated for inhibitory potencies against galectins-1, 3, 4 N (N-terminal domain), 4 C (C-terminal domain), 7, 8 N, 8 C, 9 N, and 9 C and one compound with promising affinity and selectivity for both the N- and C-terminal domain of galectin-9 was discovered. 相似文献
6.
7.
8.
Summary The kinetics of reduction of vanadium(V) ions by NaBH4 in aqueous acidic medium have been studied. The rate of the reaction depends upon the first powers of the concentrations of the reactants. The activation parameters were evaluated. Evidence is presented for the formation of vanadium(IV) as the reduction product. A plausible mechanism for the reduction reaction is suggested. 相似文献
9.
N. Pathak G. K. Mahanti T. K. Sinha Mahapatra 《International Journal of Infrared and Millimeter Waves》2007,28(11):953-960
In this paper, we present a new method based on real-coded Genetic Algorithm (GA) with elitist model for optimal design of
a reconfigurable symmetrical dual-beam uniformly spaced linear isotropic antenna array with phase-only control of quantized
phase shifters. The problem is to find a common amplitude distribution that will generate a pencil beam with zero phases and
a flat-top beam with discrete phases of a six-bit discrete phase shifter, without or with pre-fixing the value of dynamic
range ratio (|I
max/I
min|) of excitation current amplitude distribution equal to or less than five. 相似文献
10.
|