全文获取类型
收费全文 | 92篇 |
免费 | 0篇 |
专业分类
化学 | 57篇 |
数学 | 1篇 |
物理学 | 31篇 |
无线电 | 3篇 |
出版年
2016年 | 1篇 |
2015年 | 1篇 |
2013年 | 3篇 |
2012年 | 6篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1967年 | 3篇 |
排序方式: 共有92条查询结果,搜索用时 0 毫秒
71.
72.
73.
In this paper we present a density matrix formalism to treat one-photon ionization and multiphoton ionization of atoms and molecules in the presence of an external field. It is shown that Fano's results for one-photon ionization without an external field can easily be obtained from our formulation. For comparison, the Green's function method applied to multiphoton ionization of molecules is also presented. 相似文献
74.
B. L. Fain 《Mathematical Notes》1975,18(3):814-822
We consider the anisotropic spaces \(W\frac{{\bar l}}{p}(\Omega ),\bar l = \left( {l_1 ,l_2 \ldots ,l_n } \right),l_i > 0,\overline p = \left( {p_1 ,p_2 , \ldots ,p_n } \right),1< p_i< \infty ,i = 1,2, \ldots ,n\) . We extend the class of domains for which imbedding theorems for these spaces have the same form as for En. We investigate complete continuity of the corresponding imbedding operators. 相似文献
75.
76.
The 9,10–1,10-anthraquinoid tautomer was found to be characteristic of physcion and emodin and their analogs in solutions
using spectrophotometric, quantum-chemical, and correlation methods. Ionization of these compounds was accompanied by a shift
in tautomeric equilibrium. In alkaline solutions 1,10-anthraquinoid anions with a single α-hydroxy that were stabilized by
an intramolecular H-bond were formed. Tautomerism occurred in both the ground and excited states of the molecules.
__________
Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 411–415, September–October, 2005. 相似文献
77.
1,4,5,8-Tetrahydroxy-9,10-anthraquinone and its alkyl derivatives exist as equilibrium mixtures of prototropic tautomers and rotational isomers differing in the mode of intramolecular hydrogen bonding. Their electronic absorption spectra contain πl,π* bands corresponding to 9,10-, 1,10-, 1,4-, and (more rarely) 1,5-anthraquinoid structures. Introduction of substituents, solvation, ionization, and complex formation lead to displacement of tautomeric and conformational equilibria, which are responsible for the observed diversity of their absorption spectra. 相似文献
78.
The growth and sintering of Pd nanoparticles on alpha-Al(2)O(3)(0001) have been studied by noncontact atomic force microscopy (NC-AFM), low-energy ion scattering spectroscopy (LEIS), temperature-programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS). This is the first study of metal nanoparticles on a well-defined oxide surface where both NC-AFM and LEIS are used for characterization. These prove to be a powerful combination in assessing particle dimensions. The clean alumina surface showed atomically flat, 200-700 nm wide terraces. The sharp step edges are straight (within our resolution) for lengths of >300 nm and have heights in multiples of 0.2 nm. The Pd grows initially as two-dimensional (2D) islands at 300 K, with the transition to 3D particle growth at 0.25 ML (ML=monolayers). Upon heating at 1 K/s, the Pd starts to sinter below 400 K, and sinters at a nearly constant rate with increasing temperature, covering approximately 50% less of the alumina surface by approximately 1000 K, with a doubling in particle diameter and an eightfold decrease in particle number density. By approximately 1000 K, the number density was approximately 9 x 10(11)cm(2) for 0.8 ML of Pd, with an average diameter of 5 nm and an average thickness of 1 nm. 相似文献
79.
O'Halloran RL Holmes JH Altes TA Salerno M Fain SB 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2007,185(1):42-49
The theoretical dependence of the mean and standard deviation of ADC values on signal-to-noise ratio (SNR) was derived and compared to measured values in porous phantoms and the lungs of human subjects using diffusion-weighted hyperpolarized helium-3 MRI. For SNR values below 15, mean ADC values were highly SNR-dependent due to a combination of noise and choice of noise thresholding. Above SNR values of 15 and for mean ADC values within ranges relevant for evaluating lung disease (<0.6 cm2/s), the mean ADC was largely independent of SNR. The standard deviation, by contrast, was highly dependent on SNR over a much larger range, but this dependence was well predicted by theory, suggesting the histogram of ADC values might be corrected for these stochastic processes to more accurately evaluate disease using restricted diffusion measures in the lungs. 相似文献
80.