全文获取类型
收费全文 | 105篇 |
免费 | 0篇 |
专业分类
化学 | 60篇 |
物理学 | 45篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2018年 | 1篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 7篇 |
2010年 | 3篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 7篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有105条查询结果,搜索用时 78 毫秒
11.
Satoshi Kaneco Kensuke Hayashi Hideyuki Katsumata Tohru Suzuki 《International journal of environmental analytical chemistry》2013,93(13):1381-1388
A preconcentration method by adsorption of cadmium on a niobium wire was developed for the environmental waters, followed by electrothermal atomic absorption spectrometry with a tungsten tube atomizer. After the preconcentration, the niobium wire was directly inserted into the tungsten tube atomizer. In the preconcentration (adsorption) process of cadmium, the optimal immersing time was 60?s. The effects of large amounts of concomitants on the preconcentration of cadmium were evaluated. When 103–104 fold excess of matrix elements existed in aqueous solution at pH 4 and 9, the cadmium response was profoundly affected by the matrix elements. However, the cadmium absorption signal was not significantly influenced at pH 7. Therefore, pH 7 was selected for the application into the real environmental samples. Under the optimal conditions, the detection limit (3S/N) for cadmium by the niobium wire preconcentration method was 7.0?pg?mL?1 and the relative standard deviation was 6.8%. The method with preconcentration on a niobium wire was applied to the determination of cadmium in water and proved to be sensitive, simple and convenient. Because this preconcentration method can be utilized in the in situ treatment of trace cadmium in environmental water samples, it was unnecessary to carry the water samples to the analytical work place. The technique was shown to be useful for the determination of cadmium in environmental water samples at 0.1–1?µg?L?1 levels. 相似文献
12.
Electron spin resonance experiments at submillimeter and millimeter wavelengths have been performed on the random mixture, Rb2Mn(1-x)CrxCl4 of an insulating antiferromagnet Rb2MnCl4 and an insulating ferromagnet Rb2CrCl4. From the antiferromagnet resonance in the Mn-rich concentrations, the antiferromagnetic exchange field is shown to become small with Cr concentration. Thus, a competition between the antiferromagnetic and ferromagnetic exchange interactions really exists in this mixed system.A competition of the uniaxial anisotropy of Rb2MnCl4 with the planar one of Rb2CrCl4 has also been found. 相似文献
13.
Magnetic susceptibility and heat capacity measurements as a function of temperature on a single-crystal sample of a spin-ladder material, Na2Co2(C2O4)3(H2O)2, are reported. Principal susceptibilities, parallel and perpendicular to the ladder direction, respectively, show broad maxima around 22 and 17 K. Both susceptibilities decay exponentially down to about 5 K and thereafter they are essentially independent of temperature. These findings amount to a signature of a quantum phase transition from a spin-liquid to Néel ordered state previously predicted theoretically. No anomaly is found in the heat capacity around the transition temperature. 相似文献
14.
T. Katsumata H. Okada T. Kikuta T. Fukuda 《Applied Physics A: Materials Science & Processing》1987,42(2):103-109
The wavelength dependence and polarization characteristics of the infrared light scattered from an undoped GaAs crystal were investigated in the 90° angle infrared light scattering configuration. The scattering is Rayleigh scattering from scatterers which are always associated with the dislocations, and they are classified into three types,S, L
A
, andL
G
scatterers, according to their polarization characteristics. TheS, L
A
, andL
G
-scatterers are thought to be small As clusters, large As precipitates and large Ga precipitates, respectively. 相似文献
15.
Aoki M Konya Y Takagaki T Umemura K Sogame Y Katsumata T Komuro S 《Rapid communications in mass spectrometry : RCM》2011,25(13):1847-1852
Metabolomics follows the changes in concentrations of endogenous metabolites, which may reflect various disease states as well as systemic responses to environmental, therapeutic, or genetic interventions. In this study, we applied metabolomic approaches to monitor dynamic changes in plasma and urine metabolites, and compared these metabolite profiles in Eisai hyperbilirubinemic rats (EHBR, an animal model of cholestasis) with those in the parent strain of EHBR - Sprague-Dawley (SD) rats - in order to characterize cholestasis pathophysiologically. Ultra-performance liquid chromatography/tandem mass spectrometry-based analytical methods were used to assay metabolite levels. More than 250 metabolites were detected in both plasma and urine, and metabolite profiles of EHBR differed from those of SD rats. The levels of antioxidative and cytoprotective metabolites, taurine and hypotaurine, were markedly increased in urine of EHBR. The levels of many bile acids were also elevated in plasma and urine of EHBR, but the extent of elevation depended on the particular bile acid. The levels of cytoprotective ursodeoxycholic acid and its conjugates were markedly elevated, while that of cytotoxic chenodeoxycholic acid remained unchanged, suggesting the balance of bile acids had shifted resulting in decreased toxicity. In EHBR, reduced biliary excretion leads to increased systemic exposure to harmful compounds including some endogenous metabolites. Our metabolomic data suggest that mechanisms exist in EHBR that compensate for cholestasis-related damage. 相似文献
16.
Shunji Katsumata Katsumi Kimura 《Journal of Electron Spectroscopy and Related Phenomena》1975,6(4):309-319
He(I) photoelectron spectra are reported for various series of chlorine-substituted compounds: (a) CH3CH3?mClm, (b) CH3?mClmCCl3, (c) CH3?mClmCHO and (d) CH3?mClmCOCl, where m = 1, 2 and 3. In each series it is shown that the total sum of vertical ionization energies over all p-type localized molecular orbitals (LO's) has an excellent linear relationship to the number of substituted chlorine atoms. The differences in the total orbital energy sum by successive chlorine substitutions are found to be 26.7 eV for series a and b and 27.2 eV for series c and d, yielding the corresponding experimental σCCl, energies useful for sum rule considerations. The photoelectron spectra of the chloro compounds studied are interpreted with the help of the sum rule as well as CNDO/2 calculations. Orbital correlation diagrams have been constructed for these compounds. 相似文献
17.
Electron spin resonance experiments at millimeter and submillimeter wavelengths have been performed on the randomly mixed antiferromagnet with competing spin anisotropies, Fe(1?x)CoxBr2. Two antiferromagnetic resonance (AFMR) modes and extra resonances have been observed in the Co-rich concentration region. From the analysis of the AFMR, the anisotropy in the mixtures is shown to become small with concentration. This is a clear evidence for the competition of the anisotropies in these alloys. The extra modes are qualitatively explained as arising from a localized excitation of an Fe2+ spin. 相似文献
18.
An electron spin resonance experiment has been performed on the Cr-rich concentrations of the random mixture Rb2Mn(1-x)CrxCl4 of an insulating ferromagnet (Rb2CrCl4) and an insulating antiferromagnet (Rb2MnCl4). The resonance fields in x = 0.6, 0.7 and 0.8 samples begin to shift towards low field side at temperatures well above the Curie temperatures, when the external field is applied in the c-plane of the crystal. The shift of the resonance field with temperature of the x = 0.7 sample agreed well with that of the x = 0.8 sample, after scaling the temperature axis, while the shift in the x = 0.6 crystal did not. From this observation, we argue that the x = 0.7 and x = 0.8 samples have a long-range ordered ferromagnetic phase below Tc, and that the low temperature phase of the x = 0.6 sample is not a truely long-range ordered one. A weak resonance line was observed in the x = 0.8 sample below about 20 K. This resonance is discussed in connection with the re-entrant spin-glass behavior of this mixed system found in the ac susceptibility measurement. 相似文献
19.
S. Katsumata Y. Achiba K. Kimura 《Journal of Electron Spectroscopy and Related Phenomena》1979,17(4):229-236
The asymmetry parameter (β) of angular distribution of photoelectrons has been obtained with He(I) (58.4 nm) and He(II) (30.4 nm) resonance radiation for several simple compounds (N2, O2, H2O, CO2 and CS2), in order to examine how the β value depends on the excitation energy. It has been found that on going from He(I) to He(II) radiation the energy dependence of β for the nonbonding orbitals of triatomic molecules is similar to that obtained theoretically by Manson for the corresponding atomic p shells. For N2 it has also been found that there is essentially no difference in β values between two vibrational peaks (υ′= 0 and 1) of the first ionisation band in the He(II) spectrum, whereas in the He(I) spectrum an anomalous variation is observed in the β values between the two peaks as originally indicated by Carlson. These results support the interpretation of the autoionisation mechanism suggested by Mintz and Kuppermann. 相似文献
20.