全文获取类型
收费全文 | 660篇 |
免费 | 11篇 |
国内免费 | 4篇 |
专业分类
化学 | 433篇 |
晶体学 | 16篇 |
力学 | 3篇 |
数学 | 35篇 |
物理学 | 188篇 |
出版年
2023年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2016年 | 12篇 |
2015年 | 11篇 |
2014年 | 13篇 |
2013年 | 27篇 |
2012年 | 20篇 |
2011年 | 32篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 21篇 |
2007年 | 34篇 |
2006年 | 33篇 |
2005年 | 41篇 |
2004年 | 29篇 |
2003年 | 35篇 |
2002年 | 29篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 11篇 |
1998年 | 4篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 10篇 |
1984年 | 10篇 |
1983年 | 9篇 |
1982年 | 12篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1975年 | 8篇 |
1974年 | 7篇 |
1973年 | 11篇 |
1967年 | 4篇 |
排序方式: 共有675条查询结果,搜索用时 46 毫秒
1.
Katoh Katsumi Fukui Satomi Haba Ayane Higashi Eiko Saburi Tei Okada Ken 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7563-7571
Journal of Thermal Analysis and Calorimetry - Nitrocellulose (NC) is prone to spontaneous decomposition with exothermic heat release and thus is generally evaluated for stability during the storage... 相似文献
2.
3.
The self-restoration properties in VWP networks are investigated with optimization about spare wavelength by simulations. Rapid restoration can be achieved by selection of rerouting path with long delay and no delay-limitation for new routes. 相似文献
4.
We have investigated the spin-1 Ising model on the simple cubic lattice with bilinear, biquadratic interaction and anisotropic energy (BEG model). We have been specially interested in the case of antiferro biquadratic interaction, because the interaction will cause the competition with bilinear interaction and anisotropy. A two-sublattice ordering, so called the staggered quadrupole (SQ) phase, occurs as long as biquadratic interaction is negative large enough. We have obtained a full phase diagram in the whole interaction parameter space (for the positive bilinear interaction) by the Bethe approximation, and found several kinds of phase transitions, such as successive, re-entrant and double re-entrant transitions. These transitions are also confirmed by Monte Carlo simulations on simple cubic lattices. 相似文献
5.
6.
Katsumi Kubota 《Tetrahedron》2006,62(49):11397-11401
The first highly enantioselective silicon Lewis acid catalyst for an asymmetric organic transformation has been developed. The catalyst derives its activity from the strain induced in the silicon center by virtue of being constrained in a five-membered ring. A simple tridentate ligand has been developed and the derived chlorosilane complex catalyzes the Diels-Alder cycloaddition of methacrolein and cyclopentadiene with 94% ee. 相似文献
7.
Zhi-Hui Su Munehiro Okamoto Osamu Tominaga Katsumi Akita Noboru Kashiwai Y?ki Imura Tooru Ojika Yoshiyuki Nagahata Syozo Osawa 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(7):232-250
An approach to deduce the mechanism of stabilization of the hybrid-derived populations in the Ohomopterus ground beetles has been made by comparative studies on the phylogenetic trees of the mitochondrial and nuclear DNA. A phylogenetic tree based on the internal transcribed spacer (ITS) of nuclear ribosomal gene roughly reflects the relations of morphological species group, while mitochondrial NADH dehydrogenase subunit 5 (ND5) gene shows a considerable different topology on the tree; there exist several geographically-linked lineages, most of which consist of more than one species. These results suggest that the replacement of mitochondria has occurred widely in the Ohomopterus species. In most cases, hybridization is unidirectional, i.e., the species A (♂) hybridized with another species B (♀) and not vice versa, with accompanied replacement of mitochondria of A by those of B. The results also suggest that partial or complete occupation of the distribution territory by a hybrid-derived morphological species. The morphological appearance of the resultant hybrid-derivatives are recognized as that of the original species A. Emergence of a morphological new species from a hybrid-derived population has been exemplified. 相似文献
8.
9.
The 304 Å HeII photoelectron (PE) spectrum of a mixture of NO2 and N2O4 in the gaseous phase has been measured in the region up to 29 eV. By subtracting the HeII spectrum of NO2 from the mixed spectrum, the HeII spectrum due to N2O4 has been deduced, indicating that there are three new PE bands in the region 20—29 eV. Relative band intensities have also been obtained from the HeII of N2O4 below 16 eV, corrected for electron collecting efficiency. 相似文献
10.
Summary The solubility formula previously proposed was applied to the partition of halogens between water and some typical organic solvents, and the character of parameter in the formula was examined. The formula reproduces the experimental data of the solvent extraction of halogens reasonably. The ratio is controlled by the solute independently of the solvent. The ratio is unity for all solutes in the water-hydrocarbon system, and is 3
n–1 (n is periodic number) depending on the solute in the water-non-hydrocarbon system.
Lösungsmittelextraktion von Halogenen
Zusammenfassung Die früher vorgeschlagene Löslichkeitsformel wurde auf die Verteilung von Halogenen zwischen Wasser und einigen typischen organischen Lösungsmitteln angewendet und der Charakter des Parameters in der Formel untersucht. Die Formel gibt die experimentellen Werte der Halogenextraktion zufriedenstellend wieder. Das Verhältnis der -Werte wird vom Gelösten unabhängig vom Lösungsmittel bestimmt. Dieses Verhältnis ist im Wasser-Kohlenwasserstoff-System in allen Fällen gleich 1. Im System aus Wasser und Nicht-Kohlenwasserstoff hängt es vom Gelösten ab und beträgt 3 n–1 (n = Periodenzahl des Halogens).相似文献