全文获取类型
收费全文 | 233篇 |
免费 | 3篇 |
专业分类
化学 | 176篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 11篇 |
物理学 | 47篇 |
出版年
2023年 | 1篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 2篇 |
2013年 | 12篇 |
2012年 | 9篇 |
2011年 | 13篇 |
2010年 | 6篇 |
2009年 | 4篇 |
2008年 | 15篇 |
2007年 | 16篇 |
2006年 | 18篇 |
2005年 | 15篇 |
2004年 | 9篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1985年 | 4篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1967年 | 1篇 |
1961年 | 1篇 |
排序方式: 共有236条查询结果,搜索用时 375 毫秒
131.
The variational principle of Glansdorff and Prigogine is formulated for stochastic processes and the relation between this method and the rate equation method is discussed in a certain frame-work of variational functions. An application is given to the Fokker-Planck equation to describe the formation process of macroscopic order and to obtain the onset time. 相似文献
132.
Numerical studies are performed on a model for high dimensional hamiltonian systems to investigate the Arnold diffusion. We present estimates of the diffusion rate as a function of coupling, the structure of a stochastic layer, calculations of Lyapunov exponents, and some characteristics aspects of a stochastic orbit. 相似文献
133.
Yamada M Suzuki T Kanaori K Tajima K Sakamoto S Kodaki T Makino K 《Organic letters》2003,5(18):3173-3176
[reaction: see text] A gas mixture of NO and O(2) was bubbled into 2'-deoxyguanosine solution at neutral pH and 37 degrees C. A novel nitrated nucleoside was generated in the reaction mixture in addition to 8-nitroguanine, 8-nitroxanthine, 2'-deoxyxanthosine, xanthine, and guanine. The novel nucleoside was identified as N(2)-nitro-2'-deoxyguanosine by spectrometric data. 相似文献
134.
135.
136.
A coupled map lattice model with both local and global couplings is studied as a simple example of hierarchical pattern dynamics with different length scales of interactions. Several phases are classified according to domain structures, degree of chaotic dynamics, distribution function, and power spectra. In particular, a cascade process of formation and collapse of bubbles is found in some parameter regime. The state is characterized by spatiotemporal power-law correlation and few positive Lyapunov exponents. In a two-dimensional case, the state leads to a characteristic spatiotemporal pattern that may be regarded as a dynamic extension of a Turing pattern. The possible relevance to natural patterns is also discussed. (c) 2000 American Institute of Physics. 相似文献
137.
Nobuko Watanabe Kiriko Hiragaki Kunihiko Tsurumi Hisako K. Ijuin Masakatsu Matsumoto 《Tetrahedron》2017,73(14):1845-1853
Singlet-oxygenation of 3-hydroxyphenyl-substituted dihydrofurans fused with a cyclohexane 1a?c exclusively gave the corresponding syn/anti-stereoisomeric mixtures of dioxetanes 2a?c. The syn/anti-π-facial selectivity in the 1,2-cycloaddition of singlet oxygen (1O2) was found to be remarkably sensitive to the solvent as well as the reaction temperature. In fact, the solvent effect was so conspicuous that inversion of the syn/anti-π-facial selectivity was observed in different solvents, such as chloroform and toluene. An LSER (linear solvation energy relationships) analysis suggested that the Lewis-acidity/basicity and HBD (hydrogen-bond donor)/HBA (hydrogen-bond acceptor) ability as well as dipolarity/polarizability of the solvent played an important role in this change in syn/anti-π-facial selectivity. An investigation of the temperature-dependency of the singlet-oxygenation suggested that the syn/anti-π-facial-selective 1,2-cycloaddition of 1O2 to 1 was a conformationally-(entropy-) controlled process. 相似文献
138.
Dr. Kunihiko Okano Dr. Satoshi Aya Dr. Fumito Araoka Haruki Obara Shiori Sato Prof. Dr. Takashi Yamashita Prof. Dr. Hideo Takezoe Prof. Dr. Kouichi Asakura 《Chemphyschem》2015,16(1):95-98
A periodic stripe pattern is found in the nematic phase close to the smectic phase of photoresponsive achiral liquid‐crystalline compounds. The origin of the stripe patterns can be ascribed to an extremely large bent elastic constant K33. In addition, we succeeded in controlling the pattern by the following two methods: 1) the stripe disappears by a trans–cis photoisomerization upon UV light irradiation and reappears upon light termination, and 2) the stripe pattern is stabilized over the whole nematic phase, at approximately 10 °C, by polymerization of the compounds. 相似文献
139.
Tanaka-Takahashi Y Yasunami M Naruse T Hinohara K Matano T Mori K Miyazawa M Honda M Yasutomi Y Nagai Y Kimura A 《Electrophoresis》2007,28(6):918-924
The rhesus macaque exhibits individual differences in susceptibility and resistance to infectious agents such as simian immunodeficiency virus (SIV) under experimental conditions, and these may be genetically determined at least in part by major histocompatibility complex (MHC) class I polymorphism. Although the importance of defining MHC class I polymorphism is well recognized, development of a generic and comprehensive molecular typing method of MHC class I alleles of the rhesus macaque has been hampered because, during the evolution of this species, multiple copies of similar DNA sequences have been generated by duplication events including the coding sequences of Mamu-A and Mamu-B loci. We report here a newly developed reference strand-mediated conformation analysis (RSCA)-based typing method of multiple Mamu-A and Mamu-B cDNAs that allowed us to estimate the number of expressed alleles. This technique detected 1-7 Mamu-A signals and 2-12 Mamu-B signals in a single sample, indicating that the number of functional alleles may vary. By comparing the data from the parents with those from the descendants in the breeding colony, several MHC class I haplotypes consisting of variable numbers of functional Mamu-A and Mamu-B alleles could be assigned. 相似文献
140.
Satoh Y Satoh M Isobe K Mohri K Yoshida Y Fujimoto Y 《Chemical & pharmaceutical bulletin》2007,55(4):561-564
A new Panax acetylene, 3-oxo-PQ-1 (1), was isolated from Panax quinquefolium. The absolute configurations of 3-oxo-PQ-1 (1) and PQ-1 (2) were determined to be (9R,10R) and (3R,9R,10R), respectively, by synthesizing 1 and 2 starting from D-(-)-diethyl tartrate, and by synthesizing their stereoisomers from L-(+)-diethyl tartrate. The growth inhibitory effects of Panax acetylenes (1-8) and their stereoisomers against leukemia cells were tested. Unnatural acetylenes having the (3S)-configuration (2, 5, 6, 7, 8; IC(50)=0.01-0.1 microg/ml) were found to be approximately ten times more potent than natural acetylenes (IC(50)=0.1-1.0 microg/ml) with the (3R)-configuration. Potency differences due to the configuration at C-9 and C-10 were unrelated to this stereochemistry. The C(14)-polyacetylenes, PQ-8 (4) and its isomer (IC(50)=1.0-10.0 microg/ml), were found to exhibit weaker cytotoxicity than the C(17)-polyacetylenes. 相似文献