全文获取类型
收费全文 | 1876篇 |
免费 | 58篇 |
国内免费 | 8篇 |
专业分类
化学 | 1390篇 |
晶体学 | 24篇 |
力学 | 15篇 |
数学 | 117篇 |
物理学 | 396篇 |
出版年
2022年 | 12篇 |
2021年 | 13篇 |
2020年 | 20篇 |
2019年 | 18篇 |
2018年 | 20篇 |
2017年 | 10篇 |
2016年 | 42篇 |
2015年 | 42篇 |
2014年 | 41篇 |
2013年 | 62篇 |
2012年 | 83篇 |
2011年 | 99篇 |
2010年 | 63篇 |
2009年 | 48篇 |
2008年 | 97篇 |
2007年 | 110篇 |
2006年 | 96篇 |
2005年 | 97篇 |
2004年 | 107篇 |
2003年 | 87篇 |
2002年 | 87篇 |
2001年 | 50篇 |
2000年 | 43篇 |
1999年 | 19篇 |
1998年 | 26篇 |
1997年 | 14篇 |
1996年 | 25篇 |
1995年 | 26篇 |
1994年 | 25篇 |
1993年 | 21篇 |
1992年 | 19篇 |
1991年 | 28篇 |
1990年 | 26篇 |
1989年 | 21篇 |
1988年 | 18篇 |
1987年 | 11篇 |
1986年 | 26篇 |
1985年 | 22篇 |
1984年 | 26篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 22篇 |
1979年 | 15篇 |
1978年 | 16篇 |
1977年 | 24篇 |
1976年 | 9篇 |
1975年 | 13篇 |
1974年 | 13篇 |
1973年 | 16篇 |
排序方式: 共有1942条查询结果,搜索用时 0 毫秒
21.
G Giegerich M Pette K Fujita H Wekerle J T Epplen A Hinkkanen 《Journal of chromatography. A》1990,528(1):79-90
Reversed-phase high-performance liquid chromatography was applied to isolate myelin basic protein from human brain, followed by separation of proteolytic peptides thereof on the same chromatographic system. Brain tissue was delipidated under conditions that keep copurifying proteases inactive. The crude brain protein fraction was applied directly to a C4 column. The homogeneous protein obtained in this way was digested with thrombin and endoproteinase Lys-C in order to produce short defined myelin basic protein peptides. The purified peptides were used to determine the antigen fine specificity of myelin basic protein recognizing T lymphocyte lines isolated from multiple sclerosis patients. 相似文献
22.
23.
[reaction: see text] We have developed an efficient copper-catalyzed allylation of carbonyl derivatives using allyl(2-pyridyl)silanes, in which the strong directing effect of the 2-pyridyl group was observed. A useful synthesis and allylation of substituted allyl(2-pyridyl)silanes is also described. 相似文献
24.
De-Qi Yuan Yuewei Zhao Makoto Fukudome Kahee Fujita 《Journal of inclusion phenomena and macrocyclic chemistry》2007,57(1-4):125-129
One or two coumarin units were incorporated to the primary face of γ-cyclodextrin (γ-CD), and the resultant coumarin derivatives
were employed to harvest the chemical energy generated in the reaction of bis(trichlorophenyl)oxalate with hydrogen peroxide.
In comparison with the coumarin without CD cavity for molecular recognition, the coumarin–CD conjugates demonstrated much
higher chemiluminescence inetensity, indicating that the CD moiety remarkably improves the chemical energy transfer. 相似文献
25.
Chisuzu Tokoh Keiji Takabe Junji Sugiyama Minoru Fujita 《Cellulose (London, England)》2002,9(3-4):351-360
Acetobacter
xylinum was cultured in Schramm–Hestrin medium containing pectin (pectin medium), xylan (xylan medium), or glucomannan (mannan medium). X-ray diffractometry revealed that xylan and glucomannan affected the size of the cellulose crystals and their d-spacing values. Solid-state cross polarization magic angle spinning carbon-13 nuclear magnetic resonance spectroscopy indicated that the ratio of cellulose I was reduced by the addition of polysaccharides. These effects were more remarkable on the cellulose in the mannan medium than that in the xylan medium, and were scarcely observed in the pectin medium. Electron diffraction analysis revealed that these effects on hemicelluloses along cellulose microfibrils are continuous in the mannan medium and discontinuous in the xylan medium. These findings suggest that the uronic acid in the polysaccharides prevents interactions with cellulose leading to alterations of the structure of the cellulose crystal. 相似文献
26.
27.
28.
N. Takahashi T. Shimoda Y. Fujita T. Itahashi H. Miyatake 《Zeitschrift für Physik B Condensed Matter》1995,98(3):347-351
Short-lived ions12B (beta-radioactive, T1/2=20.3 ms) sustaining nuclear spin polarization were introduced into superfluid helium at 1.7 K. It was found that the12B ions were transported as charged entities under a static electric field and that the nuclear polarization was maintained throughout the lifetime of12B nuclei. Polarization of12B was determined through beta-NMR method. Snowball, a singly charged microcluster of helium atoms formed around an impurity ion, is responsible for the behaviour and thus constitutes a suitable environment for preserving nuclear polarization of the core ions12B. In a separate experiment snowballs were produced by implanting8Li (T1/2=830 ms) into liquid helium and detected by means of alpha particles from the core ions to guarantee that the snowballs survive longer than the lifetime of12B. 相似文献
29.
30.
Katsunori Wakabayashi Mitsutaka Fujita Koichi Kusakabe Kyoka Nakada 《Czechoslovak Journal of Physics》1996,46(4):1865-1866
Anoble mechanism of spin polarization is proposed for finite graphite sheet with edge. For graphite ribbon with zigzag edge, there appear peculiar ‘edge states’. These localized states comprise nearly flat band at the Fermi level, which easily causes magnetic instability. Magnetic structure is suggested from Hartree-Fock analysis of the Hubbard model, where huge magnetic moments are induced at around both of edges by weak HubbardU and are coupled antiferromagnetically with each other. 相似文献