全文获取类型
收费全文 | 1961篇 |
免费 | 30篇 |
国内免费 | 3篇 |
专业分类
化学 | 1498篇 |
晶体学 | 23篇 |
力学 | 38篇 |
数学 | 64篇 |
物理学 | 371篇 |
出版年
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 20篇 |
2015年 | 15篇 |
2014年 | 27篇 |
2013年 | 81篇 |
2012年 | 88篇 |
2011年 | 82篇 |
2010年 | 47篇 |
2009年 | 58篇 |
2008年 | 98篇 |
2007年 | 104篇 |
2006年 | 116篇 |
2005年 | 107篇 |
2004年 | 110篇 |
2003年 | 93篇 |
2002年 | 74篇 |
2001年 | 51篇 |
2000年 | 60篇 |
1999年 | 33篇 |
1998年 | 30篇 |
1997年 | 40篇 |
1996年 | 25篇 |
1995年 | 27篇 |
1994年 | 23篇 |
1993年 | 32篇 |
1992年 | 46篇 |
1991年 | 25篇 |
1990年 | 25篇 |
1989年 | 18篇 |
1988年 | 35篇 |
1987年 | 27篇 |
1986年 | 33篇 |
1985年 | 42篇 |
1984年 | 28篇 |
1983年 | 18篇 |
1982年 | 21篇 |
1981年 | 21篇 |
1980年 | 13篇 |
1979年 | 24篇 |
1978年 | 15篇 |
1977年 | 14篇 |
1975年 | 10篇 |
1974年 | 15篇 |
1973年 | 7篇 |
1966年 | 8篇 |
排序方式: 共有1994条查询结果,搜索用时 0 毫秒
961.
1st-5th generation poly(propyleneimine) dendrimers having peripheral 2,3-difluorobiphenyl mesogenic groups have been synthesized. They exhibited smectic liquid crystalline behaviour. All the liquid crystalline dendrimers exhibited a smectic A (SmA) phase and a crystal E (E) phase. The SmA-isotropic phase transition temperature increased with increasing generation. In addition, a homeotropic structure was spontaneously formed on a glass plate in the SmA phase for the 2nd, 3rd, and 4th generation dendrimers. The hometropic structure remained unchanged in the phase. 相似文献
962.
963.
964.
The stereospecific exchange of a hydroxyl group of chiral alcohols bearing a pyridylseleno group on the adjacent carbon atom with aromatic compounds occurred smoothly in the presence of Lewis acid. 相似文献
965.
966.
967.
We shall present a couple of norm inequalities which will much improve the sharp triangle inequality with n elements and its reverse inequality in a Banach space shown recently by the last three authors. 相似文献
968.
Jian-guang Yang Sheng-hai Yang Takeshi Okamoto Takeshi Bessho Shigeru Satake Ryoichi Ichino Masazumi Okido 《Surface science》2006,600(24):L318-L320
Using aqueous–organic interface (water–oleic acid) reduction of Cu2+ by ascorbic acid, hydrophobic copper monolayer and copper particles have been prepared and characterized. The resultant monolayer could be transferred from the interface onto solid substrate or be dissolved to yield an organosol and copper nanoparticles. 相似文献
969.
Takateru Kubota Chiyo Yamamoto Yoshio Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2004,42(18):4704-4710
Three polysaccharide phenylcarbamate derivatives [cellulose 2,3-bis(3,5-dimethylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate)/(2-methacryloyloxyethylcarbamate), cellulose 2,3-bis(3,5-dichlorophenylcarbamate)-6-(3,5-dichlorophenylcarbamate)/(2-methacryloyloxyethylcarbamate), and amylose 2,3-bis(3, 5-dimethylphenylcarbamate)-6-(3,5-dimethylphenylcarbamate)/(2-methacryloyloxyethylcarbamate)] with vinyl groups were prepared and coated onto silica gel to immobilize them via radical copolymerization with 2,3-dimethylbutadiene. The copolymerization efficiently proceeded, and the coated polysaccharide derivatives were mostly immobilized on the surface of the silica gel. The immobilized polysaccharide derivatives showed high chiral recognition abilities similar to those of the corresponding coated polysaccharide derivatives. They could be used with an eluent containing chloroform, which dissolved the polysaccharide derivatives. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4704–4710, 2004 相似文献
970.
H. Oji T. Tominaga K. Nakanishi M. Ohmoto K. Ogawa M. Kimura S. Kimura T. Okamoto H. Namba 《Journal of Electron Spectroscopy and Related Phenomena》2006
We performed the simulation of near edge X-ray absorption fine structure (NEXAFS) spectra of a photo-reactive copolymer with considerably large monomer units by ab initio molecular orbital calculation, in order to explain the spectral change induced by irradiation of the linearly polarized near ultra-violet (LPNUV) light. The “building block approach” is applied for the theoretical calculation to calculate the core-excited states of the polymer with such large monomer units; the monomer unit is divided into subunits, whose core-excited states are calculated individually, and the results are summed up to simulate the spectra of the polymer. With the result of the simulation, the peaks in the observed spectra were assigned. The spectral change after the LPNUV-irradiation is attributed to the change in the electronic structure caused by the breakdown of the π-conjugation system of chalconyl group after photo-dimerization. 相似文献