全文获取类型
收费全文 | 445篇 |
免费 | 4篇 |
国内免费 | 1篇 |
专业分类
化学 | 363篇 |
晶体学 | 7篇 |
力学 | 7篇 |
数学 | 11篇 |
物理学 | 62篇 |
出版年
2022年 | 3篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 9篇 |
2018年 | 7篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 9篇 |
2013年 | 18篇 |
2012年 | 23篇 |
2011年 | 36篇 |
2010年 | 16篇 |
2009年 | 20篇 |
2008年 | 27篇 |
2007年 | 35篇 |
2006年 | 35篇 |
2005年 | 22篇 |
2004年 | 24篇 |
2003年 | 24篇 |
2002年 | 19篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 5篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有450条查询结果,搜索用时 0 毫秒
111.
Yoshimura I Miyahara Y Kasagi N Yamane H Ojida A Hamachi I 《Journal of the American Chemical Society》2004,126(39):12204-12205
This communication describes a new molecular recognition chip using a semi-wet microenvironment provided by a self-assembled hydrogel. On the basis of the evidence that the molecular recognition capability of artificial chemosensors are practically retained even in the hydrogel compared to those in aqueous solution, we miniaturized the functionalized hydrogel to produce an unprecedented molecular recognition chip. We believe that the present noncovalent immobilization method is generally applicable to many chemosensors, which leads to a unique semi-wet sensor chip suitable to convenient and high-throughput assay to plural analytes. 相似文献
112.
Hideyoshi Abe Akira Kenmoku Noriyuki Yamaguch Kenjiro Hattori 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):39-47
Bi-galactose-branched cyclodextrins (Bi-Gal-CDs)(1–6) having different spacer arm lengths between two terminal galactoses were foundto have the optimum length for association with PNA lectin. Also, the inclusioninteraction of the drug depended on the length of the spacer arms. The dual association of thesecompounds was quantitatively evaluated by SPR and compared to the other oligosaccharide-branchedCDs (Scheme 1). The number and the length of the spacer arm are important for theassociation both with the lectin and drug for the purpose of targeting drug-delivery systems.The association constants K of bi-Gal-CD (2) with rat liver cells showed a 60 timeshigher association than with PNA. Direct evidence of the association between PNA andbi-Gal-CD (2) was characterized by AFM observations. The results obtained strongly suggested a method to find a new design for the targeting drug carrier. In order toincrease the association with the cell, a sufficient spacer arm length is necessary for the effectivedual recognition of the oligosaccharide-CDs. In order to increase the inclusion of thedrug, the CD structure of a multi-saccharide branch is necessary. 相似文献
113.
Akira Mori Nobuo Kato Hitoshi Takeshita Ryuko Nimura Masahiro Isobe Chihiro Jin 《Liquid crystals》2013,40(9):1425-1433
The mesomorphic properties of 2-(4-alkoxybenzoyloxy)-5-alkylaminotropones and 5-alkoxy-2-(4-alkylaminobenzoyloxy)tropones are discussed on the basis of results obtained by X-ray crystallographic and X-ray diffraction studies, as well as temperature-dependent FTIR spectral measurements. The X-ray crystallographic analysis of 2-(4-dodecylaminobenzoyloxy)-5-tetradecyloxytropone (2f) indicated that it formed a head-to-tail dimer through an intermolecular hydrogen bond between the NH and the tropone carbonyl group. The X-ray diffraction study of compound 2f suggested that the molecules formed interdigitated bilayer smectic C phases with a tilt angle of as much as c. 40° to a layer plane. The corresponding benzenoids, however, were non-mesomorphic, with higher melting points than the troponoids. In the troponoids, sigmatropic migration of the benzoyl group weakened the intermolecular hydrogen bonding and assisted the occurrence of mesomorphic properties. 相似文献
114.
115.
Yasuyuki Kagawa Noriyuki Takada Hiro Matsuda Kiyoshi Yase Moniur Halim Ifor W. Samuel 《Molecular Crystals and Liquid Crystals》2013,570(1):499-502
Abstract Photoluminescence of TCNQ-amino adducts was studied to evaluate solid state samples of photoluminescence quantum yields. High PL quantum yields suggests that TCNQ-amino adducts should be an excellent organic light emitter. Electroluminescence of TCNQ-amino adducts was demonstrated for the first time. 相似文献
116.
Hasuike Noriyuki Miyamoto Nobutoshi Funahashi Kohei Takeda Minoru 《Optical Review》2021,28(6):620-625
Optical Review - The correlation between electrical properties and surface plasmon resonance (SPR) wavelength was discussed using ITO grating coupler. ITO films were prepared on SiO $$_{2}$$ /Si... 相似文献
117.
Yasuda M Chiba K Ohigashi N Katoh Y Baba A 《Journal of the American Chemical Society》2003,125(24):7291-7300
Michael addition of stannyl ketone enolates to alpha,beta-unsaturated esters was accomplished in the presence of a catalytic amount of tetrabutylammonium bromide (Bu(4)NBr). Other typical systems using lithium enolate or silyl enolate with catalysts (TiCl(4) or Bu(4)NF) failed to give the desired products. The bromide anion from Bu(4)NBr coordinates to the tin center in enolate to accelerate the conjugate addition where a five-coordinated tin species was generated. The coordination of the bromide anion significantly raises the HOMO level of tin enolate and enhances its nucleophilicity. The conjugate addition provides the intermediate Michael adduct, which has an ester enolate moiety, and the adduct immediately transforms to alpha-stannyl gamma-ketoester by keto-enol tautomerization. This step contributes to the stabilization of the product system and leads to a thermodynamically favorable reaction course. An ab initio calculation reveals that the activation energy in the reaction using the bromide anion is lower than that of the reaction without using it. The transition state in either reaction course has a linear structure, not a cyclic one. This system can be applied to a variety of tin enolates and alpha,beta-unsaturated carbonyls involving enoates, enones, and unsaturated amides. 相似文献
118.
119.
Munehiro Nishida Takafumi Kanayama Takaya Nakajo Toshiyuki Fujii Noriyuki Hatakenaka 《Physica C: Superconductivity and its Applications》2010,470(19):832-834
We propose a one-dimensional array of superconducting quantum interference devices (SQUIDs) composed of three asymmetrically positioned Josephson junctions to realize a discrete double sine-Gordon (DSG) model. Two fluxons in this SQUID array attract each other and form bound states with internal oscillation modes. We conduct numerical simulations of a discrete DSG equation, and show that the period of the internal oscillation of a moving fluxon pair exhibits relativistic time dilation except near the speed of light. We also show that driving with a pure alternating current causes progressive motion of the bound fluxon pair even in the presence of dissipation. 相似文献
120.
Carmenza Duque Mónica Puyana Andrea Arias Oscar Osorno Noriyuki Hara 《Tetrahedron》2006,62(17):4205-4213
Chemical investigations of the MeOH-CH2Cl2 extract of Pseudopterogorgia elisabethae specimens collected in the islands of San Andrés and Providencia, Colombian Caribbean, yielded four new diterpenes (1, 3, 5, 7) along with seco-pseudopterosin J (8), and amphilectosins A (9) and B (10). The structures of the new compounds were established through spectral studies as an elisabethatriene analog named elisabethatrienol (1), 10-acetoxy-9-hydroxy- and 9-acetoxy-10-hydroxy-amphilecta-8,10,12,14-tetraenes (isolated as an interconverting mixture) (3), amphilecta-8(13),11,14-triene-9,10-dione (5), and a seco-pseudopterosin 7-O-α-l-fucopyranoside named seco-pseudopterosin K (7). Elisabethatrienol can be regarded as a biosynthetic intermediate leading to erogorgiaene. 相似文献