全文获取类型
收费全文 | 1860篇 |
免费 | 95篇 |
国内免费 | 8篇 |
专业分类
化学 | 1550篇 |
晶体学 | 22篇 |
力学 | 22篇 |
数学 | 112篇 |
物理学 | 257篇 |
出版年
2023年 | 15篇 |
2022年 | 18篇 |
2021年 | 25篇 |
2020年 | 19篇 |
2019年 | 47篇 |
2018年 | 32篇 |
2017年 | 20篇 |
2016年 | 60篇 |
2015年 | 47篇 |
2014年 | 49篇 |
2013年 | 92篇 |
2012年 | 138篇 |
2011年 | 136篇 |
2010年 | 59篇 |
2009年 | 61篇 |
2008年 | 133篇 |
2007年 | 118篇 |
2006年 | 135篇 |
2005年 | 121篇 |
2004年 | 101篇 |
2003年 | 108篇 |
2002年 | 77篇 |
2001年 | 20篇 |
2000年 | 32篇 |
1999年 | 19篇 |
1998年 | 7篇 |
1997年 | 23篇 |
1996年 | 24篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 16篇 |
1991年 | 5篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1985年 | 24篇 |
1984年 | 17篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 16篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 12篇 |
1977年 | 9篇 |
1976年 | 16篇 |
1975年 | 11篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1971年 | 2篇 |
1968年 | 3篇 |
排序方式: 共有1963条查询结果,搜索用时 15 毫秒
101.
Akio Urushima Daisuke Taura Makoto Tanaka Naomichi Horimoto Junki Tanabe Naoki Ousaka Tadashi Mori Eiji Yashima 《Angewandte Chemie (International ed. in English)》2020,59(19):7478-7486
A novel 2,6‐anthrylene‐linked bis(m‐terphenylcarboxylic acid) strand ( 1 ) self‐associates into a racemic double‐helix. In the presence of chiral mono‐ and diamines, either a right‐ or left‐handed double‐helix was predominantly induced by chiral amines sandwiched between the carboxylic acid strands with accompanying stacking of the two prochiral anthracene linker units in an enantiotopic face‐selective way, as revealed by circular dichroism and NMR spectral analyses. The photoirradiation of the optically active double helices complexed with chiral amines proceeded in a diastereo‐ (anti or syn) and enantiodifferentiating way to afford the chiral anti‐photodimer with up to 98 % enantiomeric excess when (R)‐phenylethylamine was used as a chiral double‐helix inducer. The resulting optically active anti‐photodimer can recognize the chirality of amines and diastereoselectively complex with chiral amines. 相似文献
102.
103.
Satoshi Nagao Ayaka Suda Hisashi Kobayashi Naoki Shibata Yoshiki Higuchi Shun Hirota 《化学:亚洲杂志》2020,15(11):1743-1749
Domain swapping is an exception to Anfinsen's dogma, and more than one structure can be produced from the same amino acid sequence by domain swapping. We have previously shown that myoglobin (Mb) can form a domain‐swapped dimer in which the hinge region is converted to a helical structure. In this study, we showed that domain‐swapped dimerization of Mb was achieved by a single Ala mutation of Gly at position 80. Multiple Ala mutations at positions 81 and 82 in addition to position 80 facilitated dimerization of Mb by stabilization of the dimeric states. Domain swapping tendencies correlated well with the helical propensity of the mutated residue in a series of Mb mutants with amino acids introduced to the hinge region. These findings demonstrate that a single mutation in the hinge loop to modify helical propensity can control oligomer formation, providing new ideas to create high‐order protein oligomers using domain swapping. 相似文献
104.
105.
106.
The stabilizing structure of cationic surfactant-protected platinum clusters in water and tertiary amine-protected rhodium clusters in chloroform, prepared by photo- and hydrogen-reduction, respectively, was investigated. These nanoscopic noble metal clusters present a narrow size distribution and are stable. The structural information of protective organic molecules on the surface of metal clusters was studied by transmission electron microscopy and hydrodynamic radius measurements according to the Taylor dispersion method. The size of the entire cluster with the protective layer surrounding the metal surface, obtained as Stokes' radii by the Taylor dispersion method, is considered to be fairly consistent with the sum of the naked particle size, obtained by transmission electron micrographs, and the size of the adsorbed protective layer, supporting the conformational information. 相似文献
107.
108.
Letters in Mathematical Physics - We construct explicitly strong generators of the affine $$\mathcal {W}$$-algebra $$\mathcal {W}^{K_0-N}(\mathfrak {sl}_N, f_{sub})$$ of subregular type A.... 相似文献
109.
Tairin Kawasaki Naoki Ishida Masahiro Murakami 《Angewandte Chemie (International ed. in English)》2020,59(41):18267-18271
A convenient method is reported to specifically acylate phenolic hydroxyl groups through a radical pathway. When a mixture of an aldehyde and a phenol in ethyl acetate is irradiated with blue light in the presence of iridium and nickel bromide catalysts at ambient temperature, phenoxyl and acyl radicals are transiently generated in situ and cross‐couple to furnish an ester. Aliphatic hydroxy groups remain untouched under the reaction conditions. 相似文献
110.
The title compounds, Ph2bNO and Ph3bNO, were designed as a biradical paramagnetic host, and their chelation ability was confirmed by inclusion of a size-matched alkaline-earth metal ion. The crystal structures of [Ca(hfac)2(Ph2bNO)] and [Ba(hfac)2(Ph3bNO)] were determined, where Hhfac stands for 1,1,1,5,5,5-hexafluoropentane-2,4-dione. The solution electron paramagnetic resonance spectra showed switching behavior. Five lines were found for Ph3bNO and charecterized as the hyperfine splitting due to the two nitrogen atoms. After addition of barium(II) ion, the spectrum turned to be three lines. Removal of the barium ion recovered the five line pattern. The present system can be regarded as a reversible magnetic-coupling switch by means of a supramolecular technique. 相似文献