全文获取类型
收费全文 | 536篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 360篇 |
晶体学 | 4篇 |
力学 | 18篇 |
数学 | 74篇 |
物理学 | 88篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 23篇 |
2021年 | 31篇 |
2020年 | 19篇 |
2019年 | 24篇 |
2018年 | 16篇 |
2017年 | 12篇 |
2016年 | 20篇 |
2015年 | 20篇 |
2014年 | 17篇 |
2013年 | 41篇 |
2012年 | 32篇 |
2011年 | 32篇 |
2010年 | 24篇 |
2009年 | 15篇 |
2008年 | 27篇 |
2007年 | 35篇 |
2006年 | 29篇 |
2005年 | 18篇 |
2004年 | 16篇 |
2003年 | 18篇 |
2002年 | 20篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 7篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有544条查询结果,搜索用时 31 毫秒
31.
32.
33.
It is shown that the seminal Horodecki 2-qutrit state belongs to the class of states displaying symmetry governed by a commutative subgroup of the unitary group U(3). Taking a conjugate subgroup one obtains another classes of symmetric states and one finds equivalent representations of the Horodecki state. These results are generalized to d⊗d systems. 相似文献
34.
Romuald Bartnik Dariusz Cal 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1858-1861
The regioselective synthesis of 3-diethoxyphosphonopyrazoles has been accomplished through the addition of aryl or alkyl hydrazines to (3-ethoxyacryloyl)phosphonic acid diethyl ester. An example of hydrolysis of the pyrazolephosphonic ester to the corresponding acid is described. 相似文献
35.
36.
We find a universal SO(2) symmetry of a p-form Maxwell theory for both odd and even p. For odd p, it corresponds to the duality rotations but for even p, it defines a new set of transformations which is not related to duality rotations. In both cases, a symmetry group defines a subgroup of the O(2,1) group of R-linear canonical transformations which has also a natural representation on the level of quantization condition for p-brane dyons. 相似文献
37.
[reaction: see text] Hydroxymethyl-substituted tetrahydrofurans were prepared with high diastereoselectivity by reaction of the carbanion derived from 3,4-epoxybutyl phenyl sulfone with aldehydes in the presence of a mixture of lithium and potassium tert-butoxides. Initial formation of aldol-type adducts is a nondiastereoselective but reversible process; thus, subsequent formation of one main diastereoisomer is controlled by the relative rates of cyclization. The configuration of the carbon stereocenter at the oxirane ring is inverted in the course of the S(N)2 process, and two new centers are created diastereoselectively. 相似文献
38.
39.
Dariusz Basiak Wanda Ziemkowska Paweł Socha Łukasz Dobrzycki Zbigniew Ochal Edyta Pindelska 《Journal of Coordination Chemistry》2017,70(9):1528-1535
2-Mercapto-1,3-benzothiazole (mbztH) may act as a chelating or bridging ligand. In this study, reactions of mbztH with Me3Ga and Me3In were examined. The products were characterized by NMR spectroscopy, elemental analyses, melting point, and molecular weight determinations. Formation of mononuclear chelating complexes Me2M(mbzt) (M = Ga, In) was observed in solutions. Crystallization of Me2M(mbzt) yielded uncommon non-symmetrical dinuclear complexes Me4M2(mbzt)2, in which one metal is bonded to two sulfurs and the other to two nitrogens. 相似文献
40.
Nataliya Chumalo Galyna P. Nychyporuk Rainer Pöttgen Dariusz Kaczorowski 《Journal of solid state chemistry》2010,183(12):2963-2967
The indides Ce7Ni5±xGe3±xIn6 and Pr7Ni5±xGe3±xIn6 were synthesized from the elements by arc-melting of the components. Single crystals were grown via special annealing sequences. Both structures were solved from X-ray single crystal diffraction data: new structure type, P6/m, Z=1, a=11.385(2), c=4.212(1) Å, wR2=0.0640, 634F2 values, 25 variables for Ce7Ni4.73Ge3.27In6 and a=11.355(6), c=4.183(2) Å, wR2=0.0539, 563F2 values, 25 variables for Pr7Ni4.96Ge3.04In6. Both indides show homogeneity ranges through Ni/Ge mixing (M sites). This new structure type can be derived from the AlB2 structure type by a substitution of the Al and B atoms by CeM12 and NiIn6Ce3 polyhedra (tricapped trigonal prism). Magnetic susceptibility measurements on a polycrystalline sample of Ce7Ni5Ge3In6 indicated Curie-Weiss like paramagnetic behavior down to 1.71 K with the effective magnetic moment slightly reduced in relation to the value expected for trivalent cerium ions. No magnetic ordering is evident. 相似文献