全文获取类型
收费全文 | 379篇 |
免费 | 12篇 |
国内免费 | 3篇 |
专业分类
化学 | 262篇 |
晶体学 | 1篇 |
力学 | 12篇 |
数学 | 52篇 |
物理学 | 67篇 |
出版年
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 10篇 |
2014年 | 13篇 |
2013年 | 16篇 |
2012年 | 19篇 |
2011年 | 19篇 |
2010年 | 20篇 |
2009年 | 22篇 |
2008年 | 27篇 |
2007年 | 14篇 |
2006年 | 23篇 |
2005年 | 18篇 |
2004年 | 26篇 |
2003年 | 13篇 |
2002年 | 16篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1937年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有394条查询结果,搜索用时 15 毫秒
371.
L. Cianchi S. De Gennaro F. Gulisano M. Mancini G. Spina 《Hyperfine Interactions》1990,56(1-4):1437-1441
Mössbauer spectroscopy has been used to investigate the mechanism which affects the valence state of europium in EuPd3B. The obtained results are interpreted in terms of a correlation between two non equivalent sites each in a fluctuating valence state. 相似文献
372.
Summary The lipophilicity (hydrophobicity) of some alkylamines and arylamines was determined with reversed-phase thin-layer chromatography using various water: methanol mixtures as eluent with and without adding salt to the system. The effect of various structural parameters of amines and that of the chromatographic conditions were assessed with stepwise regression analysis. The calculation proved that in case of alkylamines the lipophilicity does not depend linearly on the length of the alkyl chain, the effect of methanol and salt concentrations are intercorrelated and the influence of the alkyl chain branching is negligible. In case of arylamines the number of amino groups has the highest impact on the retention and the effect of methanol and salt is also intercorrelated. 相似文献
373.
374.
375.
Baca E. Carotenuto M. Di Leo R. Iannone G. Nigro A. Romano P. Cucolo A. M. 《Il Nuovo Cimento D》1994,16(10):1695-1699
Il Nuovo Cimento D - A systematic study of yttrium substitution for calcium in the high-temperature superconductor Bi2Sr2CaCu2O8 compound has been performed. The samples of Bi2Sr2Y x Ca1−x... 相似文献
376.
Ken S Di Gennaro G Giulietti G Sebastiano F De Carli D Garreffa G Colonnese C Passariello R Lotterie JA Maraviglia B 《Magnetic resonance imaging》2007,25(6):883-888
Patients with drug-resistant focal epilepsy may require intracranial investigations with subdural electrodes. These must be correctly localized with respect to the brain cortical surface and require appropriate monitoring. For this purpose, coregistration techniques, which fuse preimplantation 3D magnetic resonance imaging scans with postimplantation computed tomography scans, have been implemented. In order to reduce localization errors due to the fusion process, we used a coregistration method based on the maximization of mutual information (MI) in 11 patients with extratemporal epilepsy who were invasively investigated. Our registration method is based on three processing steps: rigid-body transformation for coregistration, computation of MI as a similarity measure and the use of the Downhill Simplex optimization method. After consistency analysis, the shift of the registration method reached 0.14+/-0.27 mm in translation and 0.03+/-0.14 degrees in rotation, and the accuracies assessed on voxels of skull surface and voxels of the center of the brain volume were 1.42+/-0.61 and 1.15+/-0.53 mm, respectively. The accuracy of the fusion process reached submillimeter range, and results were considered reliable for surgical planning in all studied patients. 相似文献
377.
378.
De Paoli P Isse AA Bortolamei N Gennaro A 《Chemical communications (Cambridge, England)》2011,47(12):3580-3582
The kinetics of activation of RX by a Cu(I) complex has been investigated in MeCN both in the absence and presence of halide ions. The system Cu(I)/L/X(-) (L = Me(6)TREN) is mainly composed of Cu(I)L(+), XCu(I)L and Cu(I)X(2)(-), but only Cu(I)L(+) is found to be an active catalyst reacting with RX. 相似文献
379.
D'Errico S Oliviero G Borbone N Amato J Piccialli V Varra M Mayol L Piccialli G 《Molecules (Basel, Switzerland)》2011,16(9):8110-8118
The solid-phase synthesis of the first example of a new diphosphate AICAR derivative is reported. The new substance is characterized by the presence of a 5'-phosphate group while a second phosphate moiety is installed on a 5-hydroxypentyl chain attached to the 4-N-position of AICAR. Cyclization of the diphosphate derivative by pyrophosphate bond formation allowed for the formation of a novel AICAR-based cyclic ADP-ribose (cADPR) mimic. 相似文献
380.
Mangiacapra Gennaro Wittal Matthew Capello Elisa Nazari Morad 《Nonlinear dynamics》2022,108(3):2127-2146
Nonlinear Dynamics - This paper presents a novel rigid-body navigation and control architecture within the framework of special Euclidean group $$\mathsf {SE(3)}$$ and its tangent bundle $$\mathsf... 相似文献