全文获取类型
收费全文 | 6319篇 |
免费 | 418篇 |
国内免费 | 31篇 |
专业分类
化学 | 4879篇 |
晶体学 | 28篇 |
力学 | 158篇 |
综合类 | 1篇 |
数学 | 1021篇 |
物理学 | 681篇 |
出版年
2022年 | 35篇 |
2021年 | 52篇 |
2020年 | 64篇 |
2019年 | 109篇 |
2018年 | 65篇 |
2017年 | 63篇 |
2016年 | 211篇 |
2015年 | 236篇 |
2014年 | 231篇 |
2013年 | 384篇 |
2012年 | 301篇 |
2011年 | 318篇 |
2010年 | 282篇 |
2009年 | 286篇 |
2008年 | 324篇 |
2007年 | 274篇 |
2006年 | 259篇 |
2005年 | 233篇 |
2004年 | 270篇 |
2003年 | 215篇 |
2002年 | 277篇 |
2001年 | 151篇 |
2000年 | 142篇 |
1999年 | 71篇 |
1998年 | 65篇 |
1997年 | 77篇 |
1996年 | 87篇 |
1995年 | 63篇 |
1994年 | 73篇 |
1993年 | 71篇 |
1992年 | 67篇 |
1991年 | 42篇 |
1990年 | 46篇 |
1989年 | 47篇 |
1988年 | 42篇 |
1987年 | 41篇 |
1986年 | 39篇 |
1985年 | 47篇 |
1984年 | 65篇 |
1983年 | 56篇 |
1982年 | 71篇 |
1981年 | 72篇 |
1980年 | 74篇 |
1979年 | 82篇 |
1978年 | 78篇 |
1977年 | 83篇 |
1976年 | 76篇 |
1975年 | 74篇 |
1974年 | 75篇 |
1973年 | 53篇 |
排序方式: 共有6768条查询结果,搜索用时 15 毫秒
761.
L. de Arcangelis H. J. Herrmann M. Kolb René Thomas C. Amitrano L. Peliti M. Saber G. Weisbuch Sara A. Solla F. Bagnoli A. Francescato R. Livi S. Ruffo Pablo Tamayo Michel Droz Peter Jörg Plath S. Romano Yves Pomeau Stéphane Zaleski D. Stauffer Luciano R. da Silva Alex Hansen Stéphane Roux Antonio Coniglio B. Derrida Henrik Flyvbjerg Naeem Jan Dietrich Stauffer Peter Grassberger A. Zippelius K. E. Kurten Werner Krauth Jean -Pierre Nadal Marc Mézard Per Bak Chao Tang Itzhak Webman M. L. Martins H. F. V. Resende C. Tsallis A. C. N. Magalhaes 《Journal of statistical physics》1989,55(5-6):1333-1359
762.
763.
764.
Krzysztof Ejsmont Jean‐Pierre Joly Emmanuel Wenger Benoit Guillot Christian Jelsch 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(7):o342-o344
The structural model for the title compound, C16H12N2O2, was refined using a multipolar atom model transferred from an experimental electron‐density database. The refinement showed some improvements of crystallographic statistical indices when compared with a conventional spherical neutral‐atom refinement. The title compound adopts a half‐chair conformation. The amide N atom lies almost in the plane defined by the three neighbouring C atoms. In the crystal structure, molecules are linked by weak intermolecular C—H...O and C—H...π hydrogen bonds. 相似文献
765.
Adriaan M. H. van der Veen Thomas P. J. Linsinger Andree Lamberty Jean Pauwels 《Accreditation and quality assurance》2001,6(6):257-263
To serve as a measurement standard, a (certified) reference material must be stable. For this purpose, the material should
undergo stability testing after it has been prepared. This paper looks at the statistical aspects of stability testing. Essentially,
these studies can be described with analysis of variance statistics, including variant regression analysis. The latter is
used in practice for both trend analysis and for the development of expressions for extrapolations. Extrapolation of stability
data is briefly touched upon, as far as the combined standard uncertainty of the reference material is concerned. There are
different options to validate the extrapolations made from initial stability studies, and some of them might influence the
uncertainty of the reference material and/or the shelf-life. The latter is the more commonly observed consequence of what
is called ’stability monitoring’.
Received: 6 October 2000 Accepted: 4 December 2000 相似文献
766.
Evelina Colacino Pierrick Nun Francesco Maria Colacino Jean Martinez Frdric Lamaty 《Tetrahedron》2008,64(23):5569-5576
Various C-aryl and C-alkyl-nitrones were synthesized within 0.5–2 h via condensation of an equimolar amount of aldehydes and N-substituted-hydroxylamines under solvent-free conditions in a ball-mill apparatus. Reactions can be performed without the need of excluding air and moisture and yields the expected products with no need for further purification. The study has been complemented by Differential Scanning Calorimetry (DSC) and solid-state 13C MAS nuclear magnetic resonance experiments. We have also studied the temperature profile during the reaction. A comparative study with the corresponding solvent-free microwave activated reaction showed the superiority of the ball-milling method; 31 examples are described, including the synthesis of the anti-aging agent C-phenyl-N-tert-butyl nitrone (PBN) and one of its analogues C-2-pyridyl-N-tert-butylnitrone (2-PyBN). 相似文献
767.
768.
Jean Fasel 《manuscripta mathematica》2009,130(4):411-423
We prove the excess intersection and self intersection formulae for Grothendieck–Witt groups. 相似文献
769.
An efficient route to a 5,6-dihydropyrano[3,4-b]pyridin-8-one core in two steps from enaminolactones
Cheikh Sall Sandrine Paquelet Jean Michel Chezal Yves Blache 《Tetrahedron letters》2008,49(8):1301-1304
A convenient two step conversion of heterocyclic enaminolactones to heterocyclic fused 2-pyran-1-ones is reported. The use of this method can be applied to a wide variety of aromatic and heteroaromatic amines to give potentially biologically active compounds in good yields. 相似文献
770.