全文获取类型
收费全文 | 3859篇 |
免费 | 89篇 |
国内免费 | 21篇 |
专业分类
化学 | 2570篇 |
晶体学 | 47篇 |
力学 | 75篇 |
数学 | 581篇 |
物理学 | 696篇 |
出版年
2023年 | 21篇 |
2022年 | 97篇 |
2021年 | 100篇 |
2020年 | 67篇 |
2019年 | 62篇 |
2018年 | 75篇 |
2017年 | 53篇 |
2016年 | 110篇 |
2015年 | 98篇 |
2014年 | 112篇 |
2013年 | 212篇 |
2012年 | 207篇 |
2011年 | 224篇 |
2010年 | 145篇 |
2009年 | 142篇 |
2008年 | 207篇 |
2007年 | 165篇 |
2006年 | 153篇 |
2005年 | 149篇 |
2004年 | 121篇 |
2003年 | 87篇 |
2002年 | 102篇 |
2001年 | 56篇 |
2000年 | 56篇 |
1999年 | 65篇 |
1998年 | 56篇 |
1997年 | 56篇 |
1996年 | 43篇 |
1995年 | 53篇 |
1994年 | 52篇 |
1993年 | 37篇 |
1992年 | 38篇 |
1991年 | 45篇 |
1990年 | 28篇 |
1989年 | 22篇 |
1988年 | 41篇 |
1987年 | 34篇 |
1986年 | 24篇 |
1985年 | 25篇 |
1984年 | 29篇 |
1983年 | 27篇 |
1982年 | 43篇 |
1981年 | 34篇 |
1980年 | 39篇 |
1978年 | 26篇 |
1977年 | 29篇 |
1976年 | 28篇 |
1975年 | 21篇 |
1974年 | 24篇 |
1973年 | 35篇 |
排序方式: 共有3969条查询结果,搜索用时 0 毫秒
1.
2.
3.
4.
Tom Edgar 《Journal of Algebraic Combinatorics》2007,26(3):357-362
Twisted Bruhat orders are certain partial orders on a Coxeter system (W,S) associated to initial sections of reflection orders, which are certain subsets of the set of reflections T of a Coxeter system. We determine which subsets of T give rise to a partial order on W in the same way. 相似文献
5.
6.
7.
M. Alves Da Silva M. Helena Gil A. P. Piedade J. S. Redinha A. M. Oliveira Brett J. M. Caridade Costa 《Journal of polymer science. Part A, Polymer chemistry》1991,29(2):269-274
The immobilization of catalase on grafted membranes of poly(ethylene)-g-co-acrylic acid and poly(tetrafluoroethylene)-g-co-acrylic acid and their application in hydrogen peroxide electrochemical sensors is described. The introduction of carboxylic acid groups onto a hydrophobic support provides a good environment for subsequent enzyme immobilization. This single membrane, hydrogen peroxide sensor showed significant improvement with respect to the double membrane versions. The response is very rapid, the linear range being from 10 μM up to 6 mM, with a detection limit of 4.7 μM, and a lifetime of more than 4 months. 相似文献
8.
Eggenhffner R. Masini R. Bellingeri E. Cimberle M. R. Ferdeghini C. Costa G. A. Kaiser E. Signorelli E. 《Il Nuovo Cimento D》1994,16(10):1659-1664
Il Nuovo Cimento D - The formation of Hg-based HTSC materials was investigated through the development of non-conventional techniques. The former was based on a singlestep synthesis at temperatures... 相似文献
9.
The fully frustrated planar rotator and fully frustrated XY models in two dimensions have two phase transitions: one of the Berezinskii–Kosterlitz–Thouless type and other in the Ising universality class. We use Monte Carlo simulation to study both models. We fix our attention in the Ising-like transition, which we show can be understood as a percolation transition. We obtain the critical temperature as well as the critical exponents of the mean cluster size, γ, and Fisher's exponent τ. The critical temperature agree very well with other calculations. We found that the critical exponents are smaller than in the pure two-dimensional percolation case. We interpret this as due to the long-range interaction between vortex and antivortex. 相似文献
10.
The ligand 2,2′,2″-nitrilotriphenol reacts with P(III) and P(V) compounds to form corresponding phosphorus complexes. Syntheses and NMR data of 2,2′,2″-nitrilotriphenyl phosphite ( II ), 2,2′,2″-nitrilotriphenyl phosphate ( III ) and of a hydrolysis product of II , 2,2′-[N-(2-hydroxyphenyl)imino]diphenly phosphonate ( IV ), are reported, as well as crystal structures of II and IV . Phosphite II shows a bicycloundecane framework; no N?Pinteraction is present. The phosphonate IV shows two coordinated and one dangling phenol group; the N-atom does not interact with the P-atom. Strong acids protonate II as well as III to form cations: in these, NMR evidence indicates coordination of the N-atom to the P-atom. 相似文献