全文获取类型
收费全文 | 2445篇 |
免费 | 112篇 |
国内免费 | 4篇 |
专业分类
化学 | 1938篇 |
晶体学 | 15篇 |
力学 | 32篇 |
数学 | 222篇 |
物理学 | 232篇 |
无线电 | 122篇 |
出版年
2023年 | 19篇 |
2022年 | 57篇 |
2021年 | 63篇 |
2020年 | 47篇 |
2019年 | 57篇 |
2018年 | 32篇 |
2017年 | 29篇 |
2016年 | 79篇 |
2015年 | 63篇 |
2014年 | 70篇 |
2013年 | 155篇 |
2012年 | 165篇 |
2011年 | 202篇 |
2010年 | 122篇 |
2009年 | 101篇 |
2008年 | 165篇 |
2007年 | 158篇 |
2006年 | 140篇 |
2005年 | 111篇 |
2004年 | 131篇 |
2003年 | 80篇 |
2002年 | 86篇 |
2001年 | 21篇 |
2000年 | 28篇 |
1999年 | 22篇 |
1998年 | 26篇 |
1997年 | 16篇 |
1996年 | 26篇 |
1995年 | 15篇 |
1994年 | 11篇 |
1993年 | 15篇 |
1992年 | 21篇 |
1991年 | 9篇 |
1990年 | 7篇 |
1989年 | 10篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 16篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 9篇 |
1980年 | 18篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1972年 | 5篇 |
排序方式: 共有2561条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
Emilio J. González Patricia F. Requejo Ángeles Domínguez Eugénia A. Macedo 《Journal of solution chemistry》2013,42(4):746-763
In this study, densities and speeds of sound were measured over the whole composition range, at T = (298.15, 303.15 and 308.15) K and p = 0.1 MPa, for the binary systems of ethanol, or 1-propanol, or 2-propanol and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, or 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide. The density and speed of sound data were used to calculate the corresponding excess molar volumes and excess molar isentropic compressions, which were fitted with the Redlich–Kister equation. From the obtained results, a discussion was carried out in terms of interactions and structure factors in these binary mixtures. 相似文献
85.
86.
87.
88.
Dr. Chao Zhao Dr. Louise Male Dr. Tzu-Yu Chen Joseph A. Barker Dr. Ian J. Shannon Dr. Paul A. Anderson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(61):13865-13868
(NH4)2[Zn2(O3PCH2CH2COO)2]⋅5 H2O (BIRM-1) is a new metal phosphonate material, synthesized through a simple hydrothermal reaction between zinc nitrate and 3-phosphonopropionic acid, using urea and tetraethylammonium bromide as the reaction medium. In common with other metal–organic framework materials, BIRM-1 has a large three-dimensional porous structure providing potential access to a high internal surface area. Unlike most others, it has the advantage of containing ammonium cations within the pores and has the ability to undergo cation exchange. Additionally, BIRM-1 also exhibits a reversible dehydration behavior involving an amorphization-recrystallization cycle. The ability to undergo ion exchange and dynamic structural behavior are of interest in their own right, but also increase the range of potential applications for this material. Here the crystal structure of this new metal phosphonate and its ion exchange behavior with K+ as an exemplar are studied in detail, and its unusual structure-reviving property reported. 相似文献
89.
90.
The First One‐Pot Synthesis of Metal–Organic Frameworks Functionalised with Two Transition‐Metal Complexes 下载免费PDF全文
Dr. Ana E. Platero‐Prats Dr. Antonio Bermejo Gómez Dr. Louise Samain Prof. Xiaodong Zou Prof. Belén Martín‐Matute 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):861-866
The synthesis of a metal–organic framework (UiO‐67) functionalised simultaneously with two different transition metal complexes (Ir and Pd or Rh) through a one‐pot procedure is reported for the first time. This has been achieved by an iterative modification of the synthesis parameters combined with characterisation of the resulting materials using different techniques, including X‐ray absorption spectroscopy (XAS). The method also allows the first synthesis of UiO‐67 with a very wide range of loadings (from 4 to 43 mol %) of an iridium complex ([IrCp*(bpydc)(Cl)Cl]2?; bpydc=2,2′‐bipyridine‐5,5′‐dicarboxylate, Cp*=pentamethylcyclopentadienyl) through a pre‐functionalisation methodology. 相似文献