全文获取类型
收费全文 | 11269篇 |
免费 | 268篇 |
国内免费 | 42篇 |
专业分类
化学 | 6722篇 |
晶体学 | 88篇 |
力学 | 398篇 |
数学 | 1767篇 |
物理学 | 2604篇 |
出版年
2022年 | 92篇 |
2021年 | 140篇 |
2020年 | 154篇 |
2019年 | 151篇 |
2018年 | 146篇 |
2017年 | 123篇 |
2016年 | 220篇 |
2015年 | 213篇 |
2014年 | 211篇 |
2013年 | 648篇 |
2012年 | 431篇 |
2011年 | 532篇 |
2010年 | 376篇 |
2009年 | 328篇 |
2008年 | 488篇 |
2007年 | 439篇 |
2006年 | 422篇 |
2005年 | 368篇 |
2004年 | 397篇 |
2003年 | 326篇 |
2002年 | 318篇 |
2001年 | 204篇 |
2000年 | 189篇 |
1999年 | 154篇 |
1998年 | 124篇 |
1997年 | 139篇 |
1996年 | 172篇 |
1995年 | 125篇 |
1994年 | 131篇 |
1993年 | 165篇 |
1992年 | 162篇 |
1991年 | 162篇 |
1990年 | 122篇 |
1989年 | 125篇 |
1988年 | 141篇 |
1987年 | 181篇 |
1986年 | 150篇 |
1985年 | 204篇 |
1984年 | 199篇 |
1983年 | 150篇 |
1982年 | 176篇 |
1981年 | 179篇 |
1980年 | 179篇 |
1979年 | 175篇 |
1978年 | 165篇 |
1977年 | 164篇 |
1976年 | 144篇 |
1975年 | 160篇 |
1974年 | 126篇 |
1973年 | 125篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
JETP Letters - Extraordinary multiparticle effects in quantizing magnetic fields that are manifested in strongly interacting two-dimensional electron systems in MgZnO/ZnO heterostructures have been... 相似文献
2.
3.
4.
5.
Naphthalimide‐phthalimide derivative based photoinitiating systems for polymerization reactions under blue lights 下载免费PDF全文
Pu Xiao Frédéric Dumur Jing Zhang Bernadette Graff Didier Gigmes Jean Pierre Fouassier Jacques Lalevée 《Journal of polymer science. Part A, Polymer chemistry》2015,53(5):665-674
Naphthalimide‐phthalimide derivatives (NDPDs) have been synthesized and combined with an iodonium salt, N‐vinylcarbazole, amine or 2,4,6‐tris(trichloromethyl)‐1,3,5‐triazine to produce reactive species (i.e., radicals and cations). These generated reactive species are capable of initiating the cationic polymerization of epoxides and/or the radical polymerization of acrylates upon exposure to very soft polychromatic visible lights or blue lights. Compared with the well‐known camphorquinone based systems used as references, the novel NDPD based combinations employed here demonstrate clearly higher efficiencies for the cationic polymerization of epoxides under air as well as the radical polymerization of acrylates. Remarkably, one of the NDPDs (i.e., NDPD2) based systems is characterized by an outstanding reactivity. The structure/reactivity/efficiency relationships of the investigated NDPDs were studied by fluorescence, cyclic voltammetry, laser flash photolysis, electron spin resonance spin trapping, and steady state photolysis techniques. The key parameters for their reactivity are provided. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 665–674 相似文献
6.
7.
8.
9.
Hendrik Van Maldeghem 《Journal of Geometry》1997,58(1-2):192-202
We characterize in a geometrical way those Suzuki-Tits ovoids which are defined over a perfect fieidK (or equivalently living inside a self polar symplectic quadrangle). We simplify our axioms in the particular cases that (1) the associated Suzuki group has exactly two orbits in the set of lines ofPG(3,K), and (2) the ovoid is finite.Senior Research Associate at the Belgian National Fund for Scientific Research 相似文献
10.
Photobleaching was studied during recording of confocal scanning laser microscopy. Studies on fluorescent gels of FITC-labeled
dextran were used to evaluate differential bleaching along thez-axis. Differential bleaching along the z-axis was observed and it was seen that this was related to the numerical aperture
of the objective in use. This points to the conclusion that photon energy flux density is an important parameter in photobleaching.
To check if photon energy flux density heterogeneity is affected by local variation in the refractive index of the sample,
photobleaching rates were calculated for different fluorescent objects (sections of seeds, animal cells stained with nuclear
stains, immunocytochemistry preparations) and a pronounced similarity was found between photobleaching rates and DIC images. 相似文献