全文获取类型
收费全文 | 722篇 |
免费 | 30篇 |
国内免费 | 7篇 |
专业分类
化学 | 540篇 |
晶体学 | 3篇 |
力学 | 35篇 |
数学 | 93篇 |
物理学 | 88篇 |
出版年
2022年 | 16篇 |
2021年 | 14篇 |
2020年 | 16篇 |
2019年 | 17篇 |
2018年 | 8篇 |
2017年 | 14篇 |
2016年 | 28篇 |
2015年 | 22篇 |
2014年 | 17篇 |
2013年 | 43篇 |
2012年 | 33篇 |
2011年 | 56篇 |
2010年 | 34篇 |
2009年 | 38篇 |
2008年 | 48篇 |
2007年 | 41篇 |
2006年 | 41篇 |
2005年 | 23篇 |
2004年 | 26篇 |
2003年 | 25篇 |
2002年 | 13篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1992年 | 8篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1987年 | 3篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1969年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有759条查询结果,搜索用时 0 毫秒
71.
Bernard Riss Marion Garreau Prisca Fricero Patricia Podsiadly Nicolas Berton Sophie Buchter 《Tetrahedron》2017,73(23):3202-3212
The absolute configuration of bisabolangelone has been established by an eleven step total synthesis of the corresponding TMS protected antipode starting from (R)-(+)-pulegone. Comparison of the TMS-derivatives by GC on a chiral column, allowed us to assign the absolute configuration of the synthetic compound and thus of the corresponding natural product. The latter has been confirmed by the Mosher's ester analysis of the known secondary carbinol derivative. 相似文献
72.
Pieters G Gaucher A Marrot J Maurel F Naubron JV Jean M Vanthuyne N Crassous J Prim D 《Organic letters》2011,13(16):4450-4453
The synthesis and properties of new chiral polycyclic architectures that display both helicity and a saddle-type shape are described. The enantiomers have been separated, and their absolute configuration was determined by VCD and ECD. The unprecedented molecular architecture is based on a cyclooctatriene core surrounded by an association of benzo[c]fluorene and ortho-phenylene units. 相似文献
73.
Marion Collinet-Fressancourt Nathalie Azaroual Jean-Marie Aubry Véronique Nardello-Rataj 《Tetrahedron letters》2010,51(50):6531-6534
The kinetic booster effect of dimethylsulfoxide on the chemical generation of singlet oxygen, 1O2, from the disproportionation of hydrogen peroxide catalyzed by molybdate ions in methanol has been evidenced by detection of the IR luminescence of 1O2 at 1270 nm and by 95Mo NMR spectroscopy. DMSO interacts rapidly, through a direct oxygen transfer with the stable tetraperoxomolybdate , leading to DMSO2 and to the unstable triperoxomolybdate , which releases 1O2. The procedure was applied to accelerate the dark singlet oxygenation of β-citronellol and α-terpinene. 相似文献
74.
Open shop problems with unit time operations 总被引:2,自引:0,他引:2
Peter Brucker Bernd Jurisch Marion Jurisch 《Mathematical Methods of Operations Research》1993,37(1):59-73
We show that them-machine open shop problem in which all operations have unit processing times can be polynomially transformed to a special preemptive scheduling problem onm identical parallel machines. Many results published recently as well as some new results are derived by using this transformation. The new results include solutions of open problems mentioned in a recent paper by Kubiak et al. p]A similar relationship is derived between no-wait open shop problems with unit time operations andm-machine problems with jobs having unit processing times.This work was supported by Deutsche Forschungsgemeinschaft (Project JoPTAG). 相似文献
75.
76.
We present a model of a new paramagnetic defect center which results from the interaction of atomic hydrogen with the MgO(1 0 0) surface. DFT calculations have been performed using periodic supercells and embedded cluster models where long-range polarization effects are included explicitly. The H atom promotes the creation of an oxygen vacancy (F center) by formation of the FS+(OH−) defect where an hydroxyl group is adsorbed near an electron trapped in an oxygen vacancy. This new center has some characteristics similar to those of the classical FS+ centers but a smaller formation energy; furthermore, being globally neutral, it can be treated also with supercell methods. 相似文献
77.
J. Friedl F. E. Wagner J. A. Sawicki D. C. Harris J. A. Mandarino Ph. Marion 《Hyperfine Interactions》1992,70(1-4):945-948
A survey of the197Au Mössbauer spectra of naturally occurring gold species is given. Gold minerals have been studied as natural specimens or as synthetic analogues. Gold impurities have been identified in pyrites and arsenopyrites. An example of the use of121Sb, and57Fe Mössbauer spectroscopy in characterizing gold-bearing ore minerals is given. 相似文献
78.
79.
80.
Sublette Kerry L. Plato Amy Woolsey Marion Yates R. G. Camp Carl Bair Tom 《Applied biochemistry and biotechnology》1996,57(1):1013-1019
Applied Biochemistry and Biotechnology - Preliminary experiments have shown thatT. denitrificans strain F can be immobilized in DuPont BIO-SEP beads and used to treat refinery spent sulfidic... 相似文献