全文获取类型
收费全文 | 387篇 |
免费 | 8篇 |
国内免费 | 4篇 |
专业分类
化学 | 170篇 |
晶体学 | 3篇 |
力学 | 7篇 |
数学 | 64篇 |
物理学 | 155篇 |
出版年
2023年 | 3篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2017年 | 3篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 7篇 |
2013年 | 13篇 |
2012年 | 10篇 |
2011年 | 18篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 18篇 |
2007年 | 7篇 |
2006年 | 13篇 |
2005年 | 11篇 |
2004年 | 7篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 6篇 |
2000年 | 12篇 |
1999年 | 7篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 14篇 |
1994年 | 12篇 |
1993年 | 9篇 |
1992年 | 12篇 |
1991年 | 10篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1982年 | 3篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1972年 | 3篇 |
1968年 | 4篇 |
1944年 | 2篇 |
1943年 | 6篇 |
1932年 | 2篇 |
1931年 | 3篇 |
1922年 | 2篇 |
1880年 | 2篇 |
排序方式: 共有399条查询结果,搜索用时 0 毫秒
81.
Summary The application of solid-phase microextraction (SPME) for the flavour analysis of strawberry and apple fruits has been studied.
An SPME liquid sampling method based on poly(acrylate)-coated fibers was developed. Immediate thermal desorption of the adsorbed
compounds led to the formation of Maillard products due to the high concentration of carbohydrates and amines in the samples,
remaining on the surface of the fiber. Artefact formation was significantly reduced by rinsing the fiber with water prior
to thermal desorption. 相似文献
82.
83.
84.
Two-phase mixtures of diesel fuel and aqueous ethanol were microemulsified and data were collected on rheological properties, densities, water tolerance and critical solution temperatures. For the detergentless system of diesel fuel, aqueous ethanol and butanol it was found that the relative viscosity varied directly with the volume percent of the dispersed water phase and approximates Einstein's formula. With ionic systems it was found that relative viscosities varied with increasing volume percent of dispersed water by values greater than those predicted by Brinkman and Roscoe for suspensions of diverse particle size. Water tolerances for ionic systems were greater than those observed with 1-butanol. The nature of the surfactant and its concentration determine to a large degree the microemulsion's physical properties. 相似文献
85.
Antonio L. Braga Wolmar A. Severo Filho Ricardo S. Schwab Luciano Dornelles Diogo S. Lüdtke 《Tetrahedron letters》2009,50(25):3005-4730
The synthesis of selenium- and tellurium-containing nucleosides, derived from uridine is described herein. These compounds were prepared in a concise and short synthetic route in good yields, by nucleophilic substitution of a tosylate group by organoselenium nucleophiles. 相似文献
86.
87.
88.
S. Zein El Abedin P. Giridhar P. Schwab F. Endres 《Electrochemistry communications》2010,12(8):1084-1086
In this letter we show that nanocrystalline aluminium can be electrodeposited in the Lewis acidic ionic liquid based on AlCl3 (60 mol%) and 1-(2-methoxyethyl)-3-methylimidazolium chloride ([MoeMIm]Cl) (40 mol%). The study comprised cyclic voltammetry, potentiostatic polarization, and SEM and XRD measurements. The methoxy group in the side chain of the imidazolium cation significantly influences the electrodeposition pathway of Al in comparison to [EMIm]Cl/AlCl3. Cyclic voltammetry shows a significant current loop attributed to nucleation. Shiny Al layers are obtained with an average crystallite size of about 40 nm. 相似文献
89.
Schwab DE Tard C Brecht E Peters JW Pickett CJ Szilagyi RK 《Chemical communications (Cambridge, England)》2006,(35):3696-3698
X-ray absorption spectroscopic measurements and density functional calculations suggest that the hydrogenase H-cluster is best described as an electronically inseparable 6Fe-cluster due to extensive delocalization of frontier molecular orbitals of the iron centres, sulfide and the non-innocent dithiolate ligands. 相似文献
90.
G. Münzenberg P. Armbruster S. Hofmann F. P. Heßberger H. Folger J. G. Keller V. Ninov K. Poppensieker A. B. Quint W. Reisdorf K. -H. Schmidt J. R. H. Schneider H. -J. Schött K. Sümmerer I. Zychor M. E. Leino D. Ackermann U. Gollerthan E. Hanelt W. Morawek D. Vermeulen Y. Fujita T. Schwab 《Zeitschrift für Physik A Hadrons and Nuclei》1989,334(2):163-175
A new and transparent method for the analysis of recoil distance Doppler shift data is presented, which we call thedifferentialdecay curve method (DDCM). The DDCM can be used for singles as well as for coincidence plunger data and systematic errors can be discovered with it much easier than in the conventional analysis. In addition we propose a modification of the normal plunger which we call the differential plunger. With the differential plunger in principle it is possible to determine lifetimes from quantities measured at only one target to stopper distance. The DDCM was tested with lifetime data for120Xe and128Ba. 相似文献