全文获取类型
收费全文 | 2029篇 |
免费 | 82篇 |
国内免费 | 10篇 |
专业分类
化学 | 1497篇 |
晶体学 | 56篇 |
力学 | 24篇 |
数学 | 181篇 |
物理学 | 363篇 |
出版年
2023年 | 20篇 |
2022年 | 42篇 |
2021年 | 57篇 |
2020年 | 48篇 |
2019年 | 58篇 |
2018年 | 48篇 |
2017年 | 34篇 |
2016年 | 81篇 |
2015年 | 60篇 |
2014年 | 81篇 |
2013年 | 140篇 |
2012年 | 127篇 |
2011年 | 140篇 |
2010年 | 88篇 |
2009年 | 79篇 |
2008年 | 125篇 |
2007年 | 94篇 |
2006年 | 86篇 |
2005年 | 81篇 |
2004年 | 57篇 |
2003年 | 49篇 |
2002年 | 51篇 |
2001年 | 39篇 |
2000年 | 54篇 |
1999年 | 64篇 |
1998年 | 20篇 |
1997年 | 20篇 |
1996年 | 17篇 |
1995年 | 12篇 |
1994年 | 14篇 |
1993年 | 14篇 |
1992年 | 11篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1989年 | 11篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 12篇 |
1985年 | 21篇 |
1984年 | 13篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1977年 | 15篇 |
1976年 | 7篇 |
1973年 | 6篇 |
1972年 | 8篇 |
1965年 | 9篇 |
排序方式: 共有2121条查询结果,搜索用时 62 毫秒
971.
The reduction of sulfite in acidic medium was found to lead to the production of a radical anion that provides a versatile, sensitive and readily accessible diagnostic alternative to current electrochemical detection methodologies. 相似文献
972.
A metallamacrocycle in which conjugated terthiophene groups link the metals is assembled from a labile Pd complex. 相似文献
973.
Mahato KK Rai A Rai SB 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(3):431-436
Optical absorption, fluorescence and photoacoustic spectra of Dy3+ doped in oxyfluoroborate glass has been studied. Lifetime of 4F(9/2) level has been measured for different concentration of Dy3+. Effect of concentration quenching on the lifetime and the fluorescence yield has been observed and the mechanism of energy transfer discussed. The energy transfer from Pr3+ to Dy3+ has been observed and explained in a codoped glass containing Pr3+ + Dy3+. 相似文献
974.
975.
976.
977.
McCarthy FO Chopra J Ford A Hogan SA Kerry JP O'Brien NM Ryan E Maguire AR 《Organic & biomolecular chemistry》2005,3(16):3059-3065
Beta-sitosterol is the most prevalent plant cholesterol derivative (phytosterol) and can undergo similar oxidation to cholesterol, leading to beta-sitosterol oxides. The biological impact of phytosterol oxides has only been evaluated in a phytosterol blend (usually of beta-sitosterol, campesterol, stigmasterol and dihydrobrassicasterol). The lack of pure phytosterols, including beta-sitosterol, hinders the collection of significant toxicity data on the individual beta-sitosterol oxides. An efficient synthetic route to multi-gram quantities of pure beta-sitosterol is described here, together with the first syntheses and characterisation of pure beta-sitosterol oxides. 相似文献
978.
Lagutschenkov A Fanourgakis GS Niedner-Schatteburg G Xantheas SS 《The Journal of chemical physics》2005,122(19):194310
The existence of a transitional size regime where preferential stabilization alternates between "all-surface" (all atoms on the surface of a cluster) and "internally solvated" (one water molecule at the center of the cluster, fully solvated) configurations with the addition or the removal of a single water molecule, predicted earlier with the flexible, polarizable (many-body) Thole-type model interaction potential (TTM2-F), has been confirmed from electronic structure calculations for (H2O)n, n = 17-21. The onset of the appearance of the first "interior" configuration in water clusters occurs for n = 17. The observed structural alternation between interior (n = 17, 19, 21) and all-surface (n = 18, 20) global minima in the n = 17-21 cluster regime is accompanied by a corresponding spectroscopic signature, namely, the undulation in the position of the most redshifted OH stretching vibrations according to the trend: interior configurations exhibit more redshifted OH stretching vibrations than all-surface ones. These most redshifted OH stretching vibrations form distinct groups in the intramolecular region of the spectra and correspond to localized vibrations of donor OH stretches that are connected to neighbors via "strong" (water dimer-like) hydrogen bonds and belong to a water molecule with a "free" OH stretch. 相似文献
979.
980.
K. H. Neeb J. van Calker L. J. Ottendorfer P. Haas und Anita Schmidt 《Fresenius' Journal of Analytical Chemistry》1965,213(6):446-451
Ohne Zusammenfassung 相似文献