全文获取类型
收费全文 | 393篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
化学 | 249篇 |
晶体学 | 5篇 |
力学 | 16篇 |
数学 | 34篇 |
物理学 | 98篇 |
出版年
2024年 | 7篇 |
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 14篇 |
2019年 | 18篇 |
2018年 | 10篇 |
2017年 | 20篇 |
2016年 | 19篇 |
2015年 | 18篇 |
2014年 | 15篇 |
2013年 | 32篇 |
2012年 | 31篇 |
2011年 | 29篇 |
2010年 | 16篇 |
2009年 | 17篇 |
2008年 | 24篇 |
2007年 | 18篇 |
2006年 | 17篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1971年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有402条查询结果,搜索用时 15 毫秒
91.
Peter Hammershøj Erling Thyrhaug Pernille Harris Pramod K. Ek Thomas L. Andresen Mads H. Clausen 《Tetrahedron letters》2017,58(16):1611-1615
The one-step synthesis and characterization of a series of regioisomerically pure 5-carboxy-seminaphthofluoresceins (5-carboxy-SNAFLs) is reported. The optical properties were determined in aqueous buffer at around biological pH, and highly pH sensitive, large Stokes-shift fluorophores with emission in the deep-red to near-infrared region were identified. 相似文献
92.
Pramod B. Pansuriya Muhammad D. Bala Glenn E.M. Maguire 《Supramolecular chemistry》2013,25(7-8):545-551
A novel isopropanol-pyrogallol[4]arene forms a layered structure via hydrogen bonding and C–H…π interactions. The layered structure results in encapsulation of one isopropanol molecule. The application of NMR methods to determine solution structures and crystal structures provides insight into host–guest properties and the molecular interactions between them. 相似文献
93.
94.
Sem Raj Tamang Andreas J. Achazi Haley S. Rust Pramod Dhungana Pere Miró James D. Hoefelmeyer 《Tetrahedron》2019,75(16):2365-2370
The title compound was evaluated as catalyst for Suzuki coupling of aryl halides (X?=?I, Br) with phenylboronic acid at room temperature. The rates of the reactions increase with increasing Hammet sigma constant of m-substituents on the arylhalide. The presence of ortho groups on the arylhalides had the effect of lowering the reaction rates. Density functional theory study of the mechanism for the formation of a Pd(0) complex from the title molecule was performed. Reductive elimination of chloride and the η4-BCCC moiety was endergonic and ruled out as a likely pathway. Instead, conversion of the title molecule to phenyl({2-[mesityl(quinolin-8-yl-κN)boryl]-3,5-dimethylphenyl}methyl-κC)palladium(II) complex is thermodynamically favored and predicted to further react with the solvent and the Suzuki coupling reagents to undergo reductive elimination of diphenyl to form a reactive Pd(0) complex. 相似文献
95.
96.
Lipases were found to catalyze Cannizzaro-type reaction of substituted benzaldehydes in aqueous medium at 30 °C without the addition of any external redox reagent. The ratio of alcohol product to acid product varied with nature of the substituted benzaldehyde, enzyme, and the presence of organic co-solvent. 相似文献
97.
98.
99.
100.
P. Poornesh Pramod K. Hegde M.G. Manjunatha A.V. Adhikari 《Optics & Laser Technology》2010,42(1):230-989
An experimental investigation of the third-order nonlinear optical properties of new poly{2-{5-[3,4-ditetradecyloxy-5-(1,3,4-oxadiazol-2-yl)thiophen-2-yl]-1,3,4-oxadiazol-2-yl}pyridine} (P) in tetrahydrofuran (THF) solution and in solid poly(methylmethacrylate) (PMMA) matrix, by Z-scan technique is reported. The Z-scan traces reveal that the composite films exhibit large negative nonlinear refractive index of the order 10−10 esu. The excited-state absorption cross-section was found to be larger than the ground-state absorption indicating that the operating nonlinear process is reverse saturable absorption (RSA). The new polymer P exhibits good optical power limiting properties in the nanosecond regime in solution and as well in solid PMMA matrix. 相似文献