全文获取类型
收费全文 | 595篇 |
免费 | 35篇 |
国内免费 | 5篇 |
专业分类
化学 | 458篇 |
晶体学 | 3篇 |
力学 | 16篇 |
数学 | 53篇 |
物理学 | 105篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 19篇 |
2019年 | 20篇 |
2018年 | 11篇 |
2017年 | 20篇 |
2016年 | 29篇 |
2015年 | 19篇 |
2014年 | 32篇 |
2013年 | 40篇 |
2012年 | 40篇 |
2011年 | 51篇 |
2010年 | 21篇 |
2009年 | 27篇 |
2008年 | 28篇 |
2007年 | 29篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 6篇 |
2003年 | 5篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 14篇 |
1999年 | 9篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 9篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1987年 | 7篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1972年 | 3篇 |
1961年 | 1篇 |
排序方式: 共有635条查询结果,搜索用时 6 毫秒
631.
Raimondi B La Manna G 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(3):933-938
The structure and the Raman vibrational spectrum of the complex Br(2)...3-Br-pyridine are determined by DFT calculations using different parametrizations. The calculations are performed taking into account the effects of the dichloromethane as solvent by the CPCM method. A value of 39 kJ mol(-1) for the formation enthalpy and of 1 kJ mol(-1) for the formation free energy at room temperature in presence of the solvent is found. The predicted Raman spectrum is compared with the experimental one and the essential features of the spectrum are well reproduced by the B3LYP parametrization. The intensity changes of the bands when going from the free moieties to the complex are also generally correctly predicted by the theoretical treatment. 相似文献
632.
Kalyan Kumar PasunootiHua Chai Chantel Nixon JensenBala Kishan Gorityala Siming WangXue-Wei Liu 《Tetrahedron letters》2011,52(1):80-84
The synthesis of dihydropyrimidinones via a clean multi-component Biginelli reaction under microwave irradiation is reported. The copper-catalyzed process proved to be simple, efficient, economical, and environmentally friendly. 相似文献
633.
Glucose stabilized palladium nanoparticles (PdNPs) have been prepared and the application of NPs in catalyzing both Suzuki and Heck reactions has been explored in aqueous media under microwave conditions. Both electron-rich and electron-deficient aryl halides can be coupled with a variety of boronic acids and styrene to access a wide variety of biaryl compounds and substituted alkenes in good to excellent yields. The catalyst can be recycled and reused four times with minimally affecting the morphology and efficiency of the nanoparticles. A plausible reaction mechanism has been proposed. 相似文献
634.
A simple chemical reduction method is followed to grow CdS nanoparticles at room temperature with different duration of time. The grown samples are ultrasonicated in ethanol. The dispersed samples are characterized using electron diffraction techniques. Simultaneously optical absorption, photoluminescence and longtime photorelaxation of these samples are studied at room temperature. An increase in band gap is observed in each case as compared to bulk CdS. Also particle size increases with increase of growth time and hence there is decrease of band gap with increase of growth duration. Simultaneously long time relaxation increases with increase of growth time. An attempt is made to correlate the structural, optical, electrical and opto‐electrical properties. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
635.
Vijay Babu Pathi Arindam Manna Ravuri Srinath Supriyo Adhikary Prof. Dr. Biswadip Banerji 《European journal of organic chemistry》2023,26(28):e202300256
Regioselective synthesis of N-fused benzimidazo-indolo-isoquinoline heterocycles via Pd-catalyzed domino coupling reaction of 1-(1-methyl-1H-indol-2-yl)-1H-benzimidazoles and aryl halides was developed. This one pot methodology proceeded via a five-member carbopalladacycle intermediate and provided direct and facile route to access structurally complex polyheterocycles in moderate to good yields. These unique hybrid molecules resembled structural similarity with naturally isolated alkaloids. Notably, the present domino process occurred through activation of three C−H bonds and the simultaneous formation of two new C−C bonds in one-shot. These molecules exhibited strong solid and solution phase fluorescence and their emission spectra in both the medium are reported here. 相似文献