全文获取类型
收费全文 | 522篇 |
免费 | 21篇 |
国内免费 | 1篇 |
专业分类
化学 | 359篇 |
晶体学 | 3篇 |
力学 | 15篇 |
数学 | 67篇 |
物理学 | 100篇 |
出版年
2024年 | 2篇 |
2023年 | 2篇 |
2022年 | 12篇 |
2021年 | 20篇 |
2020年 | 12篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 2篇 |
2016年 | 24篇 |
2015年 | 16篇 |
2014年 | 15篇 |
2013年 | 31篇 |
2012年 | 42篇 |
2011年 | 38篇 |
2010年 | 24篇 |
2009年 | 17篇 |
2008年 | 33篇 |
2007年 | 40篇 |
2006年 | 25篇 |
2005年 | 22篇 |
2004年 | 22篇 |
2003年 | 10篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 6篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1988年 | 6篇 |
1987年 | 1篇 |
1985年 | 4篇 |
1984年 | 9篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有544条查询结果,搜索用时 15 毫秒
1.
2.
The influence of ionic strength on the complexes formed by natural bovine serum albumin (BSA), pH 5.4 (near the isoelectric point), and sodium dodecyl sulfate (SDS) in aqueous buffered (sodium acetate) solution was investigated by using surface tension, fluorescence and small angle X-ray scattering (SAXS) techniques. Ionic strength was varied by changing sodium acetate buffer concentration from 0.020 to 0.5 M. Surface tension revealed that SDS:BSA saturation binding occurs at psp = 42 +/- 2 mM, independent of the solution ionic strength. Further, SAXS curves are consistent with the necklace and bead model, where micelle-like aggregates are randomly distributed along the partial unfolded protein. Micelle-like aggregates grow from small spheres at 10 mM SDS to small ellipsoids (upsilon = 1.3 , ratio between the largest and the shortest axes) near psp, in good agreement with micellar aggregation numbers obtained by fluorescence, independent of salt concentration. Protein-bound micelles stop growing above psp and further SDS addition induces free-micelle formation. 相似文献
3.
Lipids in foods contain a wide variety of fatty acids differing in chain length, degree of unsaturation, position and configuration of double bonds and the presence of special functional groups. Modern capillary gas chromatography offers excellent separation of fatty acids. Fused-silica capillary columns with stationary phases of medium polarity and non-polar methylsilicone stationary phases successfully separate most of the natural fatty acids. Special applications, such as the separation of complex cis-trans fatty acid mixtures and cyclic fatty acids, required particular chromatographic conditions, including the use of very long capillary columns or more polar stationary phases. The derivatization methods for the preparation of fatty acid esters also need to be optimized to obtain accurate quantitative results. This paper reviews the derivatization techniques, capillary columns and stationary phases commonly used in the gas chromatography of fatty acids in food. 相似文献
4.
van den Brand JF Ent R Anthony PL Arnold RG Arrington J Beise EJ Belz JE Bosted PE Bulten H Chapman MS Coulter KP Dietrich FS Epstein M Filippone BW Gao H Gearhart RA Geesaman DF Hansen J Holt RJ Jackson HE Jones CE Keppel CE Kinney ER Kuhn S Lee K Lorenzon W Lung A Makins NC Margaziotis DJ McKeown RD Milner RG Mueller B Napolitano J Nelson J O'Neill TG Papavassiliou V Petratos GG Potterveld DH Rock SE Spengos M Szalata ZM Tao LH van Bibber K Wasson DA White JL Zeidman B 《Physical review D: Particles and fields》1995,52(9):4868-4871
5.
Alessandro D'Aprano Camillo La Mesa Noemi Proietti Bianca Sesta Sonia Tatone 《Journal of solution chemistry》1994,23(12):1331-1346
The interactions between octyl--D-glucoside and glycine in water have been investigated by surface tension, viscosity, and density measurements. The results show that the -amino acid causes an unexpected lowering of the critical micellar concentration of octyl--D-glucoside. Such a finding has been interpreted in temss of dipole-dipole interactions between the hydrophilic site of the surfactant and the peptidic cosluttes. From three to seven amino acid molecules have been estimated to be coordinated with each glucoside unity in the micellar state. The research has been extended to glycine oligopeptides and L-lysine. The latter compound has effects similar to those observed with glycine whereas diglycine and triglycine show weaker effects on the micellization process. 相似文献
6.
Makins NC Ent R Chapman MS Hansen J Lee K Milner RG Nelson J Arnold RG Bosted PE Keppel CE Lung A Rock SE Spengos M Szalata ZM Tao LH White JL Coulter KP Geesaman DF Holt RJ Jackson HE Papavassiliou V Potterveld DH Zeidman B Arrington J Beise EJ Belz E Filippone BW Gao H Lorenzon W Mueller B McKeown RD O'Neill TG Epstein M Margaziotis DJ Napolitano J Kinney E Anthony PL van Bibber K Dietrich FS Gearhart RA Patratos GG Kuhn SE van den Brand JF Bulten H Jones CE 《Physical review letters》1994,72(13):1986-1989
7.
8.
Bonini BF Comes-Franchini M Mazzanti G Ricci A Sala M 《The Journal of organic chemistry》1996,61(21):7242-7243
9.
Alvisi D Blart E Bonini BF Mazzanti G Ricci A Zani P 《The Journal of organic chemistry》1996,61(20):7139-7146
The palladium-catalyzed desilylation-arylation of substituted vinylsilanes by p-iodoanisole in the presence of bidentate phosphine ligands is described. Apart from enhancing the rate of the reaction considerably, heteroatom-based functional groups in the vinylsilane moiety have a profound influence on the regiochemistry. A catalytic cycle for the chelation-controlled desilylation-arylation reaction involving five- and six-membered chelate rings is proposed. 相似文献