全文获取类型
收费全文 | 346篇 |
免费 | 7篇 |
国内免费 | 1篇 |
专业分类
化学 | 248篇 |
晶体学 | 2篇 |
力学 | 6篇 |
数学 | 2篇 |
物理学 | 96篇 |
出版年
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 2篇 |
2013年 | 18篇 |
2012年 | 19篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 7篇 |
2008年 | 21篇 |
2007年 | 20篇 |
2006年 | 17篇 |
2005年 | 22篇 |
2004年 | 14篇 |
2003年 | 11篇 |
2002年 | 14篇 |
2001年 | 12篇 |
2000年 | 8篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 10篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1967年 | 2篇 |
排序方式: 共有354条查询结果,搜索用时 15 毫秒
351.
Azidopropyl functionalized mesoporous silica SBA-15 were prepared with variable azide loadings of 0.03-0.7 mmol g(-1) (~2-50% of maximal surface coverage) through a direct synthesis, co-condensation approach. These materials are functionalized selectively with ethynylated organic moieties through a copper-catalyzed azide alkyne cycloaddition (CuAAC) or "click" reaction. Specific loading within a material can be regulated by either the azide loading or limiting the alkyne reagent relative to the azide loading. The immobilization of ferrocene, pyrene, tris(pyridylmethyl)amine (TPA), and iron porphyrin (FeTPP) demonstrates the robust nature and reproducibility of this two-step synthetic attachment strategy. Loading-sensitive pyrene fluorescence correlates with a theoretically random surface distribution, rather than a uniform one; site-isolation of tethered moieties ~15 ? in length occurs at loadings less than 0.02 mmol g(-1). The effect of surface loading on reactivity is observed in the oxygenation of SBA-15-[Cu(I)(TPA)]. SBA-15-[Mn(II)(TPA)]-catalyzed epoxidation exhibits a systematic dependence on surface loading. A comparison of homogeneous, site-isolated and site-dense complexes provides insight into catalyst speciation and ligand activity. 相似文献
352.
We developed hollow fibers with polycarbonate (PC) capillaries for use as a supporting tube. The PC capillaries were prepared by using a glass-drawing technique. Hollow PC fibers are safer and more flexible than hollow glass fibers because no fragments are released when the fibers are broken in various applications. Inner coating layers of silver and cyclic olefin polymer (COP) enhanced the reflection rate at the Er:YAG laser light wavelength. Using these fibers, we attained low loss for Er:YAG laser light transmission. By adjusting the drawing temperature in the fabrication of the PC capillaries, we created a smooth inner surface and uniform PC capillaries. We also demonstrated low-loss properties for visible pilot beams. 相似文献
353.
An effective procedure for decontamination of beta-lactam antibiotic residues or contaminants in the pharmaceutical manufacturing environment was investigated. Decontamination with solutions of hydrochloric acid, sodium hydroxide, hydrogen peroxide and hydroxylamine as agents for degradation was assessed. According to the results, the beta-lactam antibiotics were significantly degraded with sodium hydroxide and hydroxylamine. From the structural analysis of the degradation products of a cephem antibiotic, cefpodoxime proxetil, it was found that hydroxylamine degraded the beta-lactam structure under mild conditions, while sodium hydroxide did not. Therefore, hydroxylamine was considered an appropriate decontamination agent for beta-lactam antibiotics. 相似文献
354.
Hirotaka Nakajima Kaiji Uchida Dr. Takefumi Yoshida Dr. Yoji Horii Dr. Tetsu Sato Zhang Luming Dr. Satoshi Yamashita Dr. Yasuhiro Nakazawa Dr. Verdad C. Agulto Dr. Makoto Nakajima Dr. Brian K. Breedlove Dr. Masahiro Yamashita Dr. Hiroaki Iguchi Dr. Shinya Takaishi 《Chemphyschem》2023,24(4):e202200618
We report the water adsorption/desorption behavior and dynamic magnetic properties of the Pt−Cl chain complex [{[Pt(en)2][PtCl2(en)2]}3][{(MnCl5)Cl3}2] ⋅ 12H2O ( 1 ). Upon heating 1 in a vacuum, we obtained the dehydrated form [{[Pt(en)2][PtCl2(en)2]}3][{(MnCl5)Cl3}2] ( 1DH ). The framework structures of 1 and 1DH are identical, and both complexes underwent slow magnetic relaxation. However, the magnetic relaxation times for 1DH were shorter than those for 1 , meaning that the dynamic magnetic properties were controlled upon water vapor adsorption/desorption. From detailed analyses of the dynamic magnetic behavior, a phonon-bottleneck effect contributes to the magnetic relaxation processes. We discuss the mechanism for the changes in the magnetic relaxation processes upon dehydration in terms of the heat capacity and thermal conductivity. 相似文献