全文获取类型
收费全文 | 671篇 |
免费 | 52篇 |
国内免费 | 3篇 |
专业分类
化学 | 602篇 |
晶体学 | 14篇 |
力学 | 5篇 |
数学 | 16篇 |
物理学 | 89篇 |
出版年
2023年 | 7篇 |
2022年 | 2篇 |
2021年 | 19篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 23篇 |
2017年 | 7篇 |
2016年 | 27篇 |
2015年 | 38篇 |
2014年 | 19篇 |
2013年 | 19篇 |
2012年 | 58篇 |
2011年 | 62篇 |
2010年 | 23篇 |
2009年 | 17篇 |
2008年 | 34篇 |
2007年 | 39篇 |
2006年 | 26篇 |
2005年 | 43篇 |
2004年 | 39篇 |
2003年 | 26篇 |
2002年 | 20篇 |
2001年 | 4篇 |
2000年 | 6篇 |
1997年 | 5篇 |
1995年 | 2篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 15篇 |
1983年 | 3篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 5篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1926年 | 1篇 |
排序方式: 共有726条查询结果,搜索用时 31 毫秒
621.
622.
623.
624.
625.
626.
627.
Shin-Ya Murakami Hiroshi Kominami Yoshiya Kera Shigeru Ikeda Hidenori Noguchi Kohei Uosaki Bunsho Ohtani 《Research on Chemical Intermediates》2007,33(3-5):285-296
Electron-hole recombination in nano-sized titanium(IV) oxide (TiO2) particles with various physical properties, which have been shown to be highly active photocatalysts, was evaluated by quantitative analysis of reduced titanium species (Ti3+), which might be formed at crystalline defective sites in TiO2 particles through photo-irradiation in the presence of a hole scavenger under deaerated conditions. These highly active photocatalyst samples were synthesized by hydrothermal crystallization in organic media (HyCOM method) and post-calcination. The Ti3+ density decreased with increasing calcination temperature (T c), and a linear correlation was observed between the Ti3+ density and rate constant for electron-hole recombination evaluated by femtosecond pump-probe diffuse reflection spectroscopy. Reaction rate (R Ag) and the amount of silver ions (Ag+) adsorbed on TiO2 particles ([Ag+]ads) were measured for photocatalytic silver metal deposition along with oxygen formation from an aqueous Ag+ solution under deaerated conditions, and the slope of the R Ag versus [Ag+]ads plot was determined. Kinetic investigation of this reaction showed that the reciprocal of the slope was approximately related to the ratio of the rates for electron-hole recombination and electron trapping (k r/k e ratio). The k r/k e ratio decreased as T c increased, and the logarithm of the k r/k e ratio was linearly related with Ti3+ density. These two parameters were used as a measure for the recombination properties of TiO2 photocatalysts with various physical properties. 相似文献
628.
Ulrich Jung Mathias Müller Norihiro Fujimoto Katsuyoshi Ikeda Kohei Uosaki Ursula Cornelissen Felix Tuczek Claudia Bornholdt Dordaneh Zargarani Rainer Herges Olaf Magnussen 《Journal of colloid and interface science》2010,341(2):366-375
Self-assembled monolayers of azobenzene-containing thiols on smooth Au(1 1 1) surfaces were studied by gap-mode surface-enhanced Raman spectroscopy (gap-mode SERS). By adsorption of colloidal Au nanoparticles on top of the organic adlayer highly reproducible spectra with strongly enhanced intensities are obtained. The observed bands indicate a trans conformation of the azobenzene moieties and are in agreement with structural data for the molecular layer. A characteristic dependency on the terminal and the spacer groups of the molecules is found. Samples prepared during illumination with UV light show pronounced spectral differences that can be attributed to azobenzene in cis conformation. 相似文献
629.
A palladium-catalyzed desymmetrization of alkyne-tethered silacyclobutanes to give silacycles possessing a tetraorganosilicon stereocenter has been developed, and high chemo- and enantioselectivities have been achieved by the use of a newly synthesized chiral phosphoramidite ligand. 相似文献
630.
Tahara K Tadokoro S Kawashima Y Hirashima N 《Langmuir : the ACS journal of surfaces and colloids》2012,28(18):7114-7118
We had previously developed surface-modified poly (D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) for use as a cellular drug delivery system. The cellular uptake of PLGA-NPs was mediated predominantly by endocytosis, and this uptake was increased by surface modifications with polymers, such as chitosan (CS) and polysorbate 80 (P80). In the present study, we prepared a cell-sized giant unilamellar vesicle (GUV) that mimics a cell membrane to investigate the interaction between cell membranes and NPs. Endocytosis-like uptake of NPs into a GUV was observed when the NPs were modified with nonionic surfactant P80 probably due to change in viscoelasticity and enhanced fusion activity of the membrane induced by P80. In contrast, unmodified NPs and those modified with CS were not internalized into a GUV. These results suggest that surface properties of PLGA-NPs are an important formulation parameter for their interaction with lipid membranes. 相似文献