全文获取类型
收费全文 | 110篇 |
免费 | 0篇 |
专业分类
化学 | 82篇 |
晶体学 | 2篇 |
力学 | 7篇 |
数学 | 5篇 |
物理学 | 14篇 |
出版年
2022年 | 1篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 9篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2008年 | 13篇 |
2007年 | 4篇 |
2006年 | 7篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 4篇 |
1968年 | 1篇 |
排序方式: 共有110条查询结果,搜索用时 15 毫秒
51.
Hou Y Kondoh H Shimojo M Sako EO Ozaki N Kogure T Ohta T 《The journal of physical chemistry. B》2005,109(11):4845-4852
Synthesis and three-dimensional (3D) assembly of magnetite nanocrystals were realized by a one-pot procedure, in which Fe(acac)3 (acac = acetylacetonate) was partly reduced by hydrazine accompanied with ethylene glycol and spontaneously assembled into spherical nanostructures in the presence of surfactants including beta-cyclodextrin, oleic acid, and oleylamine. The size of the assembled spheres can coarsely be controlled in a limited range (100 nm to 2 microm) by changing the reaction temperature and the concentration of beta-cyclodextrin. X-ray diffraction and far Fourier transform infrared spectroscopy were employed to clarify the structures of magnetite in the assembled spheres. Electron diffraction pattern in a selected-area exhibits a high-crystallinity characteristic of cubic structure magnetite. We found that the formation of spherical magnetite aggregates highly depends on the presence of beta-cyclodextrin, while oleic acid and oleylamine improve the morphology of individual magnetite nanoparticles in the assembled spheres. In addition, the thermal gravimetric analysis and differential thermal analysis were applied to determine the content of magnetite in the products. Magnetic properties were also studied by using a superconducting quantum interference device magnetometer. 相似文献
52.
Hou Y Kondoh H Shimojo M Kogure T Ohta T 《The journal of physical chemistry. B》2005,109(41):19094-19098
Cobalt hydroxide nanoplatelets with a uniform hexagonal shape were prepared in high yield ( approximately 95%) by a facile hydrothermal route in the presence of poly(vinylpyrrolidone). This method provides a simple, low-cost, and large-scale route to produce beta-cobalt hydroxide nanoplatelets with an average diameter of 280 nm and a thickness of ca. 26 nm which show a predominant well-crystalline hexagonal brucite-like phase. Their thermal decomposition produced anisotropic nanoplatelets of cobalt oxides (CoO and Co3O4) under designed temperatures. The products were characterized by transmission electronic microscopy, selected-area electron diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetric, and thermogravimetric analysis. The magnetic properties of the products were investigated by a superconducting quantum interference device magnetometer. Co3O4 nanoplatelets exhibit a superparamagnetic behavior, and they might be a promising material to study the magnetic tunneling effect as anisotropic nanostructures. 相似文献
53.
The 1,3-dipolar cycloaddition reaction of 5-nitro-2-furyldiazomethane ( 1 ) with acrylonitrile, acrylamide, methyl acrylate, diethyl fumarate, methyl methacrylate and methyl cinnamate afforded the corresponding 3-substituted pyrazolines. ( 2a-f ). Similarly the pyrazoles ( 3b-d ) were prepared by addition of 1 to acetylenic compounds such as diethyl acetylenedicarboxylate, methyl phenylpropiolate and cyanoacetylene. Reaction of 1 with fumaronitrile and ω-nitro-styrene gave also the corresponding pyrazoles ( 3a and 3e ) instead of the pyrazolines. 3-(5′-Nitro-2′-furyl)-4-phenyl-5-carbomethoxypyrazoline ( 2f ) was oxidized with lead tetraacetate to the corresponding pyrazole ( 3f ), which was different from 3c , an addition product of 1 with methyl phenylpropiolate. 3-(5′-Nitro-2′-furyl)-5-carbamidopyrazoline ( 2b ) was pyrolyzed to the corresponding cyclopropane derivative 4 in low yield. 相似文献
54.
[reaction: see text] Triynes 1 could effectively be cyclotrimerized to annulated benzenes 2 by treatment with a catalytic amount of zinc powder, N-heterocyclic carbene, and CoCl(2) or FeCl(3). 相似文献
55.
Formation region and hydrogen desorption and absorption properties of the perovskite-type structure in LixNa1−xMgH3 with x = 0, 0.17, 0.33, 0.50 and 1.00 were studied in the present work. The experimental results are reasonably explained from the viewpoint of the geometric restrictions of ions that are described by so-called Goldschmidt tolerance factors. In NaMgH3 (x = 0), two plateau pressures of about 0.040 and 0.15 MPa were clearly detected by hydrogen pressure–composition (p–c) isotherm measurement at 673 K. Moreover, NaMgH3 can be reversibly formed in 1.0 MPa of hydrogen at 673 K, from the decomposed phase of elemental Na and Mg. 相似文献
56.
Y Imamura S Shibanoki T Kubo M Kogure Y Ishii Y Gotoh S Asai K Ishikawa 《Journal of chromatography. A》1990,526(1):282-288
57.
Atsunori Matsuda Yoshinori Kotani Toshihiro Kogure Masahiro Tatsumisago Tsutomu Minami 《Journal of Sol-Gel Science and Technology》2001,22(1-2):41-46
Anatase nanocrystals of 5 to 10 nm in diameter were formed in the silica-titania films by treatment with hot water. The formation of nanocrystals with hot water treatment was a unique phenomenon to the silica-titania system and the addition of organic polymers such as PEG was indispensable for the high dispersion of anatase nanocrystals in the films. The hydrolysis of Si—O—Ti bonds with hot water was considered to play an important role for the formation of anatase nanocrystals. The resultant films were transparent even after the formation of anatase nanocrystals. Acetaldehyde was photocatalytically decomposed into CO2 on the films which were subjected to a hot water treatment. The amounts of generated CO2 were twice of that of introduced acetaldehyde, indicating that the total acetaldehyde was completely decomposed to CO2. Anatase nanocrystals-dispersed films can be formed on various kinds of substrates including those with poor heat resistance such as organic polymers and organisms by this process, so that the substrates coated with the films are expected to be widely used for photocatalytic applications. 相似文献
58.
59.
60.
[reaction: see text] New types of four gelsenicine-related oxindole alkaloids were isolated from the leaves of Gelsemium elegans Benth. Gelsedilam (1) and 14-acetoxygelsedilam (2) are the first examples of 18,19-nor-type monoterpenoid indole alkaloids. Gelsefuranidine (3) and gelseiridone (4) have, respectively, an additional furan residue or an iridoid unit on the gelsenicine-related monoterpenoid indole alkaloid. 相似文献