全文获取类型
收费全文 | 213篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
化学 | 164篇 |
晶体学 | 1篇 |
力学 | 1篇 |
数学 | 6篇 |
物理学 | 47篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 4篇 |
2012年 | 6篇 |
2011年 | 12篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 16篇 |
2007年 | 13篇 |
2006年 | 15篇 |
2005年 | 14篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 7篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 2篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 11篇 |
1994年 | 1篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1974年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 15 毫秒
91.
Okubo S Okazaki T Hirose-Takai K Suenaga K Okada S Bandow S Iijima S 《Journal of the American Chemical Society》2010,132(43):15252-15258
The molecular orientation of ellipsoidal C(70) in single-walled carbon nanotubes (SWCNTs) depends on the tube diameter (d(t)). Photoluminescence (PL) studies reveal that the fullerene encapsulation effects on the optical transition energy of SWCNTs are significantly different for C(70) and C(60) at d(t) = 1.405-1.431 nm. This indicates that the transition from the "lying" alignment to the "standing" alignment occurs at d(t) ≈ 1.41 nm and the electronic states of SWCNTs are very sensitive to the interspacing between the encapsulated molecules and the SWCNTs. The present findings suggest that the electronic structure of SWCNTs is tunable not only by alternating the encapsulated molecules but also by controlling their molecular orientations, thus paving the way for development of novel SWCNT-based devices. 相似文献
92.
Ichikawa Y Okumura K Matsuda Y Hasegawa T Nakamura M Fujimoto A Masuda T Nakano K Kotsuki H 《Organic & biomolecular chemistry》2012,10(3):614-622
An efficient synthetic method for stereoselective construction of asymmetric quaternary carbon stereocenters, bearing nitrogen in the form of Boc-protected allyl amines, has been developed. This methodology is employed in the synthesis of marine alkaloids, manzacidin A and C. 相似文献
93.
Reported here is the preparation and property of 2D coordination networks composed of rodlike ligands with ethylene glycol side chains (1). Two 2D coordination networks, [[Co(1)2(H2O)2](NO3)2.1.5H2O]n and [[Ni(1)2(H(2)O)2](NO3)2.1.5H2O]n, have been synthesized and characterized by single-crystal X-ray diffraction, TG, DSC, UV-vis spectroscopy, and magnetic measurements. The structural analyses clarified that infinite 1D hydrogen-bond arrays composed of ethylene glycol chains contribute to the stabilization of 2D coordination frameworks, keeping the environment of substitution-active metal sites unchanged. They are more stable than a similar square-grid coordination network that does not possess an ethylene glycol chain on the ligand. We also succeeded in the direct observation of a reversible apical-ligand-exchange reaction at the cobalt(II) and nickel(II) ions in a single-crystal-to-single-crystal fashion because of the considerable stability as well as moderate flexibility of the framework. The cobalt-containing coordination network crystal showed chromic behavior depending on temperatures. Crystallographic and spectroscopic studies revealed that the color change of the crystal was attributed to the ligand-exchange process between H2O and a NO3 anion on the cobalt metal. Magnetic measurements indicated weak antiferromagnetic nearest-neighbor spin coupling between cobalt(II) ions. 相似文献
94.
Yoshida N Abe Y Shigeta H Nakajima A Ohsaki H Hashimoto K Watanabe T 《Journal of the American Chemical Society》2006,128(3):743-747
Flat films of methyl methacrylate-fluoroalkyl methacrylate copolymers were prepared, and their hydrophobicity was investigated. It was revealed that the F concentration directly affects the static hydrophobicity on the flat polymer surface in a systematic manner. Furthermore, the sliding behavior of a water droplet on these surfaces depends on the static hydrophobicity; the sliding motion changes from constant velocity to constant acceleration with an increase in the water contact angle. 相似文献
95.
Yoshihisa Kurosaki Dr. Toshiya Sagisaka Tomoo Matsushima Prof. Takashi Ubukata Prof. Yasushi Yokoyama 《Chemphyschem》2020,21(13):1375-1383
A chiral and thermally irreversible photochromic fulgide derivative incorporating an (R)-binaphthol unit in its acid anhydride moiety was used for the photoswitching of the pitch length of cholesteric liquid crystals. Since the absorption maximum wavelengths of both thermally stable photoisomers are nearly in the UV region (quasi-stealth photochromism), it can be exposed to visible light without inducing photochromic reactions. Therefore, when the photoswitching molecule is added to a permanent cholesteric liquid crystal whose reflection light wavelength is in the visible region, the UV light-induced photochromic reaction of the photoswitching molecule changes the wavelength of the reflection light in the visible light region. We have succeeded in regulating the color of cholesteric liquid crystalline cells between red and blue upon UV light irradiation. Attempts to introduce this system in polymer dispersed cholesteric liquid crystals are also described. 相似文献
96.
Naoya Yoshida Yuu Abe Hiroaki Shigeta Kazuyuki Takami Hisashi Osaki Toshiya Watanabe Kazuhito Hashimoto Akira Nakajima 《Journal of Sol-Gel Science and Technology》2004,31(1-3):195-199
Transparent hydrophobic polymer coating was prepared from methacrylate copolymer with molecular modeling in order to improve hydrophobicity and durability. Organic-inorganic hybridization improved the durability of the thin films. Furthermore the control of hydrophobicity and water droplet sliding properties of the flat coating was successfully performed. Water droplet sliding angle depended on the chemical structure of the materials, not on the hydrophobicity, while sliding motion simply depended on the hydrophobicity. 相似文献
97.
Jiye Jin Toshiya Hiroi Kiyohito Sato Tomoo Miwa Toyohide Takeuchi 《Analytical sciences》2002,18(5):549-554
In this study, a wall-jet flow cell with a GRC (graphite reinforced by carbon) electrode was designed for the amperometric detection of phenol and chlorophenols in liquid chromatography. The voltammetric responses of these analytes at the GRC electrodes are very similar to those at conventional glassy carbon electrodes. As the GRC electrodes were made of the same materials as commercially available mechanical pencil leads, they exhibit the advantages of low cost, simple surface renewability, lower residual current, and good electrode-to-electrode reproducibility, and thus can be used as disposable-type electrodes. Chromatographic separations of phenol, o-chlorophenol (o-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), and pentachlorophenol (PCP) were achieved with an ODS column using a mobile phase containing a mixture of CH3CN and H20 (40:60) containing 25 mM L-(+)tartaric acid (pH = 4.5). Amperometric detections were based on the electrochemical oxidation of these compounds around +0.9 V vs. Ag/AgCl. Under the optimized conditions, linear calibrations were obtained in a range up to 100 microM for phenol, o-CP, 2,4-DCP, 2,4,6-TCP, and 200 microM for PCP, with the correlation coefficients r2 of 0.9992, 0.9997, 0.9986, 0.9992, and 0.9968, respectively. The chromatographic detection limits for the tested analytes were obtained at pmol levels. 相似文献
98.
We investigate the oxidation process of a platinum surface by using the density functional theory approach under the periodic boundary condition. This oxidation process has received much attention because it is an initial step in the dissolution of platinum catalysts in polymer electrolyte fuel cells. In this research, we determine the optimized structure of ?? -PtO2-like and ??-PtO2-like oxidized platinum surfaces, which have recently been proposed on the basis of in situ X-ray diffraction analysis, at the Kohn Sham density functional theory (KS-DFT) generalized gradient approximation (GGA) level of theory. We discuss the phase transition from the ??-PtO2-like surface to the ??-PtO2-like surface, including the place-exchange reaction between oxygen and platinum atoms. We propose an intermediate structure in the phase transition, and show that the ??-PtO2-like structure can be formed directly from this intermediate structure. 相似文献
99.
Ichikawa Y Matsuda Y Okumura K Nakamura M Masuda T Kotsuki H Nakano K 《Organic letters》2011,13(10):2520-2523
The first nonracemic synthesis of (+)-geranyllinaloisocyanide, starting with (-)-lactic acid methyl ester, has been accomplished by exploiting a [3.3] sigmatropic rearrangement of allyl cyanate. The synthesis enables assignment of the S configuration of the C(3) isocyano substituted, quaternary stereogenic center in natural geranyllinaloisocyanide. 相似文献
100.
Tomohiko Nakajima Tetsuo Tsuchiya Toshiya Kumagai 《Applied Physics A: Materials Science & Processing》2011,104(3):981-985
Conducting LaNiO3 thin films have been fabricated on the borosilicate glass substrates with and without the uniaxial oriented RbLaNb2O7 seed layer by an excimer laser assisted metal organic deposition process with a KrF laser irradiation at 400°C in air. The
LaNiO3 thin film prepared on the seed layer had a very high Lotgering factor at F(100)=0.971, indicating highly (100)-oriented growth. The obtained LaNiO3 thin films with and without the seed layer showed low resistivity values, 4.42 and 1.02 mΩ cm at room temperature, respectively.
The ρ value of the (100)-oriented LaNiO3 film on the seed layer was comparably lowered to that of the films prepared at high process temperatures reported in the
previous reports. 相似文献