全文获取类型
收费全文 | 525篇 |
免费 | 5篇 |
国内免费 | 3篇 |
专业分类
化学 | 400篇 |
晶体学 | 6篇 |
力学 | 8篇 |
数学 | 41篇 |
物理学 | 78篇 |
出版年
2023年 | 4篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 7篇 |
2013年 | 25篇 |
2012年 | 18篇 |
2011年 | 27篇 |
2010年 | 5篇 |
2009年 | 13篇 |
2008年 | 43篇 |
2007年 | 32篇 |
2006年 | 32篇 |
2005年 | 42篇 |
2004年 | 36篇 |
2003年 | 23篇 |
2002年 | 22篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1997年 | 8篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 9篇 |
1977年 | 9篇 |
1976年 | 4篇 |
1975年 | 7篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1966年 | 2篇 |
排序方式: 共有533条查询结果,搜索用时 15 毫秒
81.
Hayakawa J Ikegami M Mizutani T Wahadoszamen M Momotake A Nishimura Y Arai T 《The journal of physical chemistry. A》2006,110(46):12566-12571
Photochemical properties of trans-3,3',5,5'-tetramethoxystilbene (TMST) have been studied in various polar solvents. The Stokes shift of trans-TMST was found to be increased with increasing solvent polarity. The fluorescence lifetime of trans-TMST experienced a large solvent effect changing from 2.3 ns in cyclohexane to 16.6 ns in acetonitrile. These results indicate that the excited singlet state of trans-TMST has a charge-transfer (CT) character. On the basis of the obtained results, the interior polar environment of a water-soluble TMST dendrimer is discussed. 相似文献
82.
[Structure: see text] tert-Butyl hypoiodite (t-BuOI) was found to be a powerful reagent for the cyclization of N-alkenylamides leading to a variety of N-heterocycles under extremely mild conditions. When N-alkenylsulfonamides were employed in the reaction, three- to six-membered saturated N-heterocycles were obtained in good to excellent yields with complete stereoselectivity. The method was applicable to the cyclization of alkenylbenzamide derivatives to afford N-, O- or N-, S-heterocycles. 相似文献
83.
A magnetic vortex core in a ferromagnetic circular nanodot has a resonance frequency originating from the confinement of the vortex core. By the micromagnetic simulation including the spin-transfer torque, we show that the vortex core can be resonantly excited by an ac (spin-polarized) current through the dot and that the resonance frequency can be tuned by the dot shape. The resistance measurement under the ac current successfully detects the resonance at the frequency consistent with the simulation. 相似文献
84.
Abstract It was investigated that, when an Al evaporated layer on a GaP (GaAs, GaAs1?y P y ) substrate was bombarded with total fluences of 0.1?1.0 × 1018 electrons cm?2 at 7 MeV and at 50°C, a thin heteroepitaxial layer of Al x Ga1?x P (Al x Ga1?x As, Al x Ga1?x As1?y P y ) crystal was grown on S-doped (111), (100) and (110) GaP [(110) Cr, O-doped GaAs, (100) Te-doped GaAS1?y P y ] substrates. Evidence for the creation of the epilayers before annealing was obtained from measurements using an X-ray diffractometer, an X-ray photoelectron spectrometer, a reflection high-energy electron diffractometer, a transmission electron microscope and a scanning transmission electron microscope. In the case of Al/GaP, the epitaxial layers of Al~0.25Ga~0.75P, Al~0.5Ga~0.5P and Al~0.75Ga~0.25P were grown on (111), (100) and (110) GaP substrates, respectively. Their compositions did not vary with the total electron fluence. 相似文献
85.
Toshiaki Yamaguchi Sota Shimizu Toshio Suzuki Yoshinobu Fujishiro Masanobu Awano 《Electrochemistry communications》2008,10(9):7656-1383
A high performance small-scale solid oxide fuel cell supported by a microtubular cathode was successfully developed via the extrusion of a (La0.8Sr0.2)0.97MnO3 cathode support and subsequent surface coating with a (La0.8Sr0.2)0.97MnO3–Ce0.9Gd0.1O1.95 activation layer followed by Sc2O3-doped ZrO2 electrolyte and NiO–Ce0.9Gd0.1O1.95 anode slurries. The cell was electrochemically evaluated in a humidified hydrogen (3% H2O) atmosphere, and exhibited a stable open circuit voltage above 1.05 V in the temperature range from 550 to 750 °C. Maximum power densities of 46.5, 163.2 and 452.8 mW cm−2 were generated at 550, 650 and 750 °C, respectively. The results indicate the realization of a stable and high performance cathode-supported micro SOFC. 相似文献
86.
87.
Daisuke Onoshima Noritada Kaji Manabu Tokeshi Yoshinobu Baba 《Analytical sciences》2008,24(2):181-183
We have developed a fluorescence resonance energy transfer (FRET) probe based on the conjugation of a quantum dot (QD) with dye (YOYO-3) intercalated DNA. The FRET-inducing electrostatic coupling of DNA and the QD made structural changes to the QD-DNA conjugates, which significantly prevented an enzymatic reaction between the DNA and a conventional restriction endonuclease (EcoRI). 相似文献
88.
89.
90.