全文获取类型
收费全文 | 245篇 |
免费 | 7篇 |
国内免费 | 2篇 |
专业分类
化学 | 189篇 |
晶体学 | 1篇 |
力学 | 3篇 |
数学 | 2篇 |
物理学 | 59篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 9篇 |
2012年 | 10篇 |
2011年 | 12篇 |
2010年 | 5篇 |
2009年 | 12篇 |
2008年 | 13篇 |
2007年 | 11篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 13篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 12篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1976年 | 3篇 |
1975年 | 4篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有254条查询结果,搜索用时 31 毫秒
71.
Malek M Morii M Fukuda S Fukuda Y Ishitsuka M Itow Y Kajita T Kameda J Kaneyuki K Kobayashi K Koshio Y Miura M Moriyama S Nakahata M Nakayama S Namba T Okada A Ooyabu T Saji C Sakurai N Shiozawa M Suzuki Y Takeuchi H Takeuchi Y Totsuka Y Yamada S Desai S Earl M Kearns E Messier MD Stone JL Sulak LR Walter CW Goldhaber M Barszczak T Casper D Gajewski W Kropp WR Mine S Liu DW Smy MB Sobel HW Vagins MR Gago A Ganezer KS Keig WE Ellsworth RW Tasaka S Kibayashi A Learned JG Matsuno S Takemori D 《Physical review letters》2003,90(6):061101
A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type antineutrinos that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, an upper bound of 1.2 macro nu(e) cm(-2) s(-1) was set for the supernova relic neutrino flux in the energy region E(nu)>19.3 MeV. 相似文献
72.
Nazikian R Shinohara K Kramer GJ Valeo E Hill K Hahm TS Rewoldt G Ide S Koide Y Oyama Y Shirai H Tang W 《Physical review letters》2005,94(13):135002
A low power polychromatic beam of microwaves is used to diagnose the behavior of turbulent fluctuations in the core of the JT-60U tokamak during the evolution of the internal transport barrier. A continuous reduction in the size of turbulent structures is observed concomitant with the reduction of the density scale length during the evolution of the internal transport barrier. The density correlation length decreases to the order of the ion gyroradius, in contrast with the much longer scale lengths observed earlier in the discharge, while the density fluctuation level remain similar to the level before transport barrier formation. 相似文献
73.
74.
75.
Efficient methods for stereoselective synthesis of various (E)-, (Z)-, and disubstituted 3-alkylideneoxindoles were investigated using tandem In-mediated carbometalation and ligandless Pd-catalyzed coupling reaction. 相似文献
76.
Kondo M Hayakawa Y Miyazawa M Oyama A Unoura K Kawaguchi H Naito T Maeda K Uchida F 《Inorganic chemistry》2004,43(19):5801-5803
A new two-dimensional coordination polymer with cobalticinium 1,1'-dicarboxylate (ccdc) incorporated in the framework has been prepared, the ccdc functioning as unique monoanionic dicarboxylate ligands. The compound shows a high redox activity based on the ccdc units. 相似文献
77.
Akihiro Oshima Satoshi Okubo Tomoko Gowa Oyama Masakazu Washio Seiichi Tagawa 《Radiation Physics and Chemistry》2012,81(5):584-588
Micro- and nano-fabrications of polystyrene (PS) having the atactic and syndiotactic structures were carried out with direct maskless etching using focused ion beam (FIB). Micro- and nano-scale structures were obtained with selective beam and material conditions avoiding the beam-heating and charge-up effects. The etching rates were different between atactic and syndiotactic PS. The rate of fabrication for syndiotactic PS shows higher than that of atactic one. Moreover, the direct etching was influenced by the molecular weight. The etching rate for the lower molecular weight became the faster. The FIB direct etching proceeds through the two steps (decomposition and desorption (outgas)). Both decomposition and desorption are influenced by both conformation (morphology) and configuration (stereoregularity). Furthermore, the beam profiles and fluence play the important roles to perform the nano-fabrication of PS. 相似文献
78.
D.W. Kum T. Oyama J. Wadsworth O.D. Sherby 《Journal of the mechanics and physics of solids》1983,31(2):173-186
An ultrahigh carbon (UHC) steel/mild steel laminated composite and a UHC steel/UHC steel laminate have been successfully manufactured by a roll-bonding procedure. Impact properties of these laminates, as well as of monolithic samples of the steels contained in these laminates, have been determined in the crackarrestor orientation over the temperature range 25 to ?196°C. Both notched and unnotched samples of the laminated composite and laminate have been tested. Extremely low ductile-to-brittle temperatures of ?140°C, and very high shelf energies (>325 J), have been found both for the laminated composites and the laminates. This remarkably good behavior is shown to be a result of notch blunting by delamination within the laminates. 相似文献
79.
Pure rotational spectra of trans- and cis-HOCO have been observed by Fourier transform microwave spectroscopy and the millimeter-wave double resonance technique, where gas phase spectra of the cis-conformer were observed for the first time. These radicals were produced in a supersonic jet by discharging a mixture gas of CO and H(2)O diluted in Ar. The molecular constants including the fine and hyperfine constants have been precisely determined for both conformers. Deuterated analogs have also been observed. The determined r(0) structures agree with these of ab initio calculations. The Fermi contact constants show a difference of the unpaired electron densities on the protons between the two conformers. Intensity of the spectrum for cis-HOCO was compared with that of trans-HOCO, leading to a conclusion that both conformers were produced nearly equally in abundance under the present experimental conditions. 相似文献
80.
Prof. Dr. Yutaka Matsuo Hiromi Oyama Dr. Iwao Soga Dr. Toshihiro Okamoto Dr. Hideyuki Tanaka Dr. Akinori Saeki Prof. Dr. Shu Seki Prof. Dr. Eiichi Nakamura 《化学:亚洲杂志》2013,8(1):121-128
The efficient nucleophilic addition of aryl Grignard reagents (aryl=4‐MeOC6H4, 4‐Me2NC6H4, Ph, 4‐CF3C6H4, and thienyl) to C60 in the presence of DMSO produced 1,2‐arylhydro[60]fullerenes after acid treatment. The reactions of the anions of these arylhydro[60]fullerenes with either dimethylphenylsilylmethyl iodide or dimethyl(2‐isopropoxyphenyl)silylmethyl iodide yielded the target compounds, 1‐aryl‐4‐silylmethyl[60]fullerenes. The properties and structures of these 1‐aryl‐4‐silylmethyl[60]fullerenes (aryl=4‐MeOC6H4, thienyl) were examined by electrochemical studies, X‐ray crystallography, flash‐photolysis time‐resolved microwave‐conductivity (FP‐TRMC) measurements, and electron‐mobility measurements by using a space‐charge‐limited current (SCLC) model. Organic photovoltaic devices with a polymer‐based bulk heterojunction structure and small‐molecule‐based p–n and p–i–n heterojunction configurations were fabricated by using 1‐aryl‐4‐silylmethyl[60]fullerenes as an electron acceptor. The most efficient device exhibited a power‐conversion efficiency of 3.4 % (short‐circuit current density: 8.1 mA/ cm2, open‐circuit voltage: 0.69 V, fill factor: 0.59). 相似文献