全文获取类型
收费全文 | 829篇 |
免费 | 5篇 |
国内免费 | 6篇 |
专业分类
化学 | 541篇 |
晶体学 | 10篇 |
力学 | 10篇 |
数学 | 44篇 |
物理学 | 235篇 |
出版年
2019年 | 9篇 |
2018年 | 13篇 |
2017年 | 6篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2014年 | 18篇 |
2013年 | 29篇 |
2012年 | 24篇 |
2011年 | 51篇 |
2010年 | 23篇 |
2009年 | 17篇 |
2008年 | 50篇 |
2007年 | 37篇 |
2006年 | 46篇 |
2005年 | 45篇 |
2004年 | 38篇 |
2003年 | 29篇 |
2002年 | 37篇 |
2001年 | 29篇 |
2000年 | 18篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 14篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 7篇 |
1987年 | 9篇 |
1986年 | 19篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 11篇 |
1982年 | 10篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 13篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1974年 | 7篇 |
1973年 | 8篇 |
1972年 | 4篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有840条查询结果,搜索用时 15 毫秒
81.
82.
83.
84.
H. Kageyama K. Onizuka Y. Ueda M. Nohara H. Suzuki H. Takagi 《Journal of Experimental and Theoretical Physics》2000,90(1):129-132
The specific heat of a two-dimensional spin gap system SrCu2(BO3)2 realizing the Shastry-Suther-land model was measured between 1.3 and 25 K under various magnetic fields up to 12 T. The analysis based on an isolated dimer model in a low temperature region revealed that the value of the spin gap at zero field is Δ = 34.4 K. It turned out that Δ decreases in proportion to H due to the Zeeman splitting of the excited triplet levels. This simplest model, however, fails to reproduce the result in a high-temperature region, suggesting rather strong spin-spin correlation of the system. 相似文献
85.
Ken Naitoh Yasuo Takagi Kunio Kuwahara Egon Krause Katsuya Ishii 《Fluid Dynamics Research》1990,6(5-6):277-294
The transition to turbulent flow in the compression stage of a reciprocating engine is studied by obtaining the finite-difference numerical solutions to the governing Navier-Stokes equations without using explicit turbulence models. A computational method is developed under the assumption that the flow is in a low-subsonic regime with strong compression. The numerical method is a simple extension of the well known MAC method. Computations were performed for three different chamber geometries at the engine speed of 1400 rpm. The results of the computations clearly demonstrate the transient process in which large tumbling vortices break down into smaller ones near the end of the compression process. The transition process is also caught experimentally by using Mach-Zehnder interferometry. 相似文献
86.
87.
88.
Hiroya Kitahata Kiyoharu Tadanaga Tsutomu Minami Norifumi Fujimura Taichiro Ito 《Journal of Sol-Gel Science and Technology》2000,19(1-3):589-593
Hexagonal YMnO3 has a ferroelectric property with an optimal remanent polarization along the c-axis. The c-axis oriented YMnO3 thin films with a small leakage current were prepared by the sol-gel dipping method. The c-axis orientation of the films was promoted by the addition of diethanolamine to the Mn precursor solution. A heat treatment with multiple steps led to a dense film structure with fine grains. The dense structure resulted in the decrease of the leakage current. Furthermore, when the films were heat-treated in a vacuum, the leakage current became considerably small and the ferroelectricity of the YMnO3 thin films was observed even at room temperature. 相似文献
89.
Koji Takagi Tsuyoshi Nakagawa Hidenobu Takao 《Journal of polymer science. Part A, Polymer chemistry》2008,46(24):8141-8148
The Suzuki coupling polymerization between bis(carbazole) monomer ( CzDB ) and 9,9‐dihexylfluorene‐2,7‐diboronic acid was carried out to obtain PFCz‐PEDA0 having the number‐averaged molecular weight of 7000. The absorption and emission maximum wavelengths were observed at 344 and 408 nm, respectively. The quantum yield (QY) was relatively low (0.12) because of the photo‐induced electron transfer. Subsequently, CzPEDA ‐bearing 2,5‐bis(phenylethenyl)‐4‐decyloxyanisole (PEDA) segment sandwiched with 3‐bromocarbazole units was copolymerized to give PFCz‐PEDAn (n = 05, 10, 20, 35, and 50). The content of PEDA segment in polymer could be controlled by the monomer feed ratio. In CHCl3 solution, the absorbance at around 400 nm became larger with one isosbestic point at 370 nm, and the emission peak at 448 nm became prominent with increasing the PEDA content. The QY of polymer was increased as the PEDA content, which was a consequence of the fluorescence resonance energy transfer from carbazole‐containing chromophore (energy donor) to PEDA fluorophore (energy acceptor). In spin‐coated film, the maximum QY was obtained in PFCz‐PEDA05 having the most appropriate molar balance of energy donor and acceptor units. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8141–8148, 2008 相似文献
90.