全文获取类型
收费全文 | 1508篇 |
免费 | 37篇 |
国内免费 | 7篇 |
专业分类
化学 | 1182篇 |
晶体学 | 11篇 |
力学 | 34篇 |
数学 | 116篇 |
物理学 | 209篇 |
出版年
2022年 | 7篇 |
2021年 | 14篇 |
2020年 | 18篇 |
2019年 | 24篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 25篇 |
2015年 | 24篇 |
2014年 | 25篇 |
2013年 | 62篇 |
2012年 | 83篇 |
2011年 | 109篇 |
2010年 | 49篇 |
2009年 | 44篇 |
2008年 | 96篇 |
2007年 | 99篇 |
2006年 | 91篇 |
2005年 | 63篇 |
2004年 | 72篇 |
2003年 | 72篇 |
2002年 | 63篇 |
2001年 | 22篇 |
2000年 | 32篇 |
1999年 | 18篇 |
1998年 | 23篇 |
1997年 | 15篇 |
1996年 | 26篇 |
1995年 | 9篇 |
1994年 | 26篇 |
1993年 | 13篇 |
1992年 | 19篇 |
1991年 | 19篇 |
1990年 | 13篇 |
1989年 | 13篇 |
1988年 | 19篇 |
1987年 | 18篇 |
1986年 | 19篇 |
1985年 | 19篇 |
1984年 | 21篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 13篇 |
1980年 | 14篇 |
1979年 | 17篇 |
1978年 | 15篇 |
1977年 | 7篇 |
1974年 | 7篇 |
1973年 | 6篇 |
1972年 | 5篇 |
1968年 | 6篇 |
排序方式: 共有1552条查询结果,搜索用时 15 毫秒
71.
We prove sharp Morawetz estimates — global in time with a singular weight in the spatial variables — for the linear wave, Klein-Gordon, and Schrödinger equations, for which we can characterise the maximisers. We also prove refined inequalities with respect to the angular integrability. 相似文献
72.
Dr. Ji-Rong Huang Dr. Muhammad Sohail Dr. Tohru Taniguchi Prof. Dr. Kenji Monde Prof. Dr. Fujie Tanaka 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(21):5947-5951
Spiro[4,5]decanes and polycyclic compounds bearing spiro[4,5]decane systems are important biofunctional molecules. Described are diastereoselective formal (4+1) cycloaddition reactions to afford oxindole-functionalized spiro[4,5]decanes and organocatalytic enantioselective Michael–Henry cascade reactions of the (4+1) cycloaddition products to generate spirooxindole polycyclic derivatives bearing the spiro[4,5]decane system. Spiro[4,5]decanes bearing oxindoles containing three stereogenic centers and spirooxindole polycycles having seven stereogenic centers, including two all-carbon chiral quaternary centers and one tetrasubstituted chiral carbon center, were obtained with high diastereo- and enantioselectivities. 相似文献
73.
74.
Applications of Clifford’s Geometric Algebra 总被引:1,自引:0,他引:1
We survey the development of Clifford’s geometric algebra and some of its engineering applications during the last 15 years. Several recently developed applications and their merits are discussed in some detail. We thus hope to clearly demonstrate the benefit of developing problem solutions in a unified framework for algebra and geometry with the widest possible scope: from quantum computing and electromagnetism to satellite navigation, from neural computing to camera geometry, image processing, robotics and beyond. 相似文献
75.
Dr. Yohei Hattori Tatsuya Maejima Yumi Sawae Jun-ichiro Kitai Prof. Masakazu Morimoto Dr. Ryojun Toyoda Prof. Hiroshi Nishihara Prof. Satoshi Yokojima Dr. Shinichiro Nakamura Prof. Kingo Uchida 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(50):11441-11450
The cyclization reaction of diarylethenes having an azulene ring occurs only via higher excited states. Novel diarylethenes having an azulene ring with a strong donor or acceptor were synthesized and examined in these reactions. A derivative having an electron-donating 1,3-benzodithiol-2-ylidenemethyl group at the 1-position of the azulene ring showed photochromism, whereas neither a derivative having a π-conjugated electron-donating group at the 3-position of the azulene ring nor derivatives having a π-conjugated electron-withdrawing group at the 1- or 3-position of the azulene ring showed any photochromism. The photoreactivities of these compounds were explained by calculating forces and bond orders on the excited states using density functional theory (DFT) and time-dependent (TD)-DFT. 相似文献
76.
77.
78.
79.
Tohru TakeiTakumi Ohki Yosuke HaradaNaoto Kumagai Hiroki FukumotoTake-aki Koizumi Akihiro MaedaTakahiro Kojima Yoshihisa SeiKohei Shiramizu Masahiro AbeMasashi Oota Takakazu Yamamoto 《Tetrahedron letters》2012,53(44):5907-5910
Dibromopyridines or dibromopyridone with -(CH2)m-SO3Na group(s) has been prepared via the reactions of the corresponding dibromopyridines with -OH and -NH2 groups with sultone. These compounds were converted into polymers with the -(CH2)m-SO3H groups via organometallic polycondensation. The polymer showed proton conducting properties and high stability toward oxidation. 相似文献
80.
Goto J. Oshima M. Sugawara M. Yamaguchi Y. Bi C. Bamba S. Morimoto T. 《Journal of Radioanalytical and Nuclear Chemistry》2017,314(3):1707-1714
Charged particle activation analysis (CPAA) is a rapid method with high accuracy which can analyze multi-elements simultaneously. Since multiple γ-ray detection method is expected to improve the detection efficiency and the signal-to-noise ratio, we study what design of the γ-ray detector array is the most suitable for CPAA. We take up four design candidates and investigated the responses by the radiation simulation code Geant 4. From the results, we have deduced the best design with 5 germanium detectors in close geometry. By inspecting the sensitivity in CPAA, the method is proved to be useful and applicable to 116 nuclides.
相似文献