全文获取类型
收费全文 | 403篇 |
免费 | 40篇 |
国内免费 | 109篇 |
专业分类
化学 | 376篇 |
力学 | 10篇 |
数学 | 47篇 |
物理学 | 119篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 5篇 |
2019年 | 6篇 |
2018年 | 6篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 26篇 |
2013年 | 34篇 |
2012年 | 29篇 |
2011年 | 35篇 |
2010年 | 23篇 |
2009年 | 35篇 |
2008年 | 32篇 |
2007年 | 22篇 |
2006年 | 20篇 |
2005年 | 19篇 |
2004年 | 25篇 |
2003年 | 26篇 |
2002年 | 35篇 |
2001年 | 37篇 |
2000年 | 16篇 |
1999年 | 27篇 |
1998年 | 24篇 |
1997年 | 12篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
排序方式: 共有552条查询结果,搜索用时 62 毫秒
551.
The synthesis of ditryptophan-pyridine conjugates and their binding to mercury ions is described. Conjugate 3 shows an excellent ability to sequester mercury from solution and rescue bacterial growth in a concentration-dependent survival assay. It is proposed that such compounds, composed primarily of bioessential/biodegradable components, could be potentially used as sequestrating agents for the removal of Hg(II) ions in detoxification strategies. 相似文献
552.
In this study, the non-linear analysis of the sunspot index is embedded in the non-extensive statistical theory of Tsallis (1988, 2004, 2009) , and . The q-triplet of Tsallis, as well as the correlation dimension and the Lyapunov exponent spectrum were estimated for the SVD components of the sunspot index timeseries. Also the multifractal scaling exponent spectrum f(a), the generalized Renyi dimension spectrum D(q) and the spectrum J(p) of the structure function exponents were estimated experimentally and theoretically by using the q-entropy principle included in Tsallis non-extensive statistical theory, following Arimitsu and Arimitsu (2001, 2000) and . Our analysis showed clearly the following: (a) a phase transition process in the solar dynamics from high dimensional non-Gaussian SOC state to a low dimensional non-Gaussian chaotic state, (b) strong intermittent solar turbulence and anomalous (multifractal) diffusion solar process, which is strengthened as the solar dynamics makes a phase transition to low dimensional chaos in accordance to Ruzmaikin, Zeleny and Milovanov’s studies (Zelenyi and Milovanov (1991) [21]); Milovanov and Zelenyi (1993) [22]; Ruzmakin et al. (1996) [26]) (c) faithful agreement of Tsallis non-equilibrium statistical theory with the experimental estimations of (i) non-Gaussian probability distribution function P(x), (ii) multifractal scaling exponent spectrum f(a) and generalized Renyi dimension spectrum Dq, (iii) exponent spectrum J(p) of the structure functions estimated for the sunspot index and its underlying non equilibrium solar dynamics. 相似文献