全文获取类型
收费全文 | 157201篇 |
免费 | 3021篇 |
国内免费 | 1641篇 |
专业分类
化学 | 87612篇 |
晶体学 | 2504篇 |
力学 | 6737篇 |
综合类 | 70篇 |
数学 | 14831篇 |
物理学 | 50109篇 |
出版年
2021年 | 1417篇 |
2020年 | 1609篇 |
2019年 | 1692篇 |
2018年 | 2023篇 |
2017年 | 2063篇 |
2016年 | 3049篇 |
2015年 | 2067篇 |
2014年 | 2928篇 |
2013年 | 6823篇 |
2012年 | 5716篇 |
2011年 | 6847篇 |
2010年 | 4822篇 |
2009年 | 4780篇 |
2008年 | 6438篇 |
2007年 | 6099篇 |
2006年 | 5911篇 |
2005年 | 5345篇 |
2004年 | 4795篇 |
2003年 | 4388篇 |
2002年 | 4308篇 |
2001年 | 5743篇 |
2000年 | 4171篇 |
1999年 | 3324篇 |
1998年 | 2283篇 |
1997年 | 2333篇 |
1996年 | 2207篇 |
1995年 | 2044篇 |
1994年 | 2008篇 |
1993年 | 1832篇 |
1992年 | 2299篇 |
1991年 | 2384篇 |
1990年 | 2211篇 |
1989年 | 2157篇 |
1988年 | 2117篇 |
1987年 | 2121篇 |
1986年 | 1930篇 |
1985年 | 2401篇 |
1984年 | 2410篇 |
1983年 | 1923篇 |
1982年 | 1924篇 |
1981年 | 1757篇 |
1980年 | 1741篇 |
1979年 | 2029篇 |
1978年 | 2105篇 |
1977年 | 2047篇 |
1976年 | 1978篇 |
1975年 | 1862篇 |
1974年 | 1842篇 |
1973年 | 1875篇 |
1972年 | 1237篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
We study the full counting statistics of transport electrons through a semiconductor two-level quantum dot with Rashba spin–orbit (SO) coupling, which acts as a nonabelian gauge field and thus induces the electron transition between two levels along with the spin flip. By means of the quantum master equation approach, shot noise and skewness are obtained at finite temperature with two-body Coulomb interaction. We particularly demonstrate the crucial effect of SO coupling on the super-Poissonian fluctuation of transport electrons, in terms of which the SO coupling can be probed by the zero-frequency cumulants. While the charge currents are not sensitive to the SO coupling. 相似文献
22.
23.
Jie Lu Ju-Kang Wu Yao Jiang Dr. Peng Tan Lin Zhang Yu Lei Prof. Xiao-Qin Liu Prof. Lin-Bing Sun 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(16):6490-6496
Hierarchically porous metal–organic frameworks (HP-MOFs) are promising in various applications. Most reported HP-MOFs are prepared based on the generation of mesopores in microporous frameworks, and the formed mesopores are connected by microporous channels, limiting the accessibility of mesopores for bulky molecules. A hierarchical structure is formed by constructing microporous MOFs in uninterrupted mesoporous tunnels. Using the confined space in as-prepared mesoporous silica, highly dispersed metal precursors for MOFs are coated on the internal surface of mesoporous tunnels. Ligand vapor-induced crystallization is employed to enable quantitative formation of MOFs in situ, in which sublimated ligands diffuse into mesoporous tunnels and react with metal precursors. The obtained hierarchically porous composites exhibit record-high adsorption capacity for the bulky molecule trypsin. The thermal and storage stability of trypsin is improved upon immobilization on the composites. 相似文献
24.
25.
26.
Applied Magnetic Resonance - The suggested approach allowed us to derive analytical expressions for modeling the shape of solid-echo signal and its time evolution for a system of three-spin groups... 相似文献
27.
28.
29.
30.
Mechanistic Aspects of a Highly Active Dinuclear Zinc Catalyst for the Co‐polymerization of Epoxides and CO2
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Stefan Kissling Peter T. Altenbuchner Dr. Maximilian W. Lehenmeier Dr. Eberhardt Herdtweck Dr. Peter Deglmann Dr. Uwe B. Seemann Prof. Dr. Bernhard Rieger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(22):8148-8157
The dinuclear zinc complex reported by us is to date the most active zinc catalyst for the co‐polymerization of cyclohexene oxide (CHO) and carbon dioxide. However, co‐polymerization experiments with propylene oxide (PO) and CO2 revealed surprisingly low conversions. Within this work, we focused on clarification of this behavior through experimental results and quantum chemical studies. The combination of both results indicated the formation of an energetically highly stable intermediate in the presence of propylene oxide and carbon dioxide. A similar species in the case of cyclohexene oxide/CO2 co‐polymerization was not stable enough to deactivate the catalyst due to steric repulsion. 相似文献