全文获取类型
收费全文 | 1330213篇 |
免费 | 25757篇 |
国内免费 | 7744篇 |
专业分类
化学 | 659789篇 |
晶体学 | 20317篇 |
力学 | 74464篇 |
综合类 | 108篇 |
数学 | 241421篇 |
物理学 | 367615篇 |
出版年
2021年 | 13496篇 |
2020年 | 15941篇 |
2019年 | 16051篇 |
2018年 | 12600篇 |
2016年 | 27851篇 |
2015年 | 20822篇 |
2014年 | 30461篇 |
2013年 | 74508篇 |
2012年 | 37169篇 |
2011年 | 33690篇 |
2010年 | 36849篇 |
2009年 | 39329篇 |
2008年 | 33267篇 |
2007年 | 28928篇 |
2006年 | 34977篇 |
2005年 | 27750篇 |
2004年 | 28965篇 |
2003年 | 27473篇 |
2002年 | 28640篇 |
2001年 | 27199篇 |
2000年 | 24120篇 |
1999年 | 22161篇 |
1998年 | 20910篇 |
1997年 | 20967篇 |
1996年 | 21084篇 |
1995年 | 19169篇 |
1994年 | 18619篇 |
1993年 | 18171篇 |
1992年 | 17962篇 |
1991年 | 18301篇 |
1990年 | 17439篇 |
1989年 | 17532篇 |
1988年 | 17086篇 |
1987年 | 17101篇 |
1986年 | 15992篇 |
1985年 | 22442篇 |
1984年 | 23756篇 |
1983年 | 19931篇 |
1982年 | 21651篇 |
1981年 | 20888篇 |
1980年 | 20252篇 |
1979年 | 20365篇 |
1978年 | 21706篇 |
1977年 | 21279篇 |
1976年 | 21004篇 |
1975年 | 19675篇 |
1974年 | 19335篇 |
1973年 | 19782篇 |
1972年 | 14291篇 |
1967年 | 12543篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Giang Truong Nguyen Prof. Dr. Liviu Ungur 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(30):e202200227
Employing radical bridges between anisotropic metal ions has been a viable route to achieve high-performance single-molecule magnets (SMMs). While the bridges have been mainly considered for their ability to promote exchange interactions, the crystal-field effect arising from them has not been taken into account explicitly. This lack of consideration may distort the understanding and limit the development of the entire family. To shed light on this aspect, herein we report a theoretical investigation of a series of N -radical-bridged diterbium complexes. It is found that while promoting strong exchange coupling between the terbium ions, the N -radical induces a crystal field that interferes destructively with that of the outer ligands, and thus reduces the overall SMM behavior. Based on the theoretical results, we conclude that the SMM behavior in this series could be further maximized if the crystal field of the outer ligands is designed to be collinear with that of the radical bridge. This conclusion can be generalized to all exchange-coupled SMMs. 相似文献
2.
3.
4.
5.
The European Physical Journal Special Topics - The removal of suspended particles from the interior of a thermocapillary liquid bridge via a finite-particle-size effect restricting the particle... 相似文献
6.
7.
8.
9.
R. Grosseuvres A. Comandini A. Bentaib N. Chaumeix 《Proceedings of the Combustion Institute》2019,37(2):1537-1546
The present work reports new experimental and numerical results of the combustion properties of hydrogen based mixtures diluted by nitrogen and steam. Spherical expanding flames have been studied in a spherical bomb over a large domain of equivalence ratios, initial temperatures and dilutions at an initial pressure of 100 kPa (Tini = 296, 363, 413 K; N2/O2 = 3.76, 5.67, 9; %Steam = 0, 20, 30). From these experiments, the laminar flame speed , the Markstein length L’, the activation energy Ea and the Zel'dovich β number have been determined. These parameters were also simulated using COSILAB® in order to verify the validity of the Mével et al. [1] detailed kinetic mechanism. Other parameters as the laminar flame thickness δ and the effective Lewis number Leeff were also simulated. These new results aim at providing an extended database that will be very useful in the hydrogen combustion hazard assessment for nuclear reactor power plant new design. 相似文献
10.