全文获取类型
收费全文 | 418篇 |
免费 | 16篇 |
国内免费 | 3篇 |
专业分类
化学 | 258篇 |
力学 | 16篇 |
数学 | 41篇 |
物理学 | 122篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 14篇 |
2018年 | 22篇 |
2017年 | 14篇 |
2016年 | 33篇 |
2015年 | 15篇 |
2014年 | 32篇 |
2013年 | 49篇 |
2012年 | 38篇 |
2011年 | 51篇 |
2010年 | 23篇 |
2009年 | 30篇 |
2008年 | 26篇 |
2007年 | 18篇 |
2006年 | 14篇 |
2005年 | 8篇 |
2004年 | 6篇 |
2003年 | 1篇 |
2002年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
排序方式: 共有437条查询结果,搜索用时 0 毫秒
431.
In this Letter, we study the equation of circular loops with time-dependent tension in the BTZ black hole background. We obtain various cases where cosmic string loops finally collapse to form black holes. Also, we study effect of the BTZ black hole mass and angular momentum on the evolution of cosmic string loops. We find the critical values of initial radii as a limit for the cosmic string loops collapsing to form black holes. 相似文献
432.
The breakup reactions of 8B on a 12C target at 142, 285, 790, and 936MeV/nucleon have been studied. One-proton-removal cross sections, leading to the production of 7Be fragments in the ground and first excited states (at 0.429MeV), and the longitudinal momentum distributions of the 7Be fragments are obtained in the Eikonal approximation of the Glauber Model. The results of the calculations including the contribution of the 7Be to the ground and first excited states of 8B are compared with the available experimental data. One-proton-removal cross section for the 12C(8B, 7Be)X knockout reaction at 142, 285, 790, and 936 MeV/nucleon energy has been calculated. 8B and 7Be cross sections and momentum distribution are in a good agreement with available data. 相似文献
433.
This presented study is to make comparison of cross sections to produce 117Sb and 90Nb via different reactions with particle incident energy up to 70 MeV as a part of systematic studies on particle-induced activations on enriched Sn, Y2O3 and ZrO2 targets, theoretical calculation of production yield, calculation of required thickness of target and suggestion of optimum reaction to produce Antimony-117 and Niobium-90. 相似文献
434.
435.
436.
Research on Chemical Intermediates - An efficient one-pot synthesis of 2-aminothiazoles from methylcarbonyl and thiourea has been developed using montmorillonite-K10 as a catalyst at... 相似文献
437.