全文获取类型
收费全文 | 124884篇 |
免费 | 31723篇 |
国内免费 | 34917篇 |
专业分类
化学 | 82278篇 |
晶体学 | 3397篇 |
力学 | 8436篇 |
综合类 | 2148篇 |
数学 | 18136篇 |
物理学 | 77129篇 |
出版年
2024年 | 513篇 |
2023年 | 1051篇 |
2022年 | 2526篇 |
2021年 | 2452篇 |
2020年 | 2504篇 |
2019年 | 2940篇 |
2018年 | 2816篇 |
2017年 | 4463篇 |
2016年 | 3599篇 |
2015年 | 4735篇 |
2014年 | 5247篇 |
2013年 | 7415篇 |
2012年 | 8165篇 |
2011年 | 10092篇 |
2010年 | 13798篇 |
2009年 | 14307篇 |
2008年 | 8804篇 |
2007年 | 7735篇 |
2006年 | 7214篇 |
2005年 | 6855篇 |
2004年 | 6762篇 |
2003年 | 5026篇 |
2002年 | 4981篇 |
2001年 | 5265篇 |
2000年 | 4792篇 |
1999年 | 3784篇 |
1998年 | 2766篇 |
1997年 | 2381篇 |
1996年 | 2620篇 |
1995年 | 3140篇 |
1994年 | 3146篇 |
1993年 | 3204篇 |
1992年 | 2760篇 |
1991年 | 2318篇 |
1990年 | 2008篇 |
1989年 | 2106篇 |
1988年 | 2015篇 |
1987年 | 1306篇 |
1986年 | 1314篇 |
1985年 | 933篇 |
1984年 | 1077篇 |
1982年 | 966篇 |
1981年 | 800篇 |
1980年 | 818篇 |
1979年 | 605篇 |
1978年 | 559篇 |
1977年 | 643篇 |
1976年 | 1052篇 |
1972年 | 532篇 |
1971年 | 445篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Features of the total disintegration events of heavyemulsion targets caused by 4.5A GeV/c16O
下载免费PDF全文
![点击此处可从《中国物理》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Total disintegration events produced by 4.5\,A GeV/c $^{16}$O--AgBr interactions are
analysed to investigate the characteristics of secondary charged particles produced
in such collisions. The multiplicity distributions of grey, black, and relativistic
charged particles can be well represented by Gaussian distribution. The average
multiplicity of grey particles is found to increase with the mass of projectile
increasing, while that of black particles is found to decrease with the mass of
projectile increasing. This result is in good agreement with the prediction of
fireball model. Finally, the linear dependence between grey and black particles is
observed, but there is no distinct dependence between the production of relativistic
charged particles and the target excitation. 相似文献
992.
993.
THE FIRST EXPERIMENT OF A THz GYROTRON WITH A PULSE MAGNET 总被引:1,自引:0,他引:1
T. Idehara H. Tsuchiya O. Watanabe La Agusu S. Mitsudo 《International Journal of Infrared and Millimeter Waves》2006,27(3):319-331
A THz gyrotron with a pulse magnet has been designed, constructed and operated in FIR FU. It is developed as one of high frequency
gyrotrons included in Gyrotron FU Series. The gyrotron has already achieved the first experimental result for high frequency
operations whose radiation frequency exceeds 1 THz. In this paper, the design detail and the operation test results for sub-terahertz
to terahertz range are described. The second harmonic operation is confirmed experimentally at the expected frequency of 1.005
THz due to TE6,11 cavity mode at the magnetic field intensity of 19.0 T. 相似文献
994.
强混合样本下回归加权估计的一致渐近正态性 总被引:5,自引:0,他引:5
在强混合样本下,讨论固定设计回归模型的加权函数估计的一致渐近正态性,给出一致渐近正态性的收敛速度,这个速度接近n-1/6. 相似文献
995.
The interaction of three forward beams in a BSO crystal is investigated under conditions when the two pump beams are anti-symmetrically detuned and the signal beam is phase modulated. For sinusoidal phase modulation the signal gain is shown to be dependent on the instantaneous frequency detuning. Single and double maxima in gain are obtained depending on the voltage amplitude applied to the piezoelectric mirror. For triangular phase modulation a slight asymmetry is found in the gain versus detuning curve. 相似文献
996.
997.
The melting curve of MgSiO分子动力学 MgSiO3钙钛矿 熔化温度 高压 melting temperature, molecular dynamics, high pressure Project supported by the National Natural Science Foundation of China (Grant Nos 10274055 and 10376021),the Natural Science Foundation of Gansu Province, China (Grant No 3ZS051-A25-027) and the Scientific Research Foundation of Education Bureau of Gansu Province, China (Grant No 0410-01). 2005-01-12 5/8/2005 12:00:00 AM The melting curve of MgSiO3 perovskite is simulated using molecular dynamics simulations method at high pressure. It is shown that the simulated equation of state of MgSiO3 perovskite is very successful in reproducing accurately the experimental data. The pressure dependence of the simulated melting temperature of MgSiO3 perovskite reproduces the stability of the orthorhombic perovskite phase up to high pressure of 130GPa at ambient temperature, consistent with the theoretical data of the other calculations. It is shown that its transformation to the cubic phase and melting at high pressure and high temperature are in agreement with recent experiments. 相似文献
998.
999.
In this paper, the structure of cubic CaTiO3 (001) surfaces with CaO and TiO2 terminations has been studied from density functional calculations. It has been found that the Ca atom has the largest relaxation for both kinds of terminations, and the rumpling of the CaO-terminated surface is much larger than that of TiO2-terminated surface. Also we have found that the metal atom relaxes much more prominently than the O atom does in each layer. The CaO-terminated surface is slightly more energetically favourahle than the TiO2-terminated surface from the analysis of the calculated surface energy. 相似文献
1000.