全文获取类型
收费全文 | 3769篇 |
免费 | 352篇 |
国内免费 | 450篇 |
专业分类
化学 | 1151篇 |
晶体学 | 17篇 |
力学 | 55篇 |
综合类 | 22篇 |
数学 | 123篇 |
物理学 | 2016篇 |
综合类 | 1187篇 |
出版年
2024年 | 11篇 |
2023年 | 49篇 |
2022年 | 104篇 |
2021年 | 108篇 |
2020年 | 110篇 |
2019年 | 105篇 |
2018年 | 101篇 |
2017年 | 114篇 |
2016年 | 120篇 |
2015年 | 109篇 |
2014年 | 133篇 |
2013年 | 270篇 |
2012年 | 154篇 |
2011年 | 185篇 |
2010年 | 114篇 |
2009年 | 173篇 |
2008年 | 187篇 |
2007年 | 197篇 |
2006年 | 229篇 |
2005年 | 189篇 |
2004年 | 154篇 |
2003年 | 164篇 |
2002年 | 209篇 |
2001年 | 201篇 |
2000年 | 182篇 |
1999年 | 147篇 |
1998年 | 94篇 |
1997年 | 97篇 |
1996年 | 74篇 |
1995年 | 88篇 |
1994年 | 69篇 |
1993年 | 41篇 |
1992年 | 49篇 |
1991年 | 42篇 |
1990年 | 33篇 |
1989年 | 29篇 |
1988年 | 17篇 |
1987年 | 13篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 15篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1979年 | 6篇 |
1978年 | 8篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1973年 | 3篇 |
排序方式: 共有4571条查询结果,搜索用时 140 毫秒
11.
12.
13.
Hyperfine Interactions - The technique of nuclear resonant scattering has spread out in various fields during the previous years. Those fields, which have rapidly developed and attracted the... 相似文献
14.
Alp E. E. Sturhahn W. Toellner T. S. Zhao J. Hu M. Brown D. E. 《Hyperfine Interactions》2002,144(1-4):3-20
Nuclear resonant inelastic X-ray scattering of synchrotron radiation is being applied to ever widening areas ranging from
geophysics to biophysics and materials science. Since its first demonstration in 1995 using the 57Fe resonance, the technique has now been applied to materials containing 83Kr, 151Eu, 119Sn, and 161Dy isotopes. The energy resolution has been reduced to under a millielectronvolt. This, in turn, has enabled new types of
measurements like Debye velocity of sound, as well as the study of origins of non-Debye behavior in presence of other low-energy
excitations. The effect of atomic disorder on phonon density of states has been studied in detail. The flux increase due to
the improved X-ray sources, crystal monochromators, and time-resolved detectors has been exploited for reducing sample sizes
to nano-gram levels, or using samples with dilute resonant nuclei like myoglobin, or even monolayers. Incorporation of micro-focusing
optics to the existing experimental setup enables experiments under high pressure using diamond-anvil cells. In this article,
we will review these developments.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
15.
Precise measurement of magnetic moment of short-lived β-emitting nuclei12B ( I π=1+, T 1/2=20.18 ms)
Zhou Dongmei Zheng Yongnan Du Enpeng Xu Yongjun Zhu Jiazheng Yuan Daqing Wang Zhiqiang Luo Hailong Zuo Yi Ma Ruigang Duan Xiao M. Mihara M. Fukuda K. Matsuta T. Minamisono Zhu Shengyun 《中国科学G辑(英文版)》2004,47(5):531-539
The spin polarized β-emitting nuclei12B (I
π=1+,T
1/2=20.18 ms) were produced by the nuclear reaction11B(d, p)12B and by the selection technique of the incident deuteron energy and the12B recoil angle following the nuclear reaction. The nuclear magnetic moment of the short-lived nuclei12B was measured by β-NMR with the β-NMR and β-NQR setup established for the first time in China. The nuclear magnetic moment
of12B was determined to be μ=0.99993±0.00048 nm org=0.99993±0.00048 after the precise correction of the Knight shift. 相似文献
16.
17.
主要研究在高空核爆的双指数类型电磁脉冲平面波入射时,地面附近的电磁脉冲环境。计算给出了在不同入射波状态,不同地表介质电气特性和距地面不同高度等条件下的电磁脉冲环境参数,归纳了一些规律性认识。结果显示:地面附近的电场会随距地面高度的不同而发生显著的变化,对于水平场分量,其反射场总是试图抵消入射场,而对于垂直场分量,其反射场叠加在入射场上,使得地面附近的垂直场强幅值一般大于入射波场强幅值;当入射波仰角增大时,合成电场波形的脉冲宽度会变宽;地表介质的电气特性参数不同也会对地面附近电场的波形和幅值造成一定的影响。 相似文献
18.
M. I. Al-Jarallah Fazal-ur-Rehman F. Abu-Jarad A. Al-Shukri 《Radiation measurements》2003,36(1-6):445-448
An indoor radon survey of a total of 269 dwellings, with one dosimeter per house, distributed in four Saudi Arabian cities was carried out. The objective of this survey was to carry out indoor radon measurements of two cities in the Eastern Province, Khafji and Hafr Al-Batin and to compare this with two cities in the Western Province, Al-Madina and Taif. The survey provides additional information about indoor radon concentrations in Saudi Arabia. The results of the survey in these cities showed that the overall minimum, maximum and average radon concentration were 7,137 and 30 Bqm−3, respectively. The lowest average radon concentration (20 Bqm−3) was found in Hafr Al-Batin, while the highest average concentration was found in Khafji (40 Bqm−3). 相似文献
19.
20.
用玻色子组态混合和玻色子表面δ相互作用研究核谱 总被引:2,自引:0,他引:2
用玻色子组态混合波函数和玻色子表面δ相互作用研究了三玻色子核46Ti和54Cr的sdgIBMI的能谱和E2跃迁概率,理论计算结果令人满意,比sdIBMI能拟合出更多的能级和E2跃迁概率,而且它们的误差更小. 说明g玻色子在振动区也起着重要的作用,同时进一步证明了这种玻色子组态混合模型是成功的. 相似文献