全文获取类型
收费全文 | 16363篇 |
免费 | 1008篇 |
国内免费 | 1072篇 |
专业分类
化学 | 6103篇 |
晶体学 | 45篇 |
力学 | 202篇 |
综合类 | 66篇 |
数学 | 2098篇 |
物理学 | 2117篇 |
综合类 | 7812篇 |
出版年
2024年 | 60篇 |
2023年 | 96篇 |
2022年 | 239篇 |
2021年 | 298篇 |
2020年 | 345篇 |
2019年 | 278篇 |
2018年 | 288篇 |
2017年 | 371篇 |
2016年 | 468篇 |
2015年 | 545篇 |
2014年 | 717篇 |
2013年 | 953篇 |
2012年 | 909篇 |
2011年 | 1060篇 |
2010年 | 784篇 |
2009年 | 973篇 |
2008年 | 986篇 |
2007年 | 1018篇 |
2006年 | 1002篇 |
2005年 | 816篇 |
2004年 | 639篇 |
2003年 | 722篇 |
2002年 | 684篇 |
2001年 | 516篇 |
2000年 | 529篇 |
1999年 | 397篇 |
1998年 | 365篇 |
1997年 | 317篇 |
1996年 | 351篇 |
1995年 | 281篇 |
1994年 | 248篇 |
1993年 | 197篇 |
1992年 | 207篇 |
1991年 | 159篇 |
1990年 | 166篇 |
1989年 | 136篇 |
1988年 | 99篇 |
1987年 | 71篇 |
1986年 | 31篇 |
1985年 | 21篇 |
1984年 | 17篇 |
1983年 | 9篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1979年 | 11篇 |
1978年 | 6篇 |
1976年 | 4篇 |
1974年 | 5篇 |
1973年 | 9篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
N. U. Aldiyarov K. K. Kadyrzhanov E. M. Yakushev V. S. Zhdanov 《Hyperfine Interactions》2005,164(1-4):67-72
The conditions for achievement of high resolving power of depth selective conversion electron Mössbauer spectroscopy method at a combined installation ‘electron spectrometer–nuclear gamma-resonance spectrometer’ have been obtained. There has been made a considerable step in development of the method at its realization at a magnetic sector electron spectrometer with double focusing, equipped with electron source (a sample under investigation) of large-area and position-sensitive detector. The paper presents a prospective symmetrical version of a magnetic sector electron spectrometer that allows realizing more completely possibilities of the method. It is noted that the proposed method is particularly valuable for investigations of nanosystems, nanostrutures that contain Mössbauer nuclei. 相似文献
22.
Dedushenko S. K. Makhina I. B. Mar'in A. A. Mukhanov V. A. Perfiliev Yu. D. 《Hyperfine Interactions》2004,158(1-4):417-421
A colourless quartz crystal doped with 57Fe3+ was obtained by hydrothermal synthesis in an NH4F solution. The crystal was transformed into violet amethyst by gamma-irradiation. The change in colour was accompanied by changes in the Mössbauer spectrum that can be interpreted as the conversion of trivalent iron into the tetravalent state: Fe3+→Fe4+.
相似文献23.
24.
A new scheme for controlling photodissociation through preparation of a variationally optimized linear superposition of field free vibrational eigenstates is applied for selective control of IBr and HI dissociation. The dependence of photodissociation on various field parameters and initial conditions is examined to investigate the mechanistic basis of selective control. The parametric equations of motion approach for determining vibrational dynamics as a function of field parameters without having to solve the time dependent Schrödinger equation explicitly for each field parameter separately is outlined and its use to identify field characteristics which will provide the requisite population mix represented by the optimal linear superposition of vibrational states is advocated. 相似文献
25.
An effective residual interaction between particles and holes for shell model calculations around 208Pb, derived from the interaction between free nucleons, is compared with the measured properties of proton-hole neutron states
in 208Tl and the interaction between proton holes is adjusted to newly measured level energies in 206Hg. These interaction elements are particularly relevant for neutron-rich nuclei. The adjustment of two mixing elements reproduces
the known γ-decay data in 208Tl.
Received: 2 April 2002 / Accepted: 2 May 2002 相似文献
26.
灰铸铁的应力屈服曲面及其三维热弹塑性应力解析 总被引:4,自引:0,他引:4
对原有的灰铸铁件应力屈服曲面进行了合理的简化,使其在理论上合理,工程应用上更为方便。建立了灰铸铁件三维非稳态热弹塑性应力场的有限元方法。以灰铸铁哑铃件为对象,用新屈服曲面对其应力发展过程进行了模拟,且比较了用新旧屈服面计算得到的结果。 相似文献
27.
28.
余学义 《西安科技大学学报》1996,(4)
通过分析地下开采的影响,黄土覆盖层变形裂缝规律,提出以开采方法和工艺方式来控制或减弱地表变形裂缝破坏程度,并在保护地表建筑物的前提下,最大限度回收“三下”呆滞煤炭 相似文献
29.
T. Nakamura 《The European Physical Journal A - Hadrons and Nuclei》2002,13(1-2):33-37
We present the recent experimental results on the 6He structure studied by the 6Li(t, 3He)6He reaction at 336 MeV. Above the conspicuous peaks for ground and first excited states for 6He, we have observed a broad structures at E
x∼ 5 MeV, and E
x∼ 15 MeV. The angular distribution of this structure exhibits the dominance of a ΔL = 1 transition, indicating the existence of intruder dipole states at low excitation energies in 6He. A slight admixture of positive-parity states in this structure has been indicated as well.
Received: 1 May 2001 / Accepted: 4 December 2001 相似文献
30.
Hyperfine Interactions - The giant magnetoresistance (GMR) effect was an epoch-making discovery in the field of magnetic materials research. In this article, studies on magnetic multilayered... 相似文献