全文获取类型
收费全文 | 54524篇 |
免费 | 1451篇 |
国内免费 | 16篇 |
专业分类
化学 | 31968篇 |
晶体学 | 359篇 |
力学 | 933篇 |
综合类 | 1篇 |
数学 | 10734篇 |
物理学 | 11996篇 |
出版年
2023年 | 370篇 |
2022年 | 353篇 |
2021年 | 562篇 |
2020年 | 743篇 |
2019年 | 702篇 |
2018年 | 1068篇 |
2017年 | 1001篇 |
2016年 | 1907篇 |
2015年 | 1611篇 |
2014年 | 1619篇 |
2013年 | 3535篇 |
2012年 | 3221篇 |
2011年 | 3103篇 |
2010年 | 2066篇 |
2009年 | 1763篇 |
2008年 | 2607篇 |
2007年 | 2405篇 |
2006年 | 2099篇 |
2005年 | 2096篇 |
2004年 | 1843篇 |
2003年 | 1559篇 |
2002年 | 1363篇 |
2001年 | 1068篇 |
2000年 | 1071篇 |
1999年 | 780篇 |
1998年 | 614篇 |
1997年 | 544篇 |
1996年 | 680篇 |
1995年 | 509篇 |
1994年 | 577篇 |
1993年 | 552篇 |
1992年 | 575篇 |
1991年 | 481篇 |
1990年 | 545篇 |
1989年 | 452篇 |
1988年 | 445篇 |
1987年 | 411篇 |
1986年 | 397篇 |
1985年 | 534篇 |
1984年 | 525篇 |
1983年 | 410篇 |
1982年 | 437篇 |
1981年 | 437篇 |
1980年 | 366篇 |
1979年 | 373篇 |
1978年 | 363篇 |
1977年 | 336篇 |
1976年 | 376篇 |
1975年 | 346篇 |
1974年 | 342篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Novel mixed valence states have been obtained by the treatment of cobaltous ferrocyanides (Co+2FeII) and ferricyanides (Co+2FeIII) in an ozone flow. The CN stretching bands occur at 2085 cm–1 for Co+2FeII and at 2160 cm–1 for Co+2FeIII. After the ozonization process of Co+2FeII, an intense band approximately at 2125 cm–1 is detected. This intermediate band must correspond to a mixed valence state of the type: FeII–CN–Co2+–NC–FeIII Mössbauer spectra recorded in situ during the ozonization of Co+2FeII show the presence of two components: a doublet with isomer shift and quadrupole splitting values close to the cobalti ferricyanide and a very broad line for the mixed valence state. From the Mössbauer and infrared spectra of the aged samples of the Co+2FeII after ozonization, a relaxation process to the initial state of the samples is observed but the mixed valence state is stable. 相似文献
83.
84.
In this note, we characterize the regular probability measures satisfying the Choquet-Deny convolution equation =* on Abelian topological semigroups for a given probability measure . 相似文献
85.
For eachd1 there is a constantc
d>0 such that any finite setXR
d contains a subsetYX, |Y|[1/4d(d+3)]+1 having the following property: ifEY is an ellipsoid, then |E X|c
d |X|.On leave from the Mathematical Institute of the Hungarian Academy of Sciences, 1364 Budapest, P.O. Box 127, Hungary. Supported by a research fellowship from the Science and Engineering Research Council, U.K., and by Hungarian National Foundation for Scientific Research Grant No. 1812. 相似文献
86.
87.
88.
89.
The paper deals with the regime of advanced Bénard instabilities (described usually by the Lorenz system) in a more general system formulated firstly by Obukhov. It has been shown that triplet co-operation leads to characteristic courses where some new regularities occur. 相似文献
90.
The paper deals with the computer simulation of composite theoretical electron-diffraction patterns for metastable austenitic steels, containing deformation and martensite transformation structures. In many cases generated data can be used for interpretation of experimentally determined diffraction patterns. A few examples are presented which demonstrate that the application of the composite theoretical diffraction patterns may be complicated due to various diffraction effects which can modify the geometry of experimentally obtained diffraction patterns. 相似文献