全文获取类型
收费全文 | 241篇 |
免费 | 5篇 |
国内免费 | 11篇 |
专业分类
化学 | 132篇 |
力学 | 13篇 |
数学 | 67篇 |
物理学 | 45篇 |
出版年
2023年 | 2篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 3篇 |
2018年 | 3篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 3篇 |
2013年 | 11篇 |
2012年 | 24篇 |
2011年 | 17篇 |
2010年 | 10篇 |
2009年 | 7篇 |
2008年 | 17篇 |
2007年 | 13篇 |
2006年 | 12篇 |
2005年 | 11篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1988年 | 2篇 |
1986年 | 3篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 8篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 7篇 |
1971年 | 1篇 |
1966年 | 1篇 |
1929年 | 1篇 |
1926年 | 1篇 |
1922年 | 1篇 |
1915年 | 2篇 |
1908年 | 5篇 |
1907年 | 1篇 |
1876年 | 1篇 |
排序方式: 共有257条查询结果,搜索用时 0 毫秒
31.
Richard Aron V. I. Gurariy J. B. Seoane 《Proceedings of the American Mathematical Society》2005,133(3):795-803
We show that there is an infinite-dimensional vector space of differentiable functions on every non-zero element of which is nowhere monotone. We also show that there is a vector space of dimension of functions every non-zero element of which is everywhere surjective.
32.
33.
34.
We study the existence of separation theorems by polynomials that are invariant under a group action. We show that if G is a finite subgroup of \(\textit{GL}(n,{\mathbb {C}})\), K is a set in \({\mathbb {C}}^{n}\) that is invariant under the action of G and z is a point in \({\mathbb {C}}^{n}\setminus K\) that can be separated from K by a polynomial Q, then z can be separated from K by a G-invariant polynomial P. Furthermore, if Q is homogeneous then P can be chosen to be homogeneous. As a particular case, if K is a symmetric polynomially convex compact set in \({\mathbb {C}}^{n}\) and \(z\notin K\) then there exists a symmetric polynomial that separates z and K. 相似文献
35.
Martin Kaiser Aron Wosylus Birgit Gerke Rainer Pttgen Karel Proke Michael Ruck Thomas Doert 《无机化学与普通化学杂志》2019,645(6-7):564-569
The crystal structure of the important industrial orange pigment PO82, major part of the BASF Colors & Effects® product Sicopal® Orange K/L 2430, was solved from combined X‐ray single crystal, X‐ray and neutron powder diffraction, 119Sn Mössbauer spectroscopy, transmission electron microscopy, electron diffraction, and chemical analyses. The structure contains Keggin type clusters composed of four [M3O13] trimers consisting each of three MO6 octahedra that share edges and one common oxygen atom connecting the trimers to the central ZnO4 tetrahedron. The octahedrally coordinated metal atom position is mixed occupied by Ti4+, Sn4+, and Zn2+. Adjacent Keggin clusters share vertices and are further interconnected to four ZnO4 tetrahedra. This framework of interconnected MO6 octahedra and ZnO4 tetrahedra contains channels along [110], in which the Sn2+ cations are located. 相似文献
36.
37.
Groshaus JG Dujovne I Gallais Y Hirjibehedin CF Pinczuk A Tan YW Stormer H Dennis BS Pfeiffer LN West KW 《Physical review letters》2008,100(4):046804
Neutral spin texture (ST) excitations at nu=1/3 are directly observed for the first time by resonant inelastic light scattering. They are determined to involve two simultaneous spin flips. At low magnetic fields, the ST energy is below that of the magnetoroton minimum. With increasing in-plane magnetic field these mode energies cross at a critical ratio of the Zeeman and Coulomb energies of eta(c)=0.020+/-0.001. Surprisingly, the intensity of the ST mode grows with temperature in the range in which the magnetoroton modes collapse. The temperature dependence is interpreted in terms of a competition between coexisting phases supporting different excitations. We consider the role of the ST excitations in activated transport at nu=1/3. 相似文献
38.
The interaction of electron-hole pairs with lattice vibrations exhibits a wealth of intriguing physical phenomena such as the renowned Kohn anomaly. Here we report the observation in bilayer graphene of an unusual phonon softening that provides the first experimental proof for another type of phonon anomaly. Similar to the Kohn anomaly, which is a logarithmic singularity in the phonon group velocity [W. Kohn, Phys. Rev. Lett. 2, 393 (1959)], the observed phonon anomaly exhibits a logarithmic singularity in the optical-phonon energy. Arising from a resonant electron-phonon coupling effect, the anomaly was also expected, albeit not observed, in monolayer graphene. We propose an explanation for why it is easier to observe in bilayer samples. 相似文献
39.
The loading module of mycosubtilin: an adenylation domain with fatty acid selectivity 总被引:1,自引:0,他引:1
Hansen DB Bumpus SB Aron ZD Kelleher NL Walsh CT 《Journal of the American Chemical Society》2007,129(20):6366-6367
40.
Pintér A Haberhauer G Hyla-Kryspin I Grimme S 《Chemical communications (Cambridge, England)》2007,(36):3711-3713
Configurationally stable, propeller-like triarylphosphine and triarylphosphine oxide can be synthesized; a chiral scaffold based on Lissoclinum-cyclopeptides linked via three peptide bonds with a triphenylphosphine and triphenylphosphine oxide moiety, respectively, prevents effectively epimerization at the chiral phosphorus atom. 相似文献