全文获取类型
收费全文 | 2368篇 |
免费 | 70篇 |
国内免费 | 28篇 |
专业分类
化学 | 1547篇 |
晶体学 | 27篇 |
力学 | 58篇 |
数学 | 448篇 |
物理学 | 386篇 |
出版年
2023年 | 20篇 |
2022年 | 71篇 |
2021年 | 84篇 |
2020年 | 50篇 |
2019年 | 53篇 |
2018年 | 45篇 |
2017年 | 43篇 |
2016年 | 91篇 |
2015年 | 75篇 |
2014年 | 99篇 |
2013年 | 145篇 |
2012年 | 138篇 |
2011年 | 148篇 |
2010年 | 100篇 |
2009年 | 102篇 |
2008年 | 138篇 |
2007年 | 139篇 |
2006年 | 117篇 |
2005年 | 106篇 |
2004年 | 97篇 |
2003年 | 79篇 |
2002年 | 55篇 |
2001年 | 37篇 |
2000年 | 38篇 |
1999年 | 32篇 |
1998年 | 37篇 |
1997年 | 24篇 |
1996年 | 28篇 |
1995年 | 29篇 |
1994年 | 25篇 |
1993年 | 19篇 |
1992年 | 25篇 |
1991年 | 20篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 16篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 20篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 3篇 |
1977年 | 8篇 |
1976年 | 3篇 |
1974年 | 4篇 |
1966年 | 1篇 |
排序方式: 共有2466条查询结果,搜索用时 0 毫秒
31.
We discuss several concepts of continuity, weaker than lower semicontinuity, but still implying the existence of a continuous selection for a closed convex valued multifunction from a paracompact Hausdorff topological space into a Banach space. In this way, an extension of Michael's celebrated selection theorem is given. The behavior of -envelop approximations, as well as the localization of continuous selections, is also discussed. 相似文献
32.
Krzysztof Bartkowski Maria Dimitrova Prof. Piotr J. Chmielewski Prof. Dage Sundholm Dr. Miłosz Pawlicki 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(68):15477-15482
Understanding of the aromatic properties and magnetically induced current densities of highly conjugated chromophores is important when designing molecules with strongly delocalized electronic structure. Linear extension of the triphyrin(2.1.1) skeleton with an annelated benzo[b]heterocycle fragment modifies the aromatic character by extending the electron delocalization pathway. Two-electron reduction leads to an antiaromatic triphyrin(2.1.1) ring and an aromatic benzo[b]heterocycle subunit. Current-density calculations provide detailed information about the observed pathways and their strengths. 相似文献
33.
34.
Litak Grzegorz Margielewicz Jerzy Gąska Damian Yurchenko Daniil Dąbek Krzysztof 《Nonlinear dynamics》2020,102(4):2125-2142
Nonlinear Dynamics - This paper examines the oscillations of a spherical pendulum with horizontal Lissajous excitation. The pendulum has two degrees of freedom: a rotational angle defined in the... 相似文献
35.
36.
37.
We present a detailed study of the Schrödinger picture space of states in theSU(2) Chern-Simons topological gauge theory in the simplest geometry. The space coincides with that of the solutions of the chiral Ward identities for the WZW model. We prove that its dimension is given by E. Verlinde's formulae. 相似文献
38.
Envelopes of splines in the projective plane 总被引:2,自引:0,他引:2
In this paper a family of curvesRiemannian cubicsinthe unit sphere and the real projective plane is investigated.Riemannian cubics naturally arise as solutions to variationalproblems in Riemannian spaces. It is remarkable to find thatan envelope of lines generated by a Riemannian cubic in onespace is (nearly) a Riemannian cubic in another space. 相似文献
39.
Monika Karpierz Jan Suchanicz Krzysztof Konieczny Dorota Sitko Pascal Marchet Urszula Lewczuk 《Phase Transitions》2015,88(7):662-667
The 0.5K0.5Bi0.5TiO3–0.5PbTiO3 ceramics were prepared by following a standard solid-state method. The Raman, thermal and dielectric properties of these ceramics were investigated. The X-ray measurements showed that samples have single perovskite-type structure with tetragonal symmetry. Dielectric study revealed that the dielectric behaviour of the investigated ceramics is rather of normal ferroelectrics with large thermal hysteresis. The transition temperature observed by means of differential scanning calorimetry measurements is in good agreement with that obtained from dielectric study. 相似文献
40.
A vanishing theorem and constraints are given for the Betti numbers of compact 3-Sasakian manifolds. 相似文献