全文获取类型
收费全文 | 2483篇 |
免费 | 316篇 |
国内免费 | 340篇 |
专业分类
化学 | 168篇 |
晶体学 | 2篇 |
力学 | 150篇 |
综合类 | 86篇 |
数学 | 2024篇 |
物理学 | 709篇 |
出版年
2024年 | 5篇 |
2023年 | 19篇 |
2022年 | 49篇 |
2021年 | 52篇 |
2020年 | 58篇 |
2019年 | 63篇 |
2018年 | 73篇 |
2017年 | 79篇 |
2016年 | 77篇 |
2015年 | 65篇 |
2014年 | 101篇 |
2013年 | 249篇 |
2012年 | 117篇 |
2011年 | 133篇 |
2010年 | 148篇 |
2009年 | 141篇 |
2008年 | 189篇 |
2007年 | 198篇 |
2006年 | 160篇 |
2005年 | 146篇 |
2004年 | 117篇 |
2003年 | 124篇 |
2002年 | 119篇 |
2001年 | 99篇 |
2000年 | 117篇 |
1999年 | 97篇 |
1998年 | 57篇 |
1997年 | 59篇 |
1996年 | 55篇 |
1995年 | 37篇 |
1994年 | 22篇 |
1993年 | 13篇 |
1992年 | 9篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1936年 | 2篇 |
排序方式: 共有3139条查询结果,搜索用时 15 毫秒
201.
Let f:I→I be a unimodal map on I without homtervals. We characterize the α-limit set of each point in I by considering the consecutive renormalization process of f. 相似文献
202.
We investigate certain geometric properties of the spaces of idempotent measures. In particular, we prove that the space of idempotent measures on an infinite compact metric space is homeomorphic to the Hilbert cube. 相似文献
203.
Jonathan Spreer 《Discrete Mathematics》2011,(14):1295
We investigate slicings of combinatorial manifolds as properly embedded co-dimension 1 submanifolds. Focus is given to the case of dimension 3, where slicings are (discrete) normal surfaces. For the cases of 2-neighborly 3-manifolds as well as quadrangulated slicings, lower bounds on the number of quadrilaterals of slicings depending on its genus g are presented. These are shown to be sharp for infinitely many values of g. Furthermore, we classify slicings of combinatorial 3-manifolds which are weakly neighborly polyhedral maps. 相似文献
204.
1IntroductionConsideringthecoarseuessoftheequivalencerelationonunfoldingsusedinThom'scel-ebratedlistofsevenelementarycatastrophesWassermanndeveloped(r,s)-stableunfoldingtheoryinhispaper[4]andgavetheclassificationsof(1,3)-,(3,1)-stableunfoldings.Andclassificationof(2,2)-stableunfoldingswasgivenin[51.Forthecompletenessof(r,s)-stableunfoldingtheoryanditsapplicationinbifllrcationproblemundertheframeworkof(r,s)-equiv-alenceweclassify(2,1)-stableand(1,2)-stableunfoldingsofmaPgermswithcodimentions53… 相似文献
205.
John Stephenson 《Journal of statistical physics》1990,58(3-4):579-597
Asymptotic expressions for the positions of the centres (along the real axis) of high-order cycle cardioids closest to the limit point –2 in the Mandelbrot set are obtained by a combination of numerical and analytical methods. 相似文献
206.
207.
In a Birkhoff region of instability for an exact area-preserving twist map, we construct some orbits connecting distinct Denjoy minimal sets. These sets correspond to the local, instead of global minimum of the Lagrangian action. In the earlier work, Mather constructed connecting orbits among Aubry-Mather sets and the global minimizer of the Lagrangian action. 相似文献
208.
Hajime Kaji 《Geometriae Dedicata》2003,99(1):221-229
The reflexivity, the (semi-)ordinariness, the dimension of dual varieties and the structure of Gauss maps are discussed for Segre varieties, where a Segre variety is the image of the product of two or more projective spaces under Segre embedding. A generalization is given to a theorem of A. Hefez and A. Thorup on Segre varieties of two projective spaces. In particular, a new proof is given to a theorem of F. Knop, G. Menzel, I. M. Gelfand, M.M. Kapranov and A. V. Zelevinsky that states a necessary and sufficient condition for Segre varieties to have codimension one duals. On the other hand, a negative answer is given to a problem raised by S. Kleiman and R. Piene as follows: For a projective variety of dimension at least two, do the Gauss map and the natural projection from the conormal variety to the dual variety have the same inseparable degree? 相似文献
209.
分析了K图的性质,发现在K图中过某格的所有聚合圈相应的各乘积项所含变量与该格对应的最小项均有相同的极性,在此基础上提出了得到基于K图函数RM展开式在固定极性下的最小化的图形方法,该方法可以从K图直接得到函数的最小化的RM展开式,从而省略了传统的把K图转变为bj图再求最小化的步骤,它具有直观、简单、易于掌握等特点。此外,文中还提出了该方法的改进算法。 相似文献
210.
Eugene Lerman Susan Tolman 《Transactions of the American Mathematical Society》1997,349(10):4201-4230
In the first part of the paper, we build a foundation for further work on Hamiltonian actions on symplectic orbifolds. Most importantly, we prove the orbifold versions of the abelian connectedness and convexity theorems. In the second half, we prove that compact symplectic orbifolds with completely integrable torus actions are classified by convex simple rational polytopes with a positive integer attached to each open facet and that all such orbifolds are algebraic toric varieties.