全文获取类型
收费全文 | 2390篇 |
免费 | 243篇 |
国内免费 | 264篇 |
专业分类
化学 | 86篇 |
晶体学 | 4篇 |
力学 | 171篇 |
综合类 | 69篇 |
数学 | 2010篇 |
物理学 | 557篇 |
出版年
2024年 | 7篇 |
2023年 | 35篇 |
2022年 | 34篇 |
2021年 | 52篇 |
2020年 | 81篇 |
2019年 | 59篇 |
2018年 | 60篇 |
2017年 | 62篇 |
2016年 | 82篇 |
2015年 | 71篇 |
2014年 | 137篇 |
2013年 | 144篇 |
2012年 | 90篇 |
2011年 | 108篇 |
2010年 | 109篇 |
2009年 | 138篇 |
2008年 | 153篇 |
2007年 | 183篇 |
2006年 | 143篇 |
2005年 | 134篇 |
2004年 | 134篇 |
2003年 | 132篇 |
2002年 | 124篇 |
2001年 | 87篇 |
2000年 | 93篇 |
1999年 | 95篇 |
1998年 | 63篇 |
1997年 | 77篇 |
1996年 | 48篇 |
1995年 | 32篇 |
1994年 | 35篇 |
1993年 | 17篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1980年 | 1篇 |
1977年 | 2篇 |
1972年 | 1篇 |
1957年 | 1篇 |
1936年 | 1篇 |
排序方式: 共有2897条查询结果,搜索用时 0 毫秒
21.
p阶平均曲率算子Dirichlet问题的无穷多个解 总被引:1,自引:0,他引:1
§ 1 IntroductionSince the Mountain Pass Theorem came out,the existence of nontrivial solutions,pos-sibly multiple,ofnonlinear elliptic equations has been extensively studied.In this paper,weconsider the following Dirichlet problem for p-(generalized) mean curvature operator:-div((1 +| u|2 ) p- 22 u) =f(x,u) , x∈Ω,u∈ W1 ,p0 (Ω ) , (1 .1 )whereΩ is a bounded domain in Rn(n>p>1 ) with smooth boundary Ω.First let us recall the following Dirichletproblem for p-Laplacian:-Δpu≡ -div… 相似文献
22.
Guo-lian~Xu ChandrajitL.Bajaj 《计算数学(英文版)》2003,21(5):681-688
In this paper, we provide simple and explicit formulas for computing Riemannian curvatures, mean curvature vectors, principal curvatures and principal directions for a 2-dimensional Riemannian manifold embedded in IR^k with k ≥ 3. 相似文献
23.
YunYanYANG 《数学学报(英文版)》2003,19(1):63-68
In this paper,we derive an elementary identity for smooth solutions of the following equation:△u(x) K(x)e^2u(x)=0 in R^2 and use it to get some global properties of the solutions. 相似文献
24.
We establish a link between rational homotopy theory and the problem which vector bundles admit a complete Riemannian metric of nonnegative sectional curvature. As an application, we show for a large class of simply-connected nonnegatively curved manifolds that, if lies in the class and is a torus of positive dimension, then ``most' vector bundles over admit no complete nonnegatively curved metrics.
25.
In this paper,the authors obtain the Backlund transformation on time-like surfaces with constant mean curvature in R2,1.Using this transformation,families of surfaces with constant mean curvature from known ones can be constructed. 相似文献
26.
For an integer n3 and any positive number , we establish the existence of smooth functions K on
n
{0} with |K–1|, such that the equation
has a smooth positive solution which blows up at the origin (i.e., u does not have slow decay near the origin). Furthermore, we show that in some situations K can be extended as a Lipschitz function on
n
. These provide counter-examples to a conjecture of C.-S. Lin when n>4, and a question of Taliaferro.
Mathematics Subject Classification (2000)Primary 35J60; Secondary 53C21 相似文献
27.
Some curvature conditions about the geodesics emanating from a submanifold are obtained. These conditions are used to to study the topological and geometric properties of the ambient spaces which admit some minimal submanifolds. 相似文献
28.
We construct two examples of spaces homeomorphic to R
n
(n3) each of which has a closed geodesic and admits no isoperimetric inequality. The first is a complete polyhedral metric space of nonpositive curvature, and the second is an incomplete Riemannian space with nonpositive sectional curvatures. 相似文献
29.
In this article a simple form of expressing and studying the order conditions to be satisfied by starting algorithms for Runge–Kutta methods, which use information from the two previous steps is presented. In particular, starting algorithms of highest order for Runge–Kutta–Gauss methods up to seven stages are derived. Some numerical experiments with Hamiltonian systems to compare the behaviour of the new starting algorithms with other existing ones are presented. 相似文献
30.
We construct a new family of cyclic difference sets with parameters ((3
d
– 1)/2, (3
d – 1 – 1)/2, (3
d – 2 – 1)/2) for each odd d. The difference sets are constructed with certain maps that form Jacobi sums. These new difference sets are similar to Maschietti's hyperoval difference sets, of the Segre type, in characteristic two. We conclude by calculating the 3-ranks of the new difference sets. 相似文献