全文获取类型
收费全文 | 22128篇 |
免费 | 2512篇 |
国内免费 | 2219篇 |
专业分类
化学 | 5845篇 |
晶体学 | 145篇 |
力学 | 4609篇 |
综合类 | 289篇 |
数学 | 11797篇 |
物理学 | 4174篇 |
出版年
2024年 | 65篇 |
2023年 | 265篇 |
2022年 | 425篇 |
2021年 | 496篇 |
2020年 | 712篇 |
2019年 | 641篇 |
2018年 | 637篇 |
2017年 | 729篇 |
2016年 | 868篇 |
2015年 | 639篇 |
2014年 | 993篇 |
2013年 | 1983篇 |
2012年 | 1112篇 |
2011年 | 1231篇 |
2010年 | 1046篇 |
2009年 | 1317篇 |
2008年 | 1363篇 |
2007年 | 1424篇 |
2006年 | 1220篇 |
2005年 | 1076篇 |
2004年 | 1008篇 |
2003年 | 906篇 |
2002年 | 858篇 |
2001年 | 712篇 |
2000年 | 718篇 |
1999年 | 654篇 |
1998年 | 580篇 |
1997年 | 489篇 |
1996年 | 403篇 |
1995年 | 345篇 |
1994年 | 293篇 |
1993年 | 257篇 |
1992年 | 218篇 |
1991年 | 206篇 |
1990年 | 156篇 |
1989年 | 106篇 |
1988年 | 79篇 |
1987年 | 71篇 |
1986年 | 65篇 |
1985年 | 79篇 |
1984年 | 89篇 |
1983年 | 53篇 |
1982年 | 65篇 |
1981年 | 49篇 |
1980年 | 40篇 |
1979年 | 37篇 |
1978年 | 18篇 |
1977年 | 18篇 |
1976年 | 12篇 |
1957年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
I. P. Kayumov 《Mathematical Notes》2005,78(3-4):498-502
In this paper, we prove Brennan's conjecture for conformal mappings f of the disk {z : | z| < 1} assuming that the Taylor coefficients of the function log(zf′(z)/f(z)) at zero are nonnegative. We also obtain inequalities for the integral means over the circle |z| = r of the squared modulus of the function zf′(z)/f(z). 相似文献
62.
Guy Bayada 《Journal of Mathematical Analysis and Applications》2003,282(1):212-231
The asymptotic behaviour of a Stokes flow with Tresca free boundary friction conditions when one dimension of the fluid domain tends to zero is studied. A specific Reynolds equation associated with variational inequalities is obtained and uniqueness is proved. 相似文献
63.
The general stability of single-layer cylindrical grids is studied in linear and nonlinear formulations. Dependence of the general buckling load on the geometry and stiffness parameters of a grid is established in an analytical form. Such grids are numerically analyzed for stability. It is established that the general buckling load is much less than the local buckling load. Typical general buckling modes are found. It is shown that such grids are weakly sensitive to imperfections 相似文献
64.
M. Ohsaki 《Archive of Applied Mechanics (Ingenieur Archiv)》2003,73(3-4):241-251
Summary Characteristics of optimal solutions under nonlinear buckling constraints are investigated by using a bar-spring model. It is demonstrated that optimization under buckling constraints of a symmetric system often leads to a structure with hill-top branching, where a limit point and bifurcation points coincide. A general formulation is derived for imperfection sensitivity of the critical load factor corresponding to a hill-top branching point. It is shown that the critical load is not imperfection-sensitive even for the case where an asymmetric bifurcation point exists at the limit point. 相似文献
65.
Tiegang Fang 《International Journal of Non》2008,43(9):1007-1011
The unsteady boundary layer over a semi-infinite flat plate was investigated in this paper. The flow involves the unsteady flow over a flat plate with leading edge accretion or ablation. The momentum boundary layer was further analyzed and it was shown that the leading edge ablation had a similar effect to the wall mass injection or upstream wall movement making the fluid blown away from the wall. The thermal boundary layer of the same flow was also studied. Results show that the leading edge accretion or ablation can greatly change the fluid motion and the heat transfer characteristics. 相似文献
66.
CONG Fuzhong & LI YongSchool of Mathematics Information Science Shandong Institute of Business Technology Yantai China Office of Mathematics Changchun Flight Academy of the Air Force Changchun China Department of Mathematics Jilin University Changchun China 《中国科学A辑(英文版)》2004,47(5):675-686
An effective stability result for generalized Hamiltonian systems is obtained by applying the simultaneous approximation technique due to Lochak. Among these systems, dimensions of action variables and angle variables might be distinct. 相似文献
67.
ZHANG LUMING 《应用数学学报》2005,(1)
本文首先分析线性Schrodinger方程一种高阶差分格式的构造方法,得到方程的耗散项.在此基础上对三次非线性Schrodinger方程,提出了一种精度为O(r2 h2)的差分格式,证明了该格式保持了连续方程的两个守恒量,且是收敛的与稳定的.并通过数值例子与已有隐格式进行了比较,结果表明,本文格式在计算量类似的情况下,提高了数值精度. 相似文献
68.
一类含有P-Laplacian算子的奇异边值问题解的确切个数 总被引:2,自引:0,他引:2
讨论了一类p-L ap lac ian算子型的奇异边值问题正解的确切个数以及解的性质. 相似文献
69.
The numerical prediction of the fields of inelastic strains (the linear invariant of the tensor of inelastic strains) in thermoset polyester/marble filler composite plates is discussed. A uniformly distributed load is applied to the plates, which lie on a steel base. The strain fields are predicted by means of the boundary element method by using creep test data for the composites and the polyester matrix itself. Identical creep tests were performed for two ages of the materials (1 month and 13 years), which allowed evaluating the aging effect. The study is carried out in two stages. At the first stage, the application of the generalized Maxwell-Gurevich equation to the thermoset matrix/mineral filler composite is demonstrated. The model parameters determined from the experimental creep data is used for the second stage, where the state of inelastic strains in the plates is predicted by applying the boundary element method. The influence of composite formulation (filler content) and physical aging of the polyester matrix on the state of inelastic strains in the plates is shown.__________Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 41, No. 2, pp. 145–156, March–April, 2005. 相似文献
70.
J. Giroire T. Ha‐Duong V. Moumas 《Mathematical Methods in the Applied Sciences》2005,28(13):1527-1552
This article deals with a boundary value problem for Laplace equation with a non‐linear and non‐local boundary condition. This problem comes from petroleum engineering and is used to obtain an estimation of well productivity. The non‐linear and non‐local boundary condition is written on the well boundary. On the outer reservoir boundaries, we have both Dirichlet and Neumann conditions. In this paper, we prove the existence and uniqueness of a solution to this problem. The existence is proved by Schauder theorem and the uniqueness is obtained under more restricted conditions, when the involved operator is a contraction. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献