全文获取类型
收费全文 | 3568篇 |
免费 | 298篇 |
国内免费 | 337篇 |
专业分类
化学 | 121篇 |
晶体学 | 2篇 |
力学 | 174篇 |
综合类 | 78篇 |
数学 | 3144篇 |
物理学 | 684篇 |
出版年
2024年 | 5篇 |
2023年 | 30篇 |
2022年 | 33篇 |
2021年 | 63篇 |
2020年 | 75篇 |
2019年 | 79篇 |
2018年 | 86篇 |
2017年 | 94篇 |
2016年 | 113篇 |
2015年 | 75篇 |
2014年 | 187篇 |
2013年 | 254篇 |
2012年 | 164篇 |
2011年 | 158篇 |
2010年 | 174篇 |
2009年 | 230篇 |
2008年 | 247篇 |
2007年 | 263篇 |
2006年 | 224篇 |
2005年 | 190篇 |
2004年 | 140篇 |
2003年 | 181篇 |
2002年 | 164篇 |
2001年 | 150篇 |
2000年 | 130篇 |
1999年 | 114篇 |
1998年 | 108篇 |
1997年 | 88篇 |
1996年 | 78篇 |
1995年 | 34篇 |
1994年 | 34篇 |
1993年 | 27篇 |
1992年 | 26篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 15篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 21篇 |
1984年 | 11篇 |
1983年 | 12篇 |
1982年 | 15篇 |
1981年 | 8篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1976年 | 8篇 |
1975年 | 6篇 |
1974年 | 4篇 |
排序方式: 共有4203条查询结果,搜索用时 15 毫秒
61.
本文目的在于建立确定R ̄d中Hausdorff维数dim和packing维数Dim的两个命题(定理1和定理2),进而寻求R ̄d中Hausdorff维数dim与packing维数Dim相等的条件;这使得我们能够引入分形测度的测度论定义。 相似文献
62.
范进军 《Annals of Differential Equations》2004,20(1):21-29
In this paper, by using Lyapunov function and weak noncompactness conditions, we give an existence theorem of generalized weakly solutions of Cauchy problem of differential equations in product spaces. 相似文献
63.
In the paper we obtain vector-valued inequalities for Calder6n-Zygmund operator, simply CZO on Herz space and weak Herz space. In particular.we obtain vector-valued inequalities for CZO on Lq(Rd, |x|αdμ) space, with 1< q <∞, -n <α< n(q -1), and on L1,∞(Rd,|x|αdμ) space, with -n <α< 0. 相似文献
64.
利用η-Carleson测度给出了单位球上不同Privalov以及不同加权Bergman-Privalov空间之间的复合算子是度量有界或度量紧的充要条件,并给出了一些函数理论方面的刻画. 相似文献
65.
We study bounds on averages of spectral functions corresponding to Sturm-Liouville operators on the half line for different boundary conditions. As a consequence constraints are obtained which imply existence of singular spectrum embedded in a.c. spectrum for sets of boundary conditions with positive measure and potentials vanishing in an interval [0,N]. These constraints are related to estimates on the measure of sets where the spectral density is positive. 相似文献
66.
67.
Jochen Alber Jií Fiala 《Journal of Algorithms in Cognition, Informatics and Logic》2004,52(2):134-151
We consider the parameterized problem, whether for a given set
of n disks (of bounded radius ratio) in the Euclidean plane there exists a set of k non-intersecting disks. For this problem, we expose an algorithm running in time
that is—to our knowledge—the first algorithm with running time bounded by an exponential with a sublinear exponent. For λ-precision disk graphs of bounded radius ratio, we show that the problem is fixed parameter tractable with a running time
. The results are based on problem kernelization and a new “geometric (
-separator) theorem” which holds for all disk graphs of bounded radius ratio. The presented algorithm then performs, in a first step, a “geometric problem kernelization” and, in a second step, uses divide-and-conquer based on our new “geometric separator theorem.” 相似文献
68.
In this paper we investigate the
probabilistic linear $(n,\delta)$-widths and $p$-average linear
$n$-widths of the Sobolev space $W^r_2$ equipped with the Gaussian
measure $\mu$ in the $L_{\infty}$-norm, and determine the
asymptotic equalities
\begin{eqnarray*}
\lambda_{n,\delta}(W^r_2,\mu,L_{\infty})
&\asymp&\frac{\sqrt{\ln
(n/\delta)}}{n^{r+(s-1)/2}},\\[3pt]
\lambda^{(a)}_n(W^r_2,\mu,L_{\infty})_p &\asymp&\frac{\sqrt{\ln
n}}{n^{r+(s-1)/2}}, \qquad 0 < p < \infty.
\end{eqnarray*} 相似文献
69.
70.
DUAL RECIPROCITY HYBRID BOUNDARY NODE METHOD FOR THREE-DIMENSIONAL ELASTICITY WITH BODY FORCE 总被引:1,自引:0,他引:1
Combining Dual Reciprocity Method (DRM) with Hybrid Boundary Node Method (HBNM), the Dual Reciprocity Hybrid Boundary Node Method (DRHBNM) is developed for three-dimensional linear elasticity problems with body force. This method can be used to solve the elasticity problems with body force without domain integral, which is inevitable by HBNM. To demonstrate the versatility and the fast convergence of this method, some numerical examples of 3-D elasticity problems with body forces are examined. The computational results show that the present method is effective and can be widely applied in solving practical engineering problems. 相似文献