全文获取类型
收费全文 | 20788篇 |
免费 | 3864篇 |
国内免费 | 1351篇 |
专业分类
化学 | 4295篇 |
晶体学 | 612篇 |
力学 | 984篇 |
综合类 | 116篇 |
数学 | 4126篇 |
物理学 | 15870篇 |
出版年
2024年 | 61篇 |
2023年 | 186篇 |
2022年 | 405篇 |
2021年 | 423篇 |
2020年 | 475篇 |
2019年 | 385篇 |
2018年 | 430篇 |
2017年 | 633篇 |
2016年 | 715篇 |
2015年 | 703篇 |
2014年 | 1200篇 |
2013年 | 1836篇 |
2012年 | 1305篇 |
2011年 | 1464篇 |
2010年 | 1131篇 |
2009年 | 1330篇 |
2008年 | 1550篇 |
2007年 | 1472篇 |
2006年 | 1236篇 |
2005年 | 1065篇 |
2004年 | 946篇 |
2003年 | 884篇 |
2002年 | 793篇 |
2001年 | 710篇 |
2000年 | 681篇 |
1999年 | 597篇 |
1998年 | 507篇 |
1997年 | 488篇 |
1996年 | 396篇 |
1995年 | 386篇 |
1994年 | 310篇 |
1993年 | 230篇 |
1992年 | 191篇 |
1991年 | 121篇 |
1990年 | 103篇 |
1989年 | 81篇 |
1988年 | 68篇 |
1987年 | 62篇 |
1986年 | 58篇 |
1985年 | 64篇 |
1984年 | 56篇 |
1983年 | 32篇 |
1982年 | 44篇 |
1981年 | 33篇 |
1980年 | 45篇 |
1979年 | 44篇 |
1978年 | 22篇 |
1977年 | 22篇 |
1976年 | 8篇 |
1975年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Giovanna Idone 《Journal of Mathematical Analysis and Applications》2004,290(1):147-170
Hölder regularity up to the boundary of the solutions to the Dirichlet problem for second order elliptic systems with nonlinearity q>2 and with controlled growth is proved when n?q+2. 相似文献
102.
103.
104.
Vincenzo Recupero 《Journal of Mathematical Analysis and Applications》2004,300(2):387-407
In this paper we study a model of phase relaxation for the Stefan problem with the Cattaneo–Maxwell heat flux law. We prove an existence and uniqueness result for the resulting problem and we show that its solution converges to the solution of the Stefan problem as the two relaxation parameters go to zero, provided a relation between these parameters holds. 相似文献
105.
106.
Kazuhiro Kurata Masataka Shibata Shigeru Sakamoto 《Applied Mathematics and Optimization》2004,50(3):259-278
Let $\Omega$ be a bounded domain in ${\bf R^n}$ with Lipschitz
boundary,
$\lambda >0,$ and $1\le p \le (n+2)/(n-2)$ if $n\ge 3$ and $1\le p< +\infty$
if $n=1,2$. Let $D$ be a measurable subset of $\Omega$ which belongs
to the class
$
{\cal C}_{\beta}=\{D\subset \Omega \quad | \quad |D|=\beta\}
$
for the prescribed $\beta\in (0, |\Omega|).$
For any $D\in{\cal C}_{\beta}$, it is well known that
there exists a unique
global minimizer $u\in H^1_0(\Omega)$, which we denote by
$u_D$, of the functional
\[\quad
J_{\Omega,D}(v)=\frac12\int_{\Omega}|\nabla v|^2\,
dx+\frac{\lambda}{p+1}\int_{\Omega}|v|^{p+1}\, dx
-\int_{\Omega}\chi_Dv\,dx
\]
on $H^1_0(\Omega)$.
We consider the optimization problem
$
E_{\beta,\Omega}=\inf_{D\in {\cal C}_{\beta}} J_D(u_D)
$
and say that
a subset $D^*\in {\cal C}_{\beta}$ which attains
$E_{\beta,\Omega}$
is an optimal configuration to this problem.
In this paper we show the existence, uniqueness
and non-uniqueness, and
symmetry-preserving and symmetry-breaking phenomena of the
optimal configuration $D^*$ to this
optimization problem in various settings. 相似文献
107.
Yoshiaki Yasuno Yasunori Sutoh Shuichi Makita Masahide Itoh Toyohiko Yatagai 《Optical Review》2003,10(5):498-500
A spectral interferometric optical coherence tomography (OCT) system which has polarization sensitivity is developed. This system reduces the mechanical scanning dimension by employing the principle of spectral interferometry, and measures a two dimensional cross-sectional image of biological tissue with one dimensional mechanical scanning. Sixteen OCT images with different polarization conditions are measured, and two dimensional distributions of each element of the Müller matrix of a sample to be measured are calculated. 相似文献
108.
109.
The educational system has gradually shifted from a face-to-face to an e-learning system, which has become prevalent in advanced countries with the advance of information technology, and connection of global networks. Accordingly, a growing demand is emerging for more reliable individual certification with technical precision in order to measure and record learning achievements and credentials of participants. The present system has a limit in terms of registration capacity, therefore, its accuracy has often been questioned. Against this background, an individual certification system is proposed particularly for access control in e-learning. Under our proposed system, a compact optical correlator for facial recognition is employed. This correlator was previously tested for of biometrics authentication accuracy and proved highly reliable, having recorded remarkably low error rates (below 1%). The recorded error rate is sufficiently robust that the system itself can be regarded as a valid and practical viable attestation system. 相似文献
110.