全文获取类型
收费全文 | 114493篇 |
免费 | 1303篇 |
国内免费 | 639篇 |
专业分类
化学 | 48331篇 |
晶体学 | 993篇 |
力学 | 7594篇 |
综合类 | 1篇 |
数学 | 38423篇 |
物理学 | 21093篇 |
出版年
2022年 | 268篇 |
2021年 | 385篇 |
2020年 | 461篇 |
2019年 | 432篇 |
2018年 | 10691篇 |
2017年 | 10508篇 |
2016年 | 6743篇 |
2015年 | 1591篇 |
2014年 | 1093篇 |
2013年 | 2243篇 |
2012年 | 5454篇 |
2011年 | 12438篇 |
2010年 | 6803篇 |
2009年 | 7008篇 |
2008年 | 8285篇 |
2007年 | 10365篇 |
2006年 | 2084篇 |
2005年 | 2956篇 |
2004年 | 3132篇 |
2003年 | 3278篇 |
2002年 | 2295篇 |
2001年 | 877篇 |
2000年 | 864篇 |
1999年 | 684篇 |
1998年 | 680篇 |
1997年 | 697篇 |
1996年 | 747篇 |
1995年 | 587篇 |
1994年 | 580篇 |
1993年 | 584篇 |
1992年 | 520篇 |
1991年 | 534篇 |
1990年 | 438篇 |
1989年 | 455篇 |
1988年 | 445篇 |
1987年 | 452篇 |
1986年 | 447篇 |
1985年 | 599篇 |
1984年 | 593篇 |
1983年 | 486篇 |
1982年 | 546篇 |
1981年 | 523篇 |
1980年 | 554篇 |
1979年 | 482篇 |
1978年 | 495篇 |
1977年 | 457篇 |
1976年 | 379篇 |
1975年 | 363篇 |
1974年 | 330篇 |
1973年 | 311篇 |
排序方式: 共有10000条查询结果,搜索用时 562 毫秒
41.
42.
43.
The structure, chemical composition, and magnetic properties of electrochemically deposited nanocrystalline Co-Ni-Fe films
were investigated using a number of techniques. A high saturation magnetic induction up to B
s
= 21 kG was attained. An enhancement of the saturation magnetization compared to the ideal anticipated one was revealed,
which correlated with the nonlinear behavior of the structural phase composition and lattice parameters with the change of
the composition.
The text was submitted by the authors in English. 相似文献
44.
45.
Peter Imkeller 《Probability Theory and Related Fields》1996,106(1):105-135
Summary. The analytic treatment of problems related to the asymptotic behaviour of random dynamical systems generated by stochastic
differential equations suffers from the presence of non-adapted random invariant measures. Semimartingale theory becomes accessible
if the underlying Wiener filtration is enlarged by the information carried by the orthogonal projectors on the Oseledets spaces
of the (linearized) system.
We study the corresponding problem of preservation of the semimartingale property and the validity of a priori inequalities
between the norms of stochastic integrals in the enlarged filtration and norms of their quadratic variations in case the random
element F enlarging the filtration is real valued and possesses an absolutely continuous law. Applying the tools of Malliavin’s calculus,
we give smoothness conditions on F under which the semimartingale property is preserved and a priori martingale inequalities are valid.
Received: 12 April 1995 / In revised form: 7 March 1996 相似文献
46.
Peter J. Grabner 《Random Structures and Algorithms》1993,4(1):99-110
We investigate the following process: N people select b losers by flipping coins. The 0-party continues until there are less than b losers; then the 1-party has to find the other losers by the same process. The average time for this process is about long2 N, but this result requires rather advanced methods. Furthermore, the average size of a binary tree associated to this process and the average number of coin flippings are computed. The method used in this article can be used to give asympotical solutions of a special type of bivariate recurrences. © 1993 John Wiley & Sons, Inc. 相似文献
47.
Peter A. McCoy 《Journal of Mathematical Analysis and Applications》2002,275(2):761-770
An integral transform based method is given for determining information about the locating and properties of singularities of electromagnetic fields associated with axially symmetric radiating sources. 相似文献
48.
Hendrik Van Maldeghem 《Journal of Geometry》1997,58(1-2):192-202
We characterize in a geometrical way those Suzuki-Tits ovoids which are defined over a perfect fieidK (or equivalently living inside a self polar symplectic quadrangle). We simplify our axioms in the particular cases that (1) the associated Suzuki group has exactly two orbits in the set of lines ofPG(3,K), and (2) the ovoid is finite.Senior Research Associate at the Belgian National Fund for Scientific Research 相似文献
49.
Photobleaching was studied during recording of confocal scanning laser microscopy. Studies on fluorescent gels of FITC-labeled
dextran were used to evaluate differential bleaching along thez-axis. Differential bleaching along the z-axis was observed and it was seen that this was related to the numerical aperture
of the objective in use. This points to the conclusion that photon energy flux density is an important parameter in photobleaching.
To check if photon energy flux density heterogeneity is affected by local variation in the refractive index of the sample,
photobleaching rates were calculated for different fluorescent objects (sections of seeds, animal cells stained with nuclear
stains, immunocytochemistry preparations) and a pronounced similarity was found between photobleaching rates and DIC images. 相似文献
50.