全文获取类型
收费全文 | 16875篇 |
免费 | 360篇 |
国内免费 | 255篇 |
专业分类
化学 | 1568篇 |
晶体学 | 76篇 |
力学 | 143篇 |
综合类 | 34篇 |
数学 | 14343篇 |
物理学 | 1326篇 |
出版年
2023年 | 42篇 |
2022年 | 105篇 |
2021年 | 72篇 |
2020年 | 113篇 |
2019年 | 450篇 |
2018年 | 468篇 |
2017年 | 261篇 |
2016年 | 227篇 |
2015年 | 215篇 |
2014年 | 479篇 |
2013年 | 1043篇 |
2012年 | 508篇 |
2011年 | 1115篇 |
2010年 | 862篇 |
2009年 | 1085篇 |
2008年 | 1210篇 |
2007年 | 1297篇 |
2006年 | 974篇 |
2005年 | 663篇 |
2004年 | 574篇 |
2003年 | 540篇 |
2002年 | 411篇 |
2001年 | 351篇 |
2000年 | 328篇 |
1999年 | 384篇 |
1998年 | 382篇 |
1997年 | 254篇 |
1996年 | 370篇 |
1995年 | 333篇 |
1994年 | 321篇 |
1993年 | 273篇 |
1992年 | 214篇 |
1991年 | 152篇 |
1990年 | 163篇 |
1989年 | 143篇 |
1988年 | 96篇 |
1987年 | 102篇 |
1986年 | 87篇 |
1985年 | 136篇 |
1984年 | 95篇 |
1983年 | 75篇 |
1982年 | 97篇 |
1981年 | 94篇 |
1980年 | 69篇 |
1979年 | 49篇 |
1978年 | 62篇 |
1977年 | 51篇 |
1976年 | 48篇 |
1975年 | 17篇 |
1974年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
S?awomir Solecki 《Topology and its Applications》2007,154(12):2462-2464
Let I0 be the σ-ideal of subsets of a Polish group generated by Borel sets which have perfectly many pairwise disjoint translates. We prove that a Fubini-type theorem holds between I0 and the σ-ideals of Haar measure zero sets and of meager sets. We use this result to give a simple proof of a generalization of a theorem of Balcerzak-Ros?anowski-Shelah stating that I0 on N2 strongly violates the countable chain condition. 相似文献
72.
Abdelhadi Es-Sarhir 《Journal of Differential Equations》2007,233(1):87-104
This paper deals with perturbations of the Ornstein-Uhlenbeck operator on L2-spaces with respect to a Gaussian measure μ. We perturb the generator of the Ornstein-Uhlenbeck semigroup by a certain unbounded, non-linear drift, and show various properties of the perturbed semigroup such as compactness and positivity. Strong Feller property, existence and uniqueness of an invariant measure are discussed as well. 相似文献
73.
74.
75.
We continue the studies on the so–called genuine Bernstein–Durrmeyer operators U
n
by establishing a recurrence formula for the moments and by investigating the semigroup T(t) approximated by U
n
. Moreover, for sufficiently smooth functions the degree of this convergence is estimated. We also determine the eigenstructure
of U
n
, compute the moments of T(t) and establish asymptotic formulas.
Received: January 26, 2007. 相似文献
76.
We give a new independent self-dual 3-basis for the trivial variety with two binary operations.
Received October 24, 2006; accepted in final form January 25, 2007. 相似文献
77.
78.
Chris Good 《Topology and its Applications》2007,154(3):734-740
One possible natural monotone version of countable paracompactness, MCP, turns out to have some interesting properties. We investigate various other possible monotone versions of countable paracompactness and how they are related. 相似文献
79.
D.P. Baturov 《Topology and its Applications》2007,154(2):374-383
Let M be a separable metric space consisting of more than one point. We construct perfectly normal dense subspaces Z⊂Mc2 and (under additional set-theoretic assumption) Y⊂Mc which are not collectionwise Hausdorff. 相似文献
80.
In the introduction of the Arithmetica Diophantus says that in order to solve arithmetical problems one has to “follow the way he (Diophantus) will show.” The present paper has a threefold objective. Firstly, the meaning of this sentence is discussed, the conclusion being that Diophantus had elaborated a program for handling various arithmetical problems. Secondly, it is claimed that what is analyzed in the introduction is definitions of several terms, the exhibition of their symbolism, the way one may operate with them, but, most significantly, the main stages of the program itself. And thirdly, it is argued that Diophantus' intention in the Arithmetica is to show the way the stages of his program should be practically applied in various arithmetical problems. 相似文献