全文获取类型
收费全文 | 87450篇 |
免费 | 540篇 |
国内免费 | 396篇 |
专业分类
化学 | 29767篇 |
晶体学 | 950篇 |
力学 | 6979篇 |
数学 | 32643篇 |
物理学 | 18047篇 |
出版年
2023年 | 98篇 |
2022年 | 226篇 |
2021年 | 172篇 |
2020年 | 201篇 |
2019年 | 258篇 |
2018年 | 10570篇 |
2017年 | 10422篇 |
2016年 | 6363篇 |
2015年 | 1052篇 |
2014年 | 701篇 |
2013年 | 1119篇 |
2012年 | 4286篇 |
2011年 | 11096篇 |
2010年 | 6008篇 |
2009年 | 6423篇 |
2008年 | 6996篇 |
2007年 | 9136篇 |
2006年 | 548篇 |
2005年 | 1570篇 |
2004年 | 1734篇 |
2003年 | 2100篇 |
2002年 | 1182篇 |
2001年 | 361篇 |
2000年 | 412篇 |
1999年 | 240篇 |
1998年 | 250篇 |
1997年 | 203篇 |
1996年 | 288篇 |
1995年 | 218篇 |
1994年 | 175篇 |
1993年 | 188篇 |
1992年 | 173篇 |
1991年 | 152篇 |
1990年 | 135篇 |
1989年 | 152篇 |
1988年 | 149篇 |
1987年 | 150篇 |
1986年 | 134篇 |
1985年 | 151篇 |
1984年 | 167篇 |
1983年 | 122篇 |
1982年 | 141篇 |
1981年 | 136篇 |
1980年 | 155篇 |
1979年 | 136篇 |
1978年 | 143篇 |
1977年 | 105篇 |
1975年 | 79篇 |
1974年 | 88篇 |
1973年 | 80篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
David Stanovský 《Czechoslovak Mathematical Journal》2007,57(1):191-200
We investigate the variety of residuated lattices with a commutative and idempotent monoid reduct. 相似文献
82.
For given a graph H, a graphic sequence π = (d
1, d
2,..., d
n) is said to be potentially H-graphic if there is a realization of π containing H as a subgraph. In this paper, we characterize the potentially (K
5 − e)-positive graphic sequences and give two simple necessary and sufficient conditions for a positive graphic sequence π to
be potentially K
5-graphic, where K
r is a complete graph on r vertices and K
r-e is a graph obtained from K
r by deleting one edge. Moreover, we also give a simple necessary and sufficient condition for a positive graphic sequence
π to be potentially K
6-graphic.
Project supported by National Natural Science Foundation of China (No. 10401010). 相似文献
83.
Sudoku’s french ancestors 总被引:1,自引:0,他引:1
Christian Boyer 《Mathematical Intelligencer》2007,29(1):37-44
This column is a place for those bits of contagious mathematics that travel from person to person in the community, because
they are so elegant, suprising, or appealing that one has an urge to pass them on.
Contributions are most welcome. 相似文献
84.
85.
86.
87.
We prove that any 43-fold covering of the plane with translates of a triangle can be decomposed into two coverings. 相似文献
88.
89.
Roderich Tumulka 《Foundations of Physics》2007,37(2):186-197
In a recent paper Conway and Kochen, Found. Phys. 36, 2006, claim to have established that theories of the Ghirardi-Rimini-Weber
(RW) type, i.e., of spontaneous wave function collapse, cannot be made relativistic. On the other hand, relativistic GRW-type
theories have already been presented, in my recent paper, J. Stat. Phys. 125, 2006, and by Dowker and Henson, J. Stat. Phys.
115, 2004. Here, I elucidate why these are not excluded by the arguments of Conway and Kochen.
相似文献
90.
The Bekenstein–Hawking entropy of certain black holes can be computed microscopically in string theory by mapping the elusive
problem of counting microstates of a strongly gravitating black hole to the tractable problem of counting microstates of a
weakly coupled D-brane system, which has no event horizon, and indeed comfortably fits on the head of a pin. We show here
that, contrary to widely held beliefs, the entropy of spherically symmetric black holes can easily be dwarfed by that of stationary
multi-black-hole “molecules” of the same total charge and energy. Thus, the corresponding pin-sized D-brane systems do not
even approximately count the microstates of a single black hole, but rather those of a zoo of entropically dominant multicentered
configurations.
Fourth Award in the 2007 Essay Competition of the Gravity Research Foundation. 相似文献