全文获取类型
收费全文 | 1786篇 |
免费 | 52篇 |
国内免费 | 5篇 |
专业分类
化学 | 1240篇 |
晶体学 | 3篇 |
力学 | 27篇 |
数学 | 130篇 |
物理学 | 443篇 |
出版年
2020年 | 16篇 |
2019年 | 24篇 |
2016年 | 32篇 |
2015年 | 36篇 |
2014年 | 33篇 |
2013年 | 54篇 |
2012年 | 29篇 |
2011年 | 53篇 |
2010年 | 35篇 |
2009年 | 49篇 |
2008年 | 48篇 |
2007年 | 67篇 |
2006年 | 45篇 |
2005年 | 50篇 |
2004年 | 44篇 |
2003年 | 41篇 |
2002年 | 52篇 |
2001年 | 25篇 |
2000年 | 22篇 |
1999年 | 20篇 |
1998年 | 23篇 |
1997年 | 16篇 |
1996年 | 27篇 |
1995年 | 31篇 |
1994年 | 31篇 |
1993年 | 32篇 |
1992年 | 21篇 |
1991年 | 20篇 |
1990年 | 25篇 |
1989年 | 22篇 |
1988年 | 17篇 |
1987年 | 19篇 |
1986年 | 26篇 |
1985年 | 30篇 |
1984年 | 20篇 |
1983年 | 19篇 |
1982年 | 25篇 |
1981年 | 32篇 |
1980年 | 18篇 |
1978年 | 19篇 |
1976年 | 17篇 |
1974年 | 14篇 |
1973年 | 17篇 |
1968年 | 23篇 |
1967年 | 23篇 |
1966年 | 30篇 |
1965年 | 57篇 |
1964年 | 76篇 |
1963年 | 60篇 |
1962年 | 26篇 |
排序方式: 共有1843条查询结果,搜索用时 15 毫秒
1.
2.
Ohne Zusammenfassung 相似文献
3.
Alois Smolka 《Monatshefte für Chemie / Chemical Monthly》1885,6(1):915-926
Ohne Zusammenfassung 相似文献
4.
5.
6.
In the elastic angular distributions of the systems composed of tightly bound α-nuclei, 12C+12C, 16O+16O and 16O+12C, the higher-order Airy minima are observed in the energy region between 5 and 10 MeV per nucleon. The obtained optical potentials are deeply attractive and with incomplete absorption. The same potentials successfully describe the lower-energy (molecular resonances) and the higher-energy (first Airy minimum) data. 相似文献
7.
8.
Simply generated families of trees are described by the equation T(z) = ϕ(T(z)) for their generating function. If a tree has n nodes, we say that it is increasing if each node has a label ∈ { 1,…,n}, no label occurs twice, and whenever we proceed from the root to a leaf, the labels are increasing. This leads to the concept of simple families of increasing trees. Three such families are especially important: recursive trees, heap ordered trees, and binary increasing trees. They belong to the subclass of very simple families of increasing trees, which can be characterized in 3 different ways. This paper contains results about these families as well as about polynomial families (the function ϕ(u) is just a polynomial). The random variable of interest is the level of the node (labelled) j, in random trees of size n ≥ j. For very simple families, this is independent of n, and the limiting distribution is Gaussian. For polynomial families, we can prove this as well for j,n → ∞ such that n − j is fixed. Additional results are also given. These results follow from the study of certain trivariate generating functions and Hwang's quasi power theorem. They unify and extend earlier results by Devroye, Mahmoud, and others. © 2007 Wiley Periodicals, Inc. Random Struct. Alg., 2007 相似文献
9.
This paper presents an analytic approach to the construction cost of fringe-balanced binary search trees. In [7], Mahmoud used a bottom-up approach and an urn model of Pólya. The present method is top-down and uses differential equations and Hwang's quasi-power theorem to derive the asymptotic normality of the number of rotations needed to construct such afringe balanced search tree. We also obtain the exact expectation and variance with this method. Although Pólya's urn model is no longer needed, we also present an elegant analysis of it based on an operator calculus as in [4].This research was supported by the Austrian Research Society (FWF) under the project number P12599-MAT. 相似文献
10.