全文获取类型
收费全文 | 22840篇 |
免费 | 836篇 |
国内免费 | 10篇 |
专业分类
化学 | 15237篇 |
晶体学 | 177篇 |
力学 | 369篇 |
数学 | 3813篇 |
物理学 | 4090篇 |
出版年
2023年 | 157篇 |
2022年 | 182篇 |
2021年 | 263篇 |
2020年 | 351篇 |
2019年 | 355篇 |
2018年 | 477篇 |
2017年 | 428篇 |
2016年 | 868篇 |
2015年 | 679篇 |
2014年 | 708篇 |
2013年 | 1537篇 |
2012年 | 1475篇 |
2011年 | 1449篇 |
2010年 | 872篇 |
2009年 | 813篇 |
2008年 | 1266篇 |
2007年 | 1316篇 |
2006年 | 1167篇 |
2005年 | 1079篇 |
2004年 | 988篇 |
2003年 | 757篇 |
2002年 | 651篇 |
2001年 | 501篇 |
2000年 | 455篇 |
1999年 | 335篇 |
1998年 | 232篇 |
1997年 | 221篇 |
1996年 | 290篇 |
1995年 | 214篇 |
1994年 | 234篇 |
1993年 | 199篇 |
1992年 | 195篇 |
1991年 | 180篇 |
1990年 | 174篇 |
1989年 | 151篇 |
1988年 | 141篇 |
1987年 | 139篇 |
1986年 | 138篇 |
1985年 | 202篇 |
1984年 | 198篇 |
1983年 | 129篇 |
1982年 | 131篇 |
1981年 | 144篇 |
1980年 | 145篇 |
1979年 | 96篇 |
1978年 | 99篇 |
1977年 | 104篇 |
1976年 | 83篇 |
1975年 | 87篇 |
1973年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 109 毫秒
141.
142.
143.
Let {W(t), t0} be a standard Wiener process, and let L(x, t) be its jointly continuous local time. Define
相似文献
144.
A basic problem of finite packing and covering is to determine, for a given number ofk unit balls in Euclideand-spaceE
d
, (1) the minimal volume of all convex bodies into which thek balls can be packed and (2) the maximal volume of all convex bodies which can be covered by thek balls. In the sausage conjectures by L. Fejes Tóth and J. M. Wills it is conjectured that, for alld5, linear arrangements of thek balls are best possible. In the paper several partial results are given to support both conjectures. Furthermore, some relations between finite and infinite (space) packing and covering are investigated.This paper was written while the first named author was visiting the Forschungsinstitut für Geistes- und Sozialwissenschaften at the University of Siegen. 相似文献
145.
Jan Jakóbowski 《Geometriae Dedicata》1989,29(2):221-226
It is shown in this paper that a pair of points contained in a Fano configuration in a projective plane of odd order cannot induce a Minkowski plane. From this result we derive that no pair of points in the Hughes plane of order 9 can induce a Minkowski plane. 相似文献
146.
147.
In this paper the distribution of the zeros of the error function for bestL
1-approximation by rational functions fromR
n,m
is considered. It is shown that the maximal distance between such zeros isO(1/(n–m)), ifn > m.Communicated by Edward B. Saff. 相似文献
148.
Alberto García Nora Bretón Isidore Hauser 《International Journal of Theoretical Physics》1988,27(5):635-640
It is shown that any stationary axisymmetric solution to the vacuum field equations of the Jordan-Brans-Dicke (JBD) theory may be obtained from a composition of any stationary axisymmetric vacuum Einstein spacetime with the Weyl class of metrics. Thus, generating solution techniques can be used to obtain any stationary axisymmetric JBD vacuum solution. In this manner, C. B. G. McIntosh's results concerning this topic are improved upon. 相似文献
149.
150.
S. Moncher G. Principi L. M. Gratton C. Tosello I. Czakó-Nagy A. Vértes 《Hyperfine Interactions》1989,46(1-4):535-540
Films of Fe (20 nm) and Sn (40 nm) have been deposited by PVD onto Al supports and irradiated with 100 keV Xe ions at a dose of 5×1015 ions/cm2. Scanning electron microscopy (SEM) shows that the irregular morphology of deposited Sn is considerably flattened by irradiation, which produces also a noticeable sputtering of Sn. Conversion electron Mössbauer spectroscopy (CEMS) reveals the formation at the interface of a variety of intermetallic phases which is enhanced by irradiation. These phases, seem to be insensible to prolonged (several months) room temperature aging. Their thermal stability under annealing at temperature up to 523 K has also been investigated. 相似文献
|