全文获取类型
收费全文 | 34662篇 |
免费 | 5812篇 |
国内免费 | 3952篇 |
专业分类
化学 | 23472篇 |
晶体学 | 370篇 |
力学 | 2300篇 |
综合类 | 310篇 |
数学 | 4287篇 |
物理学 | 13687篇 |
出版年
2024年 | 131篇 |
2023年 | 722篇 |
2022年 | 1320篇 |
2021年 | 1373篇 |
2020年 | 1395篇 |
2019年 | 1345篇 |
2018年 | 1254篇 |
2017年 | 1181篇 |
2016年 | 1663篇 |
2015年 | 1699篇 |
2014年 | 1972篇 |
2013年 | 2542篇 |
2012年 | 3048篇 |
2011年 | 3140篇 |
2010年 | 2125篇 |
2009年 | 1988篇 |
2008年 | 2232篇 |
2007年 | 1926篇 |
2006年 | 1735篇 |
2005年 | 1485篇 |
2004年 | 1134篇 |
2003年 | 959篇 |
2002年 | 955篇 |
2001年 | 762篇 |
2000年 | 653篇 |
1999年 | 761篇 |
1998年 | 612篇 |
1997年 | 588篇 |
1996年 | 559篇 |
1995年 | 536篇 |
1994年 | 439篇 |
1993年 | 378篇 |
1992年 | 322篇 |
1991年 | 279篇 |
1990年 | 275篇 |
1989年 | 207篇 |
1988年 | 157篇 |
1987年 | 134篇 |
1986年 | 99篇 |
1985年 | 108篇 |
1984年 | 70篇 |
1983年 | 56篇 |
1982年 | 54篇 |
1981年 | 25篇 |
1980年 | 12篇 |
1979年 | 5篇 |
1976年 | 1篇 |
1959年 | 1篇 |
1957年 | 8篇 |
1936年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Xiaojing Xiang 《Annals of the Institute of Statistical Mathematics》1995,47(1):105-117
A necessary condition for the asymptotic normality of the sample quantile estimator isf(Q(p))=F(Q(p))>0, whereQ(p) is thep-th quantile of the distribution functionF(x). In this paper, we estimate a quantile by a kernel quantile estimator when this condition is violated. We have shown that the kernel quantile estimator is asymptotically normal in some nonstandard cases. The optimal convergence rate of the mean squared error for the kernel estimator is obtained with respect to the asymptotically optimal bandwidth. A law of the iterated logarithm is also established.This research was partially supported by the new faculty award from the University of Oregon. 相似文献
142.
We estimate the kinematic measure of one convex domain moving to another under the groupG of rigid motions in
n
. We first estimate the kinematic formula for the total scalar curvature D
0gD
1
Rdv of then–2 dimensional intersection submanifold D
0gD
1. Then we use Chern and Yen's kinematic fundamental formula and our integral inequality to obtain a sufficient condition for one convex domain to contain another in
n
(4). Forn=4, we directly obtain another sufficient condition in 4. 相似文献
143.
The gyroscope in an orbiting satellite will be acted on by additional gravitational fields due to the rotation of the earth and due to the orbital velocity of the satellite. According to special relativistic gravitational theory, we deduce
L
(S)
—the gyroscope's precession rate due to the orbital velocity—and
S
(S)
—the gyroscope's precession rate due to the earth's rotation in the polar orbit case. The results are
L
(S)
= (2/3)
L
(G)
,
S
(S)
= (3/2) cos (1 - sin2 cos2)1/2
S
(G)
, where and are the gyroscope's polar angles, and
L
(G)
and
S
(G)
are the geodetic and frame-dragging precession rates predicted by general relativity, respectively. 相似文献
144.
145.
146.
X. Zhou Y. Guo X. Sun X. Lei X. Chen Z. Liu Y. Zhang H. Jin Y. Luo S. X. Wen G. J. Yuan G. S. Li C. X. Yang 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(1):3-4
The high spin states of119Te, populated in110Pd(13C,4n) and110Pd(12C,3n) reactions, have been studied through -ray spectroscopy. The level scheme has been established upto a spin of 55/2. Three-quasiparticle states, based on g2
7/2h11/2 and g7/2d5/2h11/2 configurations, have been identified. The 35/2 and 39/2 states are suggested to be the fully aligned states constituted by five valence h11/2
3, g7/2, d5/2 quasiparticles. 相似文献
147.
S. P. Zhou 《Analysis Mathematica》1994,20(2):155-159
[Zho2] {x
n
} ,
n
0 n .
Supported in part by an NSERC Postdoctoral Fellowship and a CRF grant of University of Alberta. 相似文献
Supported in part by an NSERC Postdoctoral Fellowship and a CRF grant of University of Alberta. 相似文献
148.
A difference setD in a groupG is called a skew Hadamard difference set (or an antisymmetric difference set) if and only ifG is the disjoint union ofD, D(–1), and {1}, whereD(–1)={d–1|dD}. In this note, we obtain an exponent bound for non-elementary abelian groupG which admits a skew Hadamard difference set. This improves the bound obtained previously by Johnsen, Camion and Mann. 相似文献
149.
We present an algorithm for numerically computing an absolutely continuous invariant measure associated with a piecewiseC
2 expanding mappingS: on a bounded region R
N. The method is based on the Galerkin projection principle for solving an operator equation in a Banach space. With the help of the modern notion of functions of bounded variation in multidimension, we prove the convergence of the algorithm. 相似文献
150.