全文获取类型
收费全文 | 39506篇 |
免费 | 1343篇 |
国内免费 | 5篇 |
专业分类
化学 | 21806篇 |
晶体学 | 175篇 |
力学 | 839篇 |
数学 | 6424篇 |
物理学 | 11610篇 |
出版年
2023年 | 208篇 |
2021年 | 298篇 |
2020年 | 495篇 |
2019年 | 325篇 |
2018年 | 451篇 |
2017年 | 432篇 |
2016年 | 1017篇 |
2015年 | 851篇 |
2014年 | 950篇 |
2013年 | 2126篇 |
2012年 | 1653篇 |
2011年 | 2010篇 |
2010年 | 1025篇 |
2009年 | 832篇 |
2008年 | 1896篇 |
2007年 | 1862篇 |
2006年 | 1638篇 |
2005年 | 1464篇 |
2004年 | 1145篇 |
2003年 | 996篇 |
2002年 | 922篇 |
2001年 | 795篇 |
2000年 | 708篇 |
1999年 | 491篇 |
1998年 | 436篇 |
1997年 | 437篇 |
1996年 | 549篇 |
1995年 | 499篇 |
1994年 | 509篇 |
1993年 | 591篇 |
1992年 | 505篇 |
1991年 | 373篇 |
1990年 | 417篇 |
1989年 | 335篇 |
1988年 | 356篇 |
1987年 | 363篇 |
1986年 | 318篇 |
1985年 | 496篇 |
1984年 | 493篇 |
1983年 | 455篇 |
1982年 | 465篇 |
1981年 | 478篇 |
1980年 | 427篇 |
1979年 | 396篇 |
1978年 | 437篇 |
1977年 | 409篇 |
1976年 | 370篇 |
1975年 | 355篇 |
1974年 | 330篇 |
1973年 | 343篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
171.
We estimate the concentration functions of n-fold convolutions of one-dimensional probability measures. The Kolmogorov–Rogozin inequality implies that for nondegenerate distributions these functions decrease at least as O(n
–1/2). On the other hand, Esseen(3) has shown that this rate is o(n
–1/2) iff the distribution has an infinite second moment. This statement was sharpened by Morozova.(9) Theorem 1 of this paper provides an improvement of Morozova's result. Moreover, we present more general estimates which imply the rates o(n
–1/2). 相似文献
172.
V. B. Bobrov R. Redmer G. Röpke S. A. Triger 《Theoretical and Mathematical Physics》1991,86(3):293-302
Institute of High Temperatures, USSR Academy of Sciences. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 86, No. 3, pp. 425–437, March, 1991. 相似文献
173.
R. Klein R. Grieser L. Hoog G. Huber I. Klaft P. Merz T. Kühl S. Schröder M. Grieser D. Habs W. Petrich D. Schwalm 《Zeitschrift für Physik A Hadrons and Nuclei》1992,342(4):455-461
We have performed for the first time precision spectroscopy on a coasting fast7Li+ ion beam in a storage ring. The ion beam moving with 6.4% speed of light was first electron cooled and then merged with two counterpropagating laser beams acting on two different hyperfine transitions sharing a common upper level (λ-system). One laser was frequency locked to thea 3 127J2 hfs frequency component established as a secondary frequency standard at 514 nm. The second laser was tuned over theλ-resonance, which was recorded relative to127J2 hfs components. This experiment is sensitive to the time dilation in fast moving frames and will lead to new limits for the verification of special relatively. The present status of the experiment and perspectives in accuracy are discussed. 相似文献
174.
175.
Given a simplicial complex δ on vertices {1, …,n} and a fieldF we consider the subvariety of projective (n−1)-space overF consisting of points whose homogeneous coordinates have support in δ. We give a simple rational expression for the zeta function
of this singular projective variety overF
q and show a close connection with the Betti numbers of the corresponding variety over ℂ. This connection is particularly simple
in the case when Δ is Cohen-Macaulay. 相似文献
176.
We review recent advances in the understanding of the enhanced electron–ion recombination observed in storage ring experiments. The measured recombination rates show a strong enhancement relative to what the standard radiative recombination rates predict. A transient motional electric field is induced in the merging region of an electron and an ion beam in the electron cooler. This induced field opens an additional pathway for free-bound transitions of electrons. The formed Rydberg states can be radiatively stabilized and contribute to the measured rate. We show that this “field induced recombination” (FIR) explains the gap previously observed between measurements and the standard radiative recombination rate. 相似文献
177.
C. Scheidenberger K. Beckert P. Beller F. Bosch C. Brandau D. Boutin L. Chen B. Franzke H. Geissel R. Knöbel C. Kozhuharov J. Kurcewicz S. A. Litvinov Yu. A. Litvinov M. Mazzocco G. Münzenberg F. Nolden W. R. Plaß M. Steck B. Sun H. Weick M. Winkler 《Hyperfine Interactions》2006,173(1-3):61-66
One important goal of the ILIMA project at FAIR is the study of masses and decay properties of relativistic isomeric beams
stored and cooled in the planned storage-ring complex. A new scheme is described, where a storage-cooler ring is used for
high-resolution mass separation. Experimental results on the separation of the isobaric pair 140Pr-140Ce are presented.
P. Beller, deceased. 相似文献
178.
Let R be a local ring and let (x
1, …, x
r) be part of a system of parameters of a finitely generated R-module M, where r < dimR
M. We will show that if (y
1, …, y
r) is part of a reducing system of parameters of M with (y
1, …, y
r) M = (x
1, …, x
r) M then (x
1, …, x
r) is already reducing. Moreover, there is such a part of a reducing system of parameters of M iff for all primes P ε Supp M ∩ V
R(x
1, …, x
r) with dimR
R/P = dimR
M − r the localization M
P of M at P is an r-dimensional Cohen-Macaulay module over R
P.
Furthermore, we will show that M is a Cohen-Macaulay module iff y
d is a non zero divisor on M/(y
1, …, y
d−1) M, where (y
1, …, y
d) is a reducing system of parameters of M (d:= dimR
M). 相似文献
179.
R. Schuch I. Bergström K. Blaum T. Fritioff Sz. Nagy A. Solders M. Suhonen 《Hyperfine Interactions》2006,173(1-3):73-83
We report here about measurements of reaction and decay Q values by precise determination of pairs of atomic masses. These were performed with the Penning trap mass spectrometer SMILETRAP.
Measurements with Penning traps give reliable and accurate masses, in particular Q values, due to the fact that certain systematic errors to a great deal cancel in the mass difference between the two atoms
defining the Q value. Some Q values that are of fundamental interest will be discussed here, for example, a new Q value for the 6Li (n,γ) 7Li reaction, for the β-decay of tritium, related to properties of the electron neutrino mass, and for the neutrino-less double
β-decay of 76Ge, related to the question of whether the neutrino is a Majorana particle or not. In case of the latter two we report the
most accurate Q values, namely 18,589.8(12) eV for the tritium decay and 2,038.997(46) keV for the neutrino-less double β-decay of 76Ge. 相似文献
180.