全文获取类型
收费全文 | 1105篇 |
免费 | 38篇 |
国内免费 | 10篇 |
专业分类
化学 | 636篇 |
晶体学 | 4篇 |
力学 | 35篇 |
数学 | 232篇 |
物理学 | 246篇 |
出版年
2023年 | 10篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 17篇 |
2019年 | 16篇 |
2018年 | 16篇 |
2017年 | 16篇 |
2016年 | 31篇 |
2015年 | 24篇 |
2014年 | 28篇 |
2013年 | 56篇 |
2012年 | 62篇 |
2011年 | 76篇 |
2010年 | 44篇 |
2009年 | 40篇 |
2008年 | 57篇 |
2007年 | 52篇 |
2006年 | 52篇 |
2005年 | 53篇 |
2004年 | 48篇 |
2003年 | 30篇 |
2002年 | 36篇 |
2001年 | 16篇 |
2000年 | 17篇 |
1999年 | 19篇 |
1998年 | 18篇 |
1997年 | 18篇 |
1996年 | 12篇 |
1995年 | 14篇 |
1994年 | 21篇 |
1993年 | 9篇 |
1992年 | 17篇 |
1991年 | 20篇 |
1990年 | 16篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1984年 | 22篇 |
1983年 | 8篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 11篇 |
1977年 | 7篇 |
1975年 | 7篇 |
1974年 | 5篇 |
1973年 | 9篇 |
1917年 | 4篇 |
排序方式: 共有1153条查询结果,搜索用时 468 毫秒
1.
2.
3.
Alison L. Parry 《Journal of polymer science. Part A, Polymer chemistry》2007,45(15):3178-3190
The ring‐opening metathesis polymerizations (ROMP), using RuCl2 (PCy3)2CHPh, of a series of peptide‐functionalized norbornene derivatives have been investigated. Incorporation of a PEG‐monomer was found to prevent premature precipitation of polymer strands during the course of polymerization reactions and yield water compatible polymers in high conversions. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3178–3190, 2007 相似文献
4.
In this article we extend well-known results of Livsic on theregularity of measurable solutions to the cocycle equation.Livsic proved a regularity result for real valued cocycles,but for compact Lie group valued cocycles his result was restrictedto coboundaries (that is, trivial or constant cocycles). Inthis article we prove the complete result. We present several useful applications of these results. 相似文献
5.
Nick Peatfield 《Archive for Mathematical Logic》2006,45(6):739-768
Following the introduction and preliminary investigations of analytic Zariski structures in Peatfield and Zilber (Ann pure Appl Logic 132:125–180, 2005) an example of an analytic Zariski structure extending an algebraically closed field is provided. The example is constructed using Hrushovski’s method of free amalgamation, and a topology is introduced in which we can verify the analytic Zariski axioms. 相似文献
6.
7.
Symmetry is one of the most important aesthetic criteria in graph drawing because it reveals structure in the graph. To draw
graphs symmetrically, we employ two steps. The first step is to find appropriate automorphisms. The second step is to draw
the graph to display the automorphisms. Our aim in this paper is to construct maximally symmetric straight line drawings of
triconnected planar graphs in linear time. Previously known algorithms run in quadratic time. We show that an algorithm of
Fontet can be used to find an embedding in the plane with the maximum number of symmetries, and present a new algorithm for
finding a straight line drawing that achieves that maximum. Both algorithms run in linear time. 相似文献
8.
9.
Brendan D. McKay 《Combinatorica》1990,10(4):367-377
LetRT(n), ED(n) andEOG(n) be the number of labelled regular tournaments, labelled loop-free simple Eulerian digraphs, and labelled Eulerian oriented simple graphs, respectively, onn vertices. Then, asn,, for any>0. The last two families of graphs are also enumerated by their numbers of edges. The proofs use the saddle point method applied to appropriaten-dimensional integrals. 相似文献
10.
Atomic populations and localization [lambda(A)] and delocalization [delta(A,B)] indices (LIs and DIs) are calculated for a large set of molecules at the Hartree-Fock (HF), MP2, MP4(SDQ), CISD, and QCISD levels with the 6-311++G(2d,2p) basis set. The HF method and the conventional correlation methods [MP2, MP4(SDQ), CISD, and QCISD] yield distinct sets of LIs and DIs. Yet, within the four conventional correlation methods the differences in atomic populations and LIs and DIs are small. Relative to HF, the conventional correlation methods [MP2, MP4(SDQ), CISD, QCISD] yield virtually the same LIs and DIs for molecules with large charge separations while LIs and DIs that differ significantly from the HF values--the LIs are increased and DIs decreased--are obtained for bonds with no or small charge separations. Such is the case in the archetypal homopolar molecules HC(triple bond)CH, H2C=CH2, CH3-CH3, and "protonated cyclopropane" C(3)H(7) (+), in which case the bonding may be atypical. Relative to HF, the typical effect of the conventional correlation methods is to decrease the DI between atoms. 相似文献