全文获取类型
收费全文 | 457066篇 |
免费 | 5216篇 |
国内免费 | 1597篇 |
专业分类
化学 | 252238篇 |
晶体学 | 6839篇 |
力学 | 18979篇 |
综合类 | 11篇 |
数学 | 51583篇 |
物理学 | 134229篇 |
出版年
2018年 | 2974篇 |
2016年 | 5681篇 |
2015年 | 4525篇 |
2014年 | 6255篇 |
2013年 | 19931篇 |
2012年 | 14373篇 |
2011年 | 17995篇 |
2010年 | 11465篇 |
2009年 | 11329篇 |
2008年 | 16528篇 |
2007年 | 16881篇 |
2006年 | 16216篇 |
2005年 | 14814篇 |
2004年 | 13399篇 |
2003年 | 11883篇 |
2002年 | 11693篇 |
2001年 | 13830篇 |
2000年 | 10612篇 |
1999年 | 8503篇 |
1998年 | 6791篇 |
1997年 | 6664篇 |
1996年 | 6695篇 |
1995年 | 6118篇 |
1994年 | 5863篇 |
1993年 | 5562篇 |
1992年 | 6413篇 |
1991年 | 6162篇 |
1990年 | 5857篇 |
1989年 | 5746篇 |
1988年 | 5939篇 |
1987年 | 5687篇 |
1986年 | 5435篇 |
1985年 | 7666篇 |
1984年 | 7772篇 |
1983年 | 6379篇 |
1982年 | 6818篇 |
1981年 | 6828篇 |
1980年 | 6480篇 |
1979年 | 6751篇 |
1978年 | 6931篇 |
1977年 | 6818篇 |
1976年 | 6709篇 |
1975年 | 6488篇 |
1974年 | 6290篇 |
1973年 | 6470篇 |
1972年 | 3916篇 |
1971年 | 3035篇 |
1968年 | 3375篇 |
1967年 | 3278篇 |
1966年 | 2990篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
M Lepère R Gobeille V.Malathy Devi M.A.H Smith B Aoaeh A.W Mantz 《Journal of Molecular Spectroscopy》2004,224(1):7-12
We have analyzed the methyl fluoride RQ(J,0)Q branch lines located near 1475 cm−1 using a simultaneous multi-spectrum fitting technique. In this analysis we have used previously recorded diode-laser data in which we collected many data points covering only one or two Q branch lines in a particular run. The analysis consists of simultaneously fitting 57 spectra collected with numerous pressure and path length conditions for all absorption lines. The data are concatenated to create one continuous spectrum of the Q branch. We have determined the intensity and self-broadened widths at 296 K for 23 RQ(J,0) lines. 相似文献
103.
The decomposition of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules during evaporation of unpurified raw material in ultra high vacuum was studied. The fragments were identified by mass spectrometry and the influence of these fragments and further contaminations of the raw material on the electronic structure of PTCDA thin films was measured by photoemission spectroscopy. Annealing of contaminated PTCDA films was tested as cheap and easy to perform method for (partial) post deposition purification of the contaminated films. 相似文献
104.
Equilibrium Problems with Applications to Eigenvalue Problems 总被引:5,自引:0,他引:5
In this paper, we consider equilibrium problems and introduce the concept of (S)+ condition for bifunctions. Existence results for equilibrium problems with the (S)+ condition are derived. As special cases, we obtain several existence results for the generalized nonlinear variational inequality studied by Ding and Tarafdar (Ref. 1) and the generalized variational inequality studied by Cubiotti and Yao (Ref. 2). Finally, applications to a class of eigenvalue problems are given. 相似文献
105.
In a recent paper to this journal (Whitman A M et al 2003 Waves Random Media 13 269-86) we derived a set of coupled equations that describe the intermodal scattering of acoustic radiation in a duct whose speed of sound varies randomly in space and time. In the paper we were mainly interested in modes that were not near cutoff. Here we study the solution of these equations in the vicinity of the cutoff. We find that near cutoff almost all the energy is reflected back independent of the other duct parameters. In addition to presenting these results, we analyse the mathematical structure of the equations in these regions in order to elucidate the reason for this behaviour. 相似文献
106.
We show that there are close relations between extremal problems in dual Brunn-Minkowski theory and isotropic-type properties for some Borel measures on the sphere. The methods we use allow us to obtain similar results in the context of Firey-Brunn-Minkowski theory. We also study reverse inequalities for dual mixed volumes which are related with classical positions, such as ?-position or isotropic position. 相似文献
107.
A homologous series of azomesogens, 2″-[4-(4′-n-alkoxybenzoyloxy)-2-chlorophenylazo] naphthalenes, with lateral chloro groups was synthesised. All the homologues synthesized
exhibit enantiotropic nematic mesophase. The mesomorphic properties of the present series are compared with other structurally
related series to evaluate the effect of lateral chloro group and its position on mesomorphism
This paper was presented at the 10th National Conference on Liquid Crystals held at Bangalore, India during 9–11 October 2003. 相似文献
108.
109.
Sauer, Shelah, Vapnik and Chervonenkis proved that if a set system on n vertices contains many sets, then the set system has full trace on a large set. Although the restriction on the size of the
groundset cannot be lifted, Frankl and Pach found a trace structure that is guaranteed to occur in uniform set systems even
if we do not bound the size of the groundset. In this note we shall give three sequences of structures such that every set
system consisting of sufficiently many sets contains at least one of these structures with many sets. 相似文献
110.
Using the theory of noncommutative symmetric functions, we introduce the higher order peak algebras (Sym(N))N≥1, a sequence of graded Hopf algebras which contain the descent algebra and the usual peak algebra as initial cases (N=1 and N=2). We compute their Hilbert series, introduce and study several combinatorial bases, and establish various algebraic identities
related to the multisection of formal power series with noncommutative coefficients.
Received November 19, 2004 相似文献