全文获取类型
收费全文 | 1944篇 |
免费 | 97篇 |
国内免费 | 11篇 |
专业分类
化学 | 1148篇 |
晶体学 | 7篇 |
力学 | 57篇 |
数学 | 449篇 |
物理学 | 391篇 |
出版年
2024年 | 6篇 |
2023年 | 27篇 |
2022年 | 38篇 |
2021年 | 35篇 |
2020年 | 47篇 |
2019年 | 50篇 |
2018年 | 35篇 |
2017年 | 26篇 |
2016年 | 80篇 |
2015年 | 78篇 |
2014年 | 77篇 |
2013年 | 121篇 |
2012年 | 132篇 |
2011年 | 168篇 |
2010年 | 99篇 |
2009年 | 65篇 |
2008年 | 112篇 |
2007年 | 101篇 |
2006年 | 107篇 |
2005年 | 83篇 |
2004年 | 77篇 |
2003年 | 60篇 |
2002年 | 56篇 |
2001年 | 36篇 |
2000年 | 29篇 |
1999年 | 13篇 |
1998年 | 14篇 |
1997年 | 19篇 |
1996年 | 22篇 |
1995年 | 26篇 |
1994年 | 15篇 |
1993年 | 7篇 |
1992年 | 18篇 |
1991年 | 7篇 |
1990年 | 13篇 |
1988年 | 11篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 4篇 |
1982年 | 11篇 |
1981年 | 5篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1974年 | 10篇 |
1973年 | 4篇 |
排序方式: 共有2052条查询结果,搜索用时 15 毫秒
2.
Lagrangian and Eulerian modelling approaches are compared for simulating turbulent dispersion and coalescence of droplets within a spray. Both models predict similar droplet dispersion rates and shifts in droplet size distribution due to coalescence within the spray, over a wide range of droplet and gas flows, and for sprays with different droplet-size distributions at the nozzle exit. The computer time required for simulating coalescence within a steady axisymmetric spray is of a similar order of magnitude regardless of which formulation, Eulerian or Lagrangian, is adopted. However, the Lagrangian formulation is more practical in terms of the range of applicability and ease of implementation. 相似文献
3.
Given a connected spaceX, we consider the effect of Quillen’s plus construction on the homotopy groups ofX in terms of its Postnikov decomposition. Specifically, using universal properties of the fibration sequenceAX→X→X
+, we explain the contribution of π
n
X to π
n
X
+, π
n+1
X
+ and π
n
AX, π
n+1
AX explicitly in terms of the low dimensional homology of π
n
X regarded as a module over π1
X. Key ingredients developed here for this purpose are universal II-central fibrations and a theory of universal central extensions
of modules, analogous to universal central extensions of perfect groups.
Research partially supported by NSERC of Canada. 相似文献
4.
O. Perru F. Ibrahim O. Bajeat C. Bourgeois F. Clapier E. Cottereau C. Donzaud M. Ducourtieux S. Galès D. Guillemaud-Mueller C. Lau H. Lefort F. Le Blanc A. C. Mueller J. Obert N. Pauwels J. C. Potier F. Pougheon J. Proust B. Roussière J. Sauvage O. Sorlin D. Verney 《Physics of Atomic Nuclei》2003,66(8):1421-1427
The PARRNe facility has been used to produce neutron-rich isotopes 83,84Gaby the ISOL method. Their decay has been studied, and β-γ coincidence and γ-γ coincidence data were collected as a function of time. The first two excited levels in 83Ge and the first excited level in 84Ge have been measured for the first time. 相似文献
5.
6.
Laura Bader Nicola Durante Maska Law Guglielmo Lunardon Tim Penttila 《Designs, Codes and Cryptography》2003,29(1-3):41-50
We do the tentative beginnings of a study of BLT-sets of generalised quadrangles via their symmetries. In particular, the study of whorls about a line leads us to hyperbolic reflections preserving a BLT-set of Q(4, q). 相似文献
7.
We study in this Note the continuum (macroscopic) limit for some atomistic models for crystals. The purpose is to derive densities of mechanical energies from microscopic models. In contrast to the setting of a previous study, where the microscopic structure was assumed to be periodic, it is modelled here by a stochastic lattice, which enjoys some stationarity and ergodicity properties, following notions previously introduced elsewhere. To cite this article: X. Blanc et al., C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献
8.
9.
J.P.C. Blanc 《Annals of Operations Research》2002,112(1-4):83-100
The generating function of the autocorrelations of the interdeparture times in stationary M/G/1 and GI/M/1 systems involves the probability generating function of the number of customers served in a busy period. The latter function is implicitly determined as a solution to a functional equation. Standard methods for the numerical inversion of generating functions require the values of these functions at many complex arguments. A recently discovered substitution method for contour integrals allows the numerical inversion of implicitly determined generating functions without the numerical solution of the functional equations. 相似文献
10.