全文获取类型
收费全文 | 4327篇 |
免费 | 350篇 |
国内免费 | 370篇 |
专业分类
化学 | 1746篇 |
晶体学 | 59篇 |
力学 | 531篇 |
综合类 | 25篇 |
数学 | 1151篇 |
物理学 | 1535篇 |
出版年
2024年 | 6篇 |
2023年 | 53篇 |
2022年 | 87篇 |
2021年 | 96篇 |
2020年 | 100篇 |
2019年 | 127篇 |
2018年 | 106篇 |
2017年 | 119篇 |
2016年 | 132篇 |
2015年 | 125篇 |
2014年 | 203篇 |
2013年 | 365篇 |
2012年 | 237篇 |
2011年 | 306篇 |
2010年 | 244篇 |
2009年 | 306篇 |
2008年 | 292篇 |
2007年 | 252篇 |
2006年 | 249篇 |
2005年 | 205篇 |
2004年 | 191篇 |
2003年 | 161篇 |
2002年 | 115篇 |
2001年 | 107篇 |
2000年 | 115篇 |
1999年 | 95篇 |
1998年 | 96篇 |
1997年 | 78篇 |
1996年 | 67篇 |
1995年 | 66篇 |
1994年 | 51篇 |
1993年 | 49篇 |
1992年 | 35篇 |
1991年 | 22篇 |
1990年 | 24篇 |
1989年 | 17篇 |
1988年 | 22篇 |
1987年 | 15篇 |
1986年 | 16篇 |
1985年 | 17篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 11篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 7篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 5篇 |
排序方式: 共有5047条查询结果,搜索用时 656 毫秒
41.
Ryo Ikehata 《Journal of Mathematical Analysis and Applications》2003,288(2):803-818
We generalize a previous result of Ikehata (Math. Methods Appl. Sci., in press), which studies the critical exponent problem of a semilinear damped wave equation in the one-dimensional half space, to the general N-dimensional half space case. That is to say, one can show the small data global existence of solutions of a mixed problem for the equation utt−Δu+ut=|u|p with the power p satisfying p∗(N)=1+2/(N+1)<p?N/[N−2]+ if we deal with the problem in the N-dimensional half space. 相似文献
42.
43.
In a recent work (Int. J. Solids Struct. 37 (2000) 1561) by one of the authors, an extended system for calculating critical points of equilibrium paths in imperfect structures was presented. However, the extremum nature of these points was not analyzed explicitly in that paper. In this note, we will fill in the gap and establish a sufficient condition for determining the buckling strength of imperfect structures. 相似文献
44.
45.
46.
A. Hansen M.H. Jensen K. Sneppen G. Zocchi 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(1):157-161
We present a statistical mechanics treatment of the stability of globular proteins which takes explicitly into account the
coupling between the protein and water degrees of freedom. This allows us to describe both the cold and the warm unfolding,
thus qualitatively reproducing the known thermodynamics of proteins.
Received: 19 March 1998 / Revised and Accepted: 25 May 1998 相似文献
47.
B C Anusionwu 《Pramana》2006,67(2):319-330
The thermodynamic properties of Sb-Sn and In-Sn liquid alloys have been studied using the quasi-chemical model for compound
forming binary alloys and that for simple regular alloys. The concentration fluctuation S
cc(0) and the Warren-Cowley short-range order parameter (α
1) were determined for the whole concentration range at a temperature of 770 K. The surface tensions of these liquid alloys
were determined for the whole concentration range by using energetics determined from thermodynamic calculations. In all calculations,
In-Sn manifested properties very close to alloys of ideal mixing, while Sb-Sn showed properties that are asymmetric about
equiatomic composition. Our results suggest that a weak complex of the form SbSn2 could be present in the Sb-Sn alloy at a temperature of about 770 K. 相似文献
48.
The behavior of three-dimensional bond fluctuation model chains tethered on an adsorbing flat surface was simulated by the Monte Carlo method. The dependence of the number of surface contacts M on the interaction strength e and the chain length N was investigated by a finite-size scaling law M = N[a0 + a1N1/vk + O((N 1/vk)2)] for e near the critical adsorption point ec, i.e., k ≡(e-ec)/ec closes to 0. The critical adsorption point was estimated to be ec = 0.93, and the exponents 61542; = 0.49 and 1/v= 0.57. 相似文献
49.
50.
Cl···O intramolecular contacts are analysed here. Hence the Cambridge Structural Database (CSD) search was performed to find
five-membered Cl–C=C–C=O pseudo-rings closed through Cl···O intramolecular contacts. Such rings were analysed and it was found
that some of Cl···O distances are smaller than the corresponding sum of van der Waals radii. Additionally ab initio MP2/6-311++G(d,p)
calculations and AIM analyses were carried out here on 3-chloropropenal and its fluoro derivatives to deepen the nature of
intramolecular Cl···O interactions, some of findings may indicate that they are attractive and stabilizing ones.
This paper is dedicated to Prof. T. M. Krygowski on the occasion of his 70th birthday 相似文献