全文获取类型
收费全文 | 3046篇 |
免费 | 230篇 |
国内免费 | 205篇 |
专业分类
化学 | 319篇 |
晶体学 | 7篇 |
力学 | 349篇 |
综合类 | 15篇 |
数学 | 1372篇 |
物理学 | 1419篇 |
出版年
2024年 | 2篇 |
2023年 | 30篇 |
2022年 | 41篇 |
2021年 | 41篇 |
2020年 | 76篇 |
2019年 | 75篇 |
2018年 | 74篇 |
2017年 | 73篇 |
2016年 | 82篇 |
2015年 | 84篇 |
2014年 | 159篇 |
2013年 | 228篇 |
2012年 | 144篇 |
2011年 | 212篇 |
2010年 | 140篇 |
2009年 | 224篇 |
2008年 | 245篇 |
2007年 | 200篇 |
2006年 | 152篇 |
2005年 | 138篇 |
2004年 | 155篇 |
2003年 | 133篇 |
2002年 | 119篇 |
2001年 | 91篇 |
2000年 | 73篇 |
1999年 | 74篇 |
1998年 | 56篇 |
1997年 | 62篇 |
1996年 | 54篇 |
1995年 | 32篇 |
1994年 | 34篇 |
1993年 | 33篇 |
1992年 | 29篇 |
1991年 | 9篇 |
1990年 | 12篇 |
1989年 | 11篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 5篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3481条查询结果,搜索用时 8 毫秒
101.
Vijay S. Raykar 《Physics letters. A》2010,374(45):4618-4621
A differential effective medium theory together with Brownian motion is used to predict Effective Thermal Conductivity (ETC) of CNT nanofluids. ETC was influenced significantly by Brownian motion and enhancement was higher in dilute nanofluids. A theoretical model employing an effective volume fraction with dispersibility factor agrees well with experimental data. 相似文献
102.
103.
The binding energy of an off-center hydrogenic donor impurity in weakly oblate Ellipsoidal Quantum Dot (EQD), using the expansion method within the framework of effective mass approximation in strong confinement, is investigated. In this regard, the binding energies of different states of GaAs structures, as functions of the donor position and ellipticity parameter, are calculated. The results show that variations of binding energies are proportional to the ellipticity constant, the dot dimension and the location of impurity. 相似文献
104.
105.
Guihua FeiSoon-Kyu Kim Tixiang Wang 《Journal of Mathematical Analysis and Applications》2002,267(2):665-678
In this paper, we study the existence of periodic solutions for classical Hamiltonian systems without the Palais-Smale condition. We prove that the information of the potential function contained in a finite domain is sufficient for the existence of periodic solutions. Moreover, we establish the existence of infinitely many periodic solutions without any symmetric condition on the potential function V. 相似文献
106.
We study the effective conductivity
e
for a random wire problem on the d-dimensional cubic lattice
d
, d2 in the case when random conductivities on bonds are independent identically distributed random variables. We give exact expressions for the expansion of the effective conductivity in terms of the moments of the disorder parameter up to the 5th order. In the 2D case using the duality symmetry we also derive the 6th order expansion. We compare our results with the Bruggeman approximation and show that in the 2D case it coincides with the exact solution up to the terms of 4th order but deviates from it for the higher order terms. 相似文献
107.
We study the perturbation theory for the eigenvalue problem of a formal matrix product A
1
s
1 ··· A
p
s
p, where all A
k are square and s
k {–1, 1}. We generalize the classical perturbation results for matrices and matrix pencils to perturbation results for generalized deflating subspaces and eigenvalues of such formal matrix products. As an application we then extend the structured perturbation theory for the eigenvalue problem of Hamiltonian matrices to Hamiltonian/skew-Hamiltonian pencils. 相似文献
108.
András Sütő 《Journal of statistical physics》2002,109(5-6):1051-1072
109.
Ring-shaped lead zirconate titanate (PZT) piezoelectric vibrators were subjected to non-uniform mechanical stress applied by bolt clamping. The effect of mechanical stress on the effective electromechanical coupling factor (keff) and mechanical quality factor (Qm) of the thickness and wall thickness modes was studied by an equivalent electric circuit analysis. The initiation and propagation of cracks under mechanical stress were also discussed based on the resonance method and the indentation technique. keff for both the thickness and wall thickness modes decreased with increase in mechanical stress due to de-poling of the PZT. Qm of the thickness mode dropped sharply with increase in mechanical stress while Qm of the wall thickness mode remained almost unchange. Existence of microcracks in a PZT vibrator can be detected by the occurrence of spurious vibrations at the wall thickness mode in the electrical impedance vs. frequency spectra. 相似文献
110.
V.S. Gerdjikov 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,29(2):237-241
We compare the Hamiltonian properties of the N-soliton solutions of the NLSE in the adiabatic approximation and show how it matches the Hamiltonian formulation for the
complex Toda chain which describes the adiabatic N-soliton interactions.
Received 21 October 2001 Published online 2 October 2002
RID="a"
ID="a"e-mail: gerjikov@inrne.bas.bg 相似文献