全文获取类型
收费全文 | 1943篇 |
免费 | 54篇 |
国内免费 | 135篇 |
专业分类
化学 | 467篇 |
晶体学 | 5篇 |
力学 | 154篇 |
数学 | 895篇 |
物理学 | 611篇 |
出版年
2024年 | 3篇 |
2023年 | 22篇 |
2022年 | 23篇 |
2021年 | 27篇 |
2020年 | 31篇 |
2019年 | 60篇 |
2018年 | 36篇 |
2017年 | 30篇 |
2016年 | 31篇 |
2015年 | 44篇 |
2014年 | 86篇 |
2013年 | 143篇 |
2012年 | 103篇 |
2011年 | 148篇 |
2010年 | 143篇 |
2009年 | 167篇 |
2008年 | 154篇 |
2007年 | 136篇 |
2006年 | 111篇 |
2005年 | 76篇 |
2004年 | 69篇 |
2003年 | 62篇 |
2002年 | 47篇 |
2001年 | 41篇 |
2000年 | 61篇 |
1999年 | 47篇 |
1998年 | 42篇 |
1997年 | 25篇 |
1996年 | 23篇 |
1995年 | 20篇 |
1994年 | 17篇 |
1993年 | 15篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 10篇 |
1983年 | 2篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有2132条查询结果,搜索用时 15 毫秒
181.
Martin Schechter 《Mathematische Nachrichten》1997,183(1):201-210
We study semilinear problems in which the nonlinear part is linear at infinity but behaves like a function intersecting many of the eigenvalues of the linear operator. The asymptotic linear operator can have a null space of any finite dimension. 相似文献
182.
The concept of criticality in viscously damped multi-degree-of-freedom systems is discussed. A necessary and sufficient condition for critical damping is presented. The fundamental physical basis is the same as in Beskos and Boley [ASME J. Appl. Mech. 47 (1980) 627], but numerical convenience is enhanced. 相似文献
183.
Shibo Liu 《Journal of Mathematical Analysis and Applications》2007,336(1):498-505
We obtain four nontrivial solutions for an elliptic resonant problem via Morse theory and Lyapunov-Schmidt reduction method. Our result improves some recent works. 相似文献
184.
This paper is devoted to the existence of positive solutions of a Dirichlet problem with critical exponent and a singular potential. Under various assumption on the domain Ω, which include some kinds of unbounded domains, we prove the existence of ground states and of symmetric solutions. 相似文献
185.
Tadeus Nawka Lutz Christian Anders Mario Cebulla David Zurakowski 《Journal of voice》1997,11(4):422-428
Spectral analysis of vowels during connected speech can be performed using the spectral intensity distribution within critical bands corresponding to a natural scale on the basilar membrane. Normalization of the spectra provides the opportunity to make objective comparisons independent from the recording level. An increasing envelope peak between 3,150 and 3,700 Hz has been confirmed statistically for a combination of seven vowels in three groups of male speakers with hoarse, normal, and professional voices. Each vowel is also analyzed individually. The local energy maximum is called “the speaker's formant” and can be found in the region of the fourth formant. The steepness of the spectral slope (i.e. the rate of decline) becomes less pronounced when the sonority or the intensity of the voice increases. The speaker's formant is connected with the sonorous quality of the voice. It increases gradually and is approximately 10 dB higher in professional male voices than in normal male voices at neutral loudness (60 dB at 0.3 min). The peak intensity becomes stronger (30 dB above normal voices) when the overall speaking loudness is increased to 80 dB. Shouting increases the spectral energy of the adjacent critical bands but not the speaker's formant itself. 相似文献
186.
Ravi P. Agarwal Victoria Otero-Espinar Kanishka Perera 《Journal of Mathematical Analysis and Applications》2007,331(2):1263-1274
The aim of this paper is to employ variational techniques and critical point theory to prove some sufficient conditions for the existence of multiple positive solutions to a nonlinear second order dynamic equation with homogeneous Dirichlet boundary conditions. 相似文献
187.
Jan Chabrowski 《Ricerche di matematica》2007,56(2):297-319
We consider the semilinear Neumann problem involving the critical Sobolev exponent with an indefinite weight function and
a concave purturbation. We prove the existence of two distinct solutions.
相似文献
188.
N. G. Fytas A. Malakis 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(1-2):39-43
The three-dimensional bimodal random-field Ising model is studied
via a new finite temperature numerical approach. The methods of
Wang-Landau sampling and broad histogram are implemented in a
unified algorithm by using the N-fold version of the Wang-Landau
algorithm. The simulations are performed in dominant energy
subspaces, determined by the recently developed critical minimum
energy subspace technique. The random-fields are obtained from a
bimodal distribution, that is we consider the discrete
(±Δ) case and the model is studied on cubic lattices with
sizes 4≤L ≤20. In order to extract information for the
relevant probability distributions of the specific heat and
susceptibility peaks, large samples of random-field realizations
are generated. The general aspects of the model's scaling behavior
are discussed and the process of averaging finite-size anomalies
in random systems is re-examined under the prism of the lack of
self-averaging of the specific heat and susceptibility of the
model. 相似文献
189.
建立了H02(Ω)(0∈ΩR4)中的Hardy不等式,利用临界点理论得到了含位势的非线性双调和方程非平凡解的存在性. 相似文献
190.