全文获取类型
收费全文 | 706篇 |
免费 | 13篇 |
国内免费 | 2篇 |
专业分类
化学 | 379篇 |
晶体学 | 8篇 |
力学 | 7篇 |
数学 | 158篇 |
物理学 | 169篇 |
出版年
2023年 | 7篇 |
2022年 | 6篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 9篇 |
2016年 | 18篇 |
2015年 | 22篇 |
2014年 | 12篇 |
2013年 | 32篇 |
2012年 | 33篇 |
2011年 | 35篇 |
2010年 | 32篇 |
2009年 | 28篇 |
2008年 | 42篇 |
2007年 | 34篇 |
2006年 | 39篇 |
2005年 | 18篇 |
2004年 | 15篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 15篇 |
2000年 | 21篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 11篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 10篇 |
1990年 | 10篇 |
1989年 | 9篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 9篇 |
1981年 | 7篇 |
1979年 | 5篇 |
1977年 | 4篇 |
1976年 | 10篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 9篇 |
1968年 | 9篇 |
1967年 | 4篇 |
1966年 | 4篇 |
1961年 | 4篇 |
1954年 | 5篇 |
排序方式: 共有721条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
The aim of the paper is to investigate the limit behaviour of the least squares estimator of the shift parameter of nearly unstable, nearly stable, and nearly explosive AR(1) models. Both zero start and stationary cases are treated. Connection with the maximum likelihood estimator of the shift parameter of continuous time AR(1) processes is also discussed. 相似文献
5.
Infrared (IR)-induced second-harmonic generation in the chalcogenide glasses is observed. A phenomenological approach of IR picosecond non-linear optical (NLO) response in glass is developed for the middle IR spectral range (5–15 μm). The observed effect is explained within the framework of fifth-order NLO susceptibilities. A model that reproduces the basic characteristics of the experimental data, in which the optical non-linearities caused by photoinduced electron–phonon anharmonic interactions, is proposed. The role of the IR-induced phase matching conditions in the observed phenomenon is discussed. 相似文献
6.
Monika Schuster Robert Inführ Claudia Turecek Jürgen Stampfl Franz Varga Robert Liska 《Monatshefte für Chemie / Chemical Monthly》2006,4(4):843-853
To substitute cross-linked photopolymers in rapid prototyping of mold materials and therefore extend the range of materials
which can be casted, organo-soluble photopolymers were developed. Branched bisalkylacrylamides were suitable as base component
for such formulations, due to their high reactivity, good mechanical properties, and excellent solubility of the formed polymers.
These molding materials were used to prepare cellular biocompatible materials which could be used as bone replacement materials.
Biocompatible crosslinkers based on methacrylates from hydrolyzed gelatine or lactic acid ethyleneglycol blockcopolymers and
commercially available reactive diluents are the base components of such a formulation. Biocompatibility was investigated
by osteoblast-like cells. Cellular biocompatible parts were obtained by thermal polymerization in soluble mould materials
prepared by 3D-photoshaping. 相似文献
7.
Rastislav Varga Arcady Zhukov Michail Ipatov Juan Maria Blanco Julian Gonzalez Valentina Zhukova Pavol Vojtanik 《Journal of magnetism and magnetic materials》2006
The effect of the glass coating on the single domain wall potential in amorphous glass-coated Fe-based microwire has been studied by the switching field distribution technique. The thermoactivated mechanism model is used to describe the thermally activated switching through the complex energy barrier in amorphous FeSiB microwires. Glass removal leads to the increase of the probability of the thermally activated switching pointing to the decrease of the energy barrier. 相似文献
8.
The addition of possible oxidation and/or isomerization products (butadiene, water, isomeric n-butenes) resulted in neither promotion nor inhibition in the oxidative dehydrogenation of n-butenes over tin-antimony mixed oxide catalysts. On the basis of these and other information on the influence of products an interpretation has been given to complete the reaction mechanism more realistic than those based on previous experimental results.
(, ) ( -) , . , , .相似文献
9.
We give here a rigorous formulation for a pair of consecutive simple positive zeros of the functionH
0 (which is closely related to the Riemann -function) to be a Lehmer pair of zeros ofH
0. With this formulation, we establish that each such pair of zeros gives a lower bound for the de Bruijn-Newman constant (where the Riemann Hypothesis is equivalent to the assertion that 0). We also numerically obtain the following new lower bound for :
相似文献
10.
|