全文获取类型
收费全文 | 835篇 |
免费 | 25篇 |
国内免费 | 12篇 |
专业分类
化学 | 488篇 |
晶体学 | 3篇 |
力学 | 42篇 |
数学 | 163篇 |
物理学 | 176篇 |
出版年
2023年 | 4篇 |
2022年 | 15篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 22篇 |
2018年 | 23篇 |
2017年 | 17篇 |
2016年 | 21篇 |
2015年 | 22篇 |
2014年 | 31篇 |
2013年 | 45篇 |
2012年 | 33篇 |
2011年 | 49篇 |
2010年 | 35篇 |
2009年 | 36篇 |
2008年 | 50篇 |
2007年 | 38篇 |
2006年 | 39篇 |
2005年 | 28篇 |
2004年 | 36篇 |
2003年 | 15篇 |
2002年 | 22篇 |
2001年 | 16篇 |
2000年 | 16篇 |
1999年 | 11篇 |
1998年 | 16篇 |
1997年 | 7篇 |
1996年 | 10篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 17篇 |
1990年 | 19篇 |
1989年 | 16篇 |
1987年 | 7篇 |
1986年 | 7篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1978年 | 6篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1973年 | 3篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1914年 | 2篇 |
排序方式: 共有872条查询结果,搜索用时 31 毫秒
721.
Elias Brito Aliliane Freitas Thiago Silva Thiago Guerra Sergio Azevedo 《The European Physical Journal B - Condensed Matter and Complex Systems》2015,88(6):153
We have applied first-principles calculations, based on the density functional theory, toinvestigate the stability and electronic properties of double-walled carbon nanocones,60°60°, 120°120° and 60°120° with different rotation anglesbetween the walls. We have shown that the most favorable double-walled nanocone studiedhere is that of angles of 60°60°, with rotation angle of 36° and distance between apexes of 4.22 Å.We have found that, the interaction between the walls of rotated double-walled nanoconesintroduce geometric distortion in gap states, such as in Fermi level. These results shouldhave consequences on the field emission properties of double-walled carbon nanocones.Additionally, we also investigated the spin polarization of such structures, and we havefound unpaired electrons, which induces a total spin from 1 and 1/2 for 60°60° and 60°120° double cones, respectively. 相似文献
722.
J. Chudoba M. Elias L. Fiala J. Horky T. Kouba J. Kundrat M. Lokajicek J. Schovancova J. Svec S. Belov P. Dmitrienko A. Dolbilov V. Korenkov V. Mitsyn D. Oleynik A. Petrosyan N. Rusakovich E. Tikhonenko V. Trofimov A. Uzhinsky V. Zhiltsov 《Physics of Particles and Nuclei Letters》2013,10(3):288-294
The paper describes the cooperation of JINR specialists and Czech colleagues in the field of deployment and development of modern grid technologies within the framework of the WLCG global infrastructure project. Special attention is paid to the development and usage of monitoring systems. 相似文献
723.
724.
725.
Hans-G. Elias Mohammed B. El-sabbah William M. Loris John Semen 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(2):529-532
Poly(L-leucine) and poly(L-phenylalanine) cross-link with either 2,4-toluene diisocyanate or 1,6-hexane diisocyanate but no such cross-linking resulted for poly(γ-benzyl-L-glutamate). The latter polymer cross-links, however, upon transesterification with diols. 相似文献
726.
727.
728.
Anil J. Elias M. N. Sudheendra Rao 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):367-372
Abstract 1,5- [(p-tolyl)diphenylphosphinimino] (triphenylphosphinimino)tetrasulphurtetranitride, (I) and 1,5-[di(p-tolyl)phenylphosphinimino] (triphenylphosphinimino)tetrasulphurtetranitride, (II) are the first examples of heterodisubstituted tetrasulphurtetranitride derivatives to be made. Their synthesis and structural characterization are described. 相似文献
729.
Vladimir O. Elias Bernd R. T. Simoneit Alberto S. Pereira Jari N. Cardoso 《Journal of separation science》1998,21(2):87-93
A custom-made glass capillary column coated with OV-1701-OH (88% methyl, 7% cyanopropyl, 5% phenylpolysiloxane) was used to analyze smoke samples from biomass combustion of different species of plants collected in the Amazon forest. CS2 was used as solvent in order to enhance the dissolution and analysis of the heavier molecular weight components. The performance of the column was monitored during the experiments and a moderate increase in activity was observed after taking the column to high analytical temperatures (390°C). Trennzahl values typically dropped 20–30% from 1.7/m to the average of 1.35/m. In general, the performance of the custom-made column was satisfactory and comparable to the commercial high temperature columns. The high temperature high resolution GC and GC-MS analyses revealed the presence of a number of high molecular weight components reported to occur in smoke aerosols for the first time. These components consisted of series of wax esters (long chain alcohols esterified with long chain fatty acids) with up to 58 carbon numbers, aliphatic hydrocarbons, triglycerides, triterpenyl esters (e.g. α- and β-amyryl stearate). Although other types of compounds were also detected, their complete structure elucidation solely by electron impact MS was not adequate and other techniques will be required. 相似文献
730.