全文获取类型
收费全文 | 155篇 |
免费 | 22篇 |
国内免费 | 10篇 |
专业分类
化学 | 138篇 |
晶体学 | 2篇 |
力学 | 3篇 |
综合类 | 2篇 |
物理学 | 42篇 |
出版年
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 2篇 |
2020年 | 11篇 |
2019年 | 7篇 |
2018年 | 5篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 21篇 |
2012年 | 14篇 |
2011年 | 1篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 6篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1984年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 15 毫秒
11.
Simultaneous Aromatic–Beryllium Bonds and Aromatic–Anion Interactions: Naphthalene and Pyrene as Models of Fullerenes,Carbon Single‐Walled Nanotubes,and Graphene
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Marta Marín‐Luna Prof. Ibon Alkorta Prof. José Elguero Prof. Otilia Mó Prof. Manuel Yáñez 《Chemphyschem》2015,16(12):2680-2686
The possibility of forming stable BeR2:ArH:Y? (R=H, F, Cl; ArH=naphthalene, pyrene; Y=Cl, Br) ternary complexes in which the beryllium compounds and anions are located on the opposite sides of an extended aromatic system is explored by means of MP2/aug‐cc‐pVDZ ab initio calculations. Comparison of the electron‐density distribution of these ternary complexes with the corresponding BeR2:ArH and ArH:Y? binary complexes reveals the existence of significant cooperativity between the two noncovalent interactions in the triads. The energetic effects of this cooperativity are quantified by evaluation of the three‐body interaction energy Δ3E in the framework of the many‐body interaction‐energy (MBIE) approach. Although an essential component of the interaction energies is electrostatic and is well reflected in the changes in the molecular electrostatic potential of the aromatic system on complexation, strong polarization effects, in particular for the BeR2:ArH interactions, also play a significant role. The charge transfers associated with these polarization effects are responsible for significant distortion of both the BeR2 and the aromatic moieties. The former are systematically bent in all the complexes, and the latter are curved to a degree that depends on the nature of the R substituents of the BeR2 subunit. 相似文献
12.
Abstract The emission spectra of isotopic BeO molecules as excited in low-pressure arc have been photographed in the region 300–350 nm at medium dispersion. The bands have been assigned to the c3II ? a3II system. The vibrational numbering was obtained from a study of the vibrational isotope effect. Vibrational constants for involved states are derived from least-squares fits of the measured bandhead wavenumbers. 相似文献
13.
The channelling of protons through a thin beryllium crystal is simulated in a computer. The angular dependence of the momentum
density is computed using particle trajectory approximation and is reported as the transmission spectra. In obtaining the
spectra, the energy loss suffered by protons due to electron multiple scattering is considered and the effect of thermal vibrations
treated separately. The spectra obtained are characteristic of the hcp structure of Be. Positions of the major dips in the
transmission spectra are found to correlate well with the directions of neighbouring strings. Variations in the angle of incidence
of the beam and in its initial azimuthal angle bring about modifications in the spectra depending on the transverse kinetic
energy of the incident particles and the crystalline structure of Be. Thermal vibration of the lattice does not modify the
spectra appreciably. 相似文献
14.
S V Deshmukh 《Pramana》1978,11(6):755-760
The effect of Gaunt factor correction on temperature estimation over a range 100 to 1500 eV had been studied. Greene’s analytical
expression for the quantum mechanical Gaunt factor averaged over Maxwellian distribution is used. Transmission ratios are
calculated with and without Gaunt factor for various combinations of beryllium foils, taking into account x-ray emission due
to free-free transitions. A significant difference (≳ 15%) is observed between the temperatures estimated from classical and
quantum mechanical curves, above 600 eV. Selection of foil combinations useful for estimating higher temperatures is also
discussed. 相似文献
15.
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
16.
17.
DFT calculations provide a range of detailed predictions of structures for known stoichiometries at atmospheric pressure, and of some structures at elevated pressures. 相似文献
18.
19.
The electronic bands appearing in the region 300–330 nm were produced in a low-pressure DC are with beryllium electrodes. The bands were obtained in the atmosphere of ordinary water vapour and heavy water vapour. From isotope shift studies, experimental conditions and the similarity with the bands of isoelectronic BeF, the emitting molecules were identified as BeOH and BeOD, respectively. 相似文献
20.
Lifen Wang Lei Liu Ji Chen Ali Mohsin Jung Hwan Yum Todd W. Hudnall Christopher W. Bielawski Tijana Rajh Xuedong Bai Shang-Peng Gao Gong Gu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(36):15864-15870
Using high-resolution transmission electron microscopy and electron energy-loss spectroscopy, we show that beryllium oxide crystallizes in the planar hexagonal structure in a graphene liquid cell by a wet-chemistry approach. These liquid cells can feature van-der-Waals pressures up to 1 GPa, producing a miniaturized high-pressure container for the crystallization in solution. The thickness of as-received crystals is beyond the thermodynamic ultra-thin limit above which the wurtzite phase is energetically more favorable according to the theoretical prediction. The crystallization of the planar phase is ascribed to the near-free-standing condition afforded by the graphene surface. Our calculations show that the energy barrier of the phase transition is responsible for the observed thickness beyond the previously predicted limit. These findings open a new door for exploring aqueous-solution approaches of more metal-oxide semiconductors with exotic phase structures and properties in graphene-encapsulated confined cells. 相似文献