全文获取类型
收费全文 | 73篇 |
免费 | 2篇 |
专业分类
化学 | 45篇 |
力学 | 1篇 |
数学 | 3篇 |
物理学 | 26篇 |
出版年
2023年 | 4篇 |
2022年 | 1篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 2篇 |
2017年 | 1篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 1篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 3篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1996年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有75条查询结果,搜索用时 15 毫秒
41.
On Ba2Ge2Te5, a New Telluridogermanate(III) with Chain Structure The new compound Ba2Ge2Te5 crystallizes in the orthorhombic system (space group: Pna21 (No. 33)) with lattice constants s. “Inhaltsübersicht”. In the structure distorted Ge2Te6- trigonal prisms are connected by common corners to infinite chains. 相似文献
42.
A one-dimensional gas comprising N point particles undergoing elastic collisions within a finite space described by a Sinai billiard generating identical dynamical trajectories are calculated and analyzed with regard to strict extensivity of the entropy definitions of Boltzmann–Gibbs. Due to the collisions, trajectories of gas particles are strongly correlated and exhibit both chaotic and periodic properties. Probability distributions for the position of each particle in the one-dimensional gas can be obtained analytically, elucidating that the entropy in this special case is extensive at any given number N. Furthermore, the entropy obtained can be interpreted as a measure of the extent of interactions between molecules. The results obtained for the non-mixable one-dimensional system are generalized to mixable one- and two-dimensional systems, the latter by a simple example only providing similar findings. 相似文献
43.
Davide Cassani Claudius Klare Dario Martelli Alessandro Tomasiello Alberto Zaffaroni 《Communications in Mathematical Physics》2014,327(2):577-602
We consider superconformal and supersymmetric field theories on four-dimensional Lorentzian curved space-times, and their five-dimensional holographic duals. As in the Euclidean signature case, preserved supersymmetry for a superconformal theory is equivalent to the existence of a charged conformal Killing spinor. Differently from the Euclidean case, we show that the existence of such spinors is equivalent to the existence of a null conformal Killing vector. For a supersymmetric field theory with an R-symmetry, this vector field is further restricted to be Killing. We demonstrate how these results agree with the existing classification of supersymmetric solutions of minimal gauged supergravity in five dimensions. 相似文献
44.
We study the electronic structure of a strongly correlated d-wave superconducting state. Combining a renormalized mean field theory with direct calculation of matrix elements, we obtain explicit analytical results for the nodal Fermi velocity upsilon(F), the Fermi wave vector k(F), and the momentum distribution n(k) as a function of hole doping in a Gutzwiller projected d-wave superconductor. We calculate the energy dispersion E(k) and spectral weight of the Gutzwiller-Bogoliubov quasiparticles and find that the spectral weight associated with the quasiparticle excitation at the antinodal point shows a nonmonotonic behavior as a function of doping. Results are compared to angle resolved photoemission spectroscopy of the high-temperature superconductors. 相似文献
45.
Fruit firmness constitutes an important textural property and is one of the key parameters for estimating ripening and shelf life, which has a major impact on commercialization. In order to decipher the mechanisms related to firmness of apples (Malus × domestica Borkh.), two-dimensional gel electrophoresis (2-DE) was used to compare the total proteome of high and low firmness phenotypes from apple hypanthia of a ??Golden Delicious?? × ??Dietrich?? population. A total of 36 differentially regulated protein spots were positively identified by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) and then validated against the Malus expressed sequence tags (EST) database. The findings of this study indicated a lower expression of ethylene biosynthesis related proteins in the high firmness phenotype, which could be linked to the slowing down of the ripening and softening processes. The reduced accumulation of proteins involved in ethylene biosynthesis juxtaposed to the upregulation of a transposase and a GTP-binding protein in the high firmness phenotype. The results also showed higher expression of cytoskeleton proteins in the high firmness phenotype compared to the low firmness phenotype, which play a role in maintaining cell structure and possibly fruit integrity. Finally, a number of proteins involved in detoxification and defense were expressed in fruit hypanthium. This proteomic study provides a contribution towards a better understanding of regulatory networks involved in fruit hypanthium firmness and/or softening, which could be instrumental in the development of improved fruit quality. 相似文献
46.
Enthaler B Pruns JK Wessel S Rapp C Fischer M Wittern KP 《Analytical and bioanalytical chemistry》2012,402(3):1159-1167
Localization of endogenous and exogenous compounds directly in tissue sections is a challenging task in skin research. Matrix-assisted
laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) is a powerful label-free technique that enables determination
of the distribution of a large range of biomolecules directly in tissue sections. Nevertheless, its application in this field
is limited in large part by the low adhesion of skin tissue sections to indium–tin oxide-coated (ITO) glass slides. For the
first time corona discharge (CD) treatment was used to modify the glass slide surface for improved adhesion. Localization
of endogenous cholesterol sulfate was performed directly in human skin tissue sections. A spatial resolution of approximately
30 μm was sufficient for assignment of mass signals to skin structure morphology. Furthermore, imaging of an exogenous model
compound, Nile red, was performed directly in skin tissue sections after ex-vivo penetration into porcine skin, enabling determination
of the pathway and depth of penetration. Finally, the ion density map of Nile red was compared with its high resolution fluorescence
micrograph. This work provides new insights into the application of MALDI–MSI in skin research. 相似文献
47.
48.
49.
50.
Patrick Alexa Prof. Christina Oligschleger Pascal Gröger Dr. Claudius Morchutt Dr. Vijay Vyas Prof. Bettina V. Lotsch Prof. J. Christian Schön Dr. Rico Gutzler Prof. Klaus Kern 《Chemphyschem》2019,20(18):2340-2347
Many 2D covalent polymers synthesized as single layers on surfaces show inherent disorder, expressed for example in their ring-size distribution. Systems which are expected to form the thermodynamically favored hexagonal lattice usually deviate from crystallinity and include high numbers of pentagons, heptagons, and rings of other sizes. The amorphous structure of two different covalent polymers in real space using scanning tunneling microscopy is investigated. Molecular dynamics simulations are employed to extract additional information. We show that short-range correlations exist in the structure of one polymer, i. e. that polygons are not tessellating the surface randomly but that ring neighborhoods have preferential compositions. The correlation is dictated by the energy of formation of the ring neighborhoods. 相似文献