全文获取类型
收费全文 | 584篇 |
免费 | 13篇 |
国内免费 | 1篇 |
专业分类
化学 | 388篇 |
晶体学 | 7篇 |
力学 | 7篇 |
数学 | 48篇 |
物理学 | 148篇 |
出版年
2022年 | 6篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 5篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 23篇 |
2012年 | 23篇 |
2011年 | 31篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 23篇 |
2007年 | 17篇 |
2006年 | 19篇 |
2005年 | 14篇 |
2004年 | 21篇 |
2003年 | 19篇 |
2002年 | 19篇 |
2001年 | 20篇 |
2000年 | 9篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 11篇 |
1995年 | 9篇 |
1994年 | 6篇 |
1992年 | 7篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 9篇 |
1985年 | 8篇 |
1984年 | 15篇 |
1983年 | 6篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1973年 | 5篇 |
1969年 | 6篇 |
1968年 | 5篇 |
1967年 | 6篇 |
1933年 | 4篇 |
1931年 | 5篇 |
排序方式: 共有598条查询结果,搜索用时 93 毫秒
591.
We investigate the thermodynamic properties of quantum electrodynamics in 1+1 dimensions. We derive the partition function of the canonical ensemble in discrete light cone quantization and calculate the thermodynamical potential. This central quantity is evaluated for different system sizes and coupling strengths. We investigate the continuum limit and the thermodynamical limit and present basic thermodynamical quantities as a function of temperature for the interacting system. The results are compared to the idealized cases. 相似文献
592.
We investigate a composite quantum collision model with measurements on the memory part, which effectively probe the system. The framework allows us to adjust the measurement strength, thereby tuning the dynamical map of the system. For a two-qubit setup with a symmetric and informationally complete measurement on the memory, we study the divisibility of the resulting dynamics in dependence of the measurement strength. The measurements give rise to quantum trajectories of the system and we show that the average asymptotic purity depends on the specific form of the measurement. With the help of numerical simulations, we demonstrate that the different performance of the measurements is generic and holds for almost all interaction gates between the system and the memory in the composite collision model. The discrete model is then extended to a time-continuous limit. 相似文献
593.
Michael Alexandre Günter Beyer Catherine Henrist Rudi Cloots Andr Rulmont Robert Jrme Philippe Dubois 《Macromolecular rapid communications》2001,22(8):643-646
(Nano)composites based on ethylene vinyl acetate copolymers (EVA) and montmorillonite modified by various alkylammonium cations were processed by mechanical kneading. Polymer intercalation and filler exfoliation were evidenced by X‐ray diffraction and transmission electron microscopy, respectively. Nanocomposites tensile properties showed that Young's modulus increases significantly even at very low content of the organo‐modified filler while preserving high ultimate elongation and tensile stress. The matrix thermal stability in air was increased by 40°C and, interestingly, the obtained nanocomposites present flame retardant properties. 相似文献
594.
Martin Beyer Andreas Lammers Elena V. Savchenko Gereon Niedner-Schatteburg Vladimir E. Bondybey 《ChemInform》1999,30(28):no-no
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 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
595.
Franziska Weichelt Mario Beyer Rico Emmler Roman Flyunt Evelin Beyer Michael Buchmeiser 《Macromolecular Symposia》2011,301(1):23-30
Summary: Nano-sized zinc oxide (ZnO) was chosen as a suitable candidate for the UV-protection of coatings. ZnO-based acrylate coatings were applied to polycarbonate plates, glass plates and impregnated wood. Coated samples were artificially weathered (Xenon test) for at least 1500 hours and studied with regards to their optical and mechanical properties, such as color shifts (yellowing), as well as to changes in brightness, transparency or hydrophobicity. The prepared wood coatings showed reduced yellowing and improved optical properties. 相似文献
596.
Jimmy W. Mays David Uhrig Samuel Gido Yuqing Zhu Roland Weidisch Hermis Iatrou Nikos Hadjichristidis Kunlun Hong Frederick Beyer Ralf Lach Matthias Buschnakowski 《Macromolecular Symposia》2004,215(1):111-126
Multigraft copolymers with polyisoprene backbones and polystyrene branches, having multiple regularly spaced branch points, were synthesized by anionic polymerization high vacuum techniques and controlled chlorosilane linking chemistry. The functionality of the branch points (1, 2 and 4) can be controlled, through the choice of chlorosilane linking agent. The morphologies of the various graft copolymers were investigated by transmission electron microscopy and X-ray scattering. It was concluded that the morphology of these complex architectures is governed by the behavior of the corresponding miktoarm star copolymer associated with each branch point (constituting block copolymer), which follows Milner's theoretical treatment for miktoarm stars. By comparing samples having the same molecular weight backbone and branches but different number of branches it was found that the extent of long range order decreases with increasing number of branch points. The stress-strain properties in tension were investigated for some of these multigraft copolymers. For certain compositions thermoplastic elastomer (TPE) behavior was observed, and in many instances the elongation at break was much higher (2-3X) than that of conventional triblock TPEs. 相似文献
597.
598.