全文获取类型
收费全文 | 338篇 |
免费 | 6篇 |
专业分类
化学 | 229篇 |
晶体学 | 6篇 |
力学 | 13篇 |
数学 | 40篇 |
物理学 | 56篇 |
出版年
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 6篇 |
2018年 | 3篇 |
2016年 | 6篇 |
2015年 | 2篇 |
2014年 | 9篇 |
2013年 | 14篇 |
2012年 | 30篇 |
2011年 | 18篇 |
2010年 | 8篇 |
2009年 | 11篇 |
2008年 | 20篇 |
2007年 | 17篇 |
2006年 | 18篇 |
2005年 | 18篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 11篇 |
2001年 | 8篇 |
2000年 | 8篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 6篇 |
1992年 | 5篇 |
1991年 | 3篇 |
1989年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 7篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1968年 | 4篇 |
1946年 | 1篇 |
1944年 | 1篇 |
1941年 | 2篇 |
1940年 | 1篇 |
1913年 | 1篇 |
1897年 | 1篇 |
1891年 | 1篇 |
排序方式: 共有344条查询结果,搜索用时 15 毫秒
341.
342.
Erick M. Larramendi Z-B Karla Gutiérrez Osvaldo de Melo Ulrike Woggon Detlef Schikora Klaus Lischka 《Journal of Crystal Growth》2010,312(11):1807-1812
The use of a selenium–tellurium (SeTe) mixed source in the isothermal close space sublimation growth of CdSe epilayers is considered. The epitaxial growth was performed in flowing helium by sequential exposures of the substrate to vapors of the mixed SeTe source and elemental cadmium at temperatures within 350–410 °C. In spite of the mixed source (proposed to decrease the partial pressure of Se), tellurium incorporation was small and CdSexTe(1−x) (x∼0.98) epilayers were obtained. X-ray diffraction reciprocal space mapping shows the existence of hexagonal inclusions mainly on the (1 1 1) facets of the cubic phase. Material deposition on areas of the graphite crucible exposed to the sources, contamination of the Cd source and large growth rates suggest the existence of a selenium transport process via graphite. This transport might be the result of the combination of selenium deposition on graphite with a subsequent activated desorption of selenium under cadmium exposure. It affects Cd source purity and growth kinetic bringing on a modification of the usual atomic layer deposition regimen; however, a reproducible growth rate of the epilayers was obtained. 相似文献
343.
Eurydice Arroyo Diana Tentori Alfonso Garcia Ricardo Valdez Miguel A. Armenta Osvaldo J. Nava Roberto Machorro Amelia Olivas 《Particle & Particle Systems Characterization》2023,40(6):2200200
Carbon quantum dots (CQD) have received significant attention in recent years due to their potential applications in optics and sensing. In this study, the authors report on the first characterization of the optical activity and broad absorption spectrum covering from short-wave ultraviolet, at 200 nm, to mid-infrared, at 1600 nm, of CQD synthesized using the “low-molecular-weight alcohols electrochemical carbonization” method. The CQD are analyzed using spectroscopic techniques, optical activity in the infrared, and high-resolution transmission electron microscopy. Results show a CQD size distribution of 5±3 nm and spherical morphology. The absorption spectra show increased absorption at both, high and low frequency. Additionally, the specific rotation of the CQD solution is significantly higher than that of pure ethanol, by three orders of magnitude. These findings suggest that CQD may have potential applications in polarized infrared filters and/or sensors due to their ability to rotate the polarization state of light at 1550 nm. The results of this study provide valuable insights into the optical properties of CQD and their potential for infiltration into hollow core photonic crystal fibers, making them a promising material for future research and development in the field of optics and sensing. 相似文献
344.
Roberto F. de Souza Osvaldo L. Casagrande Jr. 《Macromolecular rapid communications》2001,22(16):1293-1301
Several homogeneous and heterogeneous binary systems have been applied to olefin polymerization in order to produce polymers with improved physical and/or chemical characteristics. This article reviews the recent developments in this area focusing mainly on polymer properties, the relationship between the types of catalyst present in the binary systems, their use in the homopolymerization of ethylene and propene, and the copolymerization of ethylene and higher α‐olefins. 相似文献