全文获取类型
收费全文 | 82539篇 |
免费 | 6880篇 |
国内免费 | 5200篇 |
专业分类
化学 | 25325篇 |
晶体学 | 1847篇 |
力学 | 4595篇 |
综合类 | 363篇 |
数学 | 18041篇 |
物理学 | 44448篇 |
出版年
2022年 | 455篇 |
2021年 | 464篇 |
2020年 | 773篇 |
2019年 | 1025篇 |
2018年 | 986篇 |
2017年 | 694篇 |
2016年 | 601篇 |
2015年 | 508篇 |
2014年 | 1221篇 |
2013年 | 1844篇 |
2012年 | 1316篇 |
2011年 | 1900篇 |
2010年 | 2454篇 |
2009年 | 6985篇 |
2008年 | 7993篇 |
2007年 | 6454篇 |
2006年 | 5908篇 |
2005年 | 4046篇 |
2004年 | 3854篇 |
2003年 | 4076篇 |
2002年 | 5266篇 |
2001年 | 3780篇 |
2000年 | 3567篇 |
1999年 | 3391篇 |
1998年 | 2802篇 |
1997年 | 1963篇 |
1996年 | 1760篇 |
1995年 | 2245篇 |
1994年 | 2176篇 |
1993年 | 1637篇 |
1992年 | 1138篇 |
1991年 | 847篇 |
1990年 | 700篇 |
1989年 | 616篇 |
1988年 | 576篇 |
1987年 | 411篇 |
1986年 | 198篇 |
1985年 | 953篇 |
1984年 | 621篇 |
1983年 | 493篇 |
1982年 | 646篇 |
1981年 | 795篇 |
1980年 | 722篇 |
1979年 | 564篇 |
1978年 | 583篇 |
1977年 | 538篇 |
1976年 | 541篇 |
1975年 | 319篇 |
1974年 | 355篇 |
1973年 | 463篇 |
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
11.
《中国化学快报》2020,31(12):3183-3189
Engineered nanomaterials have attracted significantly attention as one of the most promising antimicrobial agents for against multidrug resistant infections. The toxicological responses of nanomaterials are closely related to their physicochemical properties, and establishment of a structure-activity relationship for nanomaterials at the nano-bio interface is of great significance for deep understanding antibacterial toxicity mechanisms of nanomaterials and designing safer antibacterial nanomaterials. In this study, the antibacterial behaviors of well-defined crystallographic facets of a series of Au nanocrystals, including {100}-facet cubes, {110}-facet rhombic dodecahedra, {111}-facet octahedra, {221}-facet trisoctahedra and {720}-facet concave cubes, was investigated, using the model bacteria Staphylococcus aureus. We find that Au nanocrystals display substantial facet-dependent antibacterial activities. The low-index facets of cubes, octahedra, and rhombic dodecahedra show considerable antibacterial activity, whereas the high-index facets of trisoctahedra and concave cubes remained inert under biological conditions. This result is in stark contrast to the previous paradigm that the high-index facets were considered to have higher bioactivity as compared with low-index facets. The antibacterial mechanism studies have shown that the facet-dependent antibacterial behaviors of Au nanocrystals are mainly caused by differential bacterial membrane damage as well as inhibition of cellular enzymatic activity and energy metabolism. The faceted Au nanocrystals are unique in that they do not induce generation of reactive oxygen species, as validated for most antibiotics and antimicrobial nanostructures. Our findings may provide a deeper understanding of facet-dependent toxicological responses and suggest the complexities of the nanomaterial-cell interactions, shedding some light on the development of high performance Au nanomaterials-based antibacterial therapeutics. 相似文献
12.
13.
14.
15.
16.
17.
In this work, the variation of the magnetic moments of the Ni/Pt multilayers are studied using the linearized augmented plane waves (LAPW) method in the framework of the density functional theory (DFT) implemented in the version of WIEN2K program. The systems have been modeled by seven layers slab separated in z direction by a vacuum region of four substrate layers. We present the results of the dependence of the magnetic properties with respect to the thickness variation of the different multilayers. The modeling of these systems finds an important empirical support. Experiment and theory show the same trends for the magnetic moments: hybridization effects between Ni and Pt are mostly localized at the interface. 相似文献
18.
Single-crystalline gallium nitride nanobelts have been synthesized through the reaction of gallium vapor with flowing ammonia using nickel as a catalyst. The as-synthesized products were characterized using X-ray powder diffraction (XRD), scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, and selected-area electron diffraction (SAED). XRD and SAED results revealed that the products are pure, single-crystalline GaN with hexagonal structure. The widths and thickness of the nanobelts ranged from 80 to 200 nm, and 10 to 30 nm, respectively. The lengths were up to several tens of micrometers. The nanobelts had smooth surface with no amorphous sheath, and a sharp-tip end. The growth mechanism of nanobelts was discussed. 相似文献
19.