全文获取类型
收费全文 | 176篇 |
免费 | 16篇 |
国内免费 | 16篇 |
专业分类
化学 | 148篇 |
晶体学 | 1篇 |
力学 | 6篇 |
数学 | 16篇 |
物理学 | 37篇 |
出版年
2024年 | 1篇 |
2022年 | 5篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 9篇 |
2015年 | 11篇 |
2014年 | 13篇 |
2013年 | 10篇 |
2012年 | 14篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 13篇 |
2007年 | 9篇 |
2006年 | 12篇 |
2005年 | 10篇 |
2004年 | 13篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1975年 | 1篇 |
1964年 | 2篇 |
排序方式: 共有208条查询结果,搜索用时 15 毫秒
171.
172.
173.
Jianling Zhao Xixin Wang Yongai Sun Jijing Liu Chengchun Tang 《Journal of Solid State Electrochemistry》2011,15(9):1861-1865
In this paper, we investigate the formation of microporous spheric zinc phosphate by anodization method. Zinc phosphate microporous
spheres with diameters of 5–23 μm were prepared in H3PO4 and NH4H2PO4 aqueous electrolyte when the applied voltage was 1 V. Microstructure was characterized by scanning electron microscopy. Composition
and crystal structure were confirmed through energy dispersive spectrum and X-ray diffraction analysis. The formation mechanism
of this special structure was also discussed in this paper. 相似文献
174.
Limin Guo Jianling Zhao Xixin Wang Rongqing Xu Yangxian Li 《Journal of Solid State Electrochemistry》2009,13(9):1321-1326
The formation and growth of a self-organized zirconia porous layer can be achieved directly by anodization of Zr in chloride
containing electrolytes. The morphology of the porous layers is affected by electrochemical conditions such as Cl− concentration. Zirconia nanotubes with diameters ranging from 250 to 300 nm and a length of 33 μm were formed under proper
conditions. The nanotubes have smooth and straight walls. The composition of the nanotubes was characterized by using an energy
dispersive spectrometer. Selected area electron diffraction investigation reveals that the as-anodized zirconia nanotubes
have an amorphous structure. Crystal phase transition and structural stability of the ZrO2 nanotubes after heat treatment were characterized. A possible growth mechanism is presented. 相似文献
175.
Metallic impurities within carbon nanotubes (CNTs) are considered as the main cause of their toxicity. Ultrasonication is a common procedure used to purify and obtain homogeneous dispersions of CNTs as well as to mix them with other components for further processing into composites. Herein, the influence of ultrasonication upon the bioavailability of metallic impurities in CNTs was investigated. We showed that even ultrasonication times as short as 5?min significantly enhanced the bioavailability of metallic impurities, which can therefore interact more actively with biologically important molecules. These findings will have profound impact on the processing of CNTs as well as on nanotoxicity studies. 相似文献
176.
Sonochemical formation of single-crystalline gold nanobelts 总被引:1,自引:0,他引:1
177.
An overview of the chemistry and microbiology of calcareous sponges (Calcispongiae) is provided, highlighting the potential of these sessile filter-feeding marine invertebrates and their associated bacteria for the discovery of new bioactive natural products. 103 compounds are presented and 116 references cited. 相似文献
178.
Dohnal P Hejduk M Varju J Rubovič P Roučka Š Kotrík T Plašil R Glosík J Johnsen R 《The Journal of chemical physics》2012,136(24):244304
Measurements in H(3)(+) afterglow plasmas with spectroscopically determined relative abundances of H(3)(+) ions in the para-nuclear and ortho-nuclear spin states provide clear evidence that at low temperatures (77-200 K) para-H(3)(+) ions recombine significantly faster with electrons than ions in the ortho state, in agreement with a recent theoretical prediction. The cavity ring-down absorption spectroscopy used here provides an in situ determination of the para/ortho abundance ratio and yields additional information on the translational and rotational temperatures of the recombining ions. The results show that H(3)(+) recombination with electrons occurs by both binary recombination and third-body (helium) assisted recombination, and that both the two-body and three-body rate coefficients depend on the nuclear spin states. Electron-stabilized (collisional-radiative) recombination appears to make only a small contribution. 相似文献
179.
In this paper, we propose a new branch-and-bound algorithm for the general quadratic problems with box constraints. We, first,
transform the problem into a separable form by D. C. decomposition and Cholesky factorization of a positive definite matrix.
Then a lower bounding technique is derived and a branch-and-bound algorithm is presented based on the lower bounding and rectangular
bisection. Finally, preliminary computational results are reported. 相似文献