全文获取类型
收费全文 | 10248篇 |
免费 | 1712篇 |
国内免费 | 967篇 |
专业分类
化学 | 10360篇 |
晶体学 | 85篇 |
力学 | 122篇 |
综合类 | 31篇 |
数学 | 25篇 |
物理学 | 2304篇 |
出版年
2024年 | 18篇 |
2023年 | 159篇 |
2022年 | 373篇 |
2021年 | 529篇 |
2020年 | 703篇 |
2019年 | 556篇 |
2018年 | 499篇 |
2017年 | 572篇 |
2016年 | 775篇 |
2015年 | 755篇 |
2014年 | 840篇 |
2013年 | 995篇 |
2012年 | 865篇 |
2011年 | 847篇 |
2010年 | 665篇 |
2009年 | 655篇 |
2008年 | 589篇 |
2007年 | 531篇 |
2006年 | 406篇 |
2005年 | 343篇 |
2004年 | 252篇 |
2003年 | 209篇 |
2002年 | 172篇 |
2001年 | 147篇 |
2000年 | 95篇 |
1999年 | 84篇 |
1998年 | 54篇 |
1997年 | 38篇 |
1996年 | 31篇 |
1995年 | 24篇 |
1994年 | 23篇 |
1993年 | 30篇 |
1992年 | 24篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1979年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 500 毫秒
51.
Zhicheng Xiao Ying Li Dongling Ma Linda S. Schadler Yvonne A. Akpalu 《Journal of Polymer Science.Polymer Physics》2006,44(7):1084-1095
Small‐angle light scattering (SALS) measurements were used to study the structure of titanium dioxide (TiO2)/low‐density polyethylene (LDPE) nanocomposites. The results showed that the scattering from LDPE crystalline structures and the scattering from TiO2 nanoparticles can be resolved and separated. It is shown that the independent effects of crystallization conditions and the presence of nanoparticle aggregates on the spherulitic structure of the LDPE matrix can be determined by analyzing the scattering patterns using the methods proposed. From the SALS results, we conclude that the nanoparticle surface chemistry affects both nucleation of spherulites and their structure particularly under rapid cooling conditions. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1084–1095, 2006 相似文献
52.
Hynd Remita Prem Felix Siril Israel-Martyr Mbomekalle Bineta Keita Louis Nadjo 《Journal of Solid State Electrochemistry》2006,10(7):506-511
Three Pt-based catalysts prepared in different radiolytic conditions and supported on graphite powder were packed into a carbon paste electrode configuration. They were compared to each other, to the commercial (Pt) deposited on activated carbon powder (Johnson Matthey) and to pure Vulcan XC-72 for their respective abilities toward the hydrogen evolution reaction (HER). The Tafel parameters were determined for all these electrodes. From the I–V curves and their quantitative treatment, the following order of activity emerged unambiguously and reads: (PtCO)2 (fcc structure) > (PtCO)1 (Chini cluster) > (Pt)neat > (Pt)JM (Johnson Matthey) ≫ (Vulcan XC-72). As expected, all the Pt-loaded electrodes were more efficient than Vulcan XC-72. The classification appears to be linked with the mean nanoparticle size, and for comparable sizes, with the surface morphology of the materials. The results and the stability of the electrodes suggest that the small particle sizes and the good dispersity on the carbon support were maintained during the HER. 相似文献
53.
纳米氧化铜的制备及常温脱硫效能研究 总被引:3,自引:0,他引:3
采用硝酸铜为原料、氢氧化钠溶液为沉淀剂、使用体积比为1∶1的乙醇-水溶液为分散剂的直接沉淀法制备,通过改变工艺条件得到了三种纳米氧化铜产品,平均粒径分别为25.63,10.74和7.57 nm。采用TG-DTA、FIR、XRD和TEM等对纳米氧化铜进行表征。对产品的常温脱硫活性进行了穿透试验,并与已开发的其他常温精脱硫产品进行了比较,结果表明纳米氧化铜应用于H2S脱硫,可在常温条件下具有优异的脱硫活性,对H2S的脱除精度可以达到0.05 mg·m-3以下。经过优选,产品在3 000 h-1空速下穿透硫容达到25.3%,高于同类型的其他脱硫剂产品。 相似文献
54.
55.
G. R. Kosmambetova P. E. Strizhak É. M. Moroz T. E. Konstantinova A. V. Gural’skii V. P. Kol’ko V. I. Gritsenko I. A. Danilenko O. A. Gorban 《Theoretical and Experimental Chemistry》2007,43(2):102-107
The morphological and catalytic properties of samples of nanomeric zirconium dioxide, stabilized with yttrium oxide, manufactured
via the effect of a UHF field during the process of drying precipitated zirconium hydroxide and calcination at temperatures
from 300 to 1000 °C, were studied. It was shown that the highest activity in the oxidation of CO occurred with 40 nm particles
of zirconium dioxide prepared at 1000 °C.
__________
Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 43, No. 2, pp. 96–101, March–April, 2007. 相似文献
56.
Shvalagin V. V. Stroyuk A. L. Kuchmii S. Ya. 《Theoretical and Experimental Chemistry》2004,40(3):149-153
The photoreduction of Cu2+ at the surface of ZnO nanoparticles and ZnO/Ag nanostructures was investigated. The spectral characteristics of the obtained ZnO/Cu and ZnO/Ag/Cu composites were studied in relation to the reaction conditions. It was shown that the ZnO/Ag nanoparticles have higher photocatalytic activity in the reduction of Cu2+ ions than the individual ZnO particles. 相似文献
57.
58.
59.
The adsorption, diffusion and desorption of chlorine on and from stoichiometric, reduced and partially reduced (defective) rutile TiO2{110} are investigated using ab initio density functional theory (DFT) calculations. Theoretical results are compared with experimental investigations, and microkinetic simulations based on DFT values are then used to verify the diffusion mechanisms assumed in the experimental investigations. 相似文献
60.
Studies on fluorenscence resonance energy transfer between CdS nanoparticles and DOCAI dyes 总被引:1,自引:0,他引:1
Lun Wang Yan Liu Hong Qi Chen A Ni Liang Fa Gong Xu 《中国化学快报》2007,18(3):369-372
The water-soluble CdS nanoparticles were synthesized in aqueous solution. A novel fluorescence resonance energy transfer (FRET) system with CdS nanoparticles as energy donors and 3,30-diethyl-oxadicarbocyanine iodide (DOCAI) dyes as energy accepter has been developed. 相似文献