全文获取类型
收费全文 | 397篇 |
免费 | 12篇 |
国内免费 | 18篇 |
专业分类
化学 | 286篇 |
晶体学 | 3篇 |
力学 | 11篇 |
数学 | 43篇 |
物理学 | 84篇 |
出版年
2023年 | 4篇 |
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 10篇 |
2019年 | 20篇 |
2018年 | 25篇 |
2017年 | 16篇 |
2016年 | 30篇 |
2015年 | 17篇 |
2014年 | 33篇 |
2013年 | 49篇 |
2012年 | 19篇 |
2011年 | 46篇 |
2010年 | 17篇 |
2009年 | 22篇 |
2008年 | 25篇 |
2007年 | 10篇 |
2006年 | 14篇 |
2005年 | 17篇 |
2004年 | 5篇 |
2003年 | 8篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有427条查询结果,搜索用时 15 毫秒
51.
S. Tavakol M. R. Nikpour A. Amani M. Soltani S. M. Rabiee S. M. Rezayat P. Chen M. Jahanshahi 《Journal of nanoparticle research》2013,15(1):1-16
Surface morphology, surface wettability, and size distribution of biomaterials affect their in vitro and in vivo bone regeneration potential. Since nano-hydroxyapatite has a great chemical and structural similarity to natural bone and dental tissues, incorporated biomaterial of such products could improve bioactivity and bone bonding ability. In this research, nano-hydroxyapatite (23 ± 0.09 nm) and its composites with variety of chitosan content [2, 4, and 6 g (45 ± 0.19, 32 ± 0.12, and 28 ± 0.12 nm, respectively)] were prepared via an in situ hybridization route. Size distribution of the particles, protein adsorption, and calcium deposition of powders by the osteoblast cells, gene expression and percentage of new bone formation area were investigated. The highest degree of bone regeneration potential was observed in nano-hydroxyapatite powder, while the bone regeneration was lowest in nano-hydroxyapatite with 6 g of chitosan. Regarding these data, suitable size distribution next to size distribution of hydroxyapatite in bone, smaller size, higher wettability, lower surface roughness of the nano-hydroxyapatite particles and homogeneity in surface resulted in higher protein adsorption, cell differentiation and percentage of bone formation area. Results obtained from in vivo and in vitro tests confirmed the role of surface morphology, surface wettability, mean size and size distribution of biomaterial besides surface chemistry as a temporary bone substitute. 相似文献
52.
53.
Hosna Rezaee Ali Nikpay Maryam Soltani 《Journal of Dispersion Science and Technology》2019,40(4):587-593
In this study, a pH-sensitive drug release system was prepared by zeolite Y nanoparticles and tannic acid. Zeolite Y nanoparticles were synthesized via hydrothermal synthesis of colloidal suspensions and after that, were coated with tannic acid. In order to evaluate its performance, metronidazole as an anti-protozoan drug was loaded into nanocarriers via immersing method to study the in-vitro drug delivery behavior. This nanocomposite carriers represented pH-sensitive behavior and had more and faster release in acidic medium. In-vitro effects of metronidazole-loaded nanoparticles was measured against Trichomonas gallinae trophozoites in Trypticase Yeast extract Maltose medium. The results suggested that metronidazole-loaded and tannic acid-modified zeolite Y nanoparticles could be a potential anti-trichomonal agent. 相似文献
54.
55.
56.
57.
M. N. Soltani Rad S. Behrouz M. A. Faghihi 《Journal of the Iranian Chemical Society》2014,11(2):361-367
A facile and highly efficient protocol for 1,3-dipolar cycloaddition of in situ generated nitrile oxides with terminal alkynes catalyzed by copper-doped silica cuprous sulfate (CDSCS) as a new and convenient heterogeneous nano catalyst is described. In this protocol, ‘click’ cycloaddition of various structurally diverse alkynes and imidoyl chlorides in the presence of CDSCS and NaHCO3 in a solution of i-PrOH/H2O (1:1, V/V) furnishes the corresponding 3,5-disubstituted isoxazoles in good to excellent yields at room temperature. CDSCS was approved as a chemically and thermally stable nano catalyst that can be recovered and reused for many consecutive trials without considerable decline in its reactivity. 相似文献
58.
Behzad Soltani Navid Ahmadi Nasab 《Journal of Dispersion Science and Technology》2018,39(8):1200-1207
The intercalation of indomethacin into the interlayer gallery of layered zinc hydroxide (LZH) has been successfully executed using the simple ion exchange approaches. The synthesized intercalation compound, indomethacin-LZH nanohybrid, was characterized using PXRD, FTIR, SEM, BET, and STA. From the PXRD results, the intercalation of indomethacin anions into the interlayer gallery of LZH was successful; showing the formation of a new peak at lower 2θ with a basal spacing of 21.96?Å. FTIR analysis of the nanohybrid further supported the presence of indomethacin in the interlayer of the indomethacin-LZH nanohybrid. STA analysis confirms that the nanohybrid has higher thermal stability than pure indomethacin. The in vitro release mechanism of the indomethacin anions from the indomethacin-LZH nanohybrid showed slow release, with 95% and 78% release in phosphate buffer saline (PBS) solution at pH 4.8 and 7.4, respectively. The release behavior of indomethacin from its intercalation compounds in PBS solution at pH 4.8 and 7.4 follows the Higuchi model. In addition, the nanohybrid treated with normal fibroblast cell line shows that it reduces cell viability in a dose and time-dependent manner. This study shows that the high potential of the nanohybrid as an encapsulated material for the controlled release formulation of nonsteroidal anti-inflammatory (NASID) anions. 相似文献
59.
Nahid?TavakkoliEmail author Nasrin?Soltani Faezeh?Shahdost-fard Mahbobeh?Ramezani Hossein?Salavati Mohammad?Reza?Jalali 《Mikrochimica acta》2018,185(10):479
A highly selective electrochemical sensor was fabricated based on a modified carbon paste electrode with zinc ferrite nanoparticles (ZnFe2O4 NPs). The nanocomposite has attractive properties such as high surface-to-volume ratio and good electrocatalytic activity towards the drugs acetaminophen (AC), epinephrine (EP), and melatonin (MT), best at working voltages of 0.35, 0.09 and 0.55 V (vs. Ag/AgCl), respectively. The linear ranges (and detection limits) are 6.5–135 (0.4) μmol L?1 for AC, 5–100 (0.7) μmol L?1 for EP, and 6.5–145 (3) μmol L?1 for MT. 相似文献
60.
Abolghasem Jouyban Masoumeh Abbasi Elaheh Rahimpour Mohammad Barzegar-Jalali Jalil Vaez-Gharamaleki 《Physics and Chemistry of Liquids》2018,56(5):619-626
The solubility of deferiprone (DFP) in five organic solvents including ethyl acetate, chloroform, acetonitrile, 1,4-dioxane and dichloromethane was investigated by the flask-shake method under atmospheric pressure at temperatures ranging from 293.15 to 313.15 K. In general, the solubility (mol L–1) obeyed the following order from high to low in different mono-solvents: dichloromethane > chloroform > acetonitrile > 1,4-dioxane > ethyl acetate. The solubility of DFP in the mono-solvents increased with a rise of temperature. The solubility data were successfully correlated with the van’t Hoff equation. The generated data in this work and the previously published data were used to calculate the thermodynamic parameters of the system using the modified van’t Hoff equation, and the derived thermodynamic properties were correlated using Abraham solvation parameters. 相似文献