全文获取类型
收费全文 | 688篇 |
免费 | 13篇 |
国内免费 | 3篇 |
专业分类
化学 | 421篇 |
晶体学 | 3篇 |
力学 | 25篇 |
数学 | 99篇 |
物理学 | 156篇 |
出版年
2022年 | 7篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 10篇 |
2018年 | 20篇 |
2017年 | 26篇 |
2016年 | 16篇 |
2015年 | 14篇 |
2014年 | 22篇 |
2013年 | 45篇 |
2012年 | 35篇 |
2011年 | 31篇 |
2010年 | 25篇 |
2009年 | 26篇 |
2008年 | 30篇 |
2007年 | 24篇 |
2006年 | 17篇 |
2005年 | 13篇 |
2004年 | 13篇 |
2003年 | 10篇 |
2002年 | 13篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 6篇 |
1998年 | 5篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1990年 | 9篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 9篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 14篇 |
1982年 | 4篇 |
1981年 | 9篇 |
1980年 | 11篇 |
1979年 | 12篇 |
1978年 | 14篇 |
1977年 | 18篇 |
1976年 | 6篇 |
1974年 | 10篇 |
1973年 | 9篇 |
1972年 | 8篇 |
1971年 | 8篇 |
1967年 | 4篇 |
1957年 | 7篇 |
1954年 | 5篇 |
1936年 | 4篇 |
排序方式: 共有704条查询结果,搜索用时 125 毫秒
701.
702.
Ghanshyam S. Chauhan Harinder Lal Swati Mahajan Monica Bansal 《Journal of polymer science. Part A, Polymer chemistry》2000,38(24):4506-4518
To get highly reactive polymeric materials for selective studies of enzyme immobilization, water purification, separation, and enrichment technologies, we attempted to graft 4‐vinyl pyridine (4‐VP) onto Teflon‐PFA by simultaneous γ‐ray initiation. The resulting graft copolymers were quaternized by treatment with some alkylating agents. Optimum conditions for grafting were evaluated through the variation of the total dose of radiation, the amount of water, and the monomer concentration. The effect of the solvent composition (H2O/MeOH) was also studied. In the presence of MeOH, grafting occurred less often and was nonselective as 4‐VP was incorporated on both sides in comparison with highly selective grafting in an aqueous medium. The percentages of the grafting, total conversion, and grafting efficiency and the rates of the polymerization, grafting, and homopolymerization were also evaluated. Some other monomers such as methacrylic acid, methyl methacrylate, maleic acid, acrylonitrile, and vinyl imidazole were not incorporated onto the backbone film under the optimum grafting reaction conditions evaluated for the grafting of 4‐VP. Although some grafting occurred, the graft yield was too low to be considered of any significance. The grafted films were quaternized with benzyl chloride, and quaternized and unquaternized films were used for the immobilization of lipase. The former showed high activity with lipase and has potential for development as a bioreactor. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4506–4518, 2000 相似文献
703.
Manik Lal Maity Samyadeb Mahato Prof. Dr. Subhajit Bandyopadhyay 《Angewandte Chemie (International ed. in English)》2023,62(45):e202311551
The chalcone-flavylium photochromic system switches in aqueous media. However, the chalcone→flavylium conversion requires detrimental ultra-violet (UV) light for the switching which deters their applications in the biological domain. To address this issue, we have synthesized strategically modified chalcone scaffolds that can be reversibly switched to the flavylium forms with visible light ranging from 456 nm (blue) to 640 nm (red). 相似文献
704.