全文获取类型
收费全文 | 240篇 |
免费 | 20篇 |
国内免费 | 2篇 |
专业分类
化学 | 202篇 |
数学 | 9篇 |
物理学 | 51篇 |
出版年
2024年 | 4篇 |
2023年 | 4篇 |
2022年 | 3篇 |
2021年 | 11篇 |
2020年 | 14篇 |
2019年 | 4篇 |
2018年 | 10篇 |
2017年 | 4篇 |
2016年 | 11篇 |
2015年 | 5篇 |
2014年 | 13篇 |
2013年 | 13篇 |
2012年 | 25篇 |
2011年 | 19篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 16篇 |
2007年 | 12篇 |
2006年 | 10篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 10篇 |
2002年 | 1篇 |
2001年 | 7篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 5篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1984年 | 4篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有262条查询结果,搜索用时 281 毫秒
101.
Yamashita M Yadav ND Sawaki T Takao I Kawasaki I Sugimoto Y Miyatake A Murai K Takahara A Kurume A Ohta S 《The Journal of organic chemistry》2007,72(15):5697-5703
The first asymmetric total synthesis of (-)-Linderol A, a potent inhibitor of melanin biosynthesis of cultured B-16 melanoma cells, has been achieved via two key reactions: a diastereoselective [2+2] photocycloaddition of a coumarin-3-carboxylate bearing a chiral auxiliary with 3-methyl-1-butene and a subsequent stereoconvergent transformation of the photoadducts with use of dimethylsulfoxonium methylide to afford a tetrahydrodibenzofuran derivative. 相似文献
102.
Olefin Recovery by *BEA-Type Zeolite Membrane: Affinity-Based Separation with Olefin−Ag+ Interaction
Dr. Motomu Sakai Yuto Tsuzuki Naoyuki Fujimaki Prof. Masahiko Matsukata 《化学:亚洲杂志》2021,16(9):1101-1105
Ag+ was introduced into *BEA-type zeolite membrane by an ion-exchange method to enhance olefin selectivity. Ag−*BEA membrane exhibited superior olefin separation performance for both ethylene/ethane and propylene/propane mixtures. Particularly, the separation factor for ethylene at 373 K reached 57 with the ethylene permeance of 1.6×10−7 mol m−2 s−1 Pa−1. Adsorption properties of olefin and paraffin were evaluated to discuss contribution of Ag+ to separation performance enhancement. A strong interaction between olefin and Ag+ in the membrane caused preferential adsorption of olefin against paraffin, leading to selective permeation of olefin. Ag−*BEA membrane also exhibited high olefin selectivities from olefin/N2 mixtures. The affinity-based separation through Ag−*BEA membrane showed a high potential for olefin recovery and purification from various gas mixtures. 相似文献
103.
Fukasawa Yuto Kaneko Masashi Nakashima Satoru 《Journal of Radioanalytical and Nuclear Chemistry》2021,329(1):77-84
Journal of Radioanalytical and Nuclear Chemistry - Density functional theory calculations were applied to understand the selectivity between Am3+ and Eu3+ ions with the crown ethers type ligands.... 相似文献
104.
Incremental Newton (IN) iteration, proposed by Iannazzo, is stable for computing the matrix $p$th root, and its computational cost is $\Order (n^3p)$ flops per iteration. In this paper, a cost-efficient variant of IN iteration is presented. The computational cost of the variant well agrees with $\Order (n^3 \log p)$ flops per iteration, if $p$ is up to at least 100. 相似文献
105.
Dr. Hideki Miyatake‐Ondozabal Elias Kaufmann Prof. Dr. Karl Gademann 《Angewandte Chemie (International ed. in English)》2015,54(6):1933-1936
Fidaxomicin, also known as tiacumicin B or lipiarmycin A3, is a novel macrocyclic antibiotic that is used in hospitals for the treatment of Clostridium difficile infections. This natural product has also been shown to have excellent bactericidal activity against multidrug‐resistant Mycobacterium tuberculosis. In spite of its attractive biological activity, no total synthesis has been reported to date. The enantioselective synthesis of the central 18‐membered macrolactone is reported herein. The key reactions include ring‐closing metathesis between a terminal olefin and a dienoate moiety for macrocyclization, a vinylogous Mukaiyama aldol reaction, and a Stille coupling reaction of sterically demanding substrates. The retrosynthesis involves three medium‐sized fragments, thus leading to a flexible yet convergent synthetic route. 相似文献
106.
Miura Tsutomu Iinuma Yuto Sekimoto Shun 《Journal of Radioanalytical and Nuclear Chemistry》2020,324(3):1007-1012
Journal of Radioanalytical and Nuclear Chemistry - Instrumental neutron activation analysis with internal standard correction was applied for precise determine of mg quantities of Ir in high-purity... 相似文献
107.
A novel saccharide sensor that shows a distinct color change resembling a "traffic signal" was developed. By copolymerizing a boronic acid monomer and an amine monomer on a glass plate, a boronic acid-containing thin film was obtained. After adsorbing anionic blue and yellow dyes, the thin film was immersed in aqueous saccharide solutions containing a cationic red dye. As saccharide concentration increased, the thin film changed its color from green to red via yellow. Origin of the distinct color change was attributed to a stepwise release and binding of dyes. 相似文献
108.
Yamamoto T Akai Y Nagata Y Suginome M 《Angewandte Chemie (International ed. in English)》2011,50(38):8844-8847
109.
Uchiyama H Mantani Y Kozuka H 《Langmuir : the ACS journal of surfaces and colloids》2012,28(27):10177-10182
Complex, sophisticated surface patterns on micrometer and nanometer scales are obtained when solvent evaporates from solutions containing nonvolatile solutes dropped on a solid substrate. Such evaporation-driven pattern formation has been utilized as a fabrication process of highly ordered patterns in thin films. Here, we suggested the spontaneous pattern formation induced by Bénard-Marangoni convection triggered by solvent evaporation as a novel patterning process of sol-gel-derived organic-inorganic hybrid films. Microcraters of 1.0-1.5 μm in height and of 100-200 μm in width were spontaneously formed on the surface of silica-poly(vinylpyrrolidone) hybrid films prepared via temperature-controlled dip-coating process, where the surface patterns were linearly arranged parallel to the substrate withdrawal direction. Such highly ordered micropatterns were achieved by Bénard-Marangoni convection activated at high temperatures and the unidirectional flow of the coating solution on the substrate during dip-coating. 相似文献
110.