全文获取类型
收费全文 | 144篇 |
免费 | 12篇 |
专业分类
化学 | 115篇 |
力学 | 2篇 |
数学 | 12篇 |
物理学 | 27篇 |
出版年
2023年 | 5篇 |
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 13篇 |
2019年 | 14篇 |
2018年 | 3篇 |
2017年 | 2篇 |
2016年 | 13篇 |
2015年 | 7篇 |
2014年 | 16篇 |
2013年 | 11篇 |
2012年 | 16篇 |
2011年 | 11篇 |
2010年 | 5篇 |
2009年 | 2篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 1篇 |
2005年 | 4篇 |
2004年 | 1篇 |
2003年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
排序方式: 共有156条查询结果,搜索用时 31 毫秒
1.
Giovanna Marini-Bettòlo Soumya P. Sahoo Gerald A. Poulton Thomas Y.R. Tsai Karel Wiesner 《Tetrahedron》1980,36(6):719-721
Some years ago an empirical rule, which allows the prediction of product stereochemistry in cis-photocycloaddition reactions of α,β-unsaturated ketones and olefins was tentatively proposed. Several additional examples, both selected from the literature and synthesized in our laboratory, seem to strengthen the validity of the rule. 相似文献
2.
Cost effective and green protocols for the synthesis of two new series of coumarin based blue light emitting fluorophores named as ‘Beta Fluors’ and ‘Alpha Fluors’ are described. The coumarin alkylamide based Beta Fluors are developed using a one-step multi-component process in the presence of phenyl boronic acid as an efficient green catalyst. The Alpha Fluors are structured with coumarin–triazole–carboxamide peptidomimetics and their synthesis involves the ‘click with MCR’ concept. The new fluorophores gave high Stoke’s shift values for the emission wavelengths and their structural features are promising for further fine tuning to obtain preferred emission maxima. 相似文献
3.
Soumya Chakrabarti 《General Relativity and Gravitation》2017,49(2):24
An analogue of the Oppenheimer–Synder collapsing model is treated analytically, where the matter source is a scalar field with an exponential potential. An exact solution is derived followed by matching to a suitable exterior geometry, and an analysis of the visibility of the singularity. In some situations, the collapse indeed leads to a finite time curvature singularity, which is always hidden from the exterior by an apparent horizon. 相似文献
4.
5.
6.
In this article, we propose a stochastic search based method, namely genetic algorithm in conjunction with density functional theory to evaluate structures of water‐halide microclusters, with the halide ion being Cl?, Br?, and I?. Once the structures are established, we evaluate the infrared spectroscopic modes, vertical detachment energies and natural population analysis based charges. We compare our results with available experimental and theoretical results. © 2012 Wiley Periodicals, Inc. 相似文献
7.
Single crystals of a new calcium(II) complex of benzilic acid, [Ca(C14H11O3)2(C14H12O3)2] have been successfully grown by gel diffusion technique at room temperature. Single crystal X-ray diffraction study reveals that the compound belongs to orthorhombic system with space group Fddd. The adjacent CaO8 units are linked via O–H–O interaction to form one dimensional polymeric chains. The extensive hydrogen bonding interactions lead to a supramolecular structure. The grown crystals were further characterized by elemental analysis, FT-IR, UV–Visible, thermogravimetric, powder X-ray diffraction and solid state photoluminescence studies. 相似文献
8.
Anthony T. Giduthuri Ezekiel O. Adekanmbi Soumya K. Srivastava James G. Moberly 《Electrophoresis》2021,42(5):656-666
Rare earth elements (REEs) are widely used across different industries due to their exceptional magnetic and electrical properties. In this work, Cupriavidus necator is characterized using dielectrophoretic ultra-high-frequency measurements, typically in MHz range to quantify the properties of cytoplasm in C. necator for its metal uptake/bioaccumulation capacity. Cupriavidus necator, a Gram-negative bacteria strain is exposed to REEs like europium, samarium, and neodymium in this study. Dielectrophoretic crossover frequency experiments were performed on the native C. necator species pre- and post-exposure to the REEs at MHz frequency range. The net conductivity of native C. necator, Cupriavidus europium, Cupriavidus samarium, and Cupriavidus neodymium are 15.95 ± 0.029 μS/cm, 16.15 ± 0.028 μS/cm, 16.05 ± 0.029 μS/cm, 15.61 ± 0.005 μS/cm respectively. The estimated properties of the membrane published by our group are used to develop a microfluidic sorter by modeling and simulation to separate REE absorbed C. necator from the unabsorbed native C. necator species using COMSOL Multiphysics commercial software package v5.5. 相似文献
9.
Spectroscopic and Computational Study of a Nonheme Iron Nitrosyl Center in a Biosynthetic Model of Nitric Oxide Reductase 下载免费PDF全文
Dr. Saumen Chakraborty Julian Reed Matthew Ross Dr. Mark J. Nilges Igor D. Petrik Dr. Soumya Ghosh Prof. Dr. Sharon Hammes‐Schiffer Prof. Dr. J. Timothy Sage Prof. Dr. Yong Zhang Prof. Dr. Charles E. Schulz Prof. Dr. Yi Lu 《Angewandte Chemie (International ed. in English)》2014,53(9):2417-2421
A major barrier to understanding the mechanism of nitric oxide reductases (NORs) is the lack of a selective probe of NO binding to the nonheme FeB center. By replacing the heme in a biosynthetic model of NORs, which structurally and functionally mimics NORs, with isostructural ZnPP, the electronic structure and functional properties of the FeB nitrosyl complex was probed. This approach allowed observation of the first S=3/2 nonheme {FeNO}7 complex in a protein‐based model system of NOR. Detailed spectroscopic and computational studies show that the electronic state of the {FeNO}7 complex is best described as a high spin ferrous iron (S=2) antiferromagnetically coupled to an NO radical (S= 1/2) [Fe2+‐NO.]. The radical nature of the FeB‐bound NO would facilitate N? N bond formation by radical coupling with the heme‐bound NO. This finding, therefore, supports the proposed trans mechanism of NO reduction by NORs. 相似文献
10.
A Bioorthogonal Small‐Molecule‐Switch System for Controlling Protein Function in Live Cells 下载免费PDF全文
Dr. Peng Liu Abram Calderon Dr. Georgios Konstantinidis Dr. Jian Hou Dipl. Stephanie Voss Dr. Xi Chen Fu Li Soumya Banerjee Dr. Jan‐Erik Hoffmann Christiane Theiss Dr. Leif Dehmelt Dr. Yao‐Wen Wu 《Angewandte Chemie (International ed. in English)》2014,53(38):10049-10055
Chemically induced dimerization (CID) has proven to be a powerful tool for modulating protein interactions. However, the traditional dimerizer rapamycin has limitations in certain in vivo applications because of its slow reversibility and its affinity for endogenous proteins. Described herein is a bioorthogonal system for rapidly reversible CID. A novel dimerizer with synthetic ligand of FKBP′ (SLF′) linked to trimethoprim (TMP). The SLF′ moiety binds to the F36V mutant of FK506‐binding protein (FKBP) and the TMP moiety binds to E. coli dihydrofolate reductase (eDHFR). SLF′‐TMP‐induced heterodimerization of FKBP(F36V) and eDHFR with a dissociation constant of 0.12 μM . Addition of TMP alone was sufficient to rapidly disrupt this heterodimerization. Two examples are presented to demonstrate that this system is an invaluable tool, which can be widely used to rapidly and reversibly control protein function in vivo. 相似文献