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排序方式: 共有202条查询结果,搜索用时 15 毫秒
1.
Cover Picture: Coordination Chemistry of N‐Heterocyclic Nitrenium‐Based Ligands (Chem. Eur. J. 19/2015) 下载免费PDF全文
2.
Dr. A. F. Eftaiha Dr. Abdussalam K. Qaroush Ghada G. Kayed Abdel Rahman K. Abdel Rahman Dr. Khaleel I. Assaf Prof. Dr. Matthew F. Paige 《Chemphyschem》2020,21(16):1858-1865
A series of water soluble, surface-active ionic liquids (SAILs), namely, 1-alkyl-3-methyl imidazolium chlorides ([Cn-mim]Cl) and their mixtures with palmitic acid (PA) are investigated in Langmuir monolayers and Langmuir–Blodgett films. It is inferred from the surface pressure-area isotherms that C16-mim-IL mixes non-ideally with PA and stabilizes the binary mixed films. In addition, the residence of mim-IL at the water surface is enhanced as a function of the increasing alkyl side chain length. Generally, the compressional moduli values decrease upon increasing the content of the mim-ILs over a wide range of compositions. Furthermore, film relaxation measurements indicate that the IL component is selectively excluded from the mixed films upon achieving a certain target pressure. Brewster angle microscope images demonstrate minimal changes on the PA domains in the presence of either C4- and C8-mim-ILs, whereas presence of the hexadecyl counterpart results in the formation of condensed sheets. Atomic force microscopy imaging of deposited films show the formation of propeller-like aggregates when C8- or C16-mim-IL is present in the mixed films. 相似文献
3.
Triple Emission from p‐Dimethylaminobenzonitrile–Cucurbit[8]uril Triggers the Elusive Excimer Emission 下载免费PDF全文
Dr. Mhejabeen Sayed Dr. Frank Biedermann Dr. Vanya D. Uzunova Khaleel I. Assaf Dr. Achikanath C. Bhasikuttan Dr. Haridas Pal Prof. Werner M. Nau Dr. Jyotirmayee Mohanty 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(2):691-696
The intriguing dual‐emission behavior of p‐ dimethylaminobenzonitrile (DMABN) and the identity of the associated excited states is, arguably, the most extensively investigated and also controversially discussed molecule‐ specific phenomenon of modern photochemistry. We have now found a new, third fluorescence band when DMABN is encapsulated within the water‐soluble molecular container cucurbit[8]uril (CB8). It is centered between the previously observed emissions and assigned to the elusive excimer emission from DMABN through 1:2 CB8:DMABN complex formation. Heating of the CB8 ? (DMABN)2 complex from 0 to 100 °C results in the dissociation of the ternary complex and restoration of the dual‐emission properties of the monomer. Alternatively, monomer emission can be obtained by selecting cucurbit[7]uril (CB7), a host homologue that is too small to accommodate two DMABN molecules, or by introducing ethyl instead of methyl groups at the amino terminus of the aminobenzonitrile guest. 相似文献
4.
Dr. Hee‐Sun Han Paul G. Cantalupo Dr. Assaf Rotem Dr. Shelley K. Cockrell Martial Carbonnaux Prof. James M. Pipas Prof. David A. Weitz 《Angewandte Chemie (International ed. in English)》2015,54(47):13985-13988
Metagenomic studies suggest that only a small fraction of the viruses that exist in nature have been identified and studied. Characterization of unknown viral genomes is hindered by the many genomes populating any virus sample. A new method is reported that integrates drop‐based microfluidics and computational analysis to enable the purification of any single viral species from a complex mixed virus sample and the retrieval of complete genome sequences. By using this platform, the genome sequence of a 5243 bp dsDNA virus that was spiked into wastewater was retrieved with greater than 96 % sequence coverage and more than 99.8 % sequence identity. This method holds great potential for virus discovery since it allows enrichment and sequencing of previously undescribed viruses as well as known viruses. 相似文献
5.
We prove that for every n ∈ ? there exists a metric space (X, d X), an n-point subset S ? X, a Banach space (Z, \({\left\| \right\|_Z}\)) and a 1-Lipschitz function f: S → Z such that the Lipschitz constant of every function F: X → Z that extends f is at least a constant multiple of \(\sqrt {\log n} \). This improves a bound of Johnson and Lindenstrauss [JL84]. We also obtain the following quantitative counterpart to a classical extension theorem of Minty [Min70]. For every α ∈ (1/2, 1] and n ∈ ? there exists a metric space (X, d X), an n-point subset S ? X and a function f: S → ?2 that is α-Hölder with constant 1, yet the α-Hölder constant of any F: X → ?2 that extends f satisfies \({\left\| F \right\|_{Lip\left( \alpha \right)}} > {\left( {\log n} \right)^{\frac{{2\alpha - 1}}{{4\alpha }}}} + {\left( {\frac{{\log n}}{{\log \log n}}} \right)^{{\alpha ^2} - \frac{1}{2}}}\). We formulate a conjecture whose positive solution would strengthen Ball’s nonlinear Maurey extension theorem [Bal92], serving as a far-reaching nonlinear version of a theorem of König, Retherford and Tomczak-Jaegermann [KRTJ80]. We explain how this conjecture would imply as special cases answers to longstanding open questions of Johnson and Lindenstrauss [JL84] and Kalton [Kal04]. 相似文献
6.
Mohamed E. Abouelela Hamdy K. Assaf Reda A. Abdelhamid Ehab S. Elkhyat Ahmed M. Sayed Tomasz Oszako Lassaad Belbahri Ahmed E. El Zowalaty Mohamed Salaheldin A. Abdelkader 《Molecules (Basel, Switzerland)》2021,26(6)
Severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease is a global rapidly spreading virus showing very high rates of complications and mortality. Till now, there is no effective specific treatment for the disease. Aloe is a rich source of isolated phytoconstituents that have an enormous range of biological activities. Since there are no available experimental techniques to examine these compounds for antiviral activity against SARS-CoV-2, we employed an in silico approach involving molecular docking, dynamics simulation, and binding free energy calculation using SARS-CoV-2 essential proteins as main protease and spike protein to identify lead compounds from Aloe that may help in novel drug discovery. Results retrieved from docking and molecular dynamics simulation suggested a number of promising inhibitors from Aloe. Root mean square deviation (RMSD) and root mean square fluctuation (RMSF) calculations indicated that compounds 132, 134, and 159 were the best scoring compounds against main protease, while compounds 115, 120, and 131 were the best scoring ones against spike glycoprotein. Compounds 120 and 131 were able to achieve significant stability and binding free energies during molecular dynamics simulation. In addition, the highest scoring compounds were investigated for their pharmacokinetic properties and drug-likeness. The Aloe compounds are promising active phytoconstituents for drug development for SARS-CoV-2. 相似文献
7.
Assaf Rinot 《Mathematical Logic Quarterly》2019,65(2):200-204
We present a weak sufficient condition for the existence of Souslin trees at successor of regular cardinals. The result is optimal and simultaneously improves an old theorem of Gregory and a more recent theorem of the author. 相似文献
8.
Georges Assaf Gemma Cansell Doug Critcher Stuart Field Stewart Hayes Suju Mathew Alan Pettman 《Tetrahedron letters》2010,51(38):5048-5051
We report our results on the construction of a morpholine ring system from the corresponding epoxide and amino alcohol. From this study, we were able to convert a previous four-step synthesis into a more efficient two-step process. 相似文献
9.
Dr. Debabrata Maity Dr. Khaleel I. Assaf Wilhelm Sicking Dr. Christoph Hirschhäuser Prof. Dr. Werner M. Nau Prof. Dr. Carsten Schmuck 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(57):13088-13093
A convenient supramolecular strategy for constructing a ratiometric fluorescent chemosensing ensemble, consisting of a macrocyclic host (cucurbit[8]uril CB[8]), and a pyrene-tagged amphiphilic peptide beacon (AP 1), is reported. AP 1 unfolds upon encapsulation of the pyrene termini into the hydrophobic CB[8] cavity. This changes pyrene excimer to monomer emission. Substrates with higher affinity for the CB[8] cavity can displace AP 1 from the ensemble. The released AP 1 folds again to form a pyrene excimer, which allows for the ratiometric fluorescence monitoring of the substrate. In this report, the ensemble capacity for ratiometric fluorescence monitoring of biological substrates, such as amino acid derivatives, specific peptides, and proteins, in aqueous media is demonstrated. 相似文献
10.