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81.
Son T. Nguyen John D. Williams Helena Majgier-Baranowska Bing Li Venugopal R. Neelagiri Hwa-Ok Kim 《合成通讯》2014,44(9):1307-1313
A new three-step synthesis of 6-cyanobenzo[b]furan (6) was developed, starting from commercially available 6-hydroxybenzo[b]furan-3-one (18). Key steps in this process were the first step, which was the reductive dehydration of 18 to produce 6-hydroxybenzo[b]furan (19), and the last step, which converted the aryl triflate 20 to the aryl cyanide 6 in a palladium-catalyzed cross-coupling protocol. Overall yield for this new synthesis was 49%. 相似文献
82.
A group of novel 2-aryl imidazole derivatives were synthesized and characterized by NMR spectra, X-ray, mass and CHN analysis.
An excited state intramolecular proton transfer (ESIPT) process in hydroxy imidazoles (dmip and dmtip) have been studied using
emission spectroscopy and it was detected that the two distinct ground state rotamers of I and II are responsible for the
normal and the tautomer emission respectively. In hydrocarbon solvent, the tautomer emission predominates over the normal
emission for both dmip and dmtip. This reveal that rotamer II is responsible for the tautomer emission and it is stabler than
rotamer I which causes the normal emission. In alcoholic solvent like ethanol, a dramatic enhancement of normal emission is
observed which was due to increased solvation, the more polar rotamer I become stabler than rotamer II. In dioxane—water mixtures
it is observed that the addition of water inhibits the ESIPT process due to the formation of the intermolecular hydrogen bonding
involving water. DFT calculations on energy, dipole moment, charge distribution of the rotamers in the ground and excited
states of the imidazole derivatives were performed and discussed. PES calculation indicates that the energy barrier for the
interconversion of two rotamers is too high in the excited state than the ground state. 相似文献
83.
Aritra Sarkar Jonas C. Kölsch Christian M. Berač Akhil Venugopal Ranjan Sasmal Dr. Ronja Otter Prof. Dr. Pol Besenius Prof. Dr. Subi J. George 《ChemistryOpen》2020,9(3):346-350
The pH-responsive nature of two self-assembled NDI-peptide amphiphile conjugates is reported. The diethoxy substituted NDI showed a pH-dependent assembly behaviour, as expected. In contrast, the isopropylamino- and ethoxy-substituted NDI based supramolecular polymer was stable at acidic and basic aqueous conditions. This finding highlights how subtle changes in the molecular design of π-stacked chromophore-peptide conjugates have a drastic impact on their equilibrium structure and ultimately functional properties. 相似文献
84.
1,2,3‐Triazolo[4,5,‐e]furazano[3,4,‐b]pyrazine 6‐Oxide—A Fused Heterocycle with a Roving Hydrogen Forms a New Class of Insensitive Energetic Materials
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Dr. Venugopal Thottempudi Dr. Ping Yin Dr. Jiaheng Zhang Dr. Damon A. Parrish Prof. Dr. Jean'ne M. Shreeve 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(2):542-548
The straightforward synthesis and energetic properties of a new class of energetic materials, 1,2,3‐triazolo‐ [4,5‐e]furazano[3,4‐b]pyrazine 6‐oxide and its energetic salts are described. They were characterized by IR and multinuclear NMR spectroscopy, elemental analysis, differential scanning calorimetry, and single‐crystal X‐ray diffraction are given. The X‐ray structures show that in the title compound, the hydrogen atom is bonded to the nitrogen in the pyrazine ring; however, in the salts, the negative charge is associated with the triazole nitrogen. Heats of formation for all compounds were calculated with the G2 method and then combined with experimentally determined densities to obtain detonation pressures (P) and velocities (D) by using EXPLO5 program. These new materials exhibit good densities and thermal stabilities, high heats of formation, acceptable detonation properties, and are insensitive to impact. 相似文献
85.
Chittipaka Rajitha P. K. Dubey Venkataiah Sunku Venugopal Rao Veeramaneni Manojit Pal 《Journal of heterocyclic chemistry》2013,50(3):630-637
The synthesis of novel 1,2,3‐thiadiazol derivatives containing 2H‐benzo[b][1,4]oxazin‐3(4H)‐one moiety as one of the substituents has been reported. A combined application of H3PO4/(CF3CO)2O mediated acylation followed by Hurd–Mori reaction has been explored to synthesize these compounds. The scope and limitation of this strategy along with the reaction mechanism of the key step is discussed. 相似文献
86.
Biswanath Das Avula Satyakumar Bommena Ravikanth Bommena Vittal Rao Tuniki Venugopal Raju Busi Siddhardha Upadyayula Suryanaryana Murty 《Journal of heterocyclic chemistry》2013,50(2):430-434
A novel pentacyclic heterocycle has been synthesized starting from D ‐glucose involving two crucial conversions: the intramolecular cycloaddition of O‐allyloxy furanaldoxime derived from D ‐glucose to furanopyran‐2‐isoxazoline and its diastereoselective reductive cleavage to the corresponding cis‐1,3‐amino alcohol. The antibacterial and antifungal activities of the synthesized heterocycle have been examined. 相似文献
87.
88.
Rajendiran V Murali M Suresh E Palaniandavar M Periasamy VS Akbarsha MA 《Dalton transactions (Cambridge, England : 2003)》2008,(16):2157-2170
A series of mixed ligand ruthenium(II) complexes [Ru(Hdpa)2(diimine)](ClO4)2, 1-5 where Hdpa is 2,2'-dipyridylamine and diimine is 1,10-phenanthroline (phen) and a modified/extended 1,10-phenanthroline such as, 5,6-dimethyl-1,10-phenanthroline (5,6-dmp), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq), 5-methyldipyrido[3,2-d:2',3'-f]quinoxaline (mdpq) and dipyrido[3,2-a:2',3'-c]phenazine (dppz) have been isolated and characterized by analytical and spectral methods. The complex [Ru(Hdpa)2(phen)](PF6)2 1 has been structurally characterized and the coordination geometry around Ru(II) in it is described as distorted octahedral. 1H NMR spectral data reveal that 1-5 should have a C2 symmetry lying on the diimine plane due to the rapid flapping of the coordinated Hdpa ligands. The interaction of the complexes with calf thymus (CT) DNA has been explored by using absorption and emission spectral and viscometry and electrochemical techniques and the mode of DNA binding of the complexes has been proposed. The DNA binding affinity of the complexes decreases with decrease in number of planar aromatic rings in the co-ligand supporting the intercalation of the diimine co-ligands in between the DNA base pairs. Circular dichroic spectral studies reveal that the complexes 3-5 exhibit induced circular dichroism upon binding to CT DNA. Interestingly, upon interaction with CT DNA all the complexes show an increase in anodic current in the cyclic voltammograms suggesting that they are involved in electrocatalytic guanine oxidation. Interestingly, of all the complexes, only 5 alters the DNA superhelicity upon binding with supercoiled pBR322 DNA, which is consistent with its higher DNA binding affinity. Further, the cytotoxicities of the complexes against human cervical epidermoid carcinoma cell line (ME180) have been examined. Interestingly, 5 exhibits a cytotoxicity against ME180 higher than other complexes with potency approximately 8 times more than cisplatin for 24 h incubation but 4 times lower than cisplatin for 48 h incubation. 相似文献
89.
Now-a-days, catalytic decomposition of methane (CDM) into hydrogen and carbon is a promising technique for production of fuel
cell grade hydrogen. The Ni based catalysts seems promising particularly for the production of COx free H2 by methane decomposition process. The CDM activity and longevity of the Ni based catalysts are mainly influenced by the amount
of Ni and type of support material. In this paper the CDM activity results are correlated with NiO crystallite size, Ni metal
surface area and acidity of the catalysts. In case of bimetallic catalysts addition of Cu to Ni catalysts lead to enhance
the CDM activity at higher temperature thus resulting in the increased concentration of hydrogen in the outlet stream. Finally,
some of the carbon-based catalysts are studied for methane decomposition activity at higher temperature. The surface changes
over carbon catalysts with methane decomposition are studied using various characterization techniques. 相似文献
90.
Akhil Venugopal Dr. Lorena Ruiz-Perez Dr. K. Swamynathan Dr. Chidambar Kulkarni Dr. Annalisa Calò Dr. Mohit Kumar 《Angewandte Chemie (International ed. in English)》2023,62(8):e202208681
Supramolecular systems chemistry has been an area of active research to develop nanomaterials with life-like functions. Progress in systems chemistry relies on our ability to probe the nanostructure formation in solution. Often visualizing the dynamics of nanostructures which transform over time is a formidable challenge. This necessitates a paradigm shift from dry sample imaging towards solution-based techniques. We review the application of state-of-the-art techniques for real-time, in situ visualization of dynamic self-assembly processes. We present how solution-based techniques namely optical super-resolution microscopy, solution-state atomic force microscopy, liquid-phase transmission electron microscopy, molecular dynamics simulations and other emerging techniques are revolutionizing our understanding of active and adaptive nanomaterials with life-like functions. This Review provides the visualization toolbox and futuristic vision to tap the potential of dynamic nanomaterials. 相似文献