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101.
Hamida Seba Abdelmadjid Bouabdallah Nadjib Badache Hatem Bettahar Djamal Tandjaoui 《电信纪事》2003,58(7-8):1090-1129
Multicast routing is an efficient communication mechanism for group-oriented applications. Several such applications need security guarantees: authentication, integrity confidentiality and access control. Techniques implementing these security services for point-to-point communications can not be directly used in a group communication settings. Consequently, group communication security has been extensively studied. Much current research has been dedicated to key management, which is a building block for all security mechanisms. In this paper, we describe the different existing approaches for managing keys within a group. We discuss the advantages and drawbacks of key management protocols existing in the literature and present a classification and a comparative study of these protocols. We also provide some criticisms and future directions. 相似文献
102.
In the last two decades, the volumes of chemical and biological data are constantly increasing. The problem of converting data sets into knowledge is both expensive and time-consuming, as a result a workflow technology with platforms such as KNIME, was built up to facilitate searching through multiple heterogeneous data sources and filtering for specific criteria then extracting hidden information from these large data. Before any QSAR modeling, a manual data curation is extremely recommended. However, this can be done, for small datasets, but for the extensive data accumulated recently in public databases a manual process of big data will be hardly feasible. In this work, we suggest using KNIME as an automated solution for workflow in data curation, development, and validation of predictive QSAR models from a huge dataset.In this study, we used 250250 structures from NCI database, only 3520 compounds could successfully pass through our workflow safely with their corresponding experimental log P, this property was investigated as a case study, to improve some existing log P calculation algorithms. 相似文献
103.
Alayedi Mohanad Cherifi Abdelhamid Hamida Abdelhak Ferhat Bouazza Boubakar Seddik Aljunid Syed Alwee 《Wireless Personal Communications》2021,118(4):2675-2698
Wireless Personal Communications - In this paper, a novel code named three dimensional single weight zero cross correlation (3D-SWZCC) code has been developed for spectral/time/spatial (S/T/S)... 相似文献
104.
Fahima Bekka-Hadji Isabelle Bombarda Ferhat Djoudi Sofiane Bakour Abdelaziz Touati 《Molecules (Basel, Switzerland)》2022,27(3)
The essential oils were obtained by hydrodistillation from aerial parts of Mentha pulegium L. (M. pulegium L.) and Artemisia herba alba (A. herba alba) Asso. and analyzed by gas chromatography–flame ionization detector chromatograpy (GC–FID) and gaz chromatography–mass spectrometry (GC–MS). The antibacterial activities of the oils were determined by the disk diffusion method and a microdilution broth assay against six bacteria stains. The combinations of these essential oils with antibiotics were evaluated against two multi-drug-resistant bacteria strains: imipenem-resistant Acinetobacter baumannii (IRAB S3310) and methicillin-resistant Staphylococcus aureus (MRSA S19). The chemical analysis of M. pulegium essential oil revealed the presence of pulegone (74.8%) and neoisomenthol (10.0%). A. herba alba essential oil was characterized by camphor (32.0%), α-thujone (13.7%), 1,8-cineole (9.8%), β-thujone (5.0%), bornéol (3.8%), camphene (3.6%), and p-cymene (2.1%). All strains tested except Pseudomonas aeruginosa were susceptible to these oils. The combinations of essential oils with antibiotics exerted synergism, antagonism, or indifferent effects. The best effect was observed with A. herba alba essential oil in association with cefoxitin (CX) against MRSA S19. However, for IRAB S3310, the strongest synergistic effect was observed with M. pulegium in association with amikacin (AK). This study demonstrated that M. pulegium and A. herba alba essential oils have antibacterial activities which could be potentiated by antibiotics especially in the case of IRAB S3310. 相似文献
105.
Karelina L. N. Bolginov V. V. Erkenov Sh. A. Egorov S. V. Golovchanskiy I. A. Chichkov V. I. Ben Hamida A. Ryazanov V. V. 《JETP Letters》2020,112(11):705-709
JETP Letters - A negative magnetoresistive effect has been observed for ferromagnet/superconductor/ferromagnet (FSF) microbridges based on diluted ferromagnetic PdFe alloy containing as small as 1%... 相似文献
106.
N. S. Sullivan J. A. Hamida S. Pilla K. A. Muttalib E. Genio 《Journal of Structural Chemistry》2016,57(2):301-307
We review the properties of simple diatomic molecular glasses as explored by nuclear magnetic resonance techniques and measurements of the dielectric susceptibility. We focus on the behavior of classical molecular rotors formed by solid N2–Ar mixtures and discuss the time dependent behavior in terms of replica symmetry breaking theories. 相似文献
107.
Functionalized 2‐Hydrazinobenzothiazole with Isatin and Some Carbohydrates under Conventional and Ultrasound Methods and Their Biological Activities
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Khadija O. Badahdah Hamida M. Abdel Hamid Sawsan A. Noureddin 《Journal of heterocyclic chemistry》2015,52(1):67-74
Several chemical reactions were carried out on 3‐(benzothiazol‐2‐yl‐hydrazono)‐1,3‐dihydro‐indol‐2‐one ( 2 ). 3‐(Benzothiazol‐2‐yl‐hydrazono)‐1‐alkyl‐1,3‐dihydro‐indol‐2‐one 3a , 3b , 3c have been achieved. Reaction of compound 2 with ethyl bromoacetate in the presence of K2CO3 resulted the uncyclized product 4 . Reaction of compound 2 with benzoyl chloride afforded dibenzoyl derivative 5 . Compound 2 was smoothly acetylated by acetic anhydride in pyridine to give diacetyl derivative 6b . Moreover, when compound 4 reacted with methyl hydrazine, it yielded dihydrazide derivative 7 , whereas the hydrazinolysis of this compound with hydrazine hydrate gave the monohydrazide derivative 8 . {N‐(Benzothiazol‐2‐yl‐N′‐(3‐oxo‐3,4‐dihydro‐2H‐1,2,4‐triaza‐fluoren‐9‐ylidene)hydrazino]‐acetic acid ethyl ester ( 9 ) was prepared by ring closure of compound 8 by the action of glacial acetic acid. In addition, the reaction of 2‐hydrazinobenzothiazole ( 1 ) with d ‐glucose and d ‐arabinose in the presence of acetic acid yielded the hydrazones 10a , 10b , respectively. Acetylation of compound 10b gave compound 11b . On the other hand, compound 13 was obtained by the reaction of compound 1 with gama‐d ‐galactolactone ( 12 ). Acetylation of compound 13 with acetic anhydride in pyridin gave the corresponding N1‐acetyl‐N2‐(benzothiazolyl)‐2‐yl)‐2,3,4,5,6‐penta‐O‐acetyl‐d ‐galacto‐hydrazide ( 14 ). Better yields and shorter reaction times were achieved using ultrasound irradiation. The structural investigation of the new compounds is based on chemical and spectroscopic evidence. Some selected derivatives were studied for their antimicrobial and antiviral activities. 相似文献
108.
Frédéric?Boyer Mathieu?PorezEmail author Ferhat?Morsli Yannick?Morel 《Journal of Nonlinear Science》2017,27(4):1121-1154
In animal locomotion, either in fish or flying insects, the use of flexible terminal organs or appendages greatly improves the performance of locomotion (thrust and lift). In this article, we propose a general unified framework for modeling and simulating the (bio-inspired) locomotion of robots using soft organs. The proposed approach is based on the model of Mobile Multibody Systems (MMS). The distributed flexibilities are modeled according to two major approaches: the Floating Frame Approach (FFA) and the Geometrically Exact Approach (GEA). Encompassing these two approaches in the Newton–Euler modeling formalism of robotics, this article proposes a unique modeling framework suited to the fast numerical integration of the dynamics of a MMS in both the FFA and the GEA. This general framework is applied on two illustrative examples drawn from bio-inspired locomotion: the passive swimming in von Karman Vortex Street, and the hovering flight with flexible flapping wings. 相似文献
109.
Mohammed Bakir Mark A. W. Lawrence Marhoun Ferhat Rebecca R. Conry 《Journal of Coordination Chemistry》2017,70(17):3048-3064
The reaction between di-2-pyridyl ketone thiosemicarbazone (dpktsc) and PdCl2(CH3CN)2, generated in situ from the reaction between PdCl2 and CH3CN, gave the unprecedented [Pd2Cl3(κ5-Npy,Nim,S,Npy,Nam-dpktsc-H)]·2CH3CN (1) complex (py = pyridine, im = imine and am = amide). The identity of 1 was confirmed via its elemental analysis and spectroscopic properties. Infrared and 1H-NMR spectra confirmed the coordination of (dpktsc-H)? to the palladium ions. The electronic absorption spectra measured in dmso and dmf and density functional theory (DFT) calculations revealed metal-to-ligand charge-transfer (MLCT), d–d and intra-ligand charge-transfer (ILCT) electronic transitions. X-ray structural analysis on a crystal of [Pd2Cl3(κ5-Npy,Nim,S,Npy,Nam-dpktsc-H)]·H2O (2) grown from dmf solution of 1 confirmed its formulation and showed the solid-state structure contains a web of molecules locked via a network of non-covalent interactions. Electrochemical measurements on 1 in dmf revealed metal- and ligand-based redox processes. In contrast to the electrochemical decomposition of uncoordinated dpktsc, coordinated (dpktsc-H)? in 1 does not undergo electrochemical decomposition. Electrochemical titrations of 1 with p-toluenesulfonic acid monohydrate (p-TSOH) revealed electro-catalytic proton reduction. Over-potential (η) of 180 mV for the H2 evolution was observed and is comparable to several molecular electro-catalysts for proton reduction. Controlled-potential electrolysis confirmed the electro-catalytic proton reduction by the Pd-complex. Electrochemical reactions of CO2 in the presence of 1 exhibited a proton dependence, and metal- and ligand-based electrochemical reaction. 相似文献
110.
Hamida Turki Benoit Genestie Rachid El Gharbi Sameh El Boussiry Joseph Banoub 《Rapid communications in mass spectrometry : RCM》2009,23(2):267-281
The fragmentation patterns of a series of six novel synthesized benzopyranopyrimidine derivatives 1–6, possessing the same 2‐oxo‐2H‐benzopyrano[2,3‐d]pyrimidine backbone structure, were investigated by electrospray ionization mass spectrometry (ESI‐MS) and tandem mass spectrometry (MS/MS) techniques using a quadrupole orthogonal time‐of‐flight (QqToF)‐hybrid instrument. The series of six pure benzopyranopyrimidine compounds contained three constitutional isobaric isomers (compounds 4–6). A simple methodology, based on the use of ESI (positive ion mode) and increasing the declustering potential in the atmospheric pressure/vacuum interface resulting in collision‐induced dissociation (CID), was used to enhance the formation of the product ions. In general, the novel synthetic benzopyranopyrimidine derivatives 1–6 afforded exact accurate masses for the protonated molecules. This led to the confirmation of both molecular masses and chemical structures of the studied compounds. The breakdown routes of the protonated molecules were rationalized by conducting low‐energy CID‐MS/MS analyses. It was shown that the MS/MS fragmentation routes for the protonated molecules 1 and 2 were similar, and that the MS/MS fragmentations of the constitutional isobaric protonated molecules 5 and 6 were identical. It was also shown that the gas‐phase CID fragmentations of 5 and 6 were different from that of their constitutional isomer 4. Finally, the ESI‐MS and CID‐MS/MS analyses of the protonated molecules that were obtained from the monodeuterated benzopyranopyrimidine derivatives 1–6 confirmed the values obtained for the exact masses, the precise structural assignments of all product ions and all the pathways described in the proposed CID fragmentations. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献