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61.
Design,Synthesis, and Structural Analysis of Divalent NI Compounds and Identification of a New Electron‐Donating Ligand
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Prof. Dr. Prasad V. Bharatam Minhajul Arfeen Neha Patel Priyanka Jain Sonam Bhatia Prof. Dr. Asit K. Chakraborti Dr. Sadhika Khullar Vijay Gupta Prof. Dr. Sanjay K. Mandal 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(3):1088-1096
The dative‐bond representation (L→E) in compounds with main group elements (E) has triggered extensive debate in the recent past. The scope and limits of this nonclassical coordination bond warrant comprehensive exploration. Particularly compounds with (L→N←L′)+ arrangement are of special interest because of their therapeutic importance. This work reports the design and synthesis of novel chemical species with the general structural formula (L→N←L′)+ carrying the unusual ligand cyclohexa‐2,5‐diene‐4‐(diaminomethynyl)‐1‐ylidene. Four species belonging to the (L→N←L′)+ class carrying this unconventional ligand were synthesized. Quantum chemical and X‐ray diffraction analyses showed that the electronic and geometric parameters are consistent with those of already reported divalent NI compounds. The molecular orbital analysis, geometric parameters, and spectral data clearly support the L→N and N←L′ interactions in these species. The newly identified ligand has the properties of a reactive carbene and high nucleophilicity. 相似文献
62.
The performance of multivariate curve resolution (MCR-ALS) to decompose sets of excitation emission matrices of fluorescence
(EEM) of nanocomposite materials used as analytical sensors was assessed. The two fluorescent nanocomposite materials were:
NH2-polyethylene glycol (PEG200) functionalized carbon dots, sensible to aqueous Hg(II) (CD); and, CdS quantum dots attached
to the dendrimer DAB, sensible to the ionic strength of the aqueous medium (CdS-DAB). The structures of these sets of EEM,
obtained as function of the Hg(II) concentration and ionic strength, are characterized by collinear properties (CD) and non-linear
spectral variations (CdS-DAB). MCR-ALS was able to detect that the source of the collinearities is the presence of different
size CD that show similar affinity towards Hg(II). Moreover, MCR-ALS was able to model the non-linear spectral variations
of the CdS-DAB that are induced by varying ionic strength. The chemometric pre-processing of the fluorescent data sets using
soft-modelling multivariate curve resolution like MCR-ALS is a critical step to transform these nanocomposites with interesting
fluorescent proprieties into analytical useful nanosensors. 相似文献
63.
Rute A. S. Ferreira Mariela Nolasco Ana C. Roma Ricardo L. Longo Oscar L. Malta Luis D. Carlos 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(38):12130-12139
In many EuIII‐based materials, the presence of an intermediate energy level, such as ligand‐to‐metal charge transfer (LMCT) states or defects, that mediates the energy transfer mechanisms can strongly affect the lifetime of the 5D0 state, mainly at near‐resonance (large transfer rates). We present results for the dependence of the 5D0 lifetime on the excitation wavelength for a wide class of EuIII‐based compounds: ionic salts, polyoxometalates (POMs), core/shell inorganic nanoparticles (NPs) and nanotubes, coordination polymers, β‐diketonate complexes, organic–inorganic hybrids, macro‐mesocellular foams, functionalized mesoporous silica, and layered double hydroxides (LDHs). This yet unexplained behavior is successfully modelled by a coupled set of rate equations with seven states, in which the wavelength dependence is simulated by varying the intramolecular energy transfer rates. In addition, the simulations of the rate equations for four‐ and three‐level systems show a strong dependence of the emission lifetime upon the excitation wavelength if near‐resonant non‐radiative energy transfer processes are present, indicating that the proposed scheme can be generalized to other trivalent lanthanide ions, as observed for TbIII/CeIII. Finally, the proper use of lifetime definition in the presence of energy transfer is emphasized. 相似文献
64.
P. Wagner Naumann Kellner Böttcher Max Popp R. Michel F. Westhausser F. Mach A. Bömer R. Kunze W. Simmermacher L. Wuyts Mats Weibull W. Fuchs H. Neubauer F. Haussding W. Holle Celichowski Ferd Pilz Zachariades Czak D. Crispo R. W. Tuinzing Loges V. Schenke Z. Chmielewski Z. Romański Patten Marti Hugo Ditz S. Kohn W. Möller L. Schucht Aumann J. M. Kolthoff C. A. Peters E. Guerry E. Toussaint Hermann Kaserer Ignaz K. Greisenegger A. Stutzer W. Haupt C. E. Millar F. A. Gangler Schreiner Brown Veitch F. Zöhren 《Analytical and bioanalytical chemistry》1916,55(8):404-414
65.
Reaction of 1-oxo-3-dialkylamino-1 H-naphtho[2,1-b]pyrans with N,N-dimethylformamide in the presence of phosphorus oxychloride afforded the corresponding 1-oxo-2-formyl-3-dialkyl-amino-1H-naphtho[2,1-b]pyrans. Condensation of 1-oxo-2-formyl-3-dimethylamino-1H-naphtho[2,1-b]pyran with hydrazine or monosubstituted hydrazines was found to lead to the formation of 8-alkyl(aryl)-1 1-oxo-8H,1 1H-naplitho[1′,2′:5,6] pyrano[2,3-c]pyrazoles through the intermediate hydrazones and subsequent cyclization. The same result was achieved starting from other 3-dialkylamino derivatives but in a lower yield. 相似文献
66.
Reaction of (N-alkyl-N-phenyl)ethoxycarbonylacetamides with β-naphthol in the presence of phosphorus oxychloride afforded 1-oxo-3-(N-alkyl-N-phenyl)amino-1H-naphtho[2,1-b]pyrans. These compounds underwent reaction with N,N-dimethylformamide-phosphorus oxychloride at 95° yielding a mixture of 14H-naphtho[1′,2′:5,6]pyrano[2,3-b]quinoline derivatives and 1-oxo-2-formyl-3-(N-alkyl-N-phenyl)amino-9-oxy-1H-phenalene. When the same reaction was performed at 140°, only 14-oxo-14H-naphtho[1′,2′:5,6]pyrano[2,3-b]quinoline was obtained in a very good yield. The structures of such compounds were demonstrated by spectral data and by chemical transformations. On the other hand, the expected formylation in the 2 position was achieved when 1-oxo-3-(N-alkyl-N-benzyl)amino-1H-naphtho[2,1-b]pyrans reacted with N,N-dimethylformamide-phosphorus oxychloride. 相似文献
67.
Alberto Borassi Maria M. Carnasciali Angelo Mugnoli Giorgio Roma 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(2):258-259
The title compound, C16H11ClN4O, is an anticonvulsant agent. In the crystal, a particularly short C—H?N intermolecular hydrogen bond is noted [H?N 2.22 (2) Å]. The diazepine ring has a boat conformation. 相似文献
68.
Garg Kapil Khullar Vikrant Das Sarit K. Tyagi Himanshu 《Journal of Thermal Analysis and Calorimetry》2019,135(2):1465-1478
Journal of Thermal Analysis and Calorimetry - Humidification–dehumidification desalination (HDH) systems have been found to be ideal for treating seawater at a smaller scale. It requires... 相似文献
69.
70.
Selection of the successful optimization strategy is an essential part of solving numerous practical problems yet often is a nontrivial task, especially when a function to be optimized is multidimensional and involves statistical data. Here we propose a robust optimization scheme, referred to as NR/SVD-Cdyn, which is based on a combination of the Newton–Raphson (NR) method along with singular value decomposition (SVD), and demonstrate its performance by numerically solving a system of the weighted histogram analysis method equations. Our results show significant improvement over the direct iteration and conventional NR optimization methods. The proposed scheme is universal and could be used for solving various optimization problems in the field of computational chemistry such as parameter fitting for the methods of molecular mechanics and semiempirical quantum-mechanical methods. © 2019 Wiley Periodicals, Inc. 相似文献