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211.
Eda Gungor Gulay Cote Tuba Erdogan Hakan Durmaz A. Levent Demirel Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2007,45(6):1055-1065
Heteroarm H‐shaped terpolymers, (polystyrene)(poly(methyl methacrylate))‐ poly(tert‐butyl acrylate)‐(polystyrene)(poly(methyl methacrylate)), (PS)(PMMA)‐PtBA‐(PMMA)(PS), and, (PS)(PMMA)‐poly(ethylene glycol)(PEG)‐(PMMA)(PS), through click reaction strategy between PS‐PMMA copolymer (as side chains) with an alkyne functional group at the junction point and diazide end‐functionalized PtBA or PEG (as a main chain). PS‐PMMA with alkyne functional group was prepared by sequential living radical polymerizations such as the nitroxide mediated (NMP) and the metal mediated‐living radical polymerization (ATRP) routes. The obtained H‐shaped polymers were characterized by using 1H‐NMR, GPC, DSC, and AFM measurements. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1055–1065, 2007 相似文献
212.
Densities (ρ) and viscosities (η) of different strengths of magnesium sulphate (MgSO4) in varying proportions of formamide (FA) + ethylene glycol as mixed solvents were measured at room temperature. The experimental
values of ρ and η were used to calculate the values of the apparent molar volume, (φ1,), partial molar volume, (φ1,ℴ) at infinite dilution,A- andB-coefficients of the Jones-Dole equation and free energies of activation of viscous flow, (Δμ
1
0*
) and (Δμ
2
0*
), per mole of solvent and solute respectively. The behaviour of these parameters suggests strong ion-solvent interactions
in these systems and also that MgSO4 acts as structure-maker in FA + ethylene glycol mixed solvents. 相似文献
213.
The role of spontaneous waves in the deflagration-to-detonation transition in submillimetre channels
Flame acceleration and transition to detonation in submillimetre two-dimensional planar and three-dimensional square channels were simulated by solving the compressible reactive Navier–Stokes equations. A simplified chemical–diffusive model was used to describe the diffusive transport and chemical reaction of a highly reactive mixture, such as stoichiometric ethylene and oxygen in 2D and 3D channels. The walls of the channels were modelled as no-slip and adiabatic. The initial flame acceleration and precursor shock formation were consistent with earlier results. Viscous dissipation in the boundary layer heats the reactants, which have been compressed by the precursor shock. The strength of the precursor shock and the amount of viscous dissipation increase until the temperature of the boundary layer is high enough to ignite the reactants. This produces a spontaneous wave, which, in most of the cases considered, initiates the detonation. The spontaneous wave first forms where the flame attaches to the wall in the planar channels, and forms at the corner where two walls meet in the square channels. In a separate study, the boundary layer also ignited in a computation for a circular tube containing a mixture hydrogen and oxygen represented by a detailed chemical reaction mechanism. The formation of spontaneous waves to the extent studied appears to be robust, and is relatively insensitive to channel geometry, fuel and oxidiser mixture, and the level of detail in the chemical–diffusive models used. 相似文献
214.
Hakan Durmaz Aydan Dag Elif Erdogan A. Levent Demirel Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2010,48(1):99-108
The synthesis of multiarm star block (and mixed‐block) copolymers are efficiently prepared by using Cu(I) catalyzed azide‐alkyne click reaction and the arm‐first approach. α‐Silyl protected alkyne polystyrene (α‐silyl‐alkyne‐PS) was prepared by ATRP of styrene (St) and used as macroinitiator in a crosslinking reaction with divinyl benzene to successfully give multiarm star homopolymer with alkyne periphery. Linear azide end‐functionalized poly(ethylene glycol) (PEG‐N3) and poly (tert‐butyl acrylate) (PtBA‐N3) were simply clicked with the multiarm star polymer described earlier to form star block or mixed‐block copolymers in N,N‐dimethyl formamide at room temperature for 24 h. Obtained multiarm star block and mixed‐block copolymers were identified by using 1H NMR, GPC, triple detection‐GPC, atomic force microscopy, and dynamic light scattering measurements. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 99–108, 2010 相似文献
215.
Dr. Devrani Mitra Dr. Hideaki Ogata Prof. Wolfgang Lubitz Brian C. Manor Prof. Thomas B. Rauchfuss Dr. Deborah Byrne Dr. Violaine Bonnefoy Prof. Francis E. Jenney Jr. Prof. Michael W. W. Adams Dr. Yoshitaka Yoda Dr. Ercan Alp Dr. Jiyong Zhao Prof. Stephen P. Cramer 《Angewandte Chemie (International ed. in English)》2013,52(2):469-469
216.
Hakan Durmaz Aydan Dag Ceyda Onen Ozgul Gok Amitav Sanyal Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2010,48(21):4842-4846
Dendritic 2‐ and 4‐arm PMMA‐based star polymers with furan‐protected maleimide at their focal point, (PMMA)2n‐MI and (PMMA)4n‐MI were efficiently clicked with the peripheral anthracene functionalized multiarm star polymer, (α‐anthryl functionalized‐polystyrene)m‐poly(divinyl benzene) ((α‐anthryl‐PS)m‐polyDVB) through the Diels–Alder reaction resulting in corresponding multiarm star block copolymers: (PMMA)2n‐(PS)m‐polyDVB and (PMMA)4n‐(PS)m‐polyDVB, respectively. Molecular weights (Mw,TDGPC), hydrodynamic radius (Rh), and intrinsic viscosity (η) of the multiarm star polymers were determined using three‐detection GPC (TD‐GPC). The high efficiency of this methodology to obtain such sterically demanding macromolecular constructs was deduced using 1H‐NMR and UV–vis spectroscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
217.
Hakan Durmaz Aydan Dag Nese Cerit Okan Sirkecioglu Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2010,48(24):5982-5991
Anthracene‐functionalized oxanorbornene monomer and oxanorbornenyl polystyrene (PS) with ω‐anthracene end‐functionalized macromonomer were first polymerized via ring‐opening metathesis polymerization using the first‐generation Grubbs' catalyst in dichloromethane at room temperature and then clicked with maleimide end‐functionalized polymers, poly(ethylene glycol) (PEG)‐MI, poly(methyl methacrylate) (PMMA)‐MI, and poly(tert‐butyl acrylate) (PtBA)‐MI in a Diels–Alder reaction in toluene at 120 °C to create corresponding graft copolymers, poly(oxanorbornene)‐g‐PEG, poly(oxanorbornene)‐g‐PMMA, and graft block copolymers, poly(oxanorbornene)‐g‐(PS‐b‐PEG), poly(oxanorbornene)‐g‐(PS‐b‐PMMA), and poly(oxanorbornene)‐g‐(PS‐b‐PtBA), respectively. Diels–Alder click reaction efficiency for graft copolymerization was monitored by UV–vis spectroscopy. The dn/dc values of graft copolymers and graft block copolymers were experimentally obtained using a triple detection gel permeation chromatography and subsequently introduced to the software so as to give molecular weights, intrinsic viscosity ([η]) and hydrodynamic radius (Rh) values. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
218.
Hakan Durmaz Aydan Dag Gurkan Hizal Umit Tunca 《Journal of polymer science. Part A, Polymer chemistry》2011,49(5):1195-1200
In this study, graft copolymers with regular graft points containing polystyrene (PS) backbone and poly(methyl methacrylate) (PMMA), poly(tert‐butyl acrylate) (PtBA), or poly (ethylene glycol) (PEG) side chains were simply achieved by a sequential double polymer click reactions. The linear α‐alkyne‐ω‐azide PS with an anthracene pendant unit per chain was produced via atom transfer radical polymerization of styrene initiated by anthracen‐9‐ylmethyl 2‐((2‐bromo‐2‐methylpropanoyloxy)methyl)‐2‐methyl‐3‐oxo‐3‐(prop‐2‐ynyloxy) propyl succinate. Subsequently, the azide–alkyne click coupling of this PS to create the linear multiblock PS chain with pendant anthracene sites per PS block, followed by Diels–Alder click reaction with maleimide end‐functionalized PMMA, PtBA, or PEG yielded final PS‐g‐PMMA, PS‐g‐PtBA or PS‐g‐PEG copolymers with regular grafts, respectively. Well‐defined polymers were characterized by 1H NMR, gel permeation chromatography (GPC) and triple detection GPC. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
219.
The compositions of colophony resins obtained from Pinus brutia Ten trees by three different methods (acid paste, carved hole and scraping) from Ayvacik, G?kova and Kemalpa?a in Turkey were analyzed by capillary GC-MS. The main components were the monoterpenes alpha-pinene, beta-pinene, and delta3-carene, and the diterpenic resin acids palustric, abietic, kaur-9(11)-16-en-18-oic and neoabietic acid. The synthetic colophony resins exhibited similar contents to those of the natural resins obtained from the G?kova and Kemalpa?a regions of Turkey. However, colophony resins from Ayvacik exhibited only half the diterpenic acid content as those of the G?kova and Kemalpa?a resins. Out of the three techniques, the carved hole method caused rather different percentages in the constituents of the essential oils. 相似文献
220.
Bucşa M Pollnitz A Varga RA Pîrnău A Silvestru A Vlassa M 《Dalton transactions (Cambridge, England : 2003)》2012,41(15):4506-4510
A broadening of the investigation of the ring-chain tautomeric process of N-substituted 1,3-X,N-heterocycles (X = O, S, NR) to Se containing macrocyclic compounds allowed the isolation and structurally solid state characterization of the cyclic tautomer 7, which due to the length of the aliphatic chain, is able to form a stable six-membered ring (6-endo-trig). The theoretical calculations based on the DFT method (Gaussian 03 software package) also support the fact that tautomer 7 is more stable than the chain tautomer 6. Thus, based on the ring-chain tautomerism of the macrocycles that contain alkyl chains with amino-imino, imino-alcohol or sulphur-imino groups, combined with a strategy that allows the formation of a stable six-membered ring, the main reaction products will be the cyclic tautomers. The ring-chain equilibria of these macrocycles could be exploited advantageously in different areas of macrocyclic, physical and medicinal chemistry in order to obtain compounds with practical applications. 相似文献