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91.
Federica Aiello Gloria Uccello-Barretta Claudio Picchi Samuele Nazzi Alessandra Recchimurzo Federica Balzano 《Molecules (Basel, Switzerland)》2022,27(19)
The understanding of the interaction between non-steroidal anti-inflammatory drugs and human serum albumin plays a fundamental role in the development of new drugs and new therapeutic strategies. Several studies have been performed, nevertheless, the interaction phenomena are still not fully understood. In this work, high-field solution Nuclear Magnetic Resonance (NMR) spectroscopy was applied to compare the strength of the interaction of diclofenac sodium salt, ketorolac tris salt and flurbiprofen sodium salt toward albumin. To this aim, mono- and bi-selective relaxation rate measurements were performed by applying selective π-pulses at the selected frequencies and by following magnetization recovery. On the basis of the dependence of relaxation parameters on albumin concentration, normalized affinity indexes were calculated for several protons of the drugs. Affinity indexes for diclofenac were about five-fold higher in comparison with ketorolac and flurbiprofen. Aromatic moieties of the three drugs and methine protons at the chiral centers of ketorolac and flurbiprofen were more involved in the interaction with albumin. In conclusion, NMR spectroscopy allows not only for the comparison of drug-to-protein affinities but also points out the nature of the drug sites that are more extensively involved in the interaction. 相似文献
92.
Lorenza Gardella Dario Cavallo Samuele Colonna Alberto Fina Orietta Monticelli 《Journal of polymer science. Part A, Polymer chemistry》2014,52(22):3269-3282
Novel poly(l ‐lactide) (PLLA)/poly(d ‐lactide) (PDLA)/poly(tetrahydrofuran) (PTHF) multiblock copolymers with designed molecular structure were synthesized by a two‐stage procedure. Well‐defined PDLA‐PLLA‐PTHF‐PLLA‐PDLA pentablock copolymers were prepared by sequential ring opening polymerization of l ‐ and d ‐lactides starting from PTHF glycol, with the length of the (equimolar) PLLA and PDLA blocks being varied. Then, these dihydroxyl‐terminated pentamers were transformed into multiblock copolymers by melt chain‐extension with hexamethylene diisocyanate–being the first time that the coupling of pentablock units is reported. The successful formation of macromolecular chains with a multiblock and well‐defined architecture was demonstrated by 1H NMR spectroscopy. The thermal properties and structuring of the resulting materials were investigated by means of DSC and WAXD measurements and DMA analysis. Stereocomplexation was found to be promoted during solution and melt crystallization. This approach affords materials combining the high rigidity and strength (other than improved thermal resistance) of the hard stereocomplex crystallites with the flexibility imparted by the soft block, whereby their properties can be finely tailored through the composition of the basic pentablock units without limitations on the final molecular weight. The adopted reaction conditions make this process highly appealing in view of the possibility to perform it in extruder. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 3269–3282 相似文献
93.
94.
Summary We present the results of numerical calculations, performed in the spherical geometry, of FQHE states ofN≤12 electrons in the lowest Landau level at filling ν=1/2. The extrapolated value for the energy per particle is −0.469±0.005,
in the usual unitse
2/a
0. Densities and pair correlation functions of the ground states are computed. The pair correlations are ?Wigner-crystal-like?,
with maxima corresponding to regular polyhedra. ForN=4, 8 and 10 we find that the system presents a broken rotational invariance which generalizes the broken particle-hole symmetry
already known in different gauges. Quasi-particles, quasi-holes and the ?exciton? spectrum are computed, and some microscopic
wave functions are examined. The quasi-particles and the quasi-holes are not localized; this suggests a possible ?deformability?
of the system.
Riassunto Si presentano risultati di alcuni calcoli numerici, eseguiti usando la geometria sferica, di stati FQHE diN≤12 elettroni nel livello di Landau piú basso a ?riempimento? ν=1/2. Il valore estrapolato dell'energia per particella risulta pari a −0.469±0.005, nelle usuali unitàe 2/a 0. Si calcolano la funzione densità e la funzione di correlazione di coppia corrispondenti allo stato fondamentale. Le funzioni di correlazione di coppia sono ?tipo cristallo di Wigner? con massimi corrispondenti ai poliedri regolari. PerN=4, 8 e 10 noi troviamo che il sistema presenta una simmetria rotazionale rotta che generalizza la rottura della simmetria particella-buca che era già nota in altre scelte di gauge. Si calcolano le quasi-particelle, le quasi-buche e lo spettro degli ?eccitoni?, e si esaminano alcune funzioni d'onda microscopiche. Le quasi-particelle e le quasi-buche non sono localizzate; questo suggerisce una possibile ?deformabilità? del sistema.
Резюме Мы предлагаем результаты численных вычислений, вьшолненных в сферической геометрии, FQHE состояний дляN≤12 электронов на низшем уровне Ландау при заполнении ν=1/2. Экстрополированная величина энергии на одну частицу составляет −0.469±0.005, в обыкновенных единицахe 2/a 0. Вычисляются функции плотности и функции парных корреляций для основных состояний. Функции парных корреляций оказываюгся ?подобны кристаллу Вигнера? с максимумами, соответствующими обычным многогранникам. ДляN=4,8 и 10 мы получаем, что рассматриваемая система представляет нарушенную симметрию ?частица-дырка?, уже известную в других калибровках. Вычисляются квази-частицы, квази-дырки и спектр ?экситонов?. Исследуются некоторые микроскопические волновые функции. Квази-частицы и квази-дырки не локализованы, что предполагает возможность ?деформируемости? системы.相似文献
95.
The microscopic polarization produced by a spatially constant external field is calculated from the dielectric matrices of diamond, Si, Ge, α-Sn, MgO and NaCl. Local fields and polarization charges are analyzed in real space. Strong dipoles are induced at the bond sites in semiconductors and on the anions in MgO and NaCl. The effects of the inhomogeneity on the linear and non-linear susceptibilities are discussed. 相似文献
96.
97.
Protein resistance of titanium oxide surfaces modified by biologically inspired mPEG-DOPA 总被引:1,自引:0,他引:1
Dalsin JL Lin L Tosatti S Vörös J Textor M Messersmith PB 《Langmuir : the ACS journal of surfaces and colloids》2005,21(2):640-646
In the present study, we have utilized X-ray photoelectron spectroscopy (XPS), spectroscopic ellipsometry (ELM), and optical waveguide lightmode spectroscopy (OWLS) to examine the surface adsorption and protein resistance behavior of bio-inspired polymers consisting of poly(ethylene glycol) (PEG) conjugated to peptide mimics of mussel adhesive proteins. Peptides containing up to three residues of 3,4-dihydroxyphenylalanine (DOPA), a key component of mussel adhesive proteins, were conjugated to monomethoxy-terminated PEG polymers. These mPEG-DOPA polymers were found to be highly adhesive to TiO2 surfaces, with quantitative XPS analysis providing useful insight into the binding mechanism. Additionally, the antifouling properties of immobilized PEG were reflected in the excellent resistance of mPEG-DOPA-modified TiO2 surfaces to protein adsorption. Measurements of mPEG-DOPA and human serum adsorption were related in terms of ethylene glycol (EG) surface density and serum mass adsorbed and demonstrated a threshold of approximately 15-20 EG/nm2, above which substantially little protein adsorbs. With respect to surface density of adsorbed PEG and the associated nonfouling behavior of the adlayers, strong parallels exist between the nonfouling properties of the surface-bound mPEG-DOPA polymers and PEG polymers immobilized to surfaces using other approaches. Peptide anchors containing three DOPA residues resulted in PEG surface densities higher than those achieved using several existing PEG immobilization strategies, suggesting that peptide mimics of mussel adhesive proteins may be useful for achieving high densities of protein-resistant polymers on surfaces. 相似文献
98.
99.
Bräuer B Weigend F Fittipaldi M Gatteschi D Reijerse EJ Guerri A Ciattini S Salvan G Rüffer T 《Inorganic chemistry》2008,47(15):6633-6644
In this work we present the investigation of the influence of electronic and structural variations induced by varying the N,N'-bridge on the magnetic properties of Cu(II)- bis(oxamato) complexes. For this study the complexes [Cu(opba)] (2-) ( 1, opba = o-phenylene- bis(oxamato)), [Cu(nabo)] (2-) ( 2, nabo = 2,3-naphthalene- bis(oxamato)), [Cu(acbo)] (2-) ( 3, acbo = 2,3-anthrachinone- bis(oxamato)), [Cu(pba)] (2-) ( 4, pba = propylene- bis(oxamato)), [Cu(obbo)] (2-) ( 5, obbo = o-benzyl- bis(oxamato)), and [Cu(npbo)] (2-) ( 6, npbo = 1,8-naphthalene- bis(oxamato)), and the respective structurally isomorphic Ni(II) complexes ( 8- 13) have been prepared as ( (n)Bu 4N) (+) salts. The new complex ( (n)Bu 4N) 2[Cu(R-bnbo)].2H 2O ( 7, R-bnbo = (R)-1,1'-binaphthalene-2,2'- bis(oxamato)) was synthesized and is the first chiral complex in the series of Cu(II)-bis(oxamato) complexes. The molecular structure of 7 has been determined by single crystal X-ray analysis. The Cu(II) ions of the complexes 1- 7 are eta (4)(kappa (2) N, kappa (2) O) coordinated with a more or less distorted square planar geometry for 1- 6 and a distorted tetrahedral geometry for 7. Using pulsed Electron Nuclear Double Resonance on complex 6, detailed information about the relative orientation of the hyperfine ( A) and nuclear quadrupole tensors ( Q) of the coordinating nitrogens with respect to the g tensor were obtained. Electron Paramagnetic Resonance studies in the X, Q, and W-band at variable temperatures were carried out to extract g and A values of N ligands and Cu ion for 1- 7. The hyperfine values were interpreted in terms of spin population on the corresponding atoms. The obtained trends of the spin population for the monomeric building blocks were shown to correlate to the trends obtained in the dependence of the exchange interaction of the corresponding trinuclear complexes on their geometry. 相似文献
100.
Attanasi OA De Crescentini L Favi G Filippone P Lillini S Mantellini F Santeusanio S 《Organic letters》2005,7(12):2469-2471
[reaction: see text] Here, we report the protocol for the preparation of new poly(ethylene glycol)-supported 1,2-diaza-1,3-butadiene. In addition, we discuss an application of this supported reagent in an efficient and environmentally friendly one-pot synthesis of 2-thiazol-4-one derivatives by reaction with thioamides. 相似文献