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91.
R. C.P. Rossi R. F. de Paiva M. D. da Silva P. R. Barja 《The European physical journal. Special topics》2008,153(1):479-482
Topical medicine application has been used to treat a
good number of pathological processes. Its efficacy is associated to an
efficient penetration of the drug in the internal skin layers, promoting
systemic effects and excluding the possibility of drug degradation by the
digestive tract and hepatic elimination. This work analyzes the penetration
kinetics of two soluble bases employed as vehicles for topic application:
superficial gel (Carbopol 940) and transdermic (transdermal) gel. Analysis
was performed with the photoacoustic technique, based upon the absorption of
modulated light by a sample with subsequent conversion of the absorbed
energy in heat, generating acoustic waves in the air layer adjacent to the
sample. Each of the two vehicles was evaluated through in vivo (human skin) and in vitro
application. Measurements in vitro employed samples of VitroSkin (synthetic material
with properties similar to those of real skin, employed in the
pharmaceutical industry research). Results show that the permeation was
faster for the transdermal gel, both for in vivo and in vitro measurements, indicating that
in vitro measurements may be utilized in qualitative, comparative permeation
studies. 相似文献
92.
Nuno Francisco Carla Morais João C. Paiva Paula Gameiro 《Foundations of Chemistry》2017,19(2):125-138
How can a work of art give us clues about scientific aspects? How can chemistry help a painter enhance his creativity and, above all, preserve the original characteristics of his work? Does an artist require scientific knowledge to innovate or, at least, not to be faked? Other symbiotic fields between art and science are: tattoos, as body art with physical and chemical consequences; pigments, as basic materials with interesting historiographical preparations; spectroscopy diagnosis, as very broad and thorough method of analysis (but also specific and non-intrusive); biosensors, as one of the applications of new pigments. Note also the interconnection between the several possible paths of science and art, which reflect new challenges with enormous potential investigated through a literature review and the application as a case study in an educational inquiry module. 相似文献
93.
Didley Sâmia Paiva Cazelli Maria Eduarda Sousa Barroso Rafael Brianti Pizi Marina Orlandi Thiago Belarmino de Souza Diogo Teixeira Carvalho Arlan da Silva Gonçalves Denise Coutinho Endringer 《Chemical Papers》2017,71(10):1877-1886
Sortase A is responsible for the virulence of Gram-positive pathogens, including staphylococci and streptococci. The LPETG is the peptide surface anchor signal for Sortase A. The inhibitors of this enzyme shared similar binding pattern with substrate LPETG. Eugenol and its derivatives may act as sortase A inhibitor. The antimicrobial activity of eugenol and its derivatives was tested in vitro against bacterial strains: Staphylococcus aureus, Streptococcus mutans and Escherichia coli. All the tested derivatives demonstrated antimicrobial activity. Differences between derivatives in terms of in vitro activity and interactions between the amino acid residues were correlated in the docking analysis for the same derivatives. According to the relationship observed in this study between the antimicrobial activity of eugenol and the LPETG peptide structure, some of the eugenol derivatives proved to be more active inhibiting sortase A than eugenol against microorganisms when tested at the same concentrations. 相似文献
94.
Eunice Cunha Prof. Maria Fernanda Proença Prof. Florinda Costa António J. Fernandes Marta A. C. Ferro Dr. Paulo E. Lopes Dr. Mariam González-Debs Dr. Manuel Melle-Franco Dr. Francis Leonard Deepak Dr. Maria C. Paiva 《ChemistryOpen》2015,4(2):115-119
Graphene nanoribbons (GNR) were generated in ethanol solution by unzipping pyrrolidine-functionalized carbon nanotubes under mild conditions. Evaporation of the solvent resulted in regular few-layer stacks of graphene nanoribbons observed by transmission electron microscopy (TEM) and X-ray diffraction. The experimental interlayer distance (0.49–0.56 nm) was confirmed by computer modelling (0.51 nm). Computer modelling showed that the large interlayer spacing (compared with graphite) is due to the presence of the functional groups and depends on their concentration. Stacked nanoribbons were observed to redissolve upon solvent addition. This preparation method could allow the fine-tuning of the interlayer distances by controlling the number and/or the nature of the chemical groups in between the graphene layers. 相似文献
95.
96.
Diogo Goncalves Sofia Orikov Sandro Matos Henrique Machado Salom Vieira David Bastos Daniela Gaspar Ricardo Paiva Joo Carlos Bordado Abel Rodrigues Rui Galhano dos Santos 《Molecules (Basel, Switzerland)》2021,26(23)
Biomass thermochemical liquefaction is a chemical process with multifunctional bio-oil as its main product. Under this process, the complex structure of lignocellulosic components can be hydrolysed into smaller molecules at atmospheric pressure. This work demonstrates that the liquefaction of burned pinewood from forest fires delivers similar conversion rates into bio-oil as non-burned wood does. The bio-oils from four burned biomass fractions (heartwood, sapwood, branches, and bark) showed lower moisture content and higher HHV (ranging between 32.96 and 35.85 MJ/kg) than the initial biomasses. The increased HHV resulted from the loss of oxygen, whereas the carbon and hydrogen mass fractions increased. The highest conversion of bark and heartwood was achieved after 60 min of liquefaction. Sapwood, pinewood, and branches reached a slightly higher conversion, with yields about 8% greater, but with longer liquefaction time resulting in higher energy consumption. Additionally, the van Krevelen diagram indicated that the produced bio-oils were closer and chemically more compatible (in terms of hydrogen and oxygen content) to the hydrocarbon fuels than the initial biomass counterparts. In addition, bio-oil from burned pinewood was shown to be a viable alternative biofuel for heavy industrial applications. Overall, biomass from forest fires can be used for the liquefaction process without compromising its efficiency and performance. By doing so, it recovers part of the lost value caused by wildfires, mitigating their negative effects. 相似文献
97.
M. C. Bustos F. Paiva W. L. Wendland 《Mathematical Methods in the Applied Sciences》1996,19(9):679-697
We study a non-linear generalized initial–boundary value problem of a scalar conservation law which models the sedimentation of an ideal suspension. 相似文献
98.
C. S. Munita R. P. Paiva M. A. Alves P. M. S. de Oliveira E. F. Momose 《Journal of Radioanalytical and Nuclear Chemistry》2001,248(1):93-96
Forty one ceramic fragment samples from Rezende archaeological site, Centralina city, Minas Gerais State, Brazil, were analyzed using INAA to determine the concentration of 24 chemical elements: As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, K, La, Lu, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, U, Yb and Zn. Three multivariate statistical methods, cluster, discriminant and principal components analysis were performed on the data set. The results showed that the large majority of the samples (94%) can be considered to be manufactured using the same source of raw material. 相似文献
99.
Weslley Souza Paiva Francisco Ernesto de Souza Neto Moacir Fernandes Queiroz Lucas Alighieri Neves Costa Batista Hugo Alexandre Oliveira Rocha Anabelle Camarotti de Lima Batista 《Molecules (Basel, Switzerland)》2022,27(1)
Animal chitosan (Chit-A) is gaining more acceptance in daily activities. It is used in a range of products from food supplements for weight loss to even raw materials for producing nanoparticles and hydrogel drug carriers; however, it has low antioxidant activity. Fungal oligochitosan (OChit-F) was identified as a potential substitute for Chit-A. Cunninghamella elegans is a fungus found in the Brazilian savanna (Caatinga) that produces OligoChit-F, which is a relatively poorly studied compound. In this study, 4 kDa OChit-F with a 76% deacetylation degree was extracted from C. elegans. OChit-F showed antioxidant activity similar to that of Chit-A in only one in vitro test (copper chelation) but exhibited higher activity than that of Chit-A in three other tests (reducing power, hydroxyl radical scavenging, and iron chelation). These results indicate that OChit-F is a better antioxidant than Chit-A. In addition, Chit-A significantly increased the formation of calcium oxalate crystals in vitro, particularly those of the monohydrate (COM) type; however, OChit-F had no effect on this process in vitro. In summary, OChit-F had higher antioxidant activity than Chit-A and did not induce the formation of CaOx crystals. Thus, OChit-F can be used as a Chit-A substitute in applications affected by oxidative stress. 相似文献
100.
Franguelli Fernanda Paiva Barta-Holló Berta Petruševski Vladimir M. Sajó Istvan E. Klébert Szilvia Farkas Attila Bódis Eszter Szilágyi Imre Miklós Pawar Rajendra P. Kótai László 《Journal of Thermal Analysis and Calorimetry》2021,145(6):2907-2923
Journal of Thermal Analysis and Calorimetry - Detailed vibrational (IR, Raman, far-IR) and thermal (TGA, TG–MS, DSC) analysis has been performed on... 相似文献