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131.
Novel extracellular polymeric substances produced by Cupriavidus necator IPT 027 grown on glucose and crude glycerol originated from biodiesel 下载免费PDF全文
The aim of this study was to evaluate the production and properties of novel extracellular polymeric substances (EPS) from glucose (EPS 1) and crude glycerol (CG) from castor beans oil (EPS 2). Cupriavidus necator IPT 027 cultivated with glucose and CG (35 °C, 150 rpm, 72 hr, pH 7, shaker) produced approximately 1.60 ± 0.01 and 2.83 ± 0.02 g l?1 EPS, respectively, with high‐molecular weight (3.89 × 105 and 1.89 × 107 Da) and constituted of different functional groups such as uronic acid, monosaccharides (glucose, mannose, arabinose, and fucose) and primary amine group. The composition of the fermentable substrate influenced the melting temperature (221.11 and 230.18 °C), crystallinity (34.36% and 37.11%), degradation temperature (255.06 and 296.62 °C) and morphology. EPS showed pseudoplastic non‐Newtonian fluid behavior in the aqueous solutions, presenting potential applicability biotechnological and industrial mainly in food industry as emulsifiers and biosurfactants. This is the first study on the production and characterization of EPS obtained by C. necator IPT 027 in culture with glucose and CG. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
132.
Lourenço JM Ribeiro PA Botelho do Rego AM Braz Fernandes FM Moutinho AM Raposo M 《Langmuir : the ACS journal of surfaces and colloids》2004,20(19):8103-8109
The amount of counterions in layer-by-layer (LBL) films of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) has been determined with X-ray photoelectron spectroscopy (XPS) for films prepared from solutions with various NaCl concentrations. Sodium and chloride counterions are present in LBL films produced from salt solutions, which are located at the surface and in the bulk of the films. The percentage of bulk counterions increases with the ionic strength of the polyelectrolyte before reaching a constant value. The bulk sodium/sulfur percentage ratios tend to 0.8 for samples washed with pure water and for samples washed with NaCl aqueous solutions, while the bulk chlorine/nitrogen percentage ratios tend to 0.5 for the same samples. The ratio between the percentages of polyelectrolyte ionic groups lies close to unity for all samples, indicating that counterions do not contribute to charge compensation in the polyelectrolyte during the adsorption process. The presence of counterions in LBL films is explained by Manning condensation near the polyelectrolyte ionic groups, leading to inter-polyelectrolyte ionic bondings via ionic networks. It is believed that condensation leads to the formation of NaCl crystallites in these LBL films, which was confirmed by X-ray diffraction measurements. 相似文献
133.
Supermassive Black Holes are the most entropic objects found in the universe. The Holographic Bound (HB) to the entropy is used to constrain their formation time with initial masses 106–8
M
, as inferred from observations. We find that the entropy considerations are more limiting than causality for this direct formation. Later we analyze the possibility of SMBHs growing from seed black holes. The growth of the initial mass is studied in the case of accretion of pure radiation and quintessence fields, and we find that there is a class of models that may allow this metamorphosis. Our analysis generalizes recent work for some models of quintessence capable of producing a substantial growth in a short time, while simultaneously obeying the causal and Holographic Bound limits. 相似文献
134.
Rosa IL Filho PC Neri CR Serra OA de Figueiredo AT Varela JA Longo E 《Journal of fluorescence》2011,21(4):1575-1583
This work reports on the synthesis and characterization of a new complex of Eu3+ with the 3-hydroxypicolinamide ligand (Hhpa). Here we present an approach for obtaining bis[2-carbamoyl(κO)pyridin-3-olato(κO’)]
lanthanide complexes, which were characterized through elemental analysis, thermal analysis, infrared and photoluminescence
spectroscopies (emission, excitation, luminescence lifetimes, quantum efficiencies, Judd-Ofelt parameters and quantum yields).
Although hpa can act as a bidentate ligand in different conformations, the results attest for the occurrence of a unique coordination
site of low symmetry for the Eu3+ ions, in which two anionic hpa ligands coordinate the cations through an O/O chelating system. The phosphorescence of the
synthesized gadolinium complex provides the energy of the triplet state, which is determined to be at 20,830 cm-1 over the ground state. This makes the Hhpa ligand very adequate for sensitizing the Eu3+ luminescence, which leads to a very efficient antenna effect and opens a wide range of applications for the complex in light
emitting organic-inorganic devices. 相似文献
135.
Tiago M. B. Campos Luciana S. Cividanes João Paulo B. Machado Evelyn A. N. Simonetti Liana A. Rodrigues Gilmar P. Thim 《Journal of Sol-Gel Science and Technology》2014,72(2):219-226
Mullite is an aluminosilicate widely used as a structural material for high temperature applications. This paper studies the effect of the gelation temperature on the synthesis of two mullite precursors: polymeric and colloidal silica, using both in fully-hydrolyzed silica sol, derived from sodium silicate. The gels were synthesized using aqueous silicic acid and aluminum nitrate. Ethylene glycol was added into polymeric gels. Two gelation temperatures were used: 80 and 100 °C. In the polymeric precursor, the increasing of the gelation temperature caused an increase in the silica incorporation inside the mullite crystalline lattice at 1,000 °C, and it also generated an increase in the reaction extent at all calcination temperatures. In the colloidal precursors, these effects were more intense than in the polymeric precursors in terms of yield. Colloidal samples calcined at 1,250 °C crystallized cristobalite and alpha alumina in addition to mullite when they were previously gelled at 80 °C. On the other hand, the same sample gelled at 100 °C led to only crystallized mullite. The reaction extent increased by more than 20 % for colloidal samples gelled at 100 °C compared to colloidal samples gelled at 80 °C (calcined at 1,250 °C). This increase was due to the almost total incorporation of alumina and silica in the crystalline lattice of mullite. 相似文献
136.
Paola D. D. S. Maia Diego dos Santos Baio Hayandra F. Nanini Victor Paulo F. da Silva Lissa Bantim Frambach Iuri Matheus Cabral Beatriz Pêgo Beatriz E. Ribeiro Mauro Srgio Gonalves Pavo Vania M. F. Paschoalin Heitor S. P. de Souza Anna Paola T. R. Pierucci 《Molecules (Basel, Switzerland)》2022,27(4)
Phenolic compounds (PCs) present in foods are associated with a decreased risk of developing inflammatory diseases. The aim of this study was to extract and characterize PCs from craft beer powder and evaluate their potential benefits in an experimental model of inflammatory bowel disease (IBD). PCs were extracted and quantified from pure beer samples. BALB/c mice received either the beer phenolic extract (BPE) or beer powder fortified with phenolic extract (BPFPE) of PCs daily for 20 days by gavage. Colon samples were collected for histopathological and immunohistochemical analyses. Dextran sodium sulfate (DSS)-induced mice lost more weight, had reduced colon length, and developed more inflammatory changes compared with DSS-induced mice treated with either BPE or BPFPE. In addition, in DSS-induced mice, the densities of CD4- and CD11b-positive cells, apoptotic rates, and activation of NF-κB and p-ERK1/2 MAPK intracellular signaling pathways were higher in those treated with BPE and BPFPE than in those not treated. Pretreatment with the phenolic extract and BPFPE remarkably attenuated DSS-induced colitis. The protective effect of PCs supports further investigation and development of therapies for human IBD. 相似文献
137.
Pedro A. Fernandes Elsa S. Henriques Vineet Pande Maria. J. Ramos Ana R. R. Maia André A. S. Almeida Bruno F. B. Silva Carla M. S. Ribeiro César F. B. Ribeiro David S. M. Ribeiro Diana A. P. Fonseca Eva M. S. Cunha Filipe R. N. C. Maia Joana A. A. Pereira João P. G. Pacheco Joaquim A. A. D. Ferreira Liliana R. C. Matos Manuel A. B. P. Pinto Maria C. S. Borges Paulo J. C. R. Magalhães Pedro F. R. D. Teixeira Pedro N. B. C. Veloso Ricarte J. F. Ferreira Sandro S. Gomes Tiago F. Barros Tiago S. J. T. Selão Virgínia M. M. C. Fernandes 《Theoretical chemistry accounts》2005,113(4):197-204
We present a series of new inhibitors of the association between nuclear factor kappa B (NF-B) and the corresponding B site in DNA. They were designed using the lead compound 15-deoxy-12,14 -prostaglandin J2 (PGJ2), which is a natural product with demonstrated inhibitory efficiency for this system. First, the binding mode of PGJ2 to NF-B was unraveled by GOLD docking calculation. Subsequently, substitutions were made to PGJ2 to optimize its association with NF-B. Care was taken not to strongly increase the reactivity of the new compounds, and to keep the overall shape, size and hydrophilicity of the lead compound, which should render them a similar bioavailability. Molecular mechanics calculations were performed to decide on the suitability of the substitutions, and to evaluate the energies of association with NF-B. Density functional theory calculations were performed also to study the overall reactivity of the substituted drugs towards NF-B. Important general conclusions were obtained, concerning the improvement of these natural inhibitors; namely, a set of rational methodologies were deduced to improve the association between the PGJ2 derivatives and NF-B, and their efficiency demonstrated by generating a set of substituted complexes, some of them with a very much increased affinity for NF-B, opening new doors to enlarge the therapeutic capabilities of this class of drugs. 相似文献
138.
P.J. Iunes G. Bigazzi J.C. Hadler Neto M.A. Laurenzi M.L. Balestrieri P. Norelli A.M. Osorio Araya S. Guedes C.A. Tello S. S.R. Paulo P.A.F.P. Moreira R. Palissari E.A.C. Curvo 《Radiation measurements》2005,39(6):665-668
Neutron dosimetry based on U and Th thin films was used for fission-track dating of the age standard Moldavite, the central European tektite, from the Middle Miocene deposit of Jankov (southern Bohemia, Czech Republic). Our fission-track age () agrees with a recent 40Ar/39Ar age, , based on several determinations on Moldavites from different sediments, including the Jankov deposit. This result indicates that the U and Th thin film neutron dosimetry represents a reliable alternative for an absolute approach in fission-track dating. 相似文献
139.
Sheyla Santa Isabel Marques Iracema Andrade Nascimento Paulo Fernando de Almeida Fábio Alexandre Chinalia 《Applied biochemistry and biotechnology》2013,171(8):1933-1943
Microalgae farming has been identified as the most eco-sustainable solution for producing biodiesel. However, the operation of full-scale plants is still limited by costs and the utilization of industrial and/or domestic wastes can significantly improve economic profits. Several waste effluents are valuable sources of nutrients for the cultivation of microalgae. Ethanol production from sugarcane, for instance, generates significant amounts of organically rich effluent, the vinasse. After anaerobic digestion treatment, nutrient remaining in such an effluent can be used to grow microalgae. This research aimed to testing the potential of the anaerobic treated vinasse as an alternative source of nutrients for culturing microalgae with the goal of supplying the biodiesel industrial chain with algal biomass and oil. The anaerobic process treating vinasse reached a steady state at about 17 batch cycles of 24 h producing about 0.116 m3CH4 kgCODvinasse ?1. The highest productivity of Chlorella vulgaris biomass (70 mg l?1 day?1) was observed when using medium prepared with the anaerobic digester effluent. Lipid productivity varied from 0.5 to 17 mg l?1 day?1. Thus, the results show that it is possible to integrate the culturing of microalgae with the sugarcane industry by means of anaerobic digestion of the vinasse. There is also the advantageous possibility of using by-products of the anaerobic digestion such as methane and CO2 for sustaining the system with energy and carbon source, respectively. 相似文献
140.
Paulo Augusto da Costa Filho 《Analytica chimica acta》2009,631(2):206-461
This paper reports the results of a rapid method to determine sucrose in chocolate mass using near infrared spectroscopy (NIRS). We applied a broad-based calibration approach, which consists in putting together in one single calibration samples of various types of chocolate mass. This approach increases the concentration range for one or more compositional parameters, improves the model performance and requires just one calibration model for several recipes. The data were modelled using partial least squares (PLS) and multiple linear regression (MLR). The MLR models were developed using a variable selection based on the coefficient regression of PLS and genetic algorithm (GA). High correlation coefficients (0.998, 0.997, 0.998 for PLS, MLR and GA-MLR, respectively) and low prediction errors confirms the good predictability of the models. The results show that NIR can be used as rapid method to determine sucrose in chocolate mass in chocolate factories. 相似文献