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991.
Tellechea E Cornago I Ciaurriz P Moran JF Asensio AC 《IEEE transactions on nanobioscience》2012,11(2):176-180
Superoxide dismutase enzymes (SODs) are an essential part of the first line of cellular defense system against free radicals species. They catalyze the dismutation of superoxide radicals into oxygen and hydrogen peroxide. Although several studies have examined the attachment of superoxide dismutases to nanoparticles and nanostructures, never has been used a member of the Fe/MnSOD family. In this study, the behavior of plant origin FeSOD enzyme on three different nanopatterned surfaces was investigated as a function of covalent and electrostatic binding. Fluorescence microscopy was used to demonstrate that the protein is attached only to the gold layer. We also examined the activity of SOD by a colorimetric assay, and we have shown that the enzyme remains active after attachment to the three different surfaces under both kind of binding (electrostatic and covalent). This methodology could be useful for those who want to functionalize nanostructures with a SOD enzyme and test the activity. This process could be of great interest for the development of peroxynitrite and superoxide biosensors. 相似文献
992.
993.
Paula A. Pebsworth Gretchen L. Seim Michael A. Huffman Raymond P. Glahn Elad Tako Sera L. Young 《Journal of chemical ecology》2013,39(3):447-449
Despite widespread consumption of soil among animals, the role of geophagy in health maintenance remains an enigma. It has been hypothesized that animals consume soil for supplementation of minerals and protection against toxins. Most studies determine only the total elemental composition of soil, which may not reflect the amount of minerals available to the consumer. Our aim was to test these hypotheses by evaluating the bioavailability of iron in soil consumed by chacma baboons, using a technique that simulates digestion and adsorption. Our results indicate that, despite variation in absolute iron concentration of soil samples, actual iron bioavailability was low while clay content was quite high. This suggests that iron supplementation is unlikely to be the primary motivation for geophagy in this population, and that detoxification is a plausible explanation. This study demonstrates that more research on bioavailability and clay composition is needed to determine the role geophagy plays in health maintenance. 相似文献
994.
Servaas Holvoet Paula Horny Stephane Turgeon Jean-Jacques Pireaux 《Electrochimica acta》2010,55(3):1042-2468
A new approach for the detection and visualization of nano-scaled film defects, such as fissures and holes is described. The procedure is based on a selective electrochemical deposition of bismuth onto uncovered parts of stainless steel substrates due to film cracking after deformation. Cyclic voltammetry experiments enabled the identification of the bismuth redox signals, necessary for the subsequent potentiostatic electrodeposition. A combination of XPS and ToF-SIMS analyses demonstrated that deposition with commonly used acidified electrolytes led to a significant film degradation, by defluorination and chain scission. When an identical procedure was performed in neutral conditions, which was realized by the addition of a bismuth chelating agent, no influence onto the integrity of the fluorocarbon coatings was observed. By SEM, XPS and ToF-SIMS analyses, the deposition of bismuth on the film defects was clearly demonstrated and the failures were evidenced. The identification of nano-scaled coating failures, which was extremely difficult before using common characterization tools, was now realized. This work makes part of a strategy to cover stent materials with a protective fluorocarbon layer and to examine the influence of stent expansion onto the film cohesive properties. 相似文献
995.
Suryasarathi Bose Author Vitae Author Vitae Paula Moldenaers Author Vitae 《Polymer》2010,51(5):975-1425
The current state of research in polymer/carbon nanotubes (single wall and multiwall) composites has been reviewed in context to various types of pre-treatments presently employed. The fundamental aspects of carbon nanotubes are briefly discussed and various strategies designed to alter the dispersion stability and quality of nanotubes in the composites is highlighted. A complete survey of the published data is provided and both the opportunities and the limitations in the frame of covalent and non-covalent type of pre-treatments of carbon nanotubes are juxtaposed. In this context, diverse proposed mechanisms behind different molecular level interactions between nanotubes and the functional moieties are addressed. The effects of these pre-treatments on electrical and rheological percolation thresholds are assessed as they provide an alternative means to evaluate the state of dispersion of carbon nanotubes in the composites. In this regard, the influence of various pre-treatments on the nature of charge transfer mechanisms, system dimensions etc. deduced from different parameters of classical percolation theories are also discussed. These transport parameters offer a vital clue on the nature of the pre-treatment and the effects it has on the structure-property correlations. 相似文献
996.
997.
998.
Guilherme Martins Silva Mariana Pegrucci Barcelos João Gabriel Curtolo Poiani Prof. Dr. Lorane Izabel da Silva Hage-Melim Prof. Dr. Carlos Henrique Tomich de Paula da Silva 《ChemMedChem》2019,14(16):1467-1483
Among neurodegenerative disorders, Alzheimer's disease (AD) is the most common type of dementia, and there is an urgent need to discover new and efficacious forms of treatment for it. Pathological patterns of AD include cholinergic dysfunction, increased β-amyloid (Aβ) peptide concentration, the appearance of neurofibrillary tangles, among others, all of which are strongly associated with specific biological targets. Interactions observed between these targets and potential drug candidates in AD most often occur by competitive mechanisms driven by orthosteric ligands that sometimes result in the production of side effects. In this context, the allosteric mechanism represents a key strategy; this can be regarded as the selective modulation of such targets by allosteric modulators in an advantageous manner, as this may decrease the likelihood of side effects. The purpose of this review is to present an overview of compounds that act as allosteric modulators of the main biological targets related to AD. 相似文献
999.
Jimena S. Gonzalez Paula Nicolás María Luján Ferreira Marcelo Avena Verónica L. Lassalle Vera A. Alvarez 《Polymer International》2014,63(2):258-265
Magnetic biomaterials were prepared using magnetite and chitosan‐coated magnetite nanoparticles (CSNPs) dispersed in poly(vinyl alcohol) gels. Two different methods were developed to obtain ferrogels: in situ co‐precipitation of magnetite (Ferro‐IS) and by adding previously synthesized CSNPs to the neat matrix (Ferro‐CSNPs). In both cases, the crosslinking was carried out by freezing ? thawing (F‐T). The as‐prepared materials as well as precursor CSNPs were characterized by Fourier transform infrared spectroscopy, electronic microscopy (scanning and transmission), X‐ray diffraction, ζ potential, dynamic light scattering, thermogravimetric analysis, differential scanning calorimetry and magnetic properties. The performance of these gels as protein adsorbents was evaluated. Batch adsorption experiments were carried out using bovine serum albumin (BSA) as a model. Substantially different adsorption behaviour was found using Ferro‐IS and Ferro‐CSNPs. This was assigned to dissimilar bonding mechanisms of BSA to the ferrogel matrix. Hence, biomaterials potentially useful in drug delivery as well as in protein purification fields may be prepared by a relatively simple, non‐toxic and low cost method. © 2013 Society of Chemical Industry 相似文献
1000.
In this work, functionalization of epoxy films with dansyl and naphthalimide fluorophores is described. The procedure involves UV‐photopolymerization of an epoxy formulation that includes bromomethyl reactive groups, and their post‐functionalization modification through a click strategy. Quantitative click reaction within the bulk of the film allows one to obtain films in which the fluorophore is uniformly and covalently linked throughout the epoxy network. Depending on the chromophore bounded, the films are sensitive to different stimuli. Evaluation of the fluorescence emission of the films shows a linear response towards changes in polarity but less sensitivity than that of the low‐molecular‐weight chromophore. © 2013 Society of Chemical Industry 相似文献