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31.
Inorganic fullerene-like WS2 and MoS2 nanoparticles have been synthesized using exclusively solid precursors, by reaction of the corresponding metal oxide nanopowder, sulfur and a hydrogen-releasing agent (NaBH4 or LiAlH4), achieved either by conventional furnace heating up to ∼900 °C or by photothermal ablation at far higher temperatures driven by highly concentrated white light. In contrast to the established syntheses that require toxic and hazardous gases, working solely with solid precursors permits relatively safer reactor conditions conducive to industrial scale-up.   相似文献   
32.
The distribution of the electric field in planar film–substrate GaAs structures under backgating is considered. It is shown that backgating can make the film exhibit a long-length region of a low-gradient electric field exceeding the threshold of N-type negative differential mobility, the magnitude of negative differential mobility in this region being high enough. At values of the film doping density and film thickness typical of GaAs transferred-electron devices, this region can be as long as several tens of micrometers. The underlying physical mechanism is discussed.  相似文献   
33.
Skin disorders of different etiology, such as dermatitis, atopic dermatitis, eczema, psoriasis, wounds, burns, and others, are widely spread in the population. In severe cases, they require the topical application of drugs, such as antibiotics, steroids, and calcineurin inhibitors. With milder symptoms, which do not require acute pharmacological interventions, medications, dietary supplements, and cosmetic products of plant material origin are gaining greater popularity among professionals and patients. They are applied in various pharmaceutical forms, such as raw infusions, tinctures, creams, and ointments. Although plant-based formulations have been used by humankind since ancient times, it is often unclear what the mechanisms of the observed beneficial effects are. Recent advances in the contribution of the skin microbiota in maintaining skin homeostasis can shed new light on understanding the activity of topically applied plant-based products. Although the influence of various plants on skin-related ailments are well documented in vivo and in vitro, little is known about the interaction with the network of the skin microbial ecosystem. The review aims to summarize the hitherto scientific data on plant-based topical preparations used in Poland and Ukraine and indicate future directions of the studies respecting recent developments in understanding the etiology of skin diseases. The current knowledge on investigations of interactions of plant materials/extracts with skin microbiome was reviewed for the first time.  相似文献   
34.
The Michael addition reaction between dithiomalondianilide (N,N′-diphenyldithiomalondiamide) and arylmethylidene Meldrum’s acids, accompanied by subsequent heterocyclization, was investigated along with factors affecting the mixture composition of the obtained products. The plausible mechanism includes the formation of stable Michael adducts which, under the studied conditions, undergo further transformations to yield corresponding N-methylmorpholinium 4-aryl-6-oxo-3-(N-phenylthio-carbamoyl)-1,4,5,6-tetrahydropyridin-2-thiolates and their oxidation derivatives, 4,5-dihydro-3H-[1,2]dithiolo[3,4-b]pyridin-6(7H)-ones. The structure of one such product, N-methylmorpholinium 2,2-dimethyl-5-(1-(2-nitrophenyl)-3-(phenylamino)-2-(N-phenylthiocarbamoyl)-3-thioxopropyl)-4-oxo-4H-1,3-dioxin-6-olate, was confirmed via X-ray crystallography.  相似文献   
35.
d-serine is the major co-agonist of N-methyl-D-aspartate receptors (NMDAR) at CA3/CA1 hippocampal synapses, the activation of which drives long-term potentiation (LTP). The use of mice with targeted deletion of the serine racemase (SR) enzyme has been an important tool to uncover the physiological and pathological roles of D-serine. To date, some uncertainties remain regarding the direction of LTP changes in SR-knockout (SR-KO) mice, possibly reflecting differences in inhibitory GABAergic tone in the experimental paradigms used in the different studies. On the one hand, our extracellular recordings in hippocampal slices show that neither isolated NMDAR synaptic potentials nor LTP were altered in SR-KO mice. This was associated with a compensatory increase in hippocampal levels of glycine, another physiologic NMDAR co-agonist. SR-KO mice displayed no deficits in spatial learning, reference memory and cognitive flexibility. On the other hand, SR-KO mice showed a weaker LTP and a lower increase in NMDAR potentials compared to controls when GABAA receptors were pharmacologically blocked. Our results indicate that depletion of endogenous D-serine caused a reduced inhibitory activity in CA1 hippocampal networks, altering the excitatory/inhibitory balance, which contributes to preserve functional plasticity at synapses and to maintain related cognitive abilities.  相似文献   
36.

News in Science and Engineering

New patents of the West Siberian Iron and Steel Works Joint Stock Company  相似文献   
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38.
A previously studied bubble generator was tested under new operating conditions to provide for millimeter‐sized bubbles. The basic element of the generator is a vortex chamber with water supplied through tangential ducts while gas (air) is introduced in the radial direction. Bubbles with average diameter of 0.5–2.2 mm were produced and registered by high‐speed photography. The correlation between the water‐air flow rate ratio and the characteristic bubble diameter was established and described by a relationship. Pressure oscillations in the exit section of the device were captured for two‐phase flows with fine and coarse bubbles. With a view to applications in membrane filtration and water treatment, the effect of a pin installed in the exit section of the vortex chamber on the pressure oscillations was studied. The pin results in a drastic increase in pressure amplitude, both in the flow without bubbles and in the case of gas supply.  相似文献   
39.
Brannerite‐based glass‐ceramics with relatively high actinide waste loadings are potential waste forms for the immobilization of actinide‐rich radioactive wastes containing process chemicals. In this work, the crystallization of pentavalent uranium brannerite phases in glass with the incorporation of yttrium/cerium/europium has been investigated. The formation of brannerite phases in glass has been confirmed with X‐ray diffraction and Raman spectroscopy. The evolution of microstructures and the development of micro pores in brannerite phases have been revealed by scanning electron microscopy with the nominal formula, Y0.51U0.49Ti2O6, Ce0.65U0.35Ti2O6, and Eu0.53U0.47Ti2O6, being determined with energy‐dispersive spectroscopy. The presence of dominant U5+ species has been proven with both diffuse reflectance spectroscopy and X‐ray absorption near‐edge spectroscopy. In addition, the systematic Raman band shifts with the mean cation radius in the studied brannerite series have been observed and discussed.  相似文献   
40.
Lanthanum zirconate has been prepared via a new chemical synthesis method by combining sol–gel processing and complex precipitation. The synthesis was carried out in aqueous solution under ambient conditions. The synthesized powder possessed the pyrochlore superstructure upon calcination above 1200°C. A suite of characterization techniques, including FTIR, Raman, X‐ray and electron diffraction, TEM, SEM, and nitrogen sorption were employed to investigate the microstructural evolution and bulk properties. Dense ceramics (>90% relative density) were obtained after sintering at 1400°C, without need for additional processing (i.e., hot or cold isostatic pressing) or any milling steps. A mechanism has been proposed that elucidates molecular assembly of this chemical synthesis method.  相似文献   
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