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101.
A radioreceptor assay, suitable for detecting residues in the meat of any compound with oestrogenic activity, is described. The assay is based upon the use of a purified preparation of oestrogen receptors obtained by affinity chromatography from swine uteri. The method was validated by measuring the oestrogenic activities in plasma and meat of diethylstilboestrol or oestradiol treated calves. The standard curve was performed by using oestradiol. Plasma levels of oestrogenic activity, expressed as equivalent of oestradiol, rose above control values 2 days after both diethylstilboestrol and oestradiol treatments, then declined to basal values by day 6 after the treatments. The levels of oestrogenic activity 10 days after treatment, found in the meat of diethylstilboestrol treated animals, were significantly higher than those found in control animals. No differences were found, however, between meat samples of control and oestradiol treated animals.  相似文献   
102.
Energy efficiency plays a key role in reducing global energy consumption, especially in the industrial sector, with an indirect positive impact on the competitiveness of industrial firms. Although a cultural shift toward recognizing the strategic importance of energy efficient and environmental friendly solutions is diffusing among industrial companies, also pushed by the evolution of local and international regulatory frameworks, strong barriers hampering the adoption of energy efficiency measures (EEMs) still exist. These barriers, and in particular those linked to behavioral issues, may be overcome by the use of a well-designed energy audit methodology. However, how energy audit can help overcome behavioral barriers to industrial energy efficiency remains an under-researched topic in literature. This paper presents and discusses a novel methodology for energy audit developed and implemented by a large manufacturing company. The methodology is built around four phases, and it pays special emphasis to the initial step of the audit, where the strongest resistance to the implementation of EEMs is typically found due to a lack of awareness and commitment which hampers the identification of needs and opportunities associated with the adoption of EEMs. The proposed methodology has been able to overcome in practice the typical behavioral barriers that affect the implementation of EEMs in the manufacturing sector and has strong applicability in other firms and industries.  相似文献   
103.
Due to its thermal stability, conductivity, high exciton binding energy and high electron mobility, zinc oxide is one of the most studied semiconductors in the field of photocatalysis. However, the wide bandgap requires the use of UV photons to harness its potential. A convenient way to appease such a limitation is the doping of the lattice with foreign atoms which, in turn, introduce localized states (defects) within the bandgap. Such localized states make the material optically active in the visible range and reduce the energy required to initiate photo-driven charge separation events. In this work, we employed a green synthetic procedure to achieve a high level of doping and have demonstrated how the thermal treatment during synthesis is crucial to select specific the microscopic (molecular) nature of the defect and, ultimately, the type of chemistry (reduction versus oxidation) that the material is able to perform. We found that low-temperature treatments produce material with higher efficiency in the water photosplitting reaction. This constitutes a further step in the establishment of N-doped ZnO as a photocatalyst for artificial photosynthesis.  相似文献   
104.
Titanium and its alloys represent the gold standard for orthopaedic and dental prosthetic devices, because of their good mechanical properties and biocompatibility. Recent research has been focused on surface treatments designed to promote their rapid osteointegration also in case of poor bone quality. A new surface treatment has been investigated in this research work, in order to improve tissue integration of titanium based implants. The surface treatment is able to induce a bioactive behaviour, without the introduction of a coating, and preserving mechanical properties of Ti6Al4V substrates (fatigue resistance). The application of the proposed technique results in a complex surface topography, characterized by the combination of a micro-roughness and a nanotexture, which can be coupled with the conventional macro-roughness induced by blasting. Modified metallic surfaces are rich in hydroxyls groups: this feature is extremely important for inorganic bioactivity (in vitro and in vivo apatite precipitation) and also for further functionalization procedures (grafting of biomolecules). Modified Ti6Al4V induced hydroxyapatite precipitation after 15 days soaking in simulated body fluid (SBF). The process was optimised in order to not induce cracks or damages on the surface. The surface oxide layer presents high scratch resistance.  相似文献   
105.
The impact of anthropogenic wastes of persistent organic pollutants (POPs) on the marine environment has increased in the last decades. POPs include polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs). To assess the levels of these POPs in the wild fish population, pelagic and benthopelagic predator fish species were selected as biomonitors. For detection and quantification of POPs in muscular tissues, a simple extraction through Accelerated-Solvent-Extraction (ASE) with an ‘in-line’ clean up purification approach was applied, followed by a GC–MS/MS analysis. Concentrations of sum DDT, sum HCH and endrin correlated with all PCB concentrations. Significant differences among fish species were found for all OCs and all PCBs except PCB 31 and 101. Blackspot seabream had the highest PCB concentrations; OCs were highest in tuna. Due to major concerns regarding fish population losses and the possible human chronic exposure to contaminated fish, studies addressing combined effects of multiple POPs (‘cocktail effect’) should be implemented. Our data motivate further experimental and observational studies in fish to define adequate baseline levels for cumulative human exposure and potential role of these contaminants for food safety.  相似文献   
106.
In dynamic atomic force microscopy (AFM) the cantilever is vibrated and its dynamics are monitored to probe the sample with nanoscale and atomic resolution. Amplitude and frequency modulation atomic force microscopy (AM-AFM and FM-AFM) have established themselves as the most powerful methods in the field. Nevertheless, it is still debatable whether one or the other technique is preferred in a given medium or experiment. Here, we quantitatively establish and compare the limitations in resolution of both techniques by introducing the concept of spatial horizon (SH) and quantifying it. The SH is the limiting spatial boundary beyond which collective atomic interactions do not affect the detection parameters of a given feedback system. We show that while an FM-AFM feedback can resolve a single atom or atomic defect where an AM feedback might fail, relative contrast is in fact equivalent for both feedback systems. That is, if the AM feedback could detect sufficiently small amplitude shifts and there was no noise, the detection of single atoms or atomic defects would be equivalent in AM-AFM and FM-AFM.  相似文献   
107.
In order to explain the unique thermoelectric properties of bulk nanocomposite p-type bismuth antimony telluride, its structural and electrical properties are investigated using transmission electron microscopy (TEM) and atomic force microscopy with a conductive probe (C-AFM). The material is observed to contain both nano- and micro-sized grains with sizes varying from 10 nm to 3 μm. This unique structure promotes phonon scattering, thereby decreasing the thermal conductivity to below 1 W mK(-1) at room temperature. Moreover, the C-AFM data show that the electrical conductivity of nanosized grains is higher than the bulk value and reaches 1600 S cm(-1). This results in a moderate increment of the overall electrical conductivity, thereby increasing the figure of merit (ZT) up to 1.4 at 100 °C. In addition to demonstrating a powerful scanning probe microscopy (SPM) based investigation technique that requires minimal sample preparation, our findings contribute towards better understanding of the enhancement of thermoelectric properties of nanocomposite thermoelectric materials.  相似文献   
108.
Taking inspiration from plant tendril geometry, in this study, 4D bimorph coiled structures with an internal core of graphene nanoplatelets-modified regenerated silk and an external shell of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) are fabricated by 4D printing. Finite element simulations and experimental tests demonstrate that integrating these biomaterials with different coefficients of thermal expansion results in the temperature induced self-compression and torsion of the structure. The bimorph spring also exhibits reversible contractive actuation after exposure to water environment that paves its exploitation in regenerative medicine, since core materials also have been proven to be biocompatible. Finally, the authors validate their findings with experimental measurements using such springs for temperature-mediated lengthening of an artificial intestine.  相似文献   
109.
In this paper we introduce a model and an optimization methodology for terrestrial solar thermoelectric generators (STEGs). We describe, discuss, and justify the necessary constraints on the STEG geometry that make the STEG optimization independent of individual dimensions. A simplified model shows that the thermoelectric elements in STEGs can be scaled in size without affecting the overall performance of the device, even when the properties of the thermoelectric material and the solar absorber are temperature-dependent. Consequently, the amount of thermoelectric material can be minimized to be only a negligible fraction of the total system cost. As an example, a Bi2Te3-based STEG is optimized for rooftop power generation. Peak efficiency is predicted to be 5% at the standard spectrum AM1.5G, with the thermoelectric material cost below 0.05 $/Wp. Integrating STEGs into solar hot water systems for cogeneration adds electricity at minimal extra cost. In such cogeneration systems the electric current can be adjusted throughout the day to favor either electricity or hot water production.  相似文献   
110.
Despite major progress in treating skeletal muscle disease associated with dystrophinopathies, cardiomyopathy is emerging as a major cause of death in people carrying dystrophin gene mutations that remain without a targeted cure even with new treatment directions and advances in modelling abilities. The reasons for the stunted progress in ameliorating dystrophin-associated cardiomyopathy (DAC) can be explained by the difficulties in detecting pathophysiological mechanisms which can also be efficiently targeted within the heart in the widest patient population. New perspectives are clearly required to effectively address the unanswered questions concerning the identification of authentic and effectual readouts of DAC occurrence and severity. A potential way forward to achieve further therapy breakthroughs lies in combining multiomic analysis with advanced preclinical precision models. This review presents the fundamental discoveries made using relevant models of DAC and how omics approaches have been incorporated to date.  相似文献   
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