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371.
372.
The effects of varying nitrocellulose concentrations on mechanical properties of polymeric films prepared from UV-curable acrylated urethane prepolymer were investigated. The acrylated urethane prepolymer was synthesized from isophorone diisocyanate (IPDI) and poly(propylene glycol monomethacrylate) (PPGMMA). Isobornyl acrylate (IBoA) and N-vinyl pyrrolidinone (NVP) were used as reactive diluents with the purpose of reducing the viscosity of the prepolymer as well as acting as solvent for nitrocellulose. An increase in nitrocellulose content caused an increase both in tensile strength and elongation values of polymeric films.  相似文献   
373.
Novel organofunctional siloxanes from γ-methacryloxypropyltrimethoxysilane (MPTMS) were synthesized by transesterification reactions with high monohydric alcohols, branched alcohols, ether alcohols, phenol, and mandelic acid. The factors effecting the substitution ratios were determined. Copolymers of these siloxanes with methyl methacrylate (MMA) were prepared by bulk copolymerization in glass molds and their swelling, thermal, oxygen permeability, and surface free energy characteristics were investigated in order to determine the effect of the substituted group on the produced copolymer. The changes in these properties by the crosslinking of the copolymer with ethylene glycol dimethacrylate (EGDM) were also investigated. The copolymers containing branched, nonpolar, and lengthy pendant groups were found to be highly oxygen permeable possibly due to the introduction of larger free volume by these groups. The surface energy analysis showed that the main variation was found to be in γ values rather than γ values and only ether alcohol substitution increased γ values to a greater extent.  相似文献   
374.
There have been several developments in determining the spontaneous combustion liability of coal. Most of the methods of concern have purely been based on the internal properties of the coal itself. The relation between the crossing-point method and the electrical resistance of coal was examined here to outline the spontaneous combustion tendency of coal. The electrical resistance property of coal was looked into as a decision-making parameter of the interaction matrix concept for the final decision on the spontaneous combustion tendency.  相似文献   
375.
In this paper, we propose a neuro-genetic decision support system coupled with simulation to design a job shop manufacturing system by achieving predetermined values of targeted performance measures such as flow time, number of tardy jobs, total tardiness and machine utilization at each work center. When a manufacturing system is designed, the management has to make decisions on the availability of resources or capacity, in our setting, the number of identical machines in each work station and the dispatching rule to be utilized in the shop floor to achieve performance values desired. Four different priority rules are used as Earliest due date (EDD), Shortest Processing Time (SPT), Critical ratio (CR) and First Come First Serve (FCFS). In reaching the final decision, design alternatives obtained from the proposed system are evaluated in terms of performance measures. An illustrative example is provided to explain the procedure.  相似文献   
376.
An oxygen scavenger based on a catalytic system with palladium (CSP) was recently developed to remove oxygen in food packagings. Although the CSP worked with various types of food, with some foods, an inhibition of the CSP was observed. Because such catalytic systems are susceptible to poisoning by sulfur‐containing compounds, the aim of this study was to understand the inactivation of palladium‐based catalysts in presence of foods containing volatile sulfur compounds (VSCs). To achieve this, the oxygen scavenging activity (OSA) of the CSP was evaluated in presence of selected food products. Afterwards, VSCs mainly present in these foods were exposed to the CSP, and the influence on the OSA was evaluated. Finally, headspace analysis was performed with the diluted VSCs and with the packaged food products using proton transfer reaction time‐of‐flight mass spectrometry. It was found that the catalytic activity of the CSP was inhibited when VSCs were present in the headspace in concentrations ranging between 10.8–36.0 ppbv (dimethyl sulfide, DMS), 1.2–7.2 ppbv (dimethyl disulfide), 0.7–0.9 ppbv (dimethyl trisulfide), 2.1–5.8 ppbv (methional) and 4.6–24.5 ppbv (furfuryl thiol). It was concluded that in packaged roast beef and cheese, DMS may be the compound mainly responsible for the inactivation of the CSP. In packagings containing ham, the key compounds were hydrogen sulfide and methanethiol; in peanuts, it was methanethiol; and in par‐baked buns, an accumulation of methional, DMS, butanethiol and methionol. When potato chips were packaged, it was demonstrated that when VSCs are present in low concentrations, oxygen can still be scavenged at a reduced OSA.  相似文献   
377.
This study deals with variations of electrical and superconducting features of Bi-2223 superconducting materials exposed to Ni impurity diffusion at different annealing temperatures (650 °C?≤?T?≤?850 °C) by temperature-dependent resistivity measurements. It is found that the characteristic properties improve with annealing temperature up to 700 °C as a result of enhancement in the truly-metallic characteristics, interaction quality, formation of Cooper-pairs and overlapping of Cu-3d and O-2p wave functions. Similarly, the optimum annealing temperature of 700 °C diminishes the omnipresent flaws and structural defects. Additionally, we design a strong theory (Percolation) to discuss the role of nickel impurities on fundamental aspects of material science and physical quantities as regards stabilization of superconductivity in the homogeneous regions and formation of superconducting clusters in the paths for the first time. Further, we develop an empirical relationship between the structural problems and transition temperatures to obtain a superconductor exhibiting the highest electrical and superconducting features.  相似文献   
378.
In this study, elderly persons' physical and spiritual necessities and their satisfaction in their residences are investigated by applying a comprehensive questionnaire on the residents of Trabzon Old Person's Home. By grouping the residents of the home according to their age, gender, marital status, occupation, health conditions, cultural status, and economic conditions, their expectations are determined. Physical conditions of the home are also examined in order to determine whether the necessities of the residents are met or not. The questionnaire consisting of 75 questions is applied to 60 people, and 4500 data points are analyzed by using SPSS software. In the results of this study, physical deficiencies that require elderly persons want to be in Trabzon Old Person's Home are determined. It is also determined that 86.7% of the residents are pleased with living in the old persons' home and they could get used to living in the old persons' home but 73.3% of the residents do not want to send someone in their family to the old person's home. These contradictory results show that residents do not want to live in old person's home but they adapt in there because of compulsoriness. This situation affects the residents' psychological well-being in a negative way.  相似文献   
379.
Fossil fuel reserves (coal, oil, natural gas, etc.) diminish day by day. In addition, rapid advancement of technology causes an increase in the amount of energy needed. This emerging situation resulted in ever increasing importance of renewable energy sources, and various systems are being developed to utilize these renewable energy sources effectively.In this study, information about Ayd?n–Salavatli geothermal field’s features and working principles of the 2 power plants (DORA 1 and DORA 2) in the region are given. Power plants’ energy and exergy efficiencies were calculated with the emphasis on the effects of thermal fluids used in power plants. Also, in this study, some correlations were developed.Power plants’ sections which cause exergy losses were identified. Accordingly, improvement suggestions were presented in this study. Additionally, exergoeconomic analyses were conducted while power plants’ investment costs and equipment maintenance costs were taken into consideration.  相似文献   
380.
Recent debates about renewable energy consumption manifest two main expectations. Firstly, renewable energy consumption should contribute to economic growth and secondly, it should not cause damage on environment. This study focuses on the first issue by applying Toda–Yamamoto procedure and bootstrap-corrected causality test for the US since empirical literature criticizes the Toda–Yamamoto test which bases on asymptotic distribution. The models consist of real GDP, employment, investment and kinds of renewable energy consumption. Only one causal relationship was found from biomass-waste-derived energy consumption to real GDP. No causal relationship was found between real GDP and all of the other renewable energy kinds—total renewable energy consumption, geothermal energy consumption, hydro-electric energy consumption, biomass energy consumption and biomass-wood-derived energy consumption. That is using of energy from waste cause not only solving the dumping problems but also it contributes to real GDP. For policy purpose, the results of this study suggest that countries should concentrate on energy producing from waste as an alternative energy resource.  相似文献   
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