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1.
Anilinepropylsilica hybrid powder was synthesized by a sol-gel route in basic medium using HF as catalyst. The effect of the amount of HF catalyst on the morphologies and on organic content was studied. The xerogels were characterized using FTIR, SEM and N2 adsorption-desorption isotherms. The increase in the HF quantity results in an slight increase in organic content and changes in the particle size, surface area and pore structure.  相似文献   
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Novel NOx storage-reduction (NOxSR) catalysts prepared by Pt and/or Cu impregnation of Mg–Al (60:40) hydrotalcite (HT)-type compounds show better performances in NOx storage than Pt–Ba/Al2O3 Toyota-type NOxSR catalysts at reaction temperatures lower than 250 °C. The presence of Pt or Cu considerably enhances the activity, with the former more active. The nature of the HT source, however, also influences performance. The co-presence of Pt and Cu slightly worsens the low temperature activity, but considerably promotes the resistance to deactivation after severe hydrothermal treatment and in the presence of SO2. This effect is attributed to both the possibility of formation of a Pt–Cu alloy after reduction, and the modification of the HT induced during the deposition of Cu. The overall Pt–Cu/HT performances are thus superior to those of the Pt–Ba/Al2O3 Toyota-type NOxSR catalysts.  相似文献   
4.
Mar-M 247, a nickel-base cast alloy, is used widely in aeroengines for parts such as blades, vanes and airfoil. Hastelloy X is one of the most oxidation- and corrosion-resistant nickel-base wrought alloys. In order to join such alloys in aeroengine manufacturing, laser beam welding has been carried out with lap and butt joints using a 1.2 and a 6.0 kW CO2 laser. Cracks in the fusion zone can be eliminated by deliberate misalignments in the ranging of the laser beam by 0.2−0.3 mm onto Hastelloy X. Correlations between cracking behavior, hardness of the beads and misalignments have been investigated. Metallurgical analysis using electron microscopes has revealed the redistribution of alloy elements, the microstructures of the fusion zone and microfissures in the heat-affected zone (HAZ).  相似文献   
5.
The Fritz John conditions for Pareto-optimality have been set in matrix form and used for introducing a procedure for the analytical derivation of the Pareto-optimal set in the design variables domain. Subsequently, the derivation of the Pareto-optimal set in the objective functions domain can be obtained, if possible, by a proper analytical derivation. Both the objective and constraint functions are assumed to be available in analytical form and twice differentiable and convex (or pseudo-convex). The proposed procedure to find the Pareto-optimal set is relatively simple. The computation of the determinant of a matrix is required. A symbolic manipulator can be exploited. If there are two design variables and two objective functions, the Pareto-optimal set can be easily computed by applying a simple formula derived in the paper. If the number of design variables equals the number of objective functions, the Pareto-optimal set in the design variables domain can be found by computing the product of the constraint functions times the determinant of the Jacobian of the objective functions. A number of case studies have been proposed to test the effectiveness of the proposed procedure. The optimal structural design of, respectively, a pair of compressed spheres, a cantilever with rectangular cross section have been faced and solved. Additionally the test problem proposed by Fonseca and Fleming has been addressed and solved analytically. Optimization problems with low dimensionality (2 or 3 design variables and 2 objective functions, 2 or more constraints) have been easily solved. The proposed procedure can be useful in the actual engineering practice at the earliest design stage. In this case the designer can be made aware on the proper design variables setting to obtain the desired tradeoff among conflicting objective functions.  相似文献   
6.
During the last few years, morphological, immunohistochemical, and genetic findings have placed anaplastic large cell lymphoma (ALCL) as a distinct clinicopathologic entity, and several reports have focused on the existence of different subtypes of the tumor. Particular attention has been paid to the ALCL-Hodgkin's-like (HL) subtype, which seems to be on the border between Hodgkin's disease (HD) and high-grade non-Hodgkin's lymphoma (HG-NHL). From September 1994 to July 1997, during the course of an Italian multicentric trial, 40 ALCL-HLs were randomized to receive as front-line chemotherapy MACOP-B (methotrexate with leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin-a third-generation HG-NHL regimen) or ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine-a scheme specific for HD). All patients with bulky disease in the mediastinum at diagnosis underwent local radiotherapy after the chemotherapeutic program. Complete response (CR) was achieved in 17 of the 19 (90%) patients who were treated with MACOP-B, and in 19 of the 21 (91%) patients who were administered ABVD. The probability of relapse-free survival, projected at 32 months, was 94% for the MACOP-B subset and 91% for the ABVD subset. The majority of patients with mediastinal bulky disease obtained CR (evaluated with 67Ga single photon emission computed tomography [SPECT]) after their radiotherapy. The present study suggests that ALCL-HL, in line with its borderline status, responds in an equivalent way to third-generation chemotherapy for HG-NHL and to conventional HD treatment in terms of both CR and relapse-free survival rates. However, as to the latter, a longer follow-up period may be needed before stating the absolute equivalence of the two regimens used.  相似文献   
7.
Gobbi GP 《Applied optics》1998,37(24):5505-5508
Relationships for the interpretation of polarization lidar observations of aerosols and thin clouds are presented. They allow for the separation of contributions to backscatter from solid and liquid phases by the use of either the classical backscatter and depolarization ratio parameters or the particulate cross-polarized backscatter cross sections. It is shown that different aerosol phases can be better separated by use of the latter coordinates. Emphasis is placed on the study of composition and phase properties of polar stratospheric aerosols.  相似文献   
8.
The MT2-selective melatonin receptor ligand UCM765 (N-(2-((3-methoxyphenyl)(phenyl)amino)ethyl)acetamide), showed interesting sleep inducing, analgesic and anxiolytic properties in rodents, but suffers from low water solubility and modest metabolic stability. To overcome these limitations, different strategies were investigated, including modification of metabolically liable sites, introduction of hydrophilic substituents and design of more basic derivatives. Thermodynamic solubility, microsomal stability and lipophilicity of new compounds were experimentally evaluated, together with their MT1 and MT2 binding affinities. Introduction of a m-hydroxymethyl substituent on the phenyl ring of UCM765 and replacement of the replacement of the N,N-diphenyl-amino scaffold with a N-methyl-N-phenyl-amino one led to highly soluble compounds with good microsomal stability and receptor binding affinity. Docking studies into the receptor crystal structure provided a rationale for their binding affinity. Pharmacokinetic characterization in rats highlighted higher plasma concentrations for the N-methyl-N-phenyl-amino derivative, consistent with its improved microsomal stability and makes this compound worthy of consideration for further pharmacological investigation.  相似文献   
9.
The average age of the population has grown steadily in recent decades along with the number of people suffering from chronic diseases and asking for treatments. Hospital care is expensive and often unsafe, especially for older individuals. This is particularly true during pandemics as the recent SARS-CoV-2. Hospitalization at home has become a valuable alternative to face efficiently a huge increase in treatment requests while guaranteeing a high quality of service and lower risk to fragile patients. This new model of care requires the redefinition of health services organization and the optimization of scarce resources (e.g., available nurses). In this paper, we study a Nurse Routing Problem that tries to find a good balance between hospital costs reduction and the well-being of patients, also considering realistic operational restrictions like maximum working times for the nurses and possible incompatibilities between services jointly provided to the same patient. We first propose a Mixed Integer Linear Programming formulation for the problem and use some valid inequalities to strengthen it. A simple branch-and-cut algorithm is proposed and validated to derive ground benchmarks. In addition, to efficiently solve the problem, we develop an Adaptive Large Neighborhood Search hybridized with a Kernel Search and validate its performance over a large set of different realistic working scenarios. Computational tests show how our matheuristic approach manages to find good solutions in a reasonable amount of time even in the most difficult settings. Finally, some interesting managerial insights are discussed through an economic analysis of the operating context.  相似文献   
10.
Different yeast nutrient additions were studied for the 2008 and 2009 vintages of Verdicchio grape juice fermentation. Addition of yeast derivatives at the beginning of fermentation and/or different amounts of diammonium phosphate at various times within the first half of fermentation were examined, with initial yeast assimilable nitrogen concentrations set at 200 and 250 mg l?1. Supplementation with glutathione in combination with this nitrogen addition was also evaluated. Fermentation rates were monitored throughout these fermentations carried out under different nutrient conditions. H2S production during fermentation and synthesis of volatile compounds in the finished wines were quantified; the wines also underwent sensory evaluation. The fermentation kinetics were almost exclusively influenced by the inorganic nitrogen supplementation with diammonium phosphate. H2S evolution was more affected by assimilable nitrogen than glutathione. Diammonium phosphate significantly reduced H2S production, with a further reduction in the presence of yeast derivative. This nitrogen supplementation yielded higher concentrations of acetate esters, and in particular of isoamyl acetate (fruity aromas), which positively influences the analytical and aroma profile of wines and results in a general reduction in 2-phenylethanol production (floral aromas). Overall results (two harvesting times and vintages) indicate that the management with diammonium phosphate and yeast derivative supplementation improves the kinetics of fermentation and provides a good tool to reduce H2S formation and increase the analytical and sensory quality of Verdicchio wine.  相似文献   
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