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541.
In vitro cultivated Atlantic salmon (Salmo salar L.), hepatocytes were incubated without or with a mixture of sesamin and episesamin in order to test for possible effects
on lipid metabolism. Sesamin/episesamin exposure (0.05 mM, final concentration) led to increased elongation and desaturation
of 14C 18:3n-3 to docosahexaenoic acid (14C 22:6n-3, DHA, P < 0.01) and down regulated gene expression of Δ6 and Δ5 desaturases compared to control treatment. Sesamin/episesamin further
increased the hepatocytes capacity for fatty acid β-oxidation of 14C 18:3n-3 (P < 0.01) to the 14C acid soluble products, acetate, malate and oxaloacetate, in agreement with an increased gene expression of carnitine palmitoyltransferase
I. Also the gene expression of cluster of differentiation 36 was upregulated and the expression of scavenger receptor type
B, peroxisome proliferator-activated receptors α and γ were downregulated. The amount of triacylglycerols secreted by the
cells tended to be lower in the sesamin/episesamin incubated hepatocytes than the control cells. This study shows that sesamin
has favourable effects on lipid metabolism leading to increased level of DHA, which may be of interest for aquaculture use. 相似文献
542.
Maria Sofia Sousa Ribeiro Arlindo Freitas Gonçalves Fernando António Baptista Branco 《Materials and Structures》2008,41(7):1263-1273
This paper reports the results of an experimental investigation into the action of styrene-butadiene (SB) polymer on the mechanical
properties of polymer cement mortars (PCM), comparing the results with the requirements specified in EN 1504-3 [Products and
systems for the protection and repair of concrete structures—definitions, requirements, quality control and evaluation of
conformity—part 3: structural and non-structural repair, CEN, 2005]. Setting times, shrinkage, elasticity modulus and the
microstructure building in PCM are also characterised. Tests performed on PCM confirmed the beneficial action of polymers
on tensile strength and, in particular, on flexural strength of cement mortars, whereas in compressive strength, a reduction,
at earlier ages, was observed. It is considered that this mechanical behaviour results from the polymer action on the atrophy
of hydrated Ca(OH)2 crystals and on the reduction in the density of microcracks in the paste–aggregate interface, which leads to the noticeable
improvement in flexural and tensile strengths. On the other hand, the smaller contribution of the beneficial action of the
polymer on the compressive strength, together with the delay in cement hydration and with the increase in the closed porosity
of PCM, are the main causes for the reduction in the compressive strength during the first months.
相似文献
Fernando António Baptista BrancoEmail: |
543.
This work presents a new mathematical programming model for the mixed-model assembly line balancing problem with parallel workstations and zoning constraints. It allows the user to control the process to create parallel workstations. The model's primary goal is to minimize the number of workstations along the line, for a given cycle time, and its secondary goal is to balance the workloads between and within workstations. A two-stage procedure, using a simulated annealing approach, was developed to tackle this complex problem. The first stage of the procedure looks for a sub-optimal solution to the problem's primary goal, whilst the second stage deals with the secondary goal. The procedure is illustrated with a numerical example and the results from computational experiments show that even for large-scale problems the proposed procedure performs very well. 相似文献
544.
One important issue for the Sodium Fast Reactor (SFR) concept is the reactivity of metallic sodium and its exothermal reaction with water. In particular during equipments washing operations, sodium needs to be firstly converted (‘destroyed’) into non reactive species via a chemical reaction with water. Today, such operations are performed in tanks that confine the system and mitigate the consequences of any possible abnormal condition. 相似文献
545.
Sofia Papargyri-Beskou Stefanos V. Tsinopoulos Dimitri E. Beskos 《Acta Mechanica》2011,222(3-4):351-362
The dynamic response of a fluid-saturated porous gradient elastic column to a transient disturbance is determined analytically and numerically. The basic dynamic theory of a fluid-saturated poroelastic medium due to Biot is modified by replacing the classical linear elastic model of the solid skeleton by the simple gradient elastic model of Mindlin with just one elastic constant (internal length scale) in addition to the classical ones. Thus, the new theory, which is presently restricted to the one-dimensional case, can take into account the microstructural effects of the solid skeleton. After the establishment of appropriate boundary and initial conditions, the one-dimensional dynamic column problem is solved analytically with the aid of the Laplace transform with respect to time. The time domain response is finally obtained by a numerical inversion of the transformed solution. The effect of the solid microstructure on the response is assessed and discussed. 相似文献
546.
Miguel A. Teixeira Oscar Rodríguez Sofia Rodrigues Isabel Martins Alírio E. Rodrigues 《American Institute of Chemical Engineers》2012,58(6):1939-1950
The evaluation of the performance of new products to be released on the market is essential to measure its acceptability by consumers. In this work, the performance of an added‐value product, microencapsulated perfumes applied on textiles for man suits, was predicted and evaluated. The odor intensity and character of the perfume ingredients was measured by headspace gas chromatography after dry cleaning and abrasion tests on textiles impregnated with microcapsules. The evaporation and diffusion of the fragrances in the encapsulated perfume was assessed. For this type of application, limonene has shown a better performance in the perfume mixture, being the dominant note over time and distance. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1939–1950, 2012 相似文献
547.
548.
549.
Vasco Leite Sofia B. S. D. Castro João Correia-da-Silva 《The Annals of Regional Science》2013,50(1):71-108
We extend an analytically solvable core-periphery model by introducing a monopolistically competitive sector of non-tradable goods that is mobile across regions. We find that when the elasticity of substitution among non-tradable goods is very low, there is agglomeration of all the production (of both tradable and non-tradable goods). When the elasticity of substitution among non-tradable goods is sufficiently high (“no black-hole” condition), then there is symmetric dispersion of all the production, if trade costs are high; or full agglomeration of the production of tradable goods with partial agglomeration of the production of non-tradable goods, if trade costs are low. 相似文献
550.
Jochen Bundschuh Marta Litter Virginia S.T. Ciminelli Sofia Garrido Hoyos 《Water research》2010,44(19):5828-5845
In this work, current information about the contamination of ground- and surface-water resources by arsenic from geogenic sources in Latin America is presented together with possible emerging mitigation solutions. The problem is of the same order of magnitude as other world regions, such as SE Asia, but it is often not described in English. Despite the studies undertaken by numerous local researchers, and the identification of proven treatment methods for the specific water conditions encountered, no technologies have been commercialized due to a current lack of funding and technical assistance.Emerging, low-cost technologies to mitigate the problem of arsenic in drinking water resources that are suitable for rural and urban areas lacking centralized water supplies have been evaluated. The technologies generally use simple and low-cost equipment that can easily be handled and maintained by the local population. Experiences comprise (i) coagulation/filtration with iron and aluminum salts, scaled-down for small community- and household-scale-applications, (ii) adsorption techniques using low-cost arsenic sorbents, such as geological materials (clays, laterites, soils, limestones), natural organic-based sorbents (natural biomass), and synthetic materials. TiO2-heterogeneous photocatalysis and zerovalent iron, especially using nanoscale particles, appear to be promising emergent technologies. Another promising innovative method for rural communities is the use of constructed wetlands using native perennial plants for arsenic rhizofiltration. Small-scale simple reverse osmosis equipment (which can be powered by wind or solar energy) that is suitable for small communities can also be utilized.The individual benefits of the different methods have been evaluated in terms of (i) size of the treatment device, (ii) arsenic concentration and distribution of species, chemical composition and grade of mineralization in the raw water, (iii) guidelines for the remaining As concentration, (iv) economical constrains, (v) complexity of installation and maintenance, and infrastructure constraints (e.g. electricity needs). 相似文献