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61.
62.
J García-Arumí R Pascual MJ Fonseca FR Isart R Casaroli C Mateo B Corcostegui 《Canadian Metallurgical Quarterly》1997,211(6):344-350
Relationships from benefits-costs analyses in radiography are presented. The impact of several factors (equipment, frequency of examinations, ...) on the planning of a department and special financial aspects, e.g., leasing of equipment, are discussed. The cost relationships of conventional versus digital radiography are demonstrated for the example of a 1000-bed hospital. 相似文献
63.
Advantages of diaphragms using glass fiber-reinforced polymer (GFRP) panels in conjunction with plywood panels as sheathing (hybrid diaphragms) are presented in this paper. The strength and behavior of individual connections between GFRP sheathing panels and wood framing are determined through coupon testing. Coupon test results indicate that GFRP sheathing-to-framing connections have significant increases in strength, stiffness, and energy absorption. The strength and behavior of hybrid diaphragms are determined by testing a conventional diaphragm (wood sheathing only) and a hybrid diaphragm. The hybrid diaphragm sustained 34% more load compared to the conventional diaphragm. 相似文献
64.
A. Cuadras B. Garrido J. R. Morante L. Fonseca K. Pressel B. Tillack T. Grabolla 《Journal of Electronic Materials》2004,33(9):1022-1027
We describe and model the electrical response of interface states of metal-oxide semiconductor (MOS) capacitors fabricated
from Si1−x−yGexCy strained layers as a function of C concentration. We find that the introduction of Ge and C in the epilayers leads to anomalies
in the capacitance-voltage curves in the form of kinks or plateaus. This behavior is explained by the presence of pronounced
peaks on the density of interface states in the bandgap. Our results suggest an adequate Ge/C ratio of 40 minimizes the density
of interface states. This ratio is different from the ratio of ∼10 required for stress compensation. Finally, we discuss the
implications for the introduction of Si1−x−yGexCy strained layers to fabricate MOS devices. 相似文献
65.
Amilton de Sousa LinsJr. Luís Felipe Guimarães de Souza Maria Cindra Fonseca 《Journal of Materials Engineering and Performance》2018,27(1):124-137
The use of high-strength and low-alloy steels, high design factors and increasingly stringent safety requirements have increased the operating pressure levels and, consequently, the need for further studies to avoid and prevent premature pipe failure. To evaluate the possibility of improving productivity in manual arc welding of this type of steel, this work characterizes the mechanical properties and residual stresses in API 5L X80 steel welded joints using the SMAW and FCAW processes. The residual stresses were analyzed using x-ray diffraction with the sin2 ψ method at the top and root of the welded joints in the longitudinal and transverse directions of the weld bead. The mechanical properties of the welded joints by both processes were characterized in terms of tensile strength, impact toughness and Vickers microhardness in the welded and shot peening conditions. A predominantly compressive residual stress was found, and shot peening increased the tensile strength and impact toughness in both welded joints. 相似文献
66.
Pâmela Maria Moreira Fonseca Luciano dos Santos Feitosa Adriana Barrinha Fernandes Ranato Amaro Zângaro Walter Miyakawa Carlos José de Lima 《臭氧:科学与工程》2015,37(1):85-89
Ozone gas diluted in water has been shown to produce significant results in terms of the elimination of microorganisms. Streptococcus mutans is the etiologic agent of dental caries. Methods using water containing ozone and an ultrasonic cleaner were employed for the disinfection of a curette. Streptococcus mutans was grown in a selective medium. The curette was submitted to disinfection by water containing ozone, by ultrasound, and then both techniques were combined. The results show that either method produced a significant microbial reduction, but the efficacy of both methods combined was greater. This method of disinfection proved to be both viable and cheap. 相似文献
67.
Ioan Cristian Trelea Fernanda Fonseca Stéphanie Passot Denis Flick 《Drying Technology》2015,33(15-16):1849-1858
Monitoring partial vapor pressure in the freeze-drying chamber is a cheap, global, and non-intrusive way to assess the end of the primary drying stage. Most existing dynamic freeze-drying models which predict this partial pressure describe mass transfer between the product and the condenser via a mass transfer resistance or a mass transfer coefficient. Experimental evidence suggests that such models can be significantly in error for some values of the sublimation flux, leading to physically inconsistent predictions and possibly incorrect assessment of primary drying termination, with potential risk of product damage if moving to secondary drying and increasing shelf temperature while some ice is still present. Assuming a binary gas transport model for vapor and inert gas leads to improved and consistent predictions and explains the apparent variation of the mass transfer resistance with total pressure, shelf temperature, and product sublimation area. 相似文献
68.
In the present study, an empirical model to determinate the convective heat loss, at an indoor glazing surface, is proposed. This model allows calculating the convective heat transfer coefficient and the air flow rate entering to the window cavity formed between the glazing surface and the protection device. The window blind is first studied experimentally by using a rigid paper, which is installed at four different distances from the window frame. This configuration is used as reference to determinate a global model, which is mainly composed of two correlations: one for the Nusselt number and other one for the air mass flow rate incoming to the window cavity. Then, more realistic configurations are tested: single curtains, double curtains, PVC blinds, wood blinds, Venetian blinds or polyester blinds. In general, heat transfer coefficients for these configurations are equal or higher than that obtained with a free plate. Several correlations are proposed for each configuration. 相似文献
69.
Bruno Almeida Dr. Jesús Joglar María Jesús Luque Rojas Juan Manuel Decara Francisco Javier Bermúdez‐Silva Dr. Manuel Macias‐González Dr. Montserrat Fitó Miguel Romero‐Cuevas Dr. Magí Farré Dr. María Isabel Covas Dr. Fernando Rodríguez de Fonseca Dr. Rafael de la Torre 《ChemMedChem》2010,5(10):1781-1787
A series of fatty acid amides of 3,4‐methylenedioxymethamphetamine (MDMA) catechol metabolites were synthesized in order to evaluate their biological activities. Upon administration, all synthesized compounds resulted in negative modulation of food intake in rats. The most active compounds have affinity for the CB1 receptor and/or PPAR‐α; part of their biological activity may be caused by these double interactions. 相似文献
70.
Total lead and its stable isotopes were analysed in sediment cores, leaves, stem and roots of Sacorconia fruticosa and Spartina maritima sampled from Tagus (contaminated site) and Guadiana (low anthropogenic pressure) salt marshes. Lead concentration in vegetated sediments from the Tagus marsh largely exceeded the levels in non-vegetated sediments. Depth profiles of (206)Pb/(207)Pb and (206)Pb/(208)Pb showed a decrease towards the surface ((206)Pb/(207)Pb=1.160-1.167) as a result of a higher proportion of pollutant Pb components. In contrast, sediments from Guadiana marsh exhibited low Pb concentrations and an uniform isotopic signature ((206)Pb/(207)Pb=1.172+/-0.003) with depth. This suggests a homogeneous mixing of mine-derived particles and pre-industrial sediments with minor inputs of anthropogenic Pb. Lead concentrations in roots of plants from the two marshes were higher than in leaves and stems, indicating limited transfer of Pb to aerial parts. A similar Pb isotopic signature was found in roots and in vegetated sediments, indicating that Pb uptake by plants reflects the input in sediments as determined by a significant anthropogenic contribution of Pb at Tagus and by mineralogical Pb phases at Guadiana. The accumulation in roots from Tagus marsh (max. 2870 microg g(-1) in S. fruticosa and max. 1755 microg g(-1) in S. maritima) clearly points to the dominant role of belowground biomass in the cycling of anthropogenic Pb. The fraction of anthropogenic Pb in belowground biomass was estimated based on the signature of anthropogenic Pb components in sediments ((206)Pb/(207)Pb=1.154). Since no differences exist between Pb signature in roots and upper sediments, the background and anthropogenic levels of Pb in roots were estimated. Interestingly, both background and anthropogenic Pb in roots exhibited a maximum at the same depth, although the proportion of anthropogenic Pb was relatively constant with depth (83+/-4% for S. fruticosa and 74+/-8% for S. maritima). 相似文献