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21.
22.
Recent work on CCTO is directed towards decreasing its dissipation factor and further raising its dielectric constant by using different dopants. Also attempts have been made to lower its sintering temperature by adding different sintering aids so as to save energy and use low-cost electrodes (Ag–Pd or base metal) for making multilayer capacitors. Normally, CCTO needs a processing temperature of 1100 °C and above for densification. We report the formation of dense CCTO ceramics at a temperature as low as 1000 °C by adding P2O5 as a sintering aid. The samples showed dielectric constant value as high as 40,000, though the dissipation factor values remained high like those reported for pure CCTO. 相似文献
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Jordan M. Anderson Jigna Patel Ajay S. Karakoti Nathan Greeneltch Diego J. Díaz Sudipta Seal 《Electrochimica acta》2011,56(5):2541
Nanocrystalline Pt/CeO2 composite electrodes were fabricated to study the electrochemical oxidation of methanol and ethanol. The performance of the electrodes was tested as the ceria solutions aged over time. It was observed that the performance oscillated with time, suggesting that the catalytic behavior towards alcohol oxidation was greatly dependent on the aging of the particles. These results point to a great dependence of the catalytic effect on the redox state of the ceria particles. 相似文献
25.
A. Seal A. K. Dalui M. Banerjee A. K. Mukhopadhyay K. K. Phani 《Bulletin of Materials Science》2001,24(2):151-155
The biaxial flexural strength, Young’s modulus, Vicker’s microhardness and fracture toughness data for very thin, commercial,
soda-lime-silica cover slip glass (diameter, D-18 mm, thickness, T-0.3 mm; T/D ≈ 0.02) are reported here. The ball on ring
biaxial flexure tests were conducted at room temperature as a function of the support ring diameter (≈ 10–20 mm) and cross
head speed (0.1–10 mm min−1). In addition, the Weibull modulus data were also determined. The Young’s modulus data was measured using a linear variable
differential transformer (LVDT) from biaxial flexure tests and was checked out to be comparable to the data obtained independently
from the ultrasonic time of flight measurement using a 15 MHz transducer. The microhardness data was obtained for the applied
load range of 0.1–20 N. The fracture toughnessK
IC data was obtained by the indentation technique at an applied load of 20 N. 相似文献
26.
The solution precursor plasma spray processing of nanomaterials 总被引:1,自引:0,他引:1
E. Brinley K. S. Babu S. Seal 《JOM Journal of the Minerals, Metals and Materials Society》2007,59(7):54-59
Solution precursor plasma spray (SPPS) synthesis is a simple, single-step, and rapid technique for synthesizing nano-ceramic
materials from solution precursors. This innovative method uses molecularly mixed precursors as liquids, avoiding a separate
processing method for the preparation of powders and enabling the synthesis of a wide range of metal oxide powders and coatings.
Also, this technique is considered to be promising for the formation of non-equilibrium phases in multi-component oxide systems.
This short review provides an insight into the important aspects of SPPS, the properties obtained in comparison to conventional
plasma spray, and the potential applications of the SPPS process. 相似文献
27.
Detailed magnetic properties of Pr1? x Nd x MnO3 (x = 0.3, 0.5 and 0.7) have been reported. All the samples crystallize in orthorhombic perovskite structure with Pnma space group. Magnetization measurements under field cooled (FC) protocal reveal magnetization reversal at low temperatures and low magnetic field. This indicates clear evidence of two magnetic sublattices aligned opposite to each other. There is a well-defined maximum around 48 K in the x = 0.7 sample (i.e. Pr0.3Nd0.7MnO3) in the χ′ value which is identified as paramagnetic to ferrimagnetic transition. The peak value shifts to higher temperature with decrease of x and width of the maximum broadened. It is also observable that with decrease of Nd, both the value of χ′ and χ″ decrease. An attempt is made to explain the magnetization reversal within the framework of available models. 相似文献
28.
Mixed phase (rutile/anatase) TiO2 nanorods have been synthesized using an anionic surfactant template. Nanorod synthesis has been achieved using mild reaction conditions and without using any rod-shaped template. The shape and crystallinity of the TiO2 nanomaterials can be modulated by careful control of the surfactant concentration. The novelty of the present work is that the anatase/rutile mixed phase nanorods were formed without using the well-known layer by layer assembly method or the hydrothermal method. These mixed phase TiO2 nanorods are highly luminescent, can be easily sensitized by fluorescent dyes, show significant dye adsorption ability and function as efficient photocatalysts. 相似文献
29.
Kuntal?Jana Sudipta?DeEmail author 《Clean Technologies and Environmental Policy》2015,17(6):1547-1561
Performance metrics of a system with single input and single output is straight forward and is generally termed as ‘efficiency’. However, for systems with multiple outputs, defined performance metrics has to include effects of all outputs on a rational basis. For systems with both multiple inputs and outputs such definition is even more complicated. Polygeneration is the integration of multiple utility outputs with one or more inputs for better performance. The better performance may again be assessed from different aspects, e.g., thermodynamic, economic, social, etc. Performance metrics of polygeneration is not unique. It depends on type of systems as well as objective of evaluation of it. In this paper, several possible performance parameters for polygeneration are discussed. Evaluation of performance is also tested with multi-dimensional viewpoints. Simulation results of two polygeneration schemes are used to show case studies for these defined performance parameters. Relative performance of polygeneration schemes with different fuel inputs is presented to show the performance variation of these schemes with multi-dimensional viewpoints. 相似文献
30.
This study investigates the ability of boron nitride nanotubes (BNNTs) to induce apatite formation in a simulated body fluid environment for a period of 7, 14 and 28 days. BNNTs, when soaked in the simulated body fluid, are found to induce hydroxyapatite (HA) precipitation on their surface. The precipitation process has an initial incubation period of ~ 4.6 days. The amount of HA precipitate increases gradually with the soaking time. High resolution TEM results indicated a hexagonal crystal structure of HA needles. No specific crystallographic orientation relationship is observed between BNNT and HA, which is due to the presence of a thin amorphous HA layer on the BNNT surface that disturbs a definite orientation relationship. 相似文献