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1.
Corner detection is a low-level feature detection operator that is of great use in image processing applications, for example, optical flow and structure from motion by image correspondence. The detection of corners is a computationally intensive operation. Past implementations of corner detection techniques have been restricted to software. In this paper we propose an efficient very large-scale integration (VLSI) architecture for detection of corners in images. The corner detection technique is based on the half-edge concept and the first directional derivative of Gaussian. Apart from the location of the corner points, the algorithm also computes the corner orientation and the corner angle and outputs the edge map of the image. The symmetrical properties of the masks are utilized to reduce the number of convolutions effectively, from eight to two. Therefore, the number of multiplications required per pixel is reduced from 1800 to 392. Thus, the proposed architecture yields a speed-up factor of 4.6 over conventional convolution architectures. The architecture uses the principles of pipelining and parallelism and can be implemented in VLSI. 相似文献
2.
3.
The microsecond Nd glass pulsed laser interaction with polycrystalline nickel was studied with particular emphasis on melting and the nature of the microstructural development following irradiation. The change in the melt pool shape and the melting efficiency as a function of the total laser power has been determined. Evidence is presented to show that for low energy pulse, the microstructural development accompanies fresh nucleation of grains and leads to a finer grain size than that of the substrate. At a higher energy level, growth competition leads to a coarser grain size. We also report a banded feature roughly parallel to the melt substrate interface that develops in the resolidified region during high energy interaction. These results are discussed in the light of our present understanding of rapid solidification processes. 相似文献
4.
Two AlMnZn alloys in melt-spun condition have been studied by transmission electron microscopy. The Al24Mn5Zn alloy was found to be fully icosahedral, while the Al12Mn2.9Zn alloy gave rise to decagonal quasicrystal. The decagonal phase grew in clusters with an orientation relationship between the grains suggesting nucleation on an icosahedral seed. On annealing at 500–600°C, the quasicrystalline phase transformed to a body centered orthorhombic phase L (a = 1.24, b = 1.26 andc = 3.05nm) with a high density of planar defects. This phase transforms to an ordered and defect free monoclinic phase M, a superlattice structure of L (a = c = 1.77, b = 3.05nm and β = 89.1°). The L phase is shown to be a rational approximant of the icosahedral phase. The interrelationship among quasicrystalline phases and their rational approximants in AlMnZn system are highlighted. 相似文献
5.
P. Muthuswamy C. R. Ranganathan V. Murugappan P. Santhy G. Ramanathan 《Nutrient Cycling in Agroecosystems》1990,23(3):135-140
A mathematical model has been proposed for predicting the changes in soil nitrogen status due to continuous fertilization in a continuous cropping sequence. The model also enabled the prediction of the steady state of soil nitrogen for a specified fertilizer practice.The model was applied to six years nitrogen availability data of four fertilizer practices in finger millet-maize-cowpea sequence followed in the Long Term Fertilizer Experiments conducted at Tamil Nadu Agricultural University, Coimbatore, India. The agreement between the predicted soil nitrogen status by the model and the actuals was proved by employing reliability index. 相似文献
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Low temperature steam reforming of ethanol in the temperature range of 200–360°C was studied to maximize the production of H2. The optimum reaction conditions in presence of a suitable catalyst can produce mainly the desired products H2 and CO2. Cu/Al2O3 catalysts with six different concentrations ranging from 0 to 10 wt.% Mn, were prepared, characterized and studied for the ethanol-steam reforming reaction. Maximum ethanol conversion of 60.7% and hydrogen yield of 3.74 (mol H2 / mol ethanol converted) were observed at 360°C for catalyst with 2.5 wt.% Mn loading. 相似文献
8.
Abstract: Integration of ontologies of information sources and consumers is an important phase in achieving web‐based interoperability. The present work describes an approach for identifying certain semantic conflicts while integrating ontologies of heterogeneous information sources. This paper is focused on the identification of homonymy and synonymy between elements in ontologies. In the present work the concepts of homonymy and synonymy are synonymous to naming conflicts and entity identifier conflicts, respectively, and partial synonymy is synonymous to schema isomorphism conflicts. The concept of the mask of interoperability is introduced for the identification of synonymy. The mask of interoperability is expressed in a declarative way as a set of rules, which can then be used for resolution of conflicts during integration of ontologies. As proof of concept, ontologies are implemented using the XML‐based ontology language Ontology Web Language (OWL), and the rules are implemented using the emerging rule language Semantic Web Rule Language (SWRL). This representation in OWL and SWRL allows the ontology to be executable, flexibly extendable and platform‐independent. The OWL facts and SWRL rules are used by the Jess and Bossam reasoning engine to identify semantic homonymy and synonymy. 相似文献
9.
Effect of geometry on droplet formation in the squeezing regime in a microfluidic T-junction 总被引:1,自引:0,他引:1
In the surface tension-dominated microchannel T-junction, droplets can be formed as a result of the mixing of two dissimilar,
immiscible fluids. This article presents results for very low Capillary numbers and different flow rates of the continuous
and dispersed phases. Through three-dimensional lattice Boltzmann-based simulations, the mechanism of the formation of “plugs”
in the squeezing regime has been examined and the size of the droplets quantified. Results for
Re\textc << 1 Re_{\text{c}} \ll 1 show the dependence of flow rates of the two fluids on the length of the droplets formed, which is compared with existing
experimental data. It is shown that the size of plugs formed decreases as the Capillary number increases in the squeezing
regime. This article clearly shows that the geometry effect, i.e., the widths of the two channels and the depth of the assembly,
plays an important role in the determination of the length of the plugs, a fact that was ignored in earlier experimental correlations. 相似文献
10.
Joseph Conroy Gregory Gremillion Badri Ranganathan J. Sean Humbert 《Autonomous Robots》2009,27(3):189-198
Insects are capable of robust visual navigation in complex environments using efficient information extraction and processing
approaches. This paper presents an implementation of insect inspired visual navigation that uses spatial decompositions of
the instantaneous optic flow to extract local proximity information. The approach is demonstrated in a corridor environment
on an autonomous quadrotor micro-air-vehicle (MAV) where all the sensing and processing, including altitude, attitude, and
outer loop control is performed on-board. The resulting methodology has the advantages of computation speed and simplicity,
hence are consistent with the stringent size, weight, and power requirements of MAVs. 相似文献