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301.
    
A mobile ad hoc network (MANET) is a collection of mobile nodes communicating through wireless connections without any prior network infrastructure. In such a network the broadcasting methods are widely used for sending safety messages and routing information. To transmit a broadcast message effectively in a wide and high mobility MANET (for instance in vehicular ad hoc network) is a hard task to achieve. An efficient communication algorithm must take into account several aspects like the neighborhood density, the size and shape of the network, the use of the channel. Probabilistic strategies are often used because they do not involve additional latency. Some solutions have been proposed to make their parameters vary dynamically. For instance, the retransmission probability increases when the number of neighbors decreases. But, the authors do not optimize parameters for various environments. This article aims at determining the best communication strategies for each node according to its neighborhood density. It describes a tool combining a network simulator (ns-2) and an evolutionary algorithm (EA). Five types of context are considered. For each of them, we tackle the best behavior for each node to determine the right input parameters. The proposed EA is first compared to three EAs found in the literature: two well-known EAs (NSGA-II and SPEA2) and a more recent one (DECMOSA-SQP). Then, it is applied to the MANET broadcasting problem.  相似文献   
302.
    
BACKGROUND: Aphids cause both quantitative and qualitative yield losses in cereals. Aphid feeding resulted in a significant decrease in gliadin/glutenin ratio in soft‐kernel wheat. Effect of aphid feeding on hard‐kernel wheat was examined. RESULTS: Plants of two different hard‐wheat cultivars were artificially infected by two aphid species: Sitobion avenae and Diuraphis noxia. Three different levels of caging regulated aphid density. Aphid density was highest in the cages, followed by open cages and lowest under no‐cage conditions. Numbers of D. noxia were generally higher compared to those of S. avenae. There was no significant difference in head length, mean kernel number/head, mean kernel mass/head or mean individual kernel mass between the two cultivars. Glutenin, gliadin and total protein content was analysed using size‐exclusion HPLC. Quality parameters of wheat flour were significantly different between the two cultivars. Gliadin content, total protein content and gliadin/glutenin ratio were significantly higher in Mv Magdaléna compared to Mv Magvas regardless of the level of caging and infestation, while glutenin content of uninfected Mv Magvas was significantly higher than that of Mv Magdaléna in the open cages. Aphid feeding did not induce any significant reduction in the gliadin, total protein content and gliadin/glutenin ratio of the examined hard wheat cultivars. CONCLUSION: Individual kernel mass reduction is the major factor in yield loss caused by aphids. Aphid feeding did not change the protein structure of hard‐kernel wheat. Copyright © 2007 Society of Chemical Industry  相似文献   
303.
It is proposed to present compaction relationships by plotting the inverse of the dry density versus the molding water content. In the proposed graph, the curves for equal degree of saturation become straight lines. The proposed new graph is shown to be very convenient to assess the saturated hydraulic conductivity, k sat, of non-swelling compacted clay, using a dual porosity model. The value of k sat depends on the secondary porosity between clay clods. The equation developed for equal k sat value appears also as a straight line in the proposed graph. It facilitates the prediction of k sat from field compaction data and thus the prediction of field performance of clay liners and covers.  相似文献   
304.
OBJECTIVES: This study determined the effect of alginate adhesive on various bond strengths of alginate to stainless steel. METHODS: Three test assemblies were designed and machined in stainless steel for tension, shear and cleavage tests. Alginate adhesive (Fix) was applied thinly and dried for 5 min. Alginate (Blueprint) was then loaded and allowed to set for 5 min before testing. The force at failure was measured by an Instron machine with a cross-head speed of 50 mm min(-1). RESULTS: Breaking stresses of alginate without adhesive were found to be 65 kPa (tension), 31 kPa (shear) and 10 kPa (cleavage). The bond strengths of Blueprint with Fix were 100 kPa (tension), 42 kPa (shear) and 37 kPa (cleavage) giving improvements of 53%, 37% and 270% respectively (p < 0.05). CONCLUSIONS: Alginate adhesive increases the bond strength of alginate, particularly cleavage, to stainless steel.  相似文献   
305.
The Thin-Plate Spline warp has been shown to be a very effective parameterized model of the optic flow field between images of various types of deformable surfaces, such as a paper sheet being bent. Recent work has also used such warps for images of a smooth and rigid surface. Standard Thin-Plate Spline warps are however not rigid, in the sense that they do not comply with the epipolar geometry. They are also intrinsically affine, in the sense of the affine camera model, since they are not able to simply model the effect of perspective projection.  相似文献   
306.
Gypsum microstructural evolution at elevated temperatures has been characterized in situ by environmental scanning electron microscopy and high‐temperature X‐ray tomography. As temperature increases, the observed changes in gypsum crystal morphology are related to the consequences of water loss that leads to crystal reorganization in order to minimize the specific surface. The influence of environmental scanning electron microscopy experimental conditions on the mechanisms observed is also discussed. High‐temperature X‐ray tomography gives quantitative information on porosity evolution with thermal loading. The results obtained are successfully correlated with macroscopic shrinkage measurements performed during dilatometry tests. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
307.
The localization of the deformation in strain-rate-dependent solids evolves through three distinct phases. Its onset is signalled by the first deviation from a homogeneous mode of deformation, which we propose to pinpoint by means of a linear perturbation analysis. The second stage, marked by a sharp increase of the effective strain rate in ‘shear bands’ of decreasing thickness, is analysed with a special finite element scheme that uses embedded shear-band modes of deformation. The third phase is entered with the long-term evolution of the localization and the question that arises here is whether or not stationary shear bands of finite thickness are to be expected as theoretically admissible solutions.  相似文献   
308.
Immunotherapy with cytokines may be an additional option in the treatment of primary uveal melanoma or melanoma metastases. A study of the effect of cytokines on cultured uveal melanoma cells may predict the effect that cytokines may have in vivo. Knowledge about the influence of cytokines on HLA expression may be especially beneficial, as HLA expression is essential for immune recognition. However, little is known about the normal expression of the HLA antigens on uveal melanoma cells in tissue culture. We therefore determined the HLA expression on short-term cultures of uveal melanoma cells and compared the results to the expression on tissue sections of the original tumors. In vivo and in vitro expression of the monomorphic HLA class I determinants and of HLA-A (R = 0.77) correlated well. A slightly lower agreement was observed for expression of HLA-B (R = 0.68). In vitro growth was associated with a decrease in expression of the class II determinant HLA-DR. We conclude that expression of HLA class I on cultured melanoma cells corresponds to the expression on the original tumor, allowing the applicability of cultured cells as predictors of responsiveness to cytokines in vivo.  相似文献   
309.
310.
    
This article presents a new Domain Specific Embedded Language (DSEL) dedicated to Software-Defined Radio (SDR). From a set of carefully designed components, it enables to build efficient software digital communication systems, able to take advantage of the parallelism of modern processor architectures, in a straightforward and safe manner for the programmer. In particular, proposed DSEL enables the combination of pipelining and sequence duplication techniques to extract both temporal and spatial parallelism from digital communication systems. We leverage the DSEL capabilities on a real use case: a fully digital transceiver for the widely used DVB-S2 standard designed entirely in software. Through evaluation, we show how proposed software DVB-S2 transceiver is able to get the most from modern, high-end multicore CPU targets.  相似文献   
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