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81.
李晓晓 《数码设计:surface》2010,(2):252-254
本文通过粉川警部的三个梦境来阐释动画影片中的部分蒙太奇手法。在该影片中,蒙太奇并不是导演在作品中的"例行公事",而是鲜明风格的体现。不同的运用方式营造着不同的"蒙太奇作用",在该片中主要体现在剪辑和蒙太奇效果上。 相似文献
82.
In this paper, we propose a maximum contrast analysis (MCA) method for nonnegative blind source separation, where both the mixing matrix and the source signals are nonnegative. We first show that the contrast degree of the source signals is greater than that of the mixed signals. Motivated by this observation, we propose an MCA-based cost function. It is further shown that the separation matrix can be obtained by maximizing the proposed cost function. Then we derive an iterative determinant maximization algorithm for estimating the separation matrix. In the case of two sources, a closed-form solution exists and is derived. Unlike most existing blind source separation methods, the proposed MCA method needs neither the independence assumption, nor the sparseness requirement of the sources. The effectiveness of the new method is illustrated by experiments using X-ray images, remote sensing images, infrared spectral images, and real-world fluorescence microscopy images. 相似文献
83.
Michalis Savelonas Dimitris Maroulis Manolis Sangriotis 《Computer methods and programs in biomedicine》2009,96(1):25-32
In this paper, a novel computer-based approach is proposed for malignancy risk assessment of thyroid nodules in ultrasound images. The proposed approach is based on boundary features and is motivated by the correlation which has been addressed in medical literature between nodule boundary irregularity and malignancy risk. In addition, local echogenicity variance is utilized so as to incorporate information associated with local echogenicity distribution within nodule boundary neighborhood. Such information is valuable for the discrimination of high-risk nodules with blurred boundaries from medium-risk nodules with regular boundaries. Analysis of variance is performed, indicating that each boundary feature under study provides statistically significant information for the discrimination of thyroid nodules in ultrasound images, in terms of malignancy risk. k-nearest neighbor and support vector machine classifiers are employed for the classification tasks, utilizing feature vectors derived from all combinations of features under study. The classification results are evaluated with the use of the receiver operating characteristic. It is derived that the proposed approach is capable of discriminating between medium-risk and high-risk nodules, obtaining an area under curve, which reaches 0.95. 相似文献
84.
In this paper we give an overview over a series of experiments to visualize and measure flow fields in the human vascular
system with respect to their diagnostic capabilities. The experiments utilize a selection of GPU-based sparse and dense flow
visualization algorithms to show the diagnostic opportunities for volumetric cardiovascular phase contrast magnetic resonance
imaging data sets. Besides classical hardware accelerated particle and line-based approaches, an extensible tublet-based visualization,
a four-dimensional volumetric line integral convolution and a new two-dimensional cutting plane tool for three-dimensional
velocity data sets have been implemented. To evaluate the results, several hearts of human subjects have been investigated
and a flow phantom was built to artificially simulate distinctive flow features. Our results demonstrate that we are able
to provide an interactive tool for cardiovascular diagnostics with complementary hardware accelerated visualizations.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
相似文献
Dieter SchmalstiegEmail: |
85.
Assessment of drivers' visual perception of information displayed in LED traffic signs at road construction sites
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This study investigated drivers' visual perception of information displayed in LED traffic signs under different levels of environmental luminance. Concerning the information displayed, the environmental luminance comprised four luminance contrasts, two arrow types, and three environmental luminances, which were used to identify the visibility of traffic signs at the reading distance. Regarding visible distance, visibility involved reading starting and end points, extent of glare, comfortable distance, and glare distance. According to the study results obtained by using a highly reliable glare assessment method and studying the LED traffic signs, the lower the luminance contrast of traffic signs was the higher glare the participants perceived. A luminance contrast of 6200:2066 cd/m2 provided the farthest comfortable and glare distances, enabling drivers to notice the signs comparatively earlier and have sufficient time to react accordingly. Overall, arrow type “<<<” outperformed “←” because the former was easier for drivers to read and created less glare. Regarding environmental luminance, traffic signs displayed in high and medium luminance environments (i.e., extremely sunny and cloudy days, respectively) each featured their own advantage, whereas those displayed in low luminance environments (nights) have to be further improved. 相似文献
86.
数据缓存可以显著提高读取性能,但也需要及时同步以保证数据实时性。数据源变化触发的即时同步是一种通用的解决方案。但是大压力下,数据快速变化导致的频繁同步必然对服务器性能和通信效率产生负面影响。本文介绍的数据缓存按需同步方案根据业务需求定制同步策略,可以在满足实时性指标的基础上改善服务器性能和通信效率。该方案已经成功应用于笔者团队研发的UniBase分布式内存数据库,并在实际项目中证明了其可行性。 相似文献
87.
Rui Rocha Aurélio Campilho Jorge Silva Elsa AzevedoRosa Santos 《Computer methods and programs in biomedicine》2011,101(1):94-106
A new algorithm is proposed for the semi-automatic segmentation of the near-end and the far-end adventitia boundary of the common carotid artery in ultrasound images. It uses the random sample consensus method to estimate the most significant cubic splines fitting the edge map of a longitudinal section. The consensus of the geometric model (a spline) is evaluated through a new gain function, which integrates the responses to different discriminating features of the carotid boundary: the proximity of the geometric model to any edge or to valley shaped edges; the consistency between the orientation of the normal to the geometric model and the intensity gradient; and the distance to a rough estimate of the lumen boundary.A set of 50 longitudinal B-mode images of the common carotid and their manual segmentations performed by two medical experts were used to assess the performance of the method. The image set was taken from 25 different subjects, most of them having plaques of different classes (class II to class IV), sizes and shapes.The quantitative evaluation showed promising results, having detection errors similar to the ones observed in manual segmentations for 95% of the far-end boundaries and 73% of the near-end boundaries. 相似文献
88.
89.
Ali S. Saad 《Pattern Recognition and Image Analysis》2008,18(1):63-70
Speckle can be described as random multiplicative noise. It hampers the perception and extraction of fine details in the image.
Speckle reduction techniques are applied to ultrasound images in order to reduce the noise level and improve the visual quality
for better diagnoses. It is also used as preliminary treatment before segmentation and classification. Several methods have
been proposed for speckle reduction in ultrasound images. Multiscale contrast enhancement has proven to be very efficient
for x-ray images. A recent study by Dippel et al. doing a comparison, contrast enhancement of radiographs (x-ray and mammography),
between the Laplacian pyramid and the wavelet one proves that the Laplacian pyramid method gives a better result than the
wavelet one; the filtering aspect was not taken into account. In ultrasound images a strong contrast variation exists which
is different from x-ray and mammography. In this paper a wavelet pyramid with simultaneous speckle reduction and contrast
enhancement was applied for the first time on ultrasound images with the area of interest and compared to a Laplacian enhancement
pyramid. The optimum choice of wavelet bases for ultrasound images is investigated in this study. In order to realize a fair
comparison, the same nonlinear modification in both multiscale schemes is used. The comparison proves that the wavelet pyramid
gives a much better result than the Laplacian one for simultaneous speckle reduction and contrast enhancement of ultrasound
images.
The text was submitted by the author in English.
Ali Samir Saad, 1964. 1996 PhD in image processing, Polytechnics School of the Engineering University of Nantes, France. 1993 Masters in
Electronics. 1990 Masters in Digital Image Processing, Institute of Computer Sciences and Communication University of Rennes,
France. 1989 BS in Electrical Engineering, University of Saint-Etienne. Academy of Lyon, France. 1996–2000 Research associate
at the National Center for Macromolecular Imaging. Baylor, Houston, Texas. Assistant professor at King Saud University, Dept.
of Biomedical Technology. Area of research in medical image processing and analysis, 23 publications, member of the American
Association for the Advancement of Sciences. Marquis Who’s Who in the World; Cambridge Blue Book 2006. 相似文献
90.