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Micro solder ball/bump has been widely used in electronic packaging. It has been challenging to inspect these structures as the solder balls/bumps are often embedded between the component and substrates, especially in flip-chip packaging. In this paper, a detection method for micro solder ball/bump based on the active thermography and the probabilistic neural network is investigated. A VH680 infrared imager is used to capture the thermal image of the test vehicle, SFA10 packages. The temperature curves are processed using moving average technique to remove the peak noise. And the principal component analysis (PCA) is adopted to reconstruct the thermal images. The missed solder balls can be recognized explicitly in the second principal component image. Probabilistic neural network (PNN) is then established to identify the defective bump intelligently. The hot spots corresponding to the solder balls are segmented from the PCA reconstructed image, and statistic parameters are calculated. To characterize the thermal properties of solder bump quantitatively, three representative features are selected and used as the input vector in PNN clustering. The results show that the actual outputs and the expected outputs are consistent in identification of the missed solder balls, and all the bumps were recognized accurately, which demonstrates the viability of the PNN in effective defect inspection in high-density microelectronic packaging. 相似文献
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提出了微分Haar_Gaussian小波变换算法并将其应用于边缘检测,在空域和频域中进行变换,并应用带宽匹配方法和远心测量光学系统,提高了运算速度,通过对实际大景深物体离焦像的边缘测量,得到了准确的结果。 相似文献
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一种新型二维X射线探测器 总被引:1,自引:0,他引:1
本文建立一种新型X射线探测器,它是一种矩阵寻址方式的二维探测器,由两块玻璃基板组成,分别称作阴极板和阳极板,阴极板内侧镀有行电极和X射线阴级(例如CsI),阳极板上有寻址电极,障壁,两块基板对位封接,使行电要与寻址电极互相垂直,封接后先抽高真空,然后充入氩气与CO2混合气体,本探测器具有薄,轻,图象无畸变并可以利用PDP显示器件的工艺制作大尺寸器件及大量制造等优点。 相似文献
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Non-destructive testing (NDT) refers to inspection methods employed to assess a material specimen without impairing its future usefulness. An important type of these methods is infrared (IR) for NDT (IRNDT), which employs the heat emitted by bodies/objects to rapidly and noninvasively inspect wide surfaces and to find specific defects such as delaminations, cracks, voids, and discontinuities in materials. Current advancements in sensor technology for IRNDT generate great amounts of image sequences. These data require further processing to determine the integrity of objects. Processing techniques for IRNDT data implicitly looks for defect visibility enhancement. Commonly, IRNDT community employs signal to noise ratio (SNR) to measure defect visibility. Nonetheless, current applications of SNR are local, thereby overseeing spatial information, and depend on a-priori knowledge of defect’s location. In this paper, we present a general framework to assess defect detectability based on SNR maps derived from processed IR images. The joint use of image segmentation procedures along with algorithms for filling regions of interest (ROI) estimates a reference background to compute SNR maps. Our main contributions are: (i) a method to compute SNR maps that takes into account spatial variation and are independent of a-priori knowledge of defect location in the sample, (ii) spatial background analysis in processed images, and (iii) semi-automatic calculation of segmentation algorithm parameters. We test our approach in carbon fiber and honeycomb samples with complex geometries and defects with different sizes and depths. 相似文献
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为了促进工业4.0与“中国制造2025”战略在制造行业的实施,在智能制造体系中构建有效的控制层级与设备层级,促进车间状态数据与智能制造工艺流程的结合,本文提出了通过智能仪器与智能检测技术实现车间状态智能感知与工艺流程控制的方法,并探讨了智能仪器与智能检测技术在智能制造系统中新的应用模式,同时结合实际项目进行了数字化生产线改造与建设的创新实践,提出了满足智能制造要求的智能仪器与检测技术的发展方向。经项目实践验证,通过智能检测设备与智能仪器的应用,可有效促进智能制造系统中数据采集、智能感知的实现,并为整体工艺流程的智能决策提供有效的数据资源,是智能制造系统建立与完善的关键基础。 相似文献