首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1703篇
  免费   50篇
  国内免费   25篇
化学   126篇
晶体学   3篇
力学   96篇
综合类   5篇
数学   217篇
物理学   1331篇
  2024年   1篇
  2023年   8篇
  2022年   16篇
  2021年   30篇
  2020年   30篇
  2019年   21篇
  2018年   12篇
  2017年   74篇
  2016年   80篇
  2015年   56篇
  2014年   250篇
  2013年   129篇
  2012年   76篇
  2011年   122篇
  2010年   89篇
  2009年   115篇
  2008年   95篇
  2007年   106篇
  2006年   84篇
  2005年   63篇
  2004年   54篇
  2003年   39篇
  2002年   31篇
  2001年   31篇
  2000年   16篇
  1999年   21篇
  1998年   26篇
  1997年   20篇
  1996年   15篇
  1995年   13篇
  1994年   6篇
  1993年   3篇
  1992年   11篇
  1991年   3篇
  1990年   8篇
  1989年   6篇
  1988年   5篇
  1987年   3篇
  1986年   3篇
  1985年   2篇
  1984年   4篇
  1982年   1篇
排序方式: 共有1778条查询结果,搜索用时 187 毫秒
941.
单细胞凝胶电泳其及光学图像分析   总被引:2,自引:0,他引:2  
张炜  代正民  罗明智  齐浩 《光子学报》2004,33(7):877-879
采用单细胞凝胶电泳检测DNA损伤度,运用光学图像处理软件对彗星试验得到的参数进行图像分析,结果表明:该方法快捷,灵敏度高,能够较好地应用于DNA损伤度的修复、细胞遗传、环境检测等方面.  相似文献   
942.
小波包变换与遥感图像融合   总被引:18,自引:12,他引:6  
那彦  史林  杨万海 《光子学报》2004,33(6):736-738
探讨了遥感多光谱与全色波段图像的融合问题.分析了多光谱与全色波段成像机理,提出了一种基于小波包变换的遥感图像融合方法,实验结果表明,该方法可有效综合多光谱与全色波段图像的优点,从而获得具有较高空间分辨率的多谱图像.  相似文献   
943.
稳像平台准确测试系统的研究和设计   总被引:2,自引:2,他引:0  
桂小琰  仲顺安  陈越洋 《光子学报》2004,33(12):1497-1499
对稳像平台的准确测试系统的设计和研制进行了探讨,提出了一种新的采用虚拟仪器软件Labview对前端CCD输出的图像数据进行采集和处理的稳像平台准确测试系统方案.结合稳像平台准确测试系统的具体要求阐述了对系统进行设计的理论,并对采用本方案进行实际设计时的具体步骤、参数取值、测量最大范围、误差估计以及软件设计流程给出了具体的设计方法和参数计算公式.  相似文献   
944.
The total variation model of Rudin, Osher, and Fatemi for image denoising is considered to be one of the best denoising models. Recently, by using the Bregman method, Goldstein and Osher obtained a very efficient algorithm for the solution of the ROF model. In this paper, we give a rigorous proof for the convergence of the Bregman method. We also indicate that a combination of the Bregman method with wavelet packet decomposition often enhances performance for certain texture rich images.  相似文献   
945.
In the present paper, we prove a substantially improved version of the Pontryagin maximum principle for convex multidimensional control problems of Dieudonné-Rashevsky type. Although the range of the operator describing the first-order PDE system involved in this problem has infinite codimension, we obtain first-order necessary conditions in a completely analogous form as in the one-dimensional case. Furthermore, the adjoint variables are subjected to a Weyl decomposition. We reformulate two basic problems of mathematical image processing (determination of optical flow and shape from shading problem) within the framework of optimal control, which gives the possibility to incorporate hard constraints in the problems. In the convex case, we state the necessary optimality conditions for these problems.  相似文献   
946.
In this paper, we consider linearity measure for a bounded length curves. First, we define a new linearity measure for open curve segments, and then extend method to closed curves (contours). The derived measures (for both, open curve segments and closed curves) are invariant with respect to similarity transformations. The linearity measure for open curve segments picks the value 1 if and only if the measured open line segment is a perfect straight line segment while the established linearity measures for closed curves never reach 1, as preferred.  相似文献   
947.
Digital holographic imaging fusion for a larger size object using compressive sensing is proposed. In this method, the high frequency component of the digital hologram under discrete wavelet transform is represented sparsely by using compressive sensing so that the data redundancy of digital holographic recording can be resolved validly, the low frequency component is retained totally to ensure the image quality, and multiple reconstructed images with different clear parts corresponding to a laser spot size are fused to realize the high quality reconstructed image of a larger size object. In addition, a filter combing high-pass and low-pass filters is designed to remove the zero-order term from a digital hologram effectively. The digital holographic experimental setup based on off-axis Fresnel digital holography was constructed. The feasible and comparative experiments were carried out. The fused image was evaluated by using the Tamura texture features. The experimental results demonstrated that the proposed method can improve the processing efficiency and visual characteristics of the fused image and enlarge the size of the measured object effectively.  相似文献   
948.
A laboratory-made tumor cell detection device was fabricated based on both surface plasmon resonance imaging(SPRi) and image processing.In this device,a gravity-induced flow injection chip(gFIC) was exploited to replace a pump.Also two charge coupled devices(CCDs) were used to detect HepG2 cells by SPRi and image processing,respectively.The results of two CCDs are associated.Protein A was used to modify the sensing surface.The inlet angle was carefully adjusted for the device to get an enhanced image.In the test,the contrast among cell solutions at different concentrations can be easily distinguished.The other CCD using image processing can tell false-positive in some degree.This detection is label-free,real time,and precise.  相似文献   
949.
航空影像房屋提取方法的研究中大多基于灰度影像的区域生长算法,此类算法不仅忽略了不同材质的房屋所呈现的光谱特征对提取结果的影响,而且过于依赖种子像素的选取,处理效率不高。为了从高分辨率航空影像中实现房屋的自动检测,综合利用彩色信息与屋顶材料的光谱特征,采用影像分割原理,研究了房屋自动检测的方法。首先对RGB与HIS彩色空间进行转换,利用HIS空间各分量间不相关的特点和屋顶材料光谱特征进行影像分割,分离出红色瓦片屋顶与灰色水泥屋顶区域,并利用标记分水岭算法实现房屋区域的初始分割;然后计算各标记区域内的色调均值选取种子像斑样本,进而以像斑为单元在色调分量中进行区域生长,最后经过消除小斑和矩形拟合优化处理,得到轮廓清晰的房屋区域。与传统的基于像素区域分割算法相比,该方法整个过程无需人工干预且均在一维彩色空间进行处理,计算量明显降低,同时采用改进的基于像斑区域生长算法能够兼顾邻近区域内像素的几何结构信息,使算法精度得到显著提高,采用上述方法对高分辨率航空影像进行了实验,结果证明该方法有着较高的处理效率和准确性,具有实用价值。  相似文献   
950.
In this paper, we study to use nonlocal bounded variation (NLBV) techniques to decompose an image intensity into the illumination and reflectance components. By considering spatial smoothness of the illumination component and nonlocal total variation (NLTV) of the reflectance component in the decomposition framework, an energy functional is constructed. We establish the theoretical results of the space of NLBV functions such as lower semicontinuity, approximation and compactness. These essential properties of NLBV functions are important tools to show the existence of solution of the proposed energy functional. Experimental results on both grey-level and color images are shown to illustrate the usefulness of the nonlocal total variation image decomposition model, and demonstrate the performance of the proposed method is better than the other testing methods.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号