全文获取类型
收费全文 | 232篇 |
免费 | 46篇 |
国内免费 | 10篇 |
专业分类
化学 | 50篇 |
晶体学 | 1篇 |
力学 | 7篇 |
数学 | 5篇 |
物理学 | 225篇 |
出版年
2023年 | 4篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 9篇 |
2019年 | 9篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 13篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 15篇 |
2012年 | 13篇 |
2011年 | 12篇 |
2010年 | 7篇 |
2009年 | 6篇 |
2008年 | 15篇 |
2007年 | 13篇 |
2006年 | 16篇 |
2005年 | 13篇 |
2004年 | 13篇 |
2003年 | 12篇 |
2002年 | 2篇 |
2001年 | 12篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
排序方式: 共有288条查询结果,搜索用时 15 毫秒
131.
Radiofrequency (rf) trapped ions are versatile candidates for a large panel of applications ranging from quantum information to the creation of cold molecules. Sample size can range from a single to 10^6 ions, and the internal and external energy states of the atoms can be controlled with high precision. In the experiment, we focus on different protocols related to frequency metrology using rf trapped Ca. 相似文献
132.
Mixed polarization in determining the film thickness of a silicon sphere by spectroscopic ellipsometry 下载免费PDF全文
The effect of a spherical shape on the measurement result of spectroscopic ellipsometry (SE) is analyzed,and a method to eliminate this effect is proposed.Based on the simulation result of the SE measurement on a silicon sphere by ray tracking,we find that the sphere makes the parallel incident beam of the SE be divergent after reflection,and the measurement error of the SE caused by this phenomenon is explained by the mixed polarization theory.By settling an aperture in front of the detector of the SE,we can almost eliminate the error.For the silicon sphere with a diameter of 94 mm used in the Avogadro project,the thickness error of the oxide layer caused by the spherical shape can be reduced from 0.73 nm to 0.04 nm by using the proposed method.The principle of the method and the results of the experimental verification are presented. 相似文献
133.
Accurate heterodyne interferometric ellipsometer 总被引:1,自引:0,他引:1
We describe a heterodyne interferometric ellipsometer which requires only a single reflection from the sample surface. A simple arrangement is described that enables a reference beam to be created in one arm of a modified Mach–Zehnder interferometer such that the p- and s-polarisations in this arm have a common phase and fixed relative amplitude, irrespective of the sample. When this beam is recombined interferometrically with the measurement beam, the spatially separated p and s fringes have an amplitude ratio and relative phase that are directly proportional to tanψ and Δ, respectively. Adjusting the azimuthal angle of the input linear polarisation allows both ψ-tracking to be implemented and error reduction through averaging. Measurements made with this instrument of a native oxide layer on a silicon substrate are in excellent agreement with those obtained using a commercial ellipsometer. 相似文献
134.
135.
为了准确地测量透射平行平板,提出了基于最小二乘迭代的多表面干涉条纹分析方法.依据波长调谐相移的原理,通过最小二乘迭代准确地求得每组双表面干涉条纹的实际相移值.从而准确地提取平板前后表面面形及厚度变化等信息.模拟计算结果表明.当相移值有微小偏差(小于0.2 rad)时,通过10次迭代后求得相位的峰值(PV)误差为0.005 rad,均方根(RMS)误差为0.002 rad,而相应Okada算法的PV误差为0.512 tad.RMS误差为0.103 rad.实验结果验证了该箅法的有效性. 相似文献
136.
In this paper, we generalize the notion of Shannon’s entropy power to the Rényi-entropy setting. With this, we propose generalizations of the de Bruijn identity, isoperimetric inequality, or Stam inequality. This framework not only allows for finding new estimation inequalities, but it also provides a convenient technical framework for the derivation of a one-parameter family of Rényi-entropy-power-based quantum-mechanical uncertainty relations. To illustrate the usefulness of the Rényi entropy power obtained, we show how the information probability distribution associated with a quantum state can be reconstructed in a process that is akin to quantum-state tomography. We illustrate the inner workings of this with the so-called “cat states”, which are of fundamental interest and practical use in schemes such as quantum metrology. Salient issues, including the extension of the notion of entropy power to Tsallis entropy and ensuing implications in estimation theory, are also briefly discussed. 相似文献
137.
A surface detection or 3D profilometry for microstructure (millimeter size) based on the project grating method and phase measurement techniques is presented in this paper. The advantages of this technique are simple measuring apparatus, full field and almost real-time testing. The principle and theoretical analysis of the measuring sensitivity are described and four application examples including a calibration example are also presented in this paper. Further improvement and probable applications in electronic industry are also discussed. 相似文献
138.
Increasing demands for accuracy in manufacturing and utilizing optics in synchrotron radiation facility require more precise surface measuring techniques. A novel profilometer design for testing aspherical optical elements, especially the optics used in synchrotron radiation, is presented, in which a phase plate is introduced so as to generate a pattern on the detector that can be easily and accurately centered. Compared with conventional long trace profilers, the optical system of this novel design is simple, therefore its potential error sources are greatly reduced. The feasibility of the method is validated in theory and experiments with a newly developed prototype. Experimental results show that this prototype works well even under an opening operation environment without temperature control and air conditioning. 相似文献
139.
The fixity of an ingot may greatly affect the quality of wafers produced during a wire saw process and improved mechanical clamping is a means for improving ingot fixity. Here, an optical technique that is based on laser beam deflection is described. The technique was demonstrated on ingot assemblies subjected to impulse loads within a prescribed range using an original and improved clamping system. The technique revealed that the ingot assembly had lower degrees of mean displacement and standard displacement deviation under the improved clamping system. The data on warp obtained from the actual production of wafers corroborates this finding. The technique described is an effective method of quantitatively evaluating the fixity of ingots in a wafer wire saw process. 相似文献
140.