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排序方式: 共有128条查询结果,搜索用时 46 毫秒
121.
Glan-Taylor prism is the key component of the static polarization interference imaging spectrometer. In this paper, we consider the case that optical axes of the Glan-Taylor prism have departure angles from their ideal directions that in the principal section, however principal section varies with optical axes. Ray tracing method is employed to detailedly present the light trails in the birefringent Glan-Taylor prism when the incident plane and the principal section are in the same plane. Both double refraction in the crystal and internal double reflection over the interface between the birefringent and isotropic mediums are analyzed in detail. Besides, we obtain the approximate formula about the transmission ratio of Glan-Taylor prism. Finally, the transmission ratio of Glan-Taylor prism due to the deviations of the optical axes is deduced and discussed in particular. 相似文献
122.
In this article, a portable energy dispersive X‐ray fluorescence spectrometer having determination capability for elements of Na and Mg is applied to characterization of the 58 ancient glass vessels fragments found in Xinjiang, China, successfully. These ancient glass samples were found in different historical sites dated from the Han Dynasty (202 B.C.–220 A.D.) to early Yuan Dynasty (1271–1368 A.D.). The chemical composition difference between the original weathered and inner fresh surfaces is distinguished. Using Mg, Ca, Al and K as the diagnostic elements, the glass samples analyzed are mainly classified into three types through cluster analysis. Each type of glass seems to be produced under different recipes. The techniques used to make these glasses and their possible provenances are discussed briefly. The obtained results provide new useful information for further understanding of the exchange and trade networks related to early glasses found in Xinjiang, China. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
123.
124.
双排抗滑桩滑坡推力分配影响因素分析 总被引:4,自引:0,他引:4
以作用形式较为简单的双排悬臂抗滑桩(未带连梁)为模型并基于结构力学位移法得出的双排桩滑坡推力传递分配计算公式为基础,结合推力较大的红石包滑坡作为工程实例,分别分析了双排桩静排距,前后排桩的截面尺寸和桩间土弹性模量对推力传递分配的影响,得出了以下结论:(1)当增大后排桩的刚度或减小前排桩的刚度时,桩土相互挤压作用越小, A2/A1随之减小,反之A2/A1增大。(2)增大排距b时,A1减小,A2在b=3~10m时逐渐减小,但是变化幅度不大; 在b=10~21m时,不断增大。(3)当增大桩间土弹性模量时,A2增大。(4)随着前排桩截面高度的增大,A1、A2逐渐增大; 随着后排桩截面高度的增大,A1、A2逐渐减小。 相似文献
125.
采用密度泛函理论研究了InnAsn (n≤90)管状团簇以及单壁InAs纳米管的几何结构、稳定性和电子性质. 小团簇InnAsn (n=1-3)基态结构和电子性质的计算结果与已有报道相一致. 当n≥4时优化得到了一族稳定的管状团簇, 其结构基元(In原子与As原子交替排列的四元环和六元环结构)满足共同的衍化通式. 团簇的平均结合能表明横截面为八个原子的管状团簇稳定性最好. 管状团簇前线轨道随尺寸的变化规律有效地解释了一维稳定管状团簇的生长原因, 同时也说明了实验上之所以能合成InAs纳米管的微观机理. 此外, 研究结果表明通过管状团簇的有效组装可得到宽带隙的InAs半导体单壁纳米管. 相似文献
126.
利用量子失协方法研究在非马尔科夫环境中具有时变磁场的两比特各向异性海森堡XYZ模型量子失协的动力学演化。海森堡XYZ系统的初始态为最大纠缠态 $\left|\psi_{A B}\right\rangle=(1 / \sqrt{2})(|11\rangle+|00\rangle)$ , 利用非马尔科夫量子态扩散方法解析求解非马尔科夫主方程, 得出系统的约化密度矩阵; 然后代入量子失协公式得出系统量子失协的演化动力学。讨论自旋耦合强度、环境关联系数γ和余弦磁场强度B对量子失协动力学的影响。研究发现: 当环境关联系数γ较小时, 系统的量子失协明显呈现上升趋势, 因此可以表明非马尔科夫环境具有增加系统量子失协的作用。同时较大的自旋耦合系数J和JZ以及余弦磁场强度B也具有增加系统量子失协的作用。 相似文献
127.
《Radiation Physics and Chemistry》2004,69(1):91-98
The rheological properties of styrene–butadiene rubber (SBR) loaded with dual phase filler were measured using Monsanto Processability Tester (MPT) at three different temperatures (100°C, 110°C and 130°C) and four different shear rates (61.3, 306.3, 613, and 1004.5 s−1). The effect of electron beam modification of dual phase filler in absence and presence of trimethylol propane triacrylate (TMPTA) or triethoxysilylpropyltetrasulphide (Si-69) on melt flow properties of SBR was also studied. The viscosity of all the systems decreases with shear rate indicating their pseudoplastic or shear thinning nature. The higher shear viscosity for the SBR loaded with the electron beam modified filler is explained in terms of variation in structure of the filler upon electron beam irradiation. Die swell of the modified filler loaded SBR is slightly higher than that of the unmodified filler loaded rubber, which is explained by calculating normal stress difference for the systems. Activation energy of the modified filler loaded SBR systems is also slightly higher than that of the control filler loaded SBR system. 相似文献
128.
Fe-doped 6H-SiC polycrystalline powders were synthesized by solid-state reaction of high-purity silicon, graphite and iron powder. X-ray powder diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) analysis showed the presence of little Fe3Si as secondary phase. Temperature-dependent magnetization showed two typical ferromagnetic (FM) transition temperatures located at 438 and 837 K, respectively. These features provided convincing experimental evidence to demonstrate that the presence of Fe3Si is not the nature origin of FM ordering in Fe-doped SiC. It also indicated that trace of Fe-doping in SiC will induce a high-temperature FM arrangement. 相似文献