全文获取类型
收费全文 | 268篇 |
免费 | 20篇 |
国内免费 | 40篇 |
专业分类
化学 | 171篇 |
晶体学 | 3篇 |
力学 | 12篇 |
综合类 | 3篇 |
数学 | 11篇 |
物理学 | 55篇 |
无线电 | 73篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 7篇 |
2020年 | 1篇 |
2019年 | 7篇 |
2018年 | 4篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 9篇 |
2014年 | 10篇 |
2013年 | 12篇 |
2012年 | 24篇 |
2011年 | 19篇 |
2010年 | 14篇 |
2009年 | 14篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 10篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 13篇 |
1998年 | 8篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 8篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1983年 | 1篇 |
排序方式: 共有328条查询结果,搜索用时 31 毫秒
1.
全息散斑条纹的提取及图像处理 总被引:3,自引:1,他引:2
介绍了一种新的全息散斑条纹的提取方法.理论和实验表明:对全息散斑底片逐点再现时,两伴生亮斑条纹是全息散斑底片一级衍射光的杨氏干涉条纹,与中央的杨氏条纹是一致的,有较高的条纹对比度且没有背景光晕的影响.利用计算机数字图像处理技术对伴生散斑条纹进行处理,定量测试了受静载物体的面内位移. 相似文献
2.
傅里叶变换技术在紫外可见光谱区的应用 总被引:13,自引:3,他引:13
本文评述了傅里叶变换在紫外可见光谱区的应用,探讨了傅里叶变换在紫外可见光谱学以及信号处理两方面的内容。详细介绍了傅里叶变换在紫外可见区遇到的问题、主要优点和发展前景。 相似文献
3.
Shiling Yuan Yijian Chen Guiying Xu 《Colloids and surfaces. A, Physicochemical and engineering aspects》2006,280(1-3):108-115
Molecular dynamics simulations on surfactant octadecylammonium chloride at the air/liquid interface were performed. It was found that the alkyl chains of octadecylammonium would change to order with increasing the concentration of octadecylammonium at the air/liquid interface. Some functions, such as the concentration distributions, the radial distribution function and the mean squared displacement (MSD) were evaluated to investigate the structural properties of interface. We found that the salts can affect octadecylammonium aggregate at the interface: (1) univalent ions, such as chloride and sodium ions, affect slightly the structure of monolayer and (2) bivalent ions, such as sulfate or calcium ions, affect greatly, especially for the bivalent negative ions. 相似文献
4.
本文研制了一种新的脉冲进样装置,用于火娄原子吸收分光光度法测定中药煎剂中的Ca,Mg,Fe,Mn,Zn五种金属元素含量,实验表明,利用此种装置可以同时获得两种进样方式的分析结果,线性范围比常规法宽两倍,耗样量,精密度及分析速度均优于常规法。 相似文献
5.
Han G Li J Chen G Ling L Li S Khorobrykh AA Zharmukhamedov SK Klimov VV Kuang T 《Journal of photochemistry and photobiology. B, Biology》2005,81(2):114-120
The efficiency of a trinuclear and two binuclear manganese complexes in reconstituting electron transport and O(2) evolution activity in Mn-depleted Photosystem II preparations is analyzed. The trinuclear Mn-complex is more efficient than two binuclear Mn-complexes in restoring oxygen evolution, but it is less effective as an electron donor than binuclear Mn-complexes. It is inferred from our results that recovery of electron transport and O(2) evolution with polynuclear Mn-complexes is affected with different factors. Moreover, the trinuclear Mn-complex is extremely sensitive to the addition of CaCl(2). It is suggested that there is an interaction between Ca(2+) and carboxyl within the trinuclear Mn-complex during photoactivation and this interaction benefits the ligation of Mn atom to the apo-WOC and form an active WOC. Binuclear Mn(III)Mn(III) complex shows slightly higher efficiency than binuclear Mn(III)Mn(IV) complex in restoration of O(2) evolution activity. The efficiency of three Mn-complexes in the reconstitution of WOC is in an order: trinuclear Mn(3)(III)>binuclear Mn(III)Mn(III)>binuclear Mn(III)Mn(IV). 相似文献
6.
The aggregation behavior of fluorinated surfactant in aqueous solution was investigated using dissipative particle dynamics (DPD) simulation method. Simulation results show that fluorinated surfactants behave mainly as their hydrocarbon analogues, having similar sequences of phases and aggregate structures, which are capable of building micelle, hexagonal phase and lamellar phase. But fluorinated surfactants also show interesting differences from hydrocarbon analogues, which can easily form hexagonal and lamellar structures with comparative little curvature. They can also form ellipsoid or rod-like micelles even in very low concentrations instead of spheroid ones. The dynamic aggregation behavior of fluorinated surfactants, as well as the comparison with hydrogenated ones, was also investigated. 相似文献
7.
Determination of Dopamine in the Presence of Ascorbic Acid Using a Poly(Amidosulfonic Acid) Modified Glassy Carbon Electrode 总被引:3,自引:0,他引:3
Yuzhong?ZhangEmail author Guiying?Jin Zhousheng?Yang Hong?Zhao 《Mikrochimica acta》2004,147(4):225-230
A glassy carbon electrode (GCE) was modified with electropolymerized films of amidosulfonic acid in pH 7.0 phosphate buffer solution (PBS) by cyclic voltammetry (CV). The modified electrode showed an excellent electrocatalytical effect on the oxidation of dopamine (DA). In pH 7.0 PBS, the anodic peak current increased linearly with the concentration of DA in the range of 5.0×10–7 1.0×10–4moldm–3, with a correlation coefficient of 0.9932, and a detection limit (S/N=3) of 1.0× 10–7moldm–3. The relative standard deviation of 10 successive scans was 2.5% for 1.0×10–6moldm–3 DA. The interference of ascorbic acid (AA) with the determination of DA could be eliminated because of the very distinct attracting interaction between DA cations and the negatively poly(amidosulfonic acid) film in pH 7.0 PBS. The proposed method exhibited good recovery and reproducibility. 相似文献
8.
9.
从光干涉方式,瞳窗关系和光源带宽等基本关系出发,利用空间不变系统理论解析了相移显微干涉检测系统中衍射效应的影响。为了减小横向分辨率对纵向分辨率的影响,利用相关信息提取或数字滤波的方法,获得了纳米分辨率的三维形貌。 相似文献
10.