全文获取类型
收费全文 | 126篇 |
免费 | 2篇 |
专业分类
化学 | 83篇 |
力学 | 1篇 |
综合类 | 6篇 |
数学 | 17篇 |
物理学 | 21篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 6篇 |
2017年 | 1篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 5篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 8篇 |
2006年 | 3篇 |
2005年 | 6篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1985年 | 3篇 |
排序方式: 共有128条查询结果,搜索用时 281 毫秒
1.
本文用石蜡模拟油垢,用^60Co放射源的1.25MeV平均能量的γ射线垂直入射,以一定的散射角和不同的探测立体角接收散射γ光子敫.发现散射γ计数与被测石蜡厚度之间存在不同的线性关系.结果发现,放射源与探测器之间屏蔽的好坏和合理的探测距离对提高线性度有很大关系.本实验测得最佳线性相关系数平方值为0.9981,平均测量精度为1.26mm.这对研究散射法检测油垢厚度和选择合适的探测距离提供了实验基础. 相似文献
2.
Volkan Kseli Zakir M. O. Rzaev Erhan Pikin 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1580-1593
Stimuli‐responsive poly[(N‐isopropylacrylamide‐co‐maleic anhydride)‐g‐poly(ethylene oxide)]/poly(ethylene imine) macrobranched macrocomplexes were synthesized by (1) the radical copolymerization of N‐isopropylacrylamide and maleic anhydride with α,α′‐azobisisobutyronitrile as an initiator in 1,4‐dioxane at 65 °C under a nitrogen atmosphere, (2) the polyesterification (grafting) of prepared poly(N‐isopropylacrylamide‐co‐maleic anhydride) containing less than 20 mol % anhydride units with α‐hydroxy‐ω‐methoxy‐poly(ethylene oxide)s having different number‐average molecular weights (Mn = 4000, 10,000, or 20,000), and (3) the incorporation of macrobranched copolymers with poly(ethylene imine) (Mn = 60,000). The composition and structure of the synthesized copolymer systems were determined by Fourier transform infrared, 1H and 13C NMR spectroscopy, and chemical and elemental analyses. The important properties of the copolymer systems (e.g., the viscosity, thermal and pH sensitivities, and lower critical solution temperature behavior) changed with increases in the molecular weight, composition, and length of the macrobranched hydrophobic domains. These copolymers with reactive anhydride and carboxylic groups were used for the stabilization of penicillin G acylase (PGA). The conjugation of the enzyme with the copolymers significantly increased the thermal stability of PGA (three times at 45 °C and two times at 65 °C). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1580–1593, 2003 相似文献
3.
4.
Joseph R. Lakowicz Zakir Murtaza Wayne E. Jones Jr. Kihan Kim Henryk Szmacinski 《Journal of fluorescence》1996,6(4):245-249
We report the first observation of polarized emission from a rhenium-phenanthroline complex, Re(CO)3(phen)Cl. Highly luminescent rhenium complexes are known, with quantum yields near 0.5 and lifetimes in excess of 10 s. The detection of polarized emission suggests the use of rhenium complexes as probes of the hydrodynamics of large macromolecular complexes and for use in fluorescence polarization immunoassays with gated detection. 相似文献
5.
Lian HZ Kang YF Bi SP Yasin A Shao DL Chen YJ Dai LM Tian LC 《Analytical and bioanalytical chemistry》2003,376(4):542-548
A reversed-phase high-performance liquid chromatographic method with fluorescence detection for the determination of labile monomeric aluminium has been developed through pre-column complexation using morin as the analytical reagent. The highly fluorescent aluminium-morin complex (excitation wavelength 418 nm, emission wavelength 490 nm) was separated on a Spherisorb ODS 2 column with an eluent consisting of 30% methanol and 70% water (pH 1.0 with perchloric acid). The most remarkable point of this protocol was that only the most toxic aluminium species, that is, free aqua-aluminium ion and its monomeric hydroxo complex ions, selectively respond among various aluminium complexes. This strategy has been successfully applied to direct fractionation of the toxic aluminium in natural waters and biological samples without any pretreatment. 相似文献
6.
Schmidt EG Arkin CR Fiorentino MA Laude DA 《Journal of the American Society for Mass Spectrometry》2000,11(11):1009-1015
Simultaneous excitation/detection (SED), which permits observation of ion motion during an excitation event, is used to generate real-time Fourier transform ion cyclotron resonance (FTICR) excitation profiles that track the radial extent of ion motion in a trapped-ion cell. The conventional FTICR excitation profile is collected in a series of individual experiments in which peak magnitude is monitored as excitation voltage is increased. In contrast, SED permits the single-scan detection of ion cyclotron motion within the trapped-ion cell and consequently yields the data that produces a real-time excitation profile. Data analysis techniques are presented that facilitate conversion of a time domain SED profile into an excitation profile. An order of magnitude decrease in the amount of time is required to acquire an excitation profile, while the precision of the measurement is improved. To demonstrate the utility of the technique, it is applied to the study of axial and radial ion loss mechanisms for argon, benzene, and acetophenone ions under different conditions. SED excitation profiles are also used to illustrate the facility of quadrupolar excitation for minimizing radial ion loss. 相似文献
7.
I. D. Zakir’yanova I. V. Korzun V. A. Khokhlov V. N. Dokutovich E. V. Nikolaeva B. D. Antonov 《Russian Journal of Applied Chemistry》2016,89(7):1066-1071
Data on reactivities of α- and γ-Al2O3 finely dispersed powders in a melted carbonate eutectic (Li2CO3–Na2CO3–K2CO3)eut and carbonate-chloride mixture 0.72(Li2CO3–Na2CO3–K2CO3)eut–0.28NaCl were obtained. The methods of synchronous thermal and X-ray phase analyses and Raman spectroscopy confirmed that, in contrast to γ-Al2O3, α-Al2O3 does not chemically interact with the melted carbonate eutectic and carbonate-chloride mixture (Li2CO3–Na2CO3–K2CO3)eut–NaCl can be recommended as a thickening agent for a carbonate fuel cell. 相似文献
8.
Handan Arkin 《Journal of statistical physics》2010,139(2):326-332
We have performed Parallel Tempering simulations of hydrophobic-hydrophilic heteropolymers with a simple effective, coarse-grained off-lattice model with the selected monomers and compare the global energy minimums found with Parallel Tempering algorithm with the lowest energy states identified within the multicanonical algorithm. 相似文献
9.
A novel approach for the syntheses of carbene adduct 4 is reported. A ring-enlargement strategy was employed for the synthesis of precursors 5 and 6 and established the mechanism of the formation of azulene derivative 6. Synthesis of target precursor 13, a novel precursor for the synthesis of new mesogenic materials, and its various halogenated derivatives (14–16) was carried out. 相似文献
10.
Zakir O. Ait Karra A. Idouhli R. Elyaagoubi M. Khadiri M. Dikici Burak Aityoub A. Abouelfida A. Outzourhit A. 《Journal of Solid State Electrochemistry》2022,26(10):2247-2260
Journal of Solid State Electrochemistry - In this study, copper (Cu) and silver (Ag)–doped TiO2 nanotubes were fabricated by in situ anodization method to improve their photocatalytic... 相似文献