全文获取类型
收费全文 | 287篇 |
免费 | 3篇 |
国内免费 | 10篇 |
专业分类
化学 | 275篇 |
物理学 | 15篇 |
综合类 | 10篇 |
出版年
2023年 | 2篇 |
2021年 | 5篇 |
2020年 | 6篇 |
2019年 | 7篇 |
2018年 | 1篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 10篇 |
2013年 | 12篇 |
2012年 | 20篇 |
2011年 | 14篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 17篇 |
2007年 | 21篇 |
2006年 | 11篇 |
2005年 | 25篇 |
2004年 | 26篇 |
2003年 | 4篇 |
2002年 | 8篇 |
2001年 | 12篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1982年 | 1篇 |
排序方式: 共有300条查询结果,搜索用时 0 毫秒
71.
72.
73.
74.
本文报导了 Hg~(2+)的一种新的催化测定方法,根据 Hg~(2+)催化 Fe(CN)_6~(3-)和CyDTA 的取代反应,采用固定时间法,用氰离子选择电极进行监测.该指示反应在pH4.5的醋酸盐缓冲液和75℃下进行,反应15分钟后,用冷水冷却使其终止.在 NaOH介质中测定由催化取代反应中释放出来的氰离子.电位差ΔE与 IgC_(Hg)在5×10~(-8)~1×10~(-5)mol/L 范围内成线性关系.测定结果与光度法十分相符,平均回收率为98%. 相似文献
75.
冷原子荧光法间接测定水中氰化物 总被引:6,自引:0,他引:6
本文详细研究了氰化物蒸馏条件及其稳定性问题,建立了一个冷原子荧光法间接测定水中氰化物的方法,并用于海水及氰化液中痕量CN-的测定,结果令人满意。CN-检出限为0.02μg/mL,回收率95%~98%,变异系数7.3%~8.9%。 相似文献
76.
《Journal of Coordination Chemistry》2012,65(6):691-698
Two cyano-bridged copper(II)–copper(I) mixed-valence assemblies, Cu(EAM)2[Cu(CN)2]2 1 (EAM?=?ethanolamine) and Cu(DETA)[Cu(CN)2]2·0.5H2O 2 (DETA?=?diethylenetriamine), have been prepared and structurally and magnetically characterized. IR spectra indicate the presence of bridging cyano groups in both 1 and 2, confirmed by structure analyses; Cu(I)–CN–Cu(II), Cu(I)–CN–Cu(I) and Cu(I)–Cu(I) metal bond linkages are evident. In the lattice, a 3D network is formed by two [Cu(CN)2]?? units and one [Cu(EAM)2]2+unit for 1. Variable temperature magnetic susceptibilities, measured in the 5–300?K range, indicate weak antiferromagnetic exchange interactions in complex 1. 相似文献
77.
An electrocatalytic amperometric detector for the ion chromatographic determination of CN− is described. A conducting composite that is based on a graphite-loaded sol–gel material comprises the working electrode. The composite is doped with a RuII metallodendrimer which is demonstrated to promote the electrochemical oxidation of CN− at potentials positive of 0.5 V vs. Ag/AgCl. In 6 mM NaOH, 0.05 M NaCl flowed at 1.0 ml min−1, a 5-point calibration curve with the following linear least squares parameters is obtained over the range, 1.0–30 M CN−: slope, 24.2±0.1 nA M−1; intercept, −6±2 nA; and r, 0.9997. The detection limit, 0.7 μM CN−, compares favorably to that obtained by amperometry at a silver electrode, 0.5 μM CN−, under comparable experimental conditions. A 60-min preconcentration by Donnan dialysis increases the sensitivity by a factor of 23.6. 相似文献
78.
Ion chromatographic determination of sulfide and cyanide in real matrices by using pulsed amperometric detection on a silver electrode 总被引:1,自引:0,他引:1
The determination of free sulfide and cyanide by pulsed amperometric detection (PAD) at a silver-working electrode was improved through a deep de-oxygenation (at least 10 min) of both standard and real solutions containing the two analytes and adopting a two-potential waveform able to eliminate Ag working electrode fouling. The waveform stepped around the oxidation of Ag in the presence of 0.1-0.4 M hydroxyl ion, from -0.1 to 0.1 V versus saturated calomel electrode (SCE). The eluent composition (0.4 M NaOH plus 7.5 mM oxalate solution) allowed a very good column efficiency and selectivity. The presence of a polysulfide species was hypothesized in sulfide solutions that had not been de-oxygenated and aged. The polysulfide eluted just before sulfide and was confirmed by a chemical test with SO3(2-) producing the elimination of the polysulfide peak. Detection limits, according to the Hubaux-Vos method, were 1.0 and 2.0 microg/l for S2- and CN , respectively. We demonstrated good performance of the optimized method by repeatedly injecting standard solutions and by analyzing different real matrices. The method exhibited very good accuracy and repeatability (10 microg/l and a 500 microl injection loop, had a repeatability better than 3% for sulfide and 100 microg/l had a repeatability better than 1% for cyanide). The two-potential waveform ensured long-term stability of the electrode surface that required no manual polishing procedure for at least 1 month (20 analysis per day). 相似文献
79.
80.