全文获取类型
收费全文 | 158篇 |
免费 | 1篇 |
国内免费 | 5篇 |
专业分类
化学 | 133篇 |
数学 | 1篇 |
物理学 | 30篇 |
出版年
2022年 | 1篇 |
2020年 | 4篇 |
2019年 | 1篇 |
2017年 | 2篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 9篇 |
2012年 | 11篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2008年 | 2篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 12篇 |
2004年 | 5篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 17篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 6篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 7篇 |
1988年 | 1篇 |
1982年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有164条查询结果,搜索用时 9 毫秒
31.
32.
用普通材料自制和组装一套能梯度淋洗和柱后反应光度法连续检测萃取色层柱的流出曲线的设备。详细叙述了淋洗液切换阀、六通样样阀、四通混合器、盘管反应器的制作和将国产原子吸分光光度计改装流动光度计。 相似文献
33.
34.
在pH 4.10的Britton-Robinson缓冲溶液中,肝素与碱性吩噻嗪染料硫堇形成离子缔合物时,染料发生明显的褪色。体系吸光度的降低与肝素钠浓度成正比,肝素的质量浓度在0~60μg/25 mL范围内符合比耳定律,摩尔吸光系数为3.58×106L.mol-1.cm-1。研究了表面活性剂和共存物质的影响,表明方法选择性好。用于肝素钠注射液效价的测定,相对标准偏差小于3%,回收率为96.5%~101.9%。 相似文献
35.
A method is described for leaching of nanogram amounts of mono-, di and tri-butyltin compounds and mono-, di- and tri-phenyltin compounds from sediments. The procedure is based on soaking the sediments in a water–hydrogen bromide mixture (2:3) with magnetic stirring for 1 h followed by extraction with 0.02% (w/v) tropolone solution in pentane for 2 h. Organotins are determined by GF FPD after clean-up through a Florisil column and derivatization by Grignard pentylation. The method has been applied to the study of water and sediments in different areas of south-west Spain. Predominant species are butyltins, especially tributyltin (TBT), which has high values in waters and sediments of Puerto de Santa Maria and Cadiz Bay, as well as in sediments of the Sancti Petri Channel, which suggests a harmful action on biota. A direct relation has been found beween organotin levels and distance of potential focus determined by boating activities. In addition, the relative occurrence of dibutyltin (DBT) and monobutyltin (MBT) together with TBT has been noted, possibly as a result of a degractation process, and the influence of grain size of sediment and presence of organic matter on organotin accumulation has been studied. 相似文献
36.
Optimum conditions for the colour reaction of dian with nitrous acid in acid medium followed by alkalization with ammonia have been found. Investigation showed that 2,2-dinitrodian is the main product of the reaction, accompanied by a small amount of 2,2,6-trinitrodian. The ammonium salts of those compounds are responsible for the colour. 相似文献
37.
溴酸钾-溴酚蓝-锰(Ⅱ)催化体系的研究及其在测定抗坏血酸中的应用 总被引:1,自引:0,他引:1
丁素芳 《理化检验(化学分册)》2005,41(9):642-643,647
基于在pH 3.6的HOAc-NaOAc介质中,抗坏血酸对溴酸钾、溴酚蓝、锰(Ⅱ)催化体系具有显著的活化作用,建立了测定抗坏血酸的方法。线性范围为10~125μg/25 mL,检出限为3.44×10-5g.L-1,用于药品、饮料中抗坏血酸的测定,结果满意。 相似文献
38.
《Analytical letters》2012,45(10):1719-1727
Abstract A method was developed for the automatic quantitative determination of potassium in serum, by flow injection analysis. The serum sample is directly introduced in the flow. The dilution with deionized water stream is done automatically and sequentially in the system to reach the adequate concentration to be introduced in the flame photometer. The results achieved with this method, for serum samples obtained in the Hospital of the University, had been compared with those values of the Hospital laboratory that uses manual dilution and flame photometry. The results obtained by the two methods agree within at least ±5%. About 60 samples/hour can be easily analyzed by the method proposed in this work. 相似文献
39.
40.
Dispersion behavior of aqueous solutions containing oleic acid (RH), sodium oleate (R-Na+), and NaCl was investigated by turbidity and dynamic light-scattering measurements. Changes of the size of scattering particles
in solution composed of 1 mM oleic acid and 100 mM NaCl were traced as a function of the degree of ionization α, in terms
of radius of the equivalent hydrodynamic sphere. Large associated micelles with a radius of 30 nm appeared by a slight decline
of α and existed at α higher than 0.75. They were responsible for the three-phase equilibrium (solution, micelle and aggregated
micelle, and acid–soap, (R-Na+)3RH) characterized by a constant pH of 9.75. The appearance of a new phase, (R-Na+)3RH, contributed to increase both the turbidity and averaged scattering particle size. As the breakdown of the three-phase
equilibrium, radius of scattering particles increased significantly. Finally, oleic acid oil droplets were separated from
aqueous phase at low α. When the system was buffered by tris(hydroxymethyl)aminomethane (Tris), scattering particles with
a weight-averaged hydrodynamic radius of 75 nm existed in a wide range of α from 0.85 to 0.65. In Tris buffered solution,
turbidity formation was induced by the increase in the number of aggregated particles.
Received: 12 November 1996 Accepted: 4 April 1997 相似文献