全文获取类型
收费全文 | 84篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
化学 | 31篇 |
综合类 | 1篇 |
数学 | 2篇 |
物理学 | 18篇 |
综合类 | 49篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 8篇 |
2009年 | 3篇 |
2008年 | 4篇 |
2007年 | 4篇 |
2006年 | 5篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 2篇 |
2002年 | 5篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有101条查询结果,搜索用时 15 毫秒
31.
麻棉交织物经液氨处理后,用低甲醛树脂进行免烫整理,对树脂用量、焙烘温度和时间等工艺条件,用中心旋转法进行了优化。整理后织物的释放甲醛量低于75ppm,干折皱回复在270°以上,强力保留值大于70%,达到绿色免烫整理水平。 相似文献
32.
运用三维数值模拟计算方法,计算了膜面外不同易轴取向下Nd2Fe14B/Fe65Co35磁性双层膜的磁滞回线、角度分布、成核场、矫顽力和磁能积等,并与实验结果进行了细致比较.计算结果表明:只有当易轴与外场之间的夹角β=0?时,才有明显的成核现象,其成核场和矫顽力均随着软磁相厚度Ls的增加而降低;随着易轴偏角β的增大,剩磁逐渐减小,磁滞回线的方形度降低,从而磁能积减小,在Ls=1 nm,β=0?时磁能积(561.61 kJ/m3)最大.理论计算所得的磁滞回线与实验磁滞回线符合得很好,剩磁和矫顽力的理论值与实验值相差很小. 相似文献
33.
A new method of sample preparation was developed and is reported for the first time. The approach combines in-vial filtration with dispersive solid-phase extraction (d-SPE) in a fast and convenient cleanup of QuEChERS (quick, easy, cheap, effective, rugged, and safe) extracts. The method was applied to simultaneous analysis of 42 diverse pesticides and 17 environmental contaminants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls (PCBs), and flame retardants, in shrimp as the sample matrix. Final extracts were analyzed by both low-pressure gas chromatography – triple quadrupole tandem mass spectrometry (LPGC-MS/MS), and high-performance liquid chromatography – triple quadrupole tandem mass spectrometry (HPLC-MS/MS) to provide a wide scope of analysis for targeted analytes. During method development, several different commercial sorbents for d-SPE were investigated and compared with respect to analyte recoveries. The method was validated at 10, 50, and 100 ng g−1 spiking levels (10-fold lower for PCBs), and the results for nearly all analytes were between 70 and 115% recoveries with ≤17% relative standard deviations. The method was shown to be simple, fast, and effective for multi-application analysis of chemical residues in the representative food and environmental marker matrix. 相似文献
34.
O. Buluy Y. Reznikov K. Slyusarenko M. Nobili V. Reshetnyak 《Opto-Electronics Review》2006,14(4):293-297
We describe the experiments on a magnetically-induced drift of the easy axis on a soft surface of photoaligning material fluoro-polyvinyl-cinnamate.
We found unexpected partial relaxation of the drift of the easy axis after switching the magnetic field off. This relaxation
cannot be explained in a framework of the existing models and requires additional assumptions about the drift process. We
propose a model that explains the experimental data suggesting elastic-like behaviour of the polymer fragments during the
drift of the easy axis. 相似文献
35.
Xiaoqiang Xie Ruiming Xu Bo Yan Yong Zhang Weigan Lin 《International Journal of Infrared and Millimeter Waves》2005,26(10):1453-1464
This paper presents the analysis and design of a novel millimeter-wave power combining circuit. This combing circuit is composed
of a new style 3-dB combiner, which achieves low-loss, wide-band, and symmetric power division. Different from conventional
Wilkinson hybrid, the proposed combiner requires no isolating resistor, and is easier fabricated and more suitable for millimeter
integrate circuits. Analytical and experimental work on a two-way combining circuit with wave-guide ports in Ka-band shows
the combiner has an insertion loss of 0.2dB, and a power-combining efficiency above 80% in 32–33GHz is obtained. 相似文献
36.
37.
Jan Sadílek Petra Spálovská Branislav Vrana Milada Vávrová Blahoslav Maršálek 《International journal of environmental analytical chemistry》2016,96(11):1022-1037
The comparison of four extraction techniques for isolation of five native and one labelled steroid oestrogens from sediment was described. The three conventional extraction techniques Soxhlet warm extraction (SWE), accelerated solvent extraction (ASE), microwave-assisted extraction (MAE) and a promising technique QuEChERS were tested for isolation of low environmentally relevant oestrogen concentrations using different extraction conditions. The least expensive and time-consuming method QuEChERS provided the best extraction recoveries (53–84%) from all techniques. MAE achieved the highest recovery from conventional techniques for less polar oestrogens using dichloromethane: acetone 3:1 mixture as an extraction solvent (50–71%), but for extraction of the whole group of oestrogens including more polar estriol acetone or methanol must be used. ASE provided higher extraction recoveries using dichloromethane at 60°C (53–74%) for less polar oestrogens. However, the repeatability of results was unsatisfactory and recoveries using other extraction conditions were lower than for MAE. The most time-consuming SWE achieved the worst extraction recoveries and for isolation of low oestrogen concentrations from sediments, it is completely unsuitable. 相似文献
38.
High-throughput screening (HTS) is often required in enzyme inhibitor drugs screening. Mass spectrometry (MS) provides a powerful method for high-throughput screening enzyme inhibitors because its high speed, sensitivity and property of lable free. However, most of the MS methods need complicated sampling interface system. Overall throughput was limited by sample loading in these cases. In this study, we develop a simple interface which coupled droplet segmented system to a venturi easy ambient sonic-spray ionization mass spectrometer. It is fabricated by using a single capillary to act as both sampling probe and the emitter, which simplifies the construction, reduces the cost and shorten the sampling time. Samples sucked by venturi effect are segmented to nanoliter plugs by air, then the plugs can be detected by MS directly. This system eliminated the need for flow injection which was popular used in classic scheme. The new system is applied to screen angiotensin converting enzyme inhibitors. High-throughput was achieved in analyzing 96 samples at 1.6 s per sample. The plugs formation was at 0.5s per sample. Carry-over between samples was less than 5%, the peak height RSD was 2.92% (n = 15). Dose-response curves of 3 known inhibitors were also measured to validate its potential in drug discovery. The calculated IC50 agreed well with reported values. 相似文献
39.
本文介绍了一种用规尺进行七等分圆(画正七边形)方法,该方法与传统方法相比较,具有画法简单、精度高的特点。 相似文献
40.
Rapid quick,easy, cheap,effective, rugged,and safe extraction with novel phospholipid cleanup: A streamlined ultra high performance liquid chromatography with ultraviolet detection approach for screening polycyclic aromatic hydrocarbons in avian blood cells and plasma
下载免费PDF全文
![点击此处可从《Journal of separation science》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Anthony A. Provatas Alexander V. Yevdokimov Cory A. King Emma L. Gatley James D. Stuart David C. Evers Christopher R. Perkins 《Journal of separation science》2015,38(15):2677-2683
A streamlined method has been developed for the isolation and analysis of polycyclic aromatic hydrocarbons in avian blood cells and plasma utilizing quick, easy, cheap, effective, rugged, and safe extraction in combination with novel phospholipid cleanup technology. A variety of traditional extraction and cleanup techniques have been employed in the preparation and analysis of polycyclic aromatic hydrocarbonsin a variety of matrices; liquid–liquid partitioning, solid‐phase extractions, gel permeation chromatography, and column chromatography are all effective techniques, however they are laborious and time consuming processes that require large amounts of solvent. Using quick, easy, cheap, effective, rugged, and safe extraction coupled with phospholipid cleanup, samples can be quickly screened while maintaining high throughput and sensitivity. With a liquid chromatography approach, analysis times may be kept short at 16 min while maintaining high analyte recovery. Recoveries in quality control samples ranged from 70 to 109%, with average surrogate recoveries of 80.6 ± 1.10%. The result of using a quick, easy, cheap, effective, rugged, and safe extraction approach in conjunction with phospholipid cleanup is a methodology that significantly reduces sample preparation time and solvent use while maintaining high sensitivity and reproducibility. 相似文献