全文获取类型
收费全文 | 190篇 |
免费 | 5篇 |
国内免费 | 3篇 |
专业分类
化学 | 172篇 |
数学 | 11篇 |
物理学 | 15篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 16篇 |
2017年 | 11篇 |
2016年 | 15篇 |
2015年 | 4篇 |
2014年 | 12篇 |
2013年 | 16篇 |
2012年 | 15篇 |
2011年 | 21篇 |
2010年 | 8篇 |
2009年 | 12篇 |
2008年 | 5篇 |
2007年 | 11篇 |
2006年 | 3篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 4篇 |
2001年 | 1篇 |
1998年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有198条查询结果,搜索用时 15 毫秒
131.
132.
133.
Mohammad Nahid Siddiqui Halim Hamid Redhwi 《Journal of Analytical and Applied Pyrolysis》2009,86(1):141-147
Waste plastics of different types were catalytically coprocessed with petroleum residue of light Arabian crude oil in the presence of a number of catalysts. The purpose of the study was to explore effects of various conditions such as catalyst type, amount of catalyst, reaction time, pressure and temperature on the product distribution. The waste plastic studied included low-density polyethylene (LDPE), high-density polyethylene (HDPE), polystyrene (PS) and polypropylene (PP). A series of single (waster plastic with catalyst) and binary (waste plastic and residue with catalyst) reactions were carried out in an autoclave reactor under variable reaction conditions. The reaction conditions used were 1, 3 and 5 wt.% catalysts, 30–120 min reaction time, 400–430 °C reaction temperature and 500–1200 psi hydrogen pressure. The product distribution achieved for residue/plastic/catalyst system showed higher yields of liquid fuels as compared to residue/plastic system. Hydrocarbon gases were formed as well along with heavy oils, insoluble gums and coke. At the reaction conditions of 3 wt.% NiMo catalyst, 90 min reaction time, 1200 psi hydrogen gas pressure, 430 °C temperature and residue to plastic feed ratio of 3:2 (wt.) afforded maximum conversion of the plastics into liquid fuel oils. 相似文献
134.
Majid Montazer Fatemeh Dadashian Nahid Hemmatinejad Kajal Farhoudi 《Applied biochemistry and biotechnology》2009,158(3):685-693
This research has explored the effect of laccase (Denilite ІІ S) on the physical properties of the wool fabric and confirms
the anti-felting of wool. In the experiment, laccase was applied to a wool fabric and different characteristics including
weight loss, strength, alkali solubility, felting shrinkage, water drop absorption, and dye ability with madder were studied.
The surface morphology of the wool fabrics was also observed by scanning electron microscope. The results indicated that the
wool fabric treated with laccase has a higher water drop absorption, lower felting shrinkage, and lower values of a
* and b
*. Treatment of a wool fabric with 10% or lower percentage of laccase reduced the fabric weight but increased the tensile strength.
However, using higher concentration of laccase reduced fabric weight and tensile strength. The dyeing of laccase pre-treated
wool fabric with madder indicated a lower lightness. 相似文献
135.
Maryam Bordbar Ali Yeganeh-Faal Jahanbakhsh Ghasemi Mohammad Mahdi Ahari-Mostafavi Nahid Sarlak Mohammad Taghi Baharifard 《Chemical Papers》2009,63(3):336-344
A simple, sensitive and selective spectrophotometric method for simultaneous determination of tretinoin and minoxidil using
partial least square (PLS) calibration and H-point standard addition method (HPSAM) is described. The results of the H-point
standard addition method show that minoxidil and tretinoin can be determined simultaneously with the concentration ratio of
tretinoin to minoxidil varying from 2: 1 to 1: 33 in mixed samples. A partial least squares multivariate calibration method
for the analysis of binary mixtures of tretinoin and minoxidil was also developed. The total relative standard error for applying
the PLS method to eleven synthetic samples in the concentration range of 0–10 μg mL−1 tretinoin and 0–32 μg mL−1 minoxidil was 2.59 %. Both proposed methods (PLS and HPSAM) were also successfully applied in the determination of tretinoin
and minoxidil in several synthetic pharmaceutical solutions. 相似文献
136.
Nahid Amini Mohammadreza Shariatgorji Gunnar Thorsén 《Journal of the American Society for Mass Spectrometry》2009,20(6):1207-1213
The signal intensity of low-molecular-weight compounds analyzed using surface-assisted laser desorption/ionization time-of-flight
mass spectrometry (SALDI-TOF-MS) was significantly enhanced when oxidized graphitized carbon black (GCB) particles were used
as the desorption/ionization surface. The surface of oxidized GCB contains more carboxylic acid groups than non-oxidized GCB.
Carboxylic acid groups enhance the efficiency of the ionization process and the desorption of more hydrophobic compounds.
A common pharmaceutical compound, propranolol, was successfully extracted from Baltic Sea blue mussels and quantified using
oxidized GCB as the SALDI surface, whereas deuterated propranolol was used as the internal standard. The calibration curve
showed a wide linear dynamic range of response (0.1–20 μg/mL) and good reproducibility (RSD < 10%). It was not possible to detect propranolol in Baltic Sea blue mussels when non-oxidized
GCB was used as the SALDI surface. 相似文献
137.
Mohammadreza Shariatgorji Nahid Amini Leopold L. Ilag 《Journal of nanoparticle research》2009,11(6):1509-1512
Conventional matrix-assisted laser desorption/ionization mass spectrometry is limited to analyses of higher molecular weight
compounds due to high background noise generated by the matrix in the lower mass region. Surface-assisted laser desorption/ionization
(SALDI) mass spectrometry is an alternative solution to this problem. Nanoparticles, structured silicon surfaces and carbon
allotropes are commonly used as SALDI surfaces. Here, for the first time, we demonstrate the application of silicon nitride
nanoparticles as a suitable medium for laser desorption/ionization of small drug molecules. 相似文献
138.
Md. Rafiquzzaman Md. Maksudul Islam Md. Habibur Rahman Md. Saniat Talukdar Md. Nahid Hasan 《先进技术聚合物》2016,27(10):1308-1316
The natural fibers such as jute, coir, hemp, sisal etc. are randomly used as reinforcements for composite materials because of its various advantages such as low cost, low densities, low energy consumption over conventional fibers. In addition, they are renewable as well as biodegradable, and indeed wide varieties of fibers are locally available. In this study, glass–jute fiber reinforced polymer composite is fabricated, and the mechanical properties such as tensile, flexural and impact behavior are investigated. The materials selected for the studies were jute fiber and glass fiber as the reinforcement and epoxy resin as the matrix. The hand lay‐out technique was used to fabricate these composites. Fractured surface were comprehensively examined in scanning electron microscope (SEM) to determine the microscopic fracture mode. A numerical procedure based on the finite element method was then applied to evaluate the overall behavior of this composite using the experimentally applied load. Results showed that by incorporating the optimum amount of jute fibers, the overall strength of glass fiber reinforced composite can be increased and cost saving of more than 30% can be achieved. It can thus be inferred that jute fiber can be a very potential candidate in making of composites, especially for partial replacement of high‐cost glass fibers for low load bearing applications. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
139.
Ali Reza Kazemizadeh Nahid Shajari Reza Shapouri Neda Adibpour Reza Teimuri-Mofrad 《Journal of the Iranian Chemical Society》2016,13(7):1349-1355
An isocyanide-based multicomponent reaction between cinnamic acid derivatives or 3-phenyl-2-propynoic acid, (N-isocyanimino)triphenylphosphorane, ferrocenecarbaldehyde, and dibenzylamine has been reported in excellent yields for the preparation of some new ferrocenyl-containing 1,3,4-oxadiazole derivatives. The anti-brucella activities of the products are investigated in in vitro and in vivo assays. 相似文献
140.
A rapid, simple, and sensitive differential kinetic method is presented for the determinations of acetaminophen (also known as paracetamol) and salicylamide. The method is based on their oxidation reaction by Fe3+ ion in the presence of 1, 10-phenanthroline as indicator. The reactions can be monitored spectrophotometrically by measuring the increase in the absorbance of the solution at 510 nm. Two times were selected one in which only paracetamol is oxidized by Fe3+ ion and the other in which both drugs are oxidized by Fe3+ ion. The data were evaluated by the proportional equations method. The method allowed the simultaneous determination of paracetamol and salicylamide at concentrations between 0.5-20 and 1-40 microg/mL with relative standard deviations of 3.47 and 2.58%, respectively. The method was applied to the simultaneous determination of paracetamol and salicylamide in human serum and pharmaceutical formulations. 相似文献