全文获取类型
收费全文 | 195篇 |
免费 | 4篇 |
专业分类
化学 | 119篇 |
晶体学 | 4篇 |
力学 | 13篇 |
数学 | 5篇 |
物理学 | 58篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 8篇 |
2021年 | 3篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 5篇 |
2015年 | 4篇 |
2014年 | 5篇 |
2013年 | 23篇 |
2012年 | 14篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 12篇 |
2008年 | 9篇 |
2007年 | 11篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 1篇 |
2001年 | 2篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有199条查询结果,搜索用时 15 毫秒
1.
Vanadium(IV) forms colored chelates with Erio T and Solo 6 BN (λmax 570 and 580 nm, respectively) at pH 3.8. The composition MR2 of the chelates investigated was established by continuous variation, mole ratio, slope ratio and straight-line methods spectrophotometrically. For photometric determination of V(IV) with these reagents Sandell's sensitivity, Beer's law range, Ringbom optimum range were also determined. Bjerrum and Calvin potentiometric titration technique was employed to determine the stepwise formation constants of each system. For V(IV)-Erio T system values of log K1 = 14.4, log K2 = 10.9 and for V(IV)-Solo 6 BN system log K1 = 16.1, log K2 = 11.8 were obtained. 相似文献
2.
Pharmacokinetic studies of a novel trioxane antimalarial (99/411) in rats and monkeys using LC–MS/MS
下载免费PDF全文
![点击此处可从《Biomedical chromatography : BMC》网站下载免费的PDF全文](/ch/ext_images/free.gif)
The pharmacokinetic profile of 99/411, a novel anti‐malarial drug, was established in rats (12 mg/kg of body weight) and monkeys (20 mg/kg of body weight). Following oral administration, the presence of 99/411 was rapidly determined in rat plasma, tissues, urine, feces and monkey plasma using a validated LC–MS/MS method. The tissue distribution studies in rats indicated that the drug was partially distributed in all major tissues and plasma, and peak concentration levels were achieved within 0.5–4 h. Area under the curve in different rat tissues and plasma was found in order of blood > lung > intestine > heart > muscle > brain > kidney > spleen > liver. The total recoveries (within 86 h) of 99/411 were <0.0017% and <0.08% in urine and feces, respectively. The peak plasma concentration was 3499 ng/mL in rats after ~2 h of oral administration and 697–767 ng/mL in monkeys after ~6 h of oral administration. No plasma accumulation was observed in both male and female monkeys, even after multiple dosing. The preclinical pharmacokinetic profile and tissue distribution data are expected to assist in future clinical explorations of 99/411 as a promising anti‐malarial agent. 相似文献
3.
Journal of Solid State Electrochemistry - Nanostructured MnO2 films were prepared via cathodic electrodeposition under potentiostatic condition. X-ray diffraction (XRD) analyses reveal that the... 相似文献
4.
5.
Abstract
A new semicarbazone, HL has been synthesized from quinoline-2-carboxaldehyde and N4-phenyl-3-semicarbazide and structurally and spectrochemically characterized. 1H NMR, 13C NMR, IR and electronic spectra of the compound are studied. The existence of keto form in the solid state is supported by the crystal structure and IR data. The compound crystallizes into an orthorhombic space group P212121. Intra and intermolecular hydrogen bonding interactions facilitates unit cell packing in the crystal lattice. 相似文献6.
Metal complexation with 2-hydroxy-6-methylpyridine-3-carboxylic acid has been studied. The ligand finds use in detection and determination of iron (III). The order of stability constants of the bivalent transition metal complexes is Cu > Zn > Fe > Ni > Co > Mn. b]¦de¦Die Komplexbildung von Metallen mit 2-Hydroxy-6-methylpyridin-3-carbonsäure wurde untersucht. Der Ligand findet Verwendung beim Nachweis und bei der Bestimmung von Eisen(III). Die Reihenfolge der Stabilitätskonstanten der Komplexe mit zweiwertigen Überg angsmetallen ist Cu > Zn > Fe > Ni > Co > Mn. 相似文献
7.
An effort has been made for obtaining the anharmonic properties of rocksalt structure solids starting from primary physical parameters viz. nearest-neighbor distance and hardness parameter assuming long- and short-range potentials at elevated temperatures. The elastic energy density for a deformed crystal can be expanded as power series of strains for obtaining coefficients of quadratic, cubic and quartic terms which are known as the second-, third- and fourth-order elastic constants, respectively. When the values of the higher-order elastic constants are known for a crystal, many of the anharmonic properties of the crystal can be treated within the limit of the continuum approximation in a quantitative manner. In this study, higher-order elastic constants are computed up to their melting temperature for rocksalt structure solids, which are alkali cyanides, sodium and potassium halides. The first order pressure derivatives of second- and third-order elastic constants, the second-order pressure derivatives of second-order elastic constants and partial contractions are also evaluated at different temperatures for these substances. The results thus obtained are compared with experimental data and found in well agreement with present values. 相似文献
8.
Harsh Kumar Kanchan Bhardwaj Natlia Cruz-Martins Eugenie Nepovimova Patrik Oleksak Daljeet Singh Dhanjal Sonali Bhardwaj Reena Singh Chirag Chopra Rachna Verma Prem Parkash Chauhan Dinesh Kumar Kamil Ku
a 《Molecules (Basel, Switzerland)》2021,26(11)
The ingestion of contaminated water and food is known to cause food illness. Moreover, on assessing the patients suffering from foodborne disease has revealed the role of microbes in such diseases. Concerning which different methods have been developed for protecting food from microbes, the treatment of food with chemicals has been reported to exhibit an unwanted organoleptic effect while also affecting the nutritional value of food. Owing to these challenges, the demand for natural food preservatives has substantially increased. Therefore, the interest of researchers and food industries has shifted towards fruit polyphenols as potent inhibitors of foodborne bacteria. Recently, numerous fruit polyphenols have been acclaimed for their ability to avert toxin production and biofilm formation. Furthermore, various studies have recommended using fruit polyphenols solely or in combination with chemical disinfectants and food preservatives. Currently, different nanoparticles have been synthesized using fruit polyphenols to curb the growth of pathogenic microbes. Hence, this review intends to summarize the current knowledge about fruit polyphenols as antibacterial agents against foodborne pathogens. Additionally, the application of different fruit extracts in synthesizing functionalized nanoparticles has also been discussed. 相似文献
9.
A.K. Kushwaha 《理论物理通讯》2008,50(12):1422-1426
A rigid-ion model is used to calculate the force constants and effective dynamical charges of sulphide and selenide spinels. The Raman and infrared phonon modes of normal cubic sulphide spinels MCr2S4 (M = Mn, Co, Fe, Hg, Zn, and Cd) and selenide spinels MCr2Se4 (M = Hg, Zn, and Cd) are calculated at the first Brillouin zone-centre using above model, The significant outcome of the present work is (i) the interatomic interaction between Cr-S (Se) dominates over the Cr-S(Se) and S-S(Se-Se) type of interatomic interactions, (ii) the effective dynamical charges of the bivalent metal ions are nearly zero, and (iii) the selenide spinels are less ionic than the sulphide spinels and the ionicity decreases as MnCr2S4 〉 FeCr2S4 〉 CoCr2S4 〉 and CdOr2C4 〉 ZnCr2C4 〉 HgCr2C4 (C = S and Se). The zone-center phonon frequencies, calculated using these parameters, are found to be in very good agreement with the observed results. 相似文献
10.