全文获取类型
收费全文 | 44篇 |
免费 | 2篇 |
专业分类
化学 | 20篇 |
力学 | 4篇 |
数学 | 1篇 |
物理学 | 21篇 |
出版年
2022年 | 1篇 |
2020年 | 2篇 |
2016年 | 1篇 |
2014年 | 2篇 |
2013年 | 3篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2009年 | 1篇 |
2008年 | 1篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1971年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有46条查询结果,搜索用时 125 毫秒
1.
Hettiarachchi K Green CE Ramanathan-Girish S Wu B Jackson CJ Ridge S Salem MA Lanser ME 《Journal of chromatography. A》2001,924(1-2):471-481
This paper describes a pharmacokinetic study performed in Sprague-Dawley rats after i.v. administration of a single 6-mg/kg dose of 2beta-carbomethoxy-3beta-(4-fluorophenyl)-N-(3-iodo-E-allyl)nortropane (Altropane). Plasma samples were collected from the retro-orbital sinus at times up to 3 h after drug administration, extracted by solid-phase extraction, and the drug levels determined by capillary electrophoresis (CE). Pharmacokinetic parameters were determined by a standard noncompartmental model using WinNonlin version 1.5. The maximum plasma concentrations, clearances of the drug, and areas under the curve for male and female rats were 5.74 and 7.26 microg/ml, 135.7 and 98.5 ml/kg x min, and 44.23 and 60.92 microg x min/ml, respectively. The drug was cleared very rapidly from the systemic circulation, with a terminal t(1/2) of 7 to 10 min and a mean residence time of about 11 min for both sexes. The volume of distribution was approximately 1 l/kg. No metabolites were detected when the samples were analyzed individually. However, after samples were pooled and concentrated, traces of two unknown peaks that may represent metabolites were detected in concentrates from the last two timepoints. Part I of this work [J. Chromatogr. A, 895 (2000) 87] describes validation of CE methods for the analysis of aqueous and plasma samples of Altropane, including its solid-phase extraction from rat plasma. 相似文献
2.
Development of an automated dual‐mode supercritical fluid chromatography and reversed‐phase liquid chromatography mass‐directed purification system for small‐molecule drug discovery
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)
Kanaka Hettiarachchi May Kong Andersen Yun John R. Jacobsen Qifeng Xue 《Journal of separation science》2014,37(7):775-781
We report the development of a dual‐mode mass‐directed supercritical fluid chromatography and reversed‐phase liquid chromatography purification system. The addition of a third pump allows for flexible mobile phase control between the two techniques, and enables operation of either chromatography mode within minutes by activation of a set of switching valves on a single system. Software control, fluidic pathways, interface to the mass spectrometer, and fraction collection have been modified for compatibility between both separation methods. The conditioning solvent and tuning parameters for the mass spectrometer were adjusted to achieve an ideal signal trace in either mode with good linearity (r2 > 0.970) over a range of concentrations and minimal noise for accurate peak detection and isolation. The registration success rate is 90% and overall sample recovery for either technique is 80?90%. Combining two orthogonal separation and purification modes in one single system has improved the purification throughput of complex mixtures and has been a valuable, cost‐saving tool in our laboratory. 相似文献
3.
4.
We succeeded in cryopreserving of innala (Solenostemon rotundifolius) in vitro-grown young lateral buds by vitrification. Nodal segments from in vitro-grown shoots (2-4 mm in length) were cultured on MS medium containing 0.1M sucrose in Petri dishes for 3 weeks under 16-h photoperiod at 25 degree C. This pre-growth induced a large number of uniform young lateral buds. Nodal segments (0.5 to 1.0 mm in length) with two lateral buds were dissected from the shoots and precultured with 0.3 M sucrose for 2 days at 25 degree C. They were then treated with loading solution containing 2 M glycerol and 0.4 M sucrose (LS solution) for 20 min at 25 degree C and dehydrated with the PVS2 vitrification solution for 18 min at 25(C prior to either rapid immersion in liquid nitrogen. Surviving lateral buds resumed growth within 3 days and developed shoots without intermediary callus formation. The average growth recovery after cryopreservation amounted to 85%. 相似文献
5.
Synthesis of 6‐Fluoro‐7‐cyclic Amino‐substituted Dicarboxylic Acid Quinolones and their Antibacterial Activity
下载免费PDF全文
![点击此处可从《Journal of heterocyclic chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A. Ravi Kumar G. Sathaiah A. Chandra Shekhar K. Raju P. Shanthan Rao B. Narsaiah Y. Kanaka Raju U. S. N. Murthy V. Srimai M. Ramesh T. Parthasarathy 《Journal of heterocyclic chemistry》2014,51(Z1):E114-E122
Novel 1‐carboxymethyl‐6‐fluoro‐7‐cyclic amino‐substituted‐4‐oxo‐1,4‐dihydroquinolone‐3‐carboxylic acids 7a , 7b , 7c , 7d , 7e , 7f , 7g , 7h , 7i , 7j , 7k , 7l , 7m , 7n were synthesized as a new class of quinolones. Ethyl‐6‐fluoro‐7‐chloro‐1,4‐dihydro‐4‐quinoline‐3‐carboxylic acid was prepared from conventional method and reacted with ethyl bromoacetate to furnish N‐carboxymethyl derivatives. The compounds were screed against various Gram‐positive and Gram‐negative bacterial strains. Antibacterial activity data is validated by molecular docking studies. 相似文献
6.
7.
N.F. Hettiarachchi R.D. Greenough D. Fort D.W. Jones 《Journal of magnetism and magnetic materials》1982,25(3):310-316
The magnetic susceptibilities of single crystal dysprosium and terbium-50% holmium have been measured in their paramagnetic phases. The effect of annealing has been investigated and heating the sample to ≈ 360 K for ≈ 18 h causes ≈ 4% reduction in χ273. Abrupt departures from Curie-Weiss behaviour occur at ≈ 257, 227, 199 K in Dy, and at 250, 214 and 197 K in Tb-50% Ho, coinciding with previously observed anomalies in the thermal expansion. This behaviour is attributed to the presence of residual antiferromagnetic order in the paramagnetic phase which is perturbed when the periodicity of the helical spin structure, estimated from neutron diffraction data, is commensurate with the hexagonal crystal lattice. 相似文献
8.
9.
Large amplitude flexural vibrations of slender beams, and thin circular and rectangular plates have been studied when a compatible longitudinal or inplane mode is coupled with the fundamental flexural mode. It is shown that the effect of longitudinal or inplane deformation and inertia is to reduce the non-linearity in the flexural frequency-amplitude relationship. Further, for slender beams and thin plates, the effect of longitudinal or inplane inertia is negligible. 相似文献
10.
The dynamics of neural networks is influenced strongly by the spectrum of eigenvalues of the matrix describing their synaptic connectivity. In large networks, elements of the synaptic connectivity matrix can be chosen randomly from appropriate distributions, making results from random matrix theory highly relevant. Unfortunately, classic results on the eigenvalue spectra of random matrices do not apply to synaptic connectivity matrices because of the constraint that individual neurons are either excitatory or inhibitory. Therefore, we compute eigenvalue spectra of large random matrices with excitatory and inhibitory columns drawn from distributions with different means and equal or different variances. 相似文献