首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   78篇
  免费   1篇
化学   15篇
数学   6篇
物理学   58篇
  2018年   1篇
  2014年   1篇
  2013年   1篇
  2012年   5篇
  2011年   2篇
  2010年   1篇
  2008年   3篇
  2007年   2篇
  2006年   2篇
  2005年   2篇
  2003年   2篇
  2002年   5篇
  2001年   3篇
  2000年   4篇
  1999年   2篇
  1998年   1篇
  1997年   1篇
  1995年   3篇
  1994年   4篇
  1993年   4篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   6篇
  1987年   1篇
  1984年   3篇
  1983年   1篇
  1977年   3篇
  1976年   2篇
  1974年   2篇
  1973年   1篇
  1970年   1篇
  1969年   1篇
  1967年   1篇
排序方式: 共有79条查询结果,搜索用时 885 毫秒
1.
The application of liquid chromatography/mass spectrometry (LC/MS) followed by principal components analysis (PCA) has been successfully applied to the screening of rat urine following the administration of three candidate pharmaceuticals. With this methodology it was possible to differentiate the control samples from the dosed samples and to identify the components of the mass spectrum responsible for the separation. These data clearly show that LC/MS is a viable alternative, or complementary, technique to proton NMR for metabonomics applications in drug discovery and development.  相似文献   
2.
The base catalyzed hydrolysis of 2-phenyl-2-oxo-3-(2,6-dimethylphenyl)-1,3,2-oxazaphospholidine, 6, and 2-phenyl-2-oxo-3-(2,6-diisopropylphenyl)-1,3,2-oxazaphospholidine, 7, yields ring opened products involving 95% and 100% P-O cleavage, respectively.  相似文献   
3.
4.
5.
The transverse mass spectra of Omega, J/psi, and psi' in Pb+Pb collisions at 158A GeV are studied within a hydrodynamical model of the quark-gluon-plasma expansion and hadronization. The model reproduces the existing data with the common hadronization parameters: temperature T = T(H) congruent with 170 MeV and average collective transverse velocity v(T) congruent with 0.2.  相似文献   
6.
The pion multiplicity per participating nucleon in central nucleus–nucleus collisions at the energies 2–15 AGeV is significantly smaller than in nucleon–nucleon interactions at the same collision energy. This effect of pion suppression is argued to appear due to the evolution of the system produced at the early stage of heavy–ion collisions towards a local thermodynamic equilibrium and further isentropic expansion. Received: 21 July 1997 / Revised version: 12 November 1997 / Published online: 26 February 1998  相似文献   
7.
Specific MRI techniques have been used to determine the dimensional and compositional properties of atherosclerotic lesions in carotid endarterectomy tissues. A quantitative comparison of areas of specific features in typical tissue segments was performed using MR images and histologic images. The mean difference for the measurements by the two methods was 4.5% for the total vessel, 5.3% for the internal carotid artery lumen, and 5.0% for the external carotid lumen. For other less abundant components, the mean difference was 14.2%. For direct characterization, individual tissue components were isolated by microdissection and their T1 and T2 relaxation times measured. Highly calcified areas typically had rather short T1 (452-837 ms) and short T2 (10.4-18.4 ms). In contrast, regions enriched in lipid had much longer T1 (1,380-1,480 ms) and longer T2 (35.3-49.0 ms). Other components such as thrombus had intermediate T1 (1,180 ms) and short T2 (15.4 ms). T2 parametric imaging was used as a complementary approach for segmentation and quantitation of tissue components. In fresh tissue, several different components exhibited different T2 ranges: calcified/solid lipid (13-18 ms). cellular/ECM (9-30 ms), fluid lipid (35-40 ms): fibrous (50-60 ms). These results demonstrate the utility of MRI for identifying and quantifying specific components of atherosclerotic plaque ex vivo, and suggest its value for these measurements in vivo as well.  相似文献   
8.
Transparent conductive oxide (TCO) thin films play a significant role in recent optical technologies. Displays of various types, photovoltaic systems, and opto-electronic devices use these films as transparent signal electrodes. They are used as heating surfaces and active control layers. Oxides of TCO materials such as: tin, indium, zinc, cadmium, titanium and the like, exhibit their properties. However, indium oxide and indium oxide doped with tin (ITO) coatings are the most used in this technology.In this work, we present conductive transparent indium oxide thin films which were prepared using a novel triode sputtering method. A pure In2O3 target of 2 in. in diameter was used in a laboratory triode sputtering system. This system provided plane plasma discharge at a relatively low pressure 0.5-5 mTorr of pure argon. The substrate temperature was varied during the experiments from room temperature up to 200 °C. The films were deposited on glass, silicon, and flexible polyimide substrates. The films were characterized for optical and electrical properties and compared with the indium oxide films deposited by magnetron sputtering.  相似文献   
9.
The shock stability condition in the relativistic hydrodynamics is found. This criterion is applied to a quark-gluon plasma shock-like hadronization transition.  相似文献   
10.
Experimental data for nucleus-nucleus collisions at the CERN SPS suggest that an ideal hadron gas model is unable to account simultaneously (same baryonic chemical potential and temperature at freeze-out) for the strange anti-baryon to baryon ratios and pion abundances. Using a thermodynamically consistent excluded volume model we examine possibilities to account for the observed excess of pions.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号