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   93篇
  免费   3篇
  国内免费   1篇
化学   74篇
晶体学   1篇
数学   12篇
物理学   10篇
  2022年   1篇
  2018年   1篇
  2016年   1篇
  2015年   4篇
  2014年   3篇
  2013年   4篇
  2011年   3篇
  2010年   2篇
  2009年   2篇
  2008年   9篇
  2007年   7篇
  2006年   2篇
  2005年   3篇
  2004年   6篇
  2003年   4篇
  2002年   4篇
  2001年   2篇
  1999年   1篇
  1998年   1篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1992年   1篇
  1991年   4篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
  1979年   6篇
  1978年   2篇
  1977年   1篇
  1975年   1篇
  1974年   4篇
  1954年   1篇
排序方式: 共有97条查询结果,搜索用时 437 毫秒
51.
In this work we study the effect of the symmetry energy on several properties of neutron stars. First, we discuss its effect on the density, proton fraction and pressure of the neutron star crust-core transition. We show that whereas the first two quantities present a clear correlation with the slope parameter L of the symmetry energy, no satisfactory correlation is seen between the transition pressure and L . However, a linear combination of the slope and curvature parameters at ρ = 0.1 fm?3 is well correlated with the transition pressure. In the second part we analyze the effect of the symmetry energy on the pasta phase. It is shown that the size of the pasta clusters, number of nucleons and the cluster proton fraction depend on the density dependence of the symmetry energy: a small L gives rise to larger clusters. The influence of the equation of state at subsaturation densities on the extension of the inner crust of the neutron star is also discussed. Finally, the effect of the density dependence of the symmetry energy on the strangeness content of neutron stars is studied in the last part of the work. It is found that charged (neutral) hyperons appear at smaller (larger) densities for smaller values of the slope parameter L. A linear correlation between the radius and the strangeness content of a star with a fixed mass is also found.  相似文献   
52.
53.
54.
Magnetophoretic velocimetry detected the spin transition of a single Co-Fe Prussian Blue analogous micro-crystal in water induced by a single-shot pulse laser.  相似文献   
55.
The magnetic field-induced migration of particles in liquids is a highly-promising technique for the micro-separation analysis of bioparticles, such as cells and large DNA. Here, new methods that make use of magnetophoresis and electromagnetophoresis to induce the migration of microparticles in liquids are briefly reviewed. Magnetic force and Lorentz force are utilized in the new methods. Some typical examples of the use of these methods are described, and the advantages of using a superconducting magnet for them are demonstrated.  相似文献   
56.
A gas chromatography-selected ion monitoring procedure with chemical ionization is described for the determination of bromovalerylurea (BVU) in human plasma. BVU was extracted with ether after addition of 2-bromo-2-methylpropylurea as an internal standard. The lower limit of BVU quantification by this method was 2 ng/0.1 ml plasma volume. This procedure was used to determine the sequential plasma levels of BVU in a human volunteer following a single oral dose of a commercial analgesic.  相似文献   
57.
A novel thermosensitive poly(N-vinylisobutyramide)(polyNVIBA) hydrogel was prepared by the copolymerization of N-vinylisobutyramide (NVIBA) with butylene-bis-NVA(B-BNVA) as a crosslinker in a high yield. The swelling transition behavior was examined in comparison with poly(N-isopropylacrylamide)(polyNIPAAm) hydrogel. The resulting polyNVIBA hydrogel clearly showed a swelling transion in water at ca. 41°C. To control the transition temperature (Tt) of the gel, crosslinked copolymers of NVIBA and N-vinylacetamide (NVA) were prepared and compared with copolymers of N-isopropylacrylamide(NIPAAm) and NVA. The incorporation of NVA led to a higher swelling transition temperature. Tt of poly(NVIBA-co-NVA) gels was almost the same as those in water-soluble poly(NVIBA-co-NVA). The responses for a swelling transition of polyNVIBA and poly(NVIBA-co-NVA) gels were sharp in comparison to polyNIPAAm gels. PolyNVIBA and poly(NVIBA-co-NVA) gels desorbed 98% of water above Tt. The characteristic and the mechanism of the phase transition on the hydrogels were discussed. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 3377–3384, 1997  相似文献   
58.
An efficient total synthesis of aperidine was accomplished using a Rh-catalyzed C-H insertion of a cis-dihydrobenzofuran ring. To circumvent the facile epimerization of the cis-dihydrobenzofuran ring, we designed and prepared the C-H insertion precursor diazoamide by Raines' protocol. Finally, the efficient incorporation of a guanidine group and mild deprotection conditions yielded this labile natural product.  相似文献   
59.
Application of magnetic field on the separation and analysis of nano/microparticles is a growing subject in analytical separation chemistry. The migration phenomenon of a particle under inhomogeneous magnetic field is called magnetophoresis. The migration velocity depends on the magnetic susceptibility and the size of a particle. Therefore, magnetophoresis allows us to determine the magnetic susceptibility of particles, and to separate particles based on the magnetic properties. Magnetic separation of ferromagnetic particles in liquid has been utilized for a long time. For example, a high gradient magnetic separation under the non-uniform magnetic field generated by ferromagnetic mesh has been utilized in a wide region from chemical industry to bioscience. Recent progress on magnetic nanoparticles and microfluidic devices has made it possible to extend the range of application. Furthermore, it has been demonstrated that the very sensitive measurement of the magnetic susceptibility of microparticles can be performed by observing magnetophoretic velocity. In this review, we mainly introduce novel separation and detection methods based on magnetophoresis, which have been invented in this decade, and then new principles of particle migration under magnetic field are presented.  相似文献   
60.
A gas chromatographic mass spectrometric procedure using selected ion monitoring is described for the quantification of gallopamil in human plasma. Gas chromatographic separation of gallopamil from phenolic metabolite isomers is made possible by treatment with ethyl chloroformate. The detection limit for the quantitation by the present method is 0.09 ng/ml of plasma. The method has sufficient sensitivity to permit pharmacokinetic studies with human subjects following the oral administration of gallopamil hydrochloride.  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