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   106篇
  免费   2篇
化学   63篇
晶体学   7篇
力学   1篇
数学   2篇
物理学   35篇
  2021年   1篇
  2018年   3篇
  2017年   1篇
  2016年   1篇
  2014年   1篇
  2013年   7篇
  2012年   7篇
  2011年   4篇
  2010年   4篇
  2009年   3篇
  2008年   3篇
  2007年   2篇
  2006年   6篇
  2005年   10篇
  2004年   1篇
  2003年   7篇
  2002年   5篇
  2001年   2篇
  2000年   2篇
  1998年   2篇
  1997年   1篇
  1995年   1篇
  1993年   1篇
  1992年   2篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
  1981年   5篇
  1980年   4篇
  1978年   3篇
  1976年   3篇
  1974年   1篇
  1966年   1篇
  1963年   1篇
排序方式: 共有108条查询结果,搜索用时 31 毫秒
71.
The infrared band of dinitrogen species adsorbed on a Co/Al2O3 catalyst was observed at 2214 cm-1, which shifted in the presence of adsorbed and gaseous hydrogen.  相似文献   
72.
A novel way of determining the Hamiltonian of the interacting boson model (IBM) is proposed. Based on the fact that the potential energy surface of the mean-field model, e.g., the Skyrme model, can be simulated by that of the IBM, parameters of the IBM Hamiltonian are obtained. By this method, the multifermion dynamics of surface deformation can be mapped, in a good approximation, onto a boson system. The validity of this process is examined for Sm and Ba isotopes, and an application is presented to an unexplored territory of the nuclear chart, namely, the right lower corner of 208Pb.  相似文献   
73.
The tensor force is implemented into the mean-field model so that the evolution of nuclear shells can be described for exotic nuclei as well as stable ones. Besides the tensor-force part simulating the meson exchange, the model is an extension of the successful Gogny model. One of the major issues of rare-isotope beam physics is a reduced spin-orbit splitting in neutron-rich exotic nuclei. It will be shown that the effect of the tensor force on this splitting is larger than or about equal to the one due to the neutron skin. We will present predictions for stable and exotic nuclei with comparisons to conventional results and experimental data.  相似文献   
74.
"Substituent on benzenesulfonyl group" effect of 8-benzenesulfonamidoquinoline [N-(8-quinolyl)benzenesulfonamide, Hbsq] as bidentate chelate extractant for divalent metal cations was investigated with using Hbsq and its eight derivatives. Introduction of electron-withdrawing substituent on the benzenesulfonyl group in Hbsq enhanced the extractability that originated from its inductive effect. Furthermore, a bulky substituent on an ortho-position of the benzenesulfonyl group resulted in no steric effect in extraction, whereas the existence of two substituents on each ortho-position caused lower extraction performance due to steric hindrance.  相似文献   
75.
76.
77.
78.
The first examples of air‐stable 20π‐electron 5,10,15,20‐tetraaryl‐5,15‐diaza‐5,15‐dihydroporphyrins, their 18π‐electron dications, and the 19π‐electron radical cation were prepared through metal‐templated annulation of nickel(II) bis(5‐arylamino‐3‐chloro‐8‐mesityldipyrrin) complexes followed by oxidation. The neutral 20π‐electron derivatives are antiaromatic and the cationic 18π‐electron derivatives are aromatic in terms of the magnetic criterion of aromaticity. The meso N atoms in these diazaporphyrinoids give rise to characteristic redox and optical properties for the compounds that are not typical of isoelectronic 5,10,15,20‐tetraarylporphyrins.  相似文献   
79.
X-ray photoelectron (XPS) and ultraviolet photoelectron (UPS) spectroscopic techniques have been employed to study the chemisorption of various molecules over metal-phthalocyanines (MePc). It was revealed that pyridine is adsorbed on the Fe atom in FePc which is accompanied by a change in the spin state without transfer of net electron charge, while HCOOH is heterolytically dissociated, the formate ion staying on the central metal atom and the proton on the bridge N atom of the porphyrin ring. H2O on MgPc behaved like HCOOH, with a proton being adsorbed at a bridge N atom. On the basis of these results, the catalytic decomposition of HCOOH and adsorption of pyridine on MePc are discussed.  相似文献   
80.
Abstract— On treatment with 8-methoxypsoralen plus near UV light, an excisionless ( uvrB- ) strain of Escherichia coli showed about 3– and 10 times higher sensitivities to killing and mutation, respectively, than its parental strain. On re-irradiation with near UV in the absence of unbound psoralen, the uvrB- strain pretreated with psoralen plus near UV showed a decrease in both survival and mutation. After treatment with psoralen plus near UV, re-irradiation of T7 DNA in the absence of unbound psoralen caused an increase in the cross-linked fraction with an equivalent decrease in the non-cross-linked fraction. From these and previous results, we conclude that monoadducts produced by treatment with psoralen plus near UV are converted to cross-links by further irradiation and that, in E. coli , monoadducts are responsible for the mutation induced by psoralen-plus-light whereas cross-links are the major cause of its lethal action.  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