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   177篇
  免费   0篇
化学   54篇
晶体学   6篇
力学   35篇
物理学   82篇
  2022年   2篇
  2021年   2篇
  2020年   7篇
  2019年   2篇
  2018年   7篇
  2017年   7篇
  2016年   10篇
  2015年   4篇
  2014年   6篇
  2013年   3篇
  2012年   2篇
  2010年   4篇
  2009年   4篇
  2008年   4篇
  2007年   4篇
  2006年   5篇
  2004年   5篇
  2002年   4篇
  1999年   3篇
  1998年   4篇
  1997年   3篇
  1995年   3篇
  1989年   3篇
  1988年   2篇
  1987年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1979年   1篇
  1978年   3篇
  1977年   3篇
  1976年   2篇
  1975年   4篇
  1973年   10篇
  1972年   3篇
  1971年   6篇
  1970年   4篇
  1969年   4篇
  1968年   2篇
  1967年   2篇
  1966年   2篇
  1963年   1篇
  1962年   1篇
  1961年   3篇
  1959年   2篇
  1957年   1篇
排序方式: 共有177条查询结果,搜索用时 15 毫秒
81.
Complex metal oxides with the composition LiNi0.33Mn0.33Co0.33O2 prepared by various methods: sol–gel method, solid-phase method, and thermal destruction of metal-containing compounds in oil were studied. The results of elemental analysis, TGA/DSC, powder X-ray diffraction, SEM, TEM, as well as the results of electrochemical testing of the cathodes based on the obtained materials are presented. The complex metal oxides LiNi0.33Mn0.33Co0.33O2 prepared by sol–gel processes and thermal destruction of metal-containing compounds in oil consist of primary nanosized crystallites with an average size of 90 nm covered by a nanometer carbon layer, which improves the electrochemical characteristics of lithium ion batteries.  相似文献   
82.
Results of the optical diagnostics of the plasma armature in railgun macroparticle accelerators are summarized. Determining the structure of the plasma armature and measuring its brightness and temperature at an initial stage of high-current discharge are the focus of attention. Experiments show that the plasma induced by the electric explosion of a copper foil undergoes complex variations that include plasma stratification. The plasma structure continuously changes, being of a complicated, irregular character. The lifetime of an individual stratum changes within 1 to 10 μs. In experiments on solid-body acceleration, the arc burns for a long time at the foil site, where a strong electrode erosion takes place. As the body passes through the railgun channel, the plasma armature continuously increases its length so that it gradually occupies the entire accelerator channel. the current is observed to redistribute itself from the front towards the end face of the plasma armature. The maximum brightness temperature measured in the experiments is 26000±2600 K. As is shown by the experiments, it is arguable that a magnetic-compressed discharge may be realized in a railgun solid-body accelerator with a plasma armature  相似文献   
83.
84.
85.
Methods for the synthesis of compounds containing two or more pyrimidine rings linked through aliphatic chains with different numbers of carbon atoms are described.Deceased.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 335–340, February, 1995  相似文献   
86.
The effect of fine grinding of gold-bearing geochemical samples on the representative sample size and the recovery of gold and silver in fire-assay fusion was studied experimentally. A method is proposed for the improvement of grinding and sampling procedures in fire assay.  相似文献   
87.
The dependence of the representative weight of a geological sample of quartz sulfide gold-containing ores on their particle size is studied. It is shown that the weight of the furrow samples selected in the chemical assay of gold-containing ores of the first group can be reduced two-to threefold.  相似文献   
88.
89.
The appearance of magnetization in a crystal of molecular magnets under the action of a circular polarized electromagnetic wave of millimeter range is considered. The time dependence of magnetization is obtained for the case of resonance and for approximation of the single relaxation time.  相似文献   
90.
Experience in applying conventional and epithermal neutron activation analysis for some challenging areas of life sciences and material science is reviewed. For more than 30 years of its operation the radioanalytical complex REGATA at the IBR-2 reactor in Dubna has become a source of analytical data for the environmental studies, marine geology, biotechnology and medicine, technological process of diamond and boron nitride synthesis, archaeology, nanomaterials, etc. In spite of competing non-nuclear analytical techniques (AAS, ICP-ES, ICP-MS, etc.), the reactor neutron activation analysis (NAA) as a primary (ratio) method continues to be the most powerful multielement analytical technique providing quantification of trace elements at ultralow levels. Combined with modern statistical data treatment of large arrays of data, GIS (geographic information system) technologies, electron scanning microscopy, tomography, and others, NAA serves to obtain actual, practical results resumed in the review. The perspectives of using the upgraded reactor IBR-2M for analytical investigations are discussed.  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