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   171篇
  免费   2篇
化学   91篇
晶体学   3篇
力学   6篇
数学   20篇
物理学   53篇
  2022年   6篇
  2021年   5篇
  2020年   5篇
  2019年   5篇
  2018年   4篇
  2017年   12篇
  2016年   16篇
  2015年   5篇
  2014年   8篇
  2013年   14篇
  2012年   7篇
  2011年   10篇
  2010年   4篇
  2009年   5篇
  2008年   5篇
  2007年   6篇
  2006年   7篇
  2005年   4篇
  2004年   5篇
  2003年   3篇
  2002年   2篇
  2001年   2篇
  2000年   2篇
  1999年   4篇
  1998年   3篇
  1997年   2篇
  1996年   3篇
  1995年   2篇
  1994年   3篇
  1993年   4篇
  1991年   1篇
  1986年   1篇
  1984年   3篇
  1983年   2篇
  1980年   1篇
  1978年   1篇
  1974年   1篇
排序方式: 共有173条查询结果,搜索用时 0 毫秒
71.
A new direct measurement of the final dt sticking probability s using a special data analysis called the survived muon method is presented. The data were obtained at PSI using a high pressure ionization chamber with H/D/T gas mixtures. The method can provide information on final sticking dt +n independent of theoretical models of stripping and initial sticking. It was found: s=(0.57±0.07±0.02)%. The experiment and the analysis method are discussed in detail.  相似文献   
72.
The sticking process dt + n, which constitutes the most severe limit to the number of fusions which a muon can catalyze, is reviewed. Many attempts were made to determine by calculations and measurements the probability for initial sticking s 0 (immediately after dt fusion) and for final sticking s (after the came to rest). Previous results based on neutron disappearance rates and on the observation of -X-rays were controversial and also in some disagreement with theory. New data are reported from PSI on direct observation of final sticking, using a setup with the St. Petersburg ionization chamber. These data mark a significant improvement in reliability and may clarify questions concerning previous discrepancies. The new results is s(0.56±0.04)%, lower than the theory prediction s=(0.65±0.03)%, at medium density.  相似文献   
73.
74.
75.
A series of volatile mixed-ligand iridium(I) complexes [Ir(cod)(L)] (cod = cyclooctadiene-1,5, L = R1C(O)CHC(O)R2, R1 = CF3, R2 = CF3 – hfac 1, Me – tfac 2; tBu – ptac 3, Ph – btfac 4, R1 = R2 = Me – acac 5; tBu – thd 6) was synthesized and investigated in terms of usage in metal-organic chemical vapor deposition processes. Compounds 3 and 4 were obtained for the first time. All compounds were investigated by elemental analysis, NMR spectroscopy, thermogravimetry, and mass spectrometry. Crystal structures of 24 and 6 were determined by single-crystal XRD. The influence of β-diketonate ligand on the thermal properties of complexes in condensed and gas phase was revealed. The following volatility order was arranged: L = hfac 1 > tfac 2 ≈ ptac 3 > acac 5 > thd 6 > btfac 4. Complexes 1 and 6 vapors demonstrated the lowest and the highest thermostability, respectively.  相似文献   
76.
Computer simulation has been used to study the properties of radiation defects in a graphene sheet. Several possible stable configurations of 3D radiation defects in graphene have been simulated. Several types of absorbed species were calculated involving a single carbon atom and a dumbbell absorbed at graphene sheet surface and a dumbbell configuration at a vacancy created by radiation knocking out a carbon atom. The calculations also included the effect of structural relaxation. The defect caused by the atom being displaced from the structure converted the sheet from metallic to semiconducting.  相似文献   
77.
78.
79.
X-ray phase analysis, synchronous thermal analysis, and IR spectroscopy were used to study the process in which an iron-molybdenum catalyst for partial oxidation of methanol to formaldehyde is prepared. The influence exerted by the pH of the medium on the composition, structure, and properties of the oxide Fe–Mo catalyst was examined. It was found that the amount of the active component in a sample obtained at pH 2 is the largest, and the sample exhibits the best activity in the reaction of methanol oxidation to formaldehyde. The possibility was examined of the occurrence of side reactions in which carbon monoxide is converted. It was found that the conversion occurs only on samples obtained at pH > 2.  相似文献   
80.
Russian Journal of Applied Chemistry - Pressure-sensitive polymer adhesives based on styrene–butadiene–styrene rubbers and aromatic petroleum hydrocarbon resins making the block...  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