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   270篇
  免费   4篇
  国内免费   5篇
化学   149篇
晶体学   6篇
力学   11篇
数学   77篇
物理学   36篇
  2023年   1篇
  2022年   7篇
  2021年   6篇
  2020年   10篇
  2019年   12篇
  2018年   9篇
  2017年   9篇
  2016年   16篇
  2015年   8篇
  2014年   14篇
  2013年   21篇
  2012年   14篇
  2011年   9篇
  2010年   8篇
  2009年   8篇
  2008年   11篇
  2007年   4篇
  2006年   6篇
  2005年   5篇
  2004年   3篇
  2003年   6篇
  2002年   6篇
  2001年   3篇
  2000年   3篇
  1998年   2篇
  1997年   1篇
  1996年   6篇
  1995年   7篇
  1994年   9篇
  1993年   6篇
  1992年   3篇
  1991年   3篇
  1990年   2篇
  1989年   2篇
  1988年   7篇
  1987年   4篇
  1986年   4篇
  1985年   3篇
  1984年   7篇
  1983年   3篇
  1981年   5篇
  1980年   1篇
  1979年   1篇
  1974年   1篇
  1973年   1篇
  1972年   1篇
  1970年   1篇
排序方式: 共有279条查询结果,搜索用时 15 毫秒
11.
12.
Journal of Radioanalytical and Nuclear Chemistry - To keep the accredited category for the gamma spectrometry test in our laboratory, the efficiency curves of a HPGe detector for soil sample in...  相似文献   
13.
14.
The copper ferrite-catalyzed, directed coupling of ortho-arylated phenols and dialkylformamides in the presence of a peroxide oxidant is described. Acyclic and cyclic amides were compatible with the reaction conditions. The copper ferrite catalyst is heterogeneous since substantial leaching was not detected and re-use of the catalyst for 9 consecutive reactions proceeded without a significant decrease in yield. To the best of our knowledge, this transformation has not been previously performed under heterogeneous catalysis conditions.  相似文献   
15.
Le Dung 《偏微分方程通讯》2013,38(3-4):413-433
We show that a-priori weak Lp dissipativity implies strong L dissipativity for a class of weakly coupled quasilinear parabolic systems satisfies general structure conditions. The existence of global attractors of general nonlinear reaction diffusion systems will be proven.  相似文献   
16.
17.
18.
Hypersonic longitudinal sound velocities in five silicate and alumino-silicate liquids have been measured between 293 and 2550 K by Brillouin spectroscopy. Together with previous observations for four other glasses and liquids of the system SiO2-Al2O3-CaO-MgO, these results are used to discuss changes in hypersonic velocities in three adjacent temperature domains, i.e., below, in, and above the glass transformation range. The temperature dependence of Brillouin velocities is consistent with the observed variations with temperature of viscosity, density, and mean heat capacity for the same three temperature domains. These variations of physical properties of alumino-silicate liquids are qualitatively in agreement with the Inherent Structure Theory for liquids.  相似文献   
19.
Journal of Radioanalytical and Nuclear Chemistry - The aim of this study was to find trace elements that increase risk of breast cancer based on the deviation of the concentration of trace elements...  相似文献   
20.
Mineral sands are mined in several countries to supply to the titanium and zircon producing industries. Coastal black mineral sands usually contain, besides ilmenite (FeTiO3) and rutile (TiO2), radioactive minerals such as zircon (ZrSiO4) and monazite (RePO4). Radon and thoron activity concentration originated from natural radioactive contents of the black mineral sand was monitored at the extraction and processing for black minerals in the coastal areas of Ha Tinh Province, one of the around 40 coastal mineral sand deposits in Vietnam. The survey was carried out with the Raduet chambers made by Radosys Ltd—Hungary. The obtained results for 25 investigated points show that the measured values are not high in the residential houses and in case of the sand extraction site as well. At the titanium processing plant the measured values were higher than outside the facility (Radon: 18–55 Bq/m3 with average of 34 Bq/3 and Thoron 33–118 Bq/m3 with average of 58 Bq/m3) but still comparable to the average concentration of the world published by UNSCEAR. The typical outdoor levels of radon and thoron gas are each of the order of 10 Bq/m3. Although the radon concentrations were low in the zircon and titanium processing plants, the thoron concentrations in the houses for separating rutile and zircon were very high. At zircon processing factory, the thoron concentration could reach 2,931 Bq/m3 and the estimated annual effective dose would be 21.4 mSv/a. Intervention has to be taken in order to reduce the thoron level in this factory since the level of thoron and its progenies corresponding to an annual occupational effective dose is beyond the action level of 6 mSv/a.  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