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   281756篇
  免费   30602篇
  国内免费   263篇
  2018年   2500篇
  2016年   3319篇
  2015年   4663篇
  2014年   5218篇
  2013年   7831篇
  2012年   8383篇
  2011年   8619篇
  2010年   5687篇
  2009年   5209篇
  2008年   7663篇
  2007年   7795篇
  2006年   7365篇
  2005年   7075篇
  2004年   6980篇
  2003年   6721篇
  2002年   6516篇
  2001年   11830篇
  2000年   11856篇
  1999年   9374篇
  1998年   3425篇
  1997年   3649篇
  1996年   3543篇
  1995年   3152篇
  1994年   3131篇
  1993年   3124篇
  1992年   7920篇
  1991年   7886篇
  1990年   7560篇
  1989年   7518篇
  1988年   6882篇
  1987年   6627篇
  1986年   6049篇
  1985年   6230篇
  1984年   5178篇
  1983年   4370篇
  1982年   3403篇
  1981年   3173篇
  1980年   2976篇
  1979年   4966篇
  1978年   3832篇
  1977年   3739篇
  1976年   3442篇
  1975年   3801篇
  1974年   4196篇
  1973年   4109篇
  1972年   3677篇
  1971年   3442篇
  1970年   3092篇
  1969年   3009篇
  1968年   2759篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
Irradiation conditions in which laboratory animals were kept in experimental laboratories of Chernobyl and Kiev after the accident at the Chernobyl A.P.S. are described. The data are presented on the spectral structural and activity of radionuclides in the diet as well as in the organs and tissues of the animals. The radiation loads have been estimated with regard to an external gamma component and the internal one contributed by the incorporated radionuclides. It has been shown that radiation doses received by the animals during their lifetime due to these contributions do not exceed units of cGy.  相似文献   
113.
On the basis of their own data and the literature the authors have analyzed the mechanism of biological action of low-level radiation on cells. In studying the harmful effect of gamma-radiation (10-40 cGy) on HeLa cells it was shown that damages occurred in 12 postirradiation generations. Analysis of cell distribution within the colonies has demonstrated that the share of colonies with low cell content and the number of giant cell increase. These data indicate that low-level radiation causes reproductive cell death that can occur not immediately but in later generations.  相似文献   
114.
115.
Peak area matching and linear regression were used to quantify eight chlorinated pesticides and polychlorinated biphenyls (as Aroclor 1260) in human serum. There are no statistically significant differences in data obtained by these two quantifying techniques which were indicated by the paired t-test. For chlorinated pesticides, p = 0.053-0.62, and for polychlorinated biphenyls (as Aroclor 1260), p = 0.64. Analyte residues for the chlorinated pesticides ranged from 0.5 ppb for hexachlorobenzene (HCB) to 186 ppb for dichlorodiphenyldichloroethylene (DDE). Analyte residues for the polychlorinated biphenyls (as Aroclor 1260) ranged from 5-114 ppb. The absolute mean percent difference between the two quantifying techniques ranged from 0.06% for DDE to 8.06% for dieldrin (HEOD) among the chlorinated pesticides. The absolute mean percent difference between the two quantifying techniques for the polychlorinated biphenyls (as Aroclor 1260) was 3.4%. Peak area matching and linear regression were found to be comparable for quantifying these environmental residues in serum when the following conditions apply: 1) the concentration of the chlorinated pesticides is greater than or equal to 0.5 ppb (e.g., HCB, hexachlorocyclohexane (HCCH), oxychlordane (OC), heptachlor epoxide (HE), transnonachlor (TN), HEOD, and dichlorodiphenyltrichloroethane (DDT); 2) the concentration of the chlorinated pesticide is greater than or equal to 3 ppb (e.g., DDE); and 3) the total concentration of polychlorinated biphenyls (e.g., as Aroclor 1260) is greater than or equal to 5 ppb.  相似文献   
116.
117.
118.
119.
120.
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