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   276244篇
  免费   30296篇
  国内免费   254篇
  306794篇
  2016年   3080篇
  2015年   4297篇
  2014年   4850篇
  2013年   7381篇
  2012年   7938篇
  2011年   8192篇
  2010年   5436篇
  2009年   5013篇
  2008年   7416篇
  2007年   7534篇
  2006年   7173篇
  2005年   6920篇
  2004年   6830篇
  2003年   6607篇
  2002年   6402篇
  2001年   11755篇
  2000年   11800篇
  1999年   9333篇
  1998年   3392篇
  1997年   3623篇
  1996年   3524篇
  1995年   3128篇
  1994年   3114篇
  1993年   3108篇
  1992年   7875篇
  1991年   7858篇
  1990年   7517篇
  1989年   7480篇
  1988年   6863篇
  1987年   6608篇
  1986年   6028篇
  1985年   6220篇
  1984年   5155篇
  1983年   4343篇
  1982年   3376篇
  1981年   3149篇
  1980年   2949篇
  1979年   4957篇
  1978年   3817篇
  1977年   3733篇
  1976年   3438篇
  1975年   3790篇
  1974年   4182篇
  1973年   4095篇
  1972年   3670篇
  1971年   3439篇
  1970年   3088篇
  1969年   2997篇
  1968年   2747篇
  1967年   2374篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
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   
102.
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   
103.
104.
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   
105.
106.
107.
108.
109.
110.
In experiments on CBA mice it was shown that migration of 51Cr-labeled spleen lymphocytes, injected intravenously, to lymph nodes of intact recipients was suppressed 6-24 months after the administration of a radiopharmaceutic preparation of selenium-75-selenomethionine in a quantity forming the doses of 1 Gy and 1.5 Gy absorbed within the whole body and lymphoid organs, respectively. Migration of labeled lymphocytes to the liver, kidneys and lungs, as well as their retention in the circulating blood, were increased. As the result of the migration disorders the specific affinity of lymphocytes for peripheral lymphoid tissue decreased.  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