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   580篇
  免费   31篇
  国内免费   1篇
  612篇
  2024年   3篇
  2023年   5篇
  2022年   8篇
  2021年   17篇
  2020年   13篇
  2019年   20篇
  2018年   17篇
  2017年   10篇
  2016年   13篇
  2015年   23篇
  2014年   27篇
  2013年   41篇
  2012年   40篇
  2011年   25篇
  2010年   20篇
  2009年   20篇
  2008年   22篇
  2007年   23篇
  2006年   24篇
  2005年   20篇
  2004年   21篇
  2003年   26篇
  2002年   12篇
  2001年   12篇
  2000年   11篇
  1999年   5篇
  1998年   7篇
  1997年   6篇
  1996年   4篇
  1991年   3篇
  1989年   3篇
  1988年   5篇
  1987年   3篇
  1986年   3篇
  1984年   3篇
  1983年   6篇
  1979年   2篇
  1978年   5篇
  1977年   4篇
  1976年   7篇
  1975年   8篇
  1974年   7篇
  1973年   8篇
  1972年   7篇
  1971年   10篇
  1970年   5篇
  1969年   5篇
  1968年   4篇
  1967年   6篇
  1966年   3篇
排序方式: 共有612条查询结果,搜索用时 0 毫秒
601.
602.
In order to characterize the protein composition of rat bile, the bile duct was cannulated in 250 g male Wistar rats and biliary proteins were examined over 48 h. Total protein secretion was monitored by the Cu2+--Folin differential test while individual proteins were characterized by sodium dodecyl sulfate (SDS) and non-SDS polyacrylamide gel electrophoresis. The relative contribution of various proteins was evaluated by densitometric scanning of the stained gels. It was observed that both total biliary protein secretion and the protein polypeptide profiles remained constant throughout the 48h. This is in comparison with biliary bile-acid secretion which fluctuates markedly during this time period both in quantity and composition. It is concluded that biliary secretion is probably not related to the biliary secretion of bile acids.  相似文献   
603.
604.
605.
The objectives of the study were to determine the chemical constituents of rainbow trout (Salmo gairdneri) during the first 14 months of life, to study the effects of starvation on the body composition of trout, and to measure organ weights during the first 14 months of life. Body fat and protein content as a percentage of body weight increased with age, the water content declined, and the ash content remained constant during the first 14 months of life. There were no significant differences in body composition between immature male and female rainbow trout. Total body ions as a proportion of ash content decreased until the 10th month and then began to increase. During starvation, fat was used as the primary source of energy while water and ash content increased and protein content remained constant as a percentage of body weight. The gall bladder, liver, and air bladder remained relatively constant as a percentage of body weight during the first year of life. As body weight increased, the relative weight of brain, heart, and digestive system decreased while the gonad and spleen weight increased.  相似文献   
606.
607.
608.
Summary Culture studies revealed that 54.3 % of 70 mouth samples and 15.1 % of 371 throat samples from captive male and female baboons contained yeasts.Candida albicans was found to be the highest single species isolated from the oral cavity of both sexes, with the exception ofTrichosporon, which was slightly higher in the mouths of female baboons.There is a slight indication that the yeast flora of the female oral cavity is higher than that of the male. Similarly, there is a close parallelism between the oral mycoflora of human beings and that of the baboons studied.  相似文献   
609.
Human adenovirus cloning vectors based on infectious bacterial plasmids   总被引:8,自引:0,他引:8  
By making use of the fact that human adenovirus DNA circularizes in infected cells, and that circular forms of the viral genome are infectious, we have developed an improved adenovirus-based cloning system. A deletion mutant of adenovirus type 5 (Ad5) with deletions in early regions 1 (E1) and 3 (E3) was converted to a bacterial plasmid which can regenerate infectious virus following transfection into human 293 cells. A single XbaI recognition site in the deleted E3 region serves as a site for the insertion of foreign DNA. We have used this system to clone a number of genes into the Ad5 genome and describe the insertion of the neomycin/G418 resistance marker into Ad5 as an example.  相似文献   
610.
Many investigators have sought, but failed to find, ethnic differences in the number and regional distribution of active sweat glands. In this study measurements have been made of sweat secreted on one hand and also on the whole body of Whites and Blacks walking in desert heat. Whites numbered 31 men and 27 women, ages 30 to 88 years; there were 21 Black men and 31 Black women, ages 16 to 61 years. Each walked on three occasions for 1 hour at a rate that required an oxygen consumption of about 40% of aerobic capacity. Ambient temperature ranged from 32 to 44°C in 1979 and 1980; means were 38.4°C in 1979 and 36.7°C in 1980. There was no sweat in the gloves of many Blacks; this was true of only a few Whites. Volume of body sweat increased in both races with rate of walking; volume of hand sweat increased more in Whites than in Blacks. The Mann-Whitney test revealed that volumes of hand sweat were significantly greater for Whites than for Blacks. It was concluded that in desert walks most Whites and few Blacks sweat freely on their hands. In samples of hand sweat, Na+, K+, and Cl? were determined. Concentrations of each ion varied widely in both races, and were unrelated to race. Concentrations of Na+ and Cl? generally are somewhat higher in hand sweat than in body sweat; concentrations of K+ are much higher. It follows that the values for concentration of Na+ and Cl? reported in Table 3 probably are somewhat higher than would have been found in body sweat, and concentrations of K+ are probably much higher.  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