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   281190篇
  免费   16051篇
  国内免费   658篇
林业   24327篇
农学   14202篇
基础科学   2980篇
  45614篇
综合类   27894篇
农作物   17627篇
水产渔业   17696篇
畜牧兽医   116312篇
园艺   6421篇
植物保护   24826篇
  2021年   2546篇
  2020年   2932篇
  2019年   3722篇
  2018年   4353篇
  2017年   4733篇
  2016年   5005篇
  2015年   4461篇
  2014年   5852篇
  2013年   16427篇
  2012年   7574篇
  2011年   9680篇
  2010年   7948篇
  2009年   8415篇
  2008年   9013篇
  2007年   8224篇
  2006年   8555篇
  2005年   7763篇
  2004年   7571篇
  2003年   7426篇
  2002年   6621篇
  2001年   7515篇
  2000年   7212篇
  1999年   6460篇
  1998年   4251篇
  1997年   4297篇
  1996年   4034篇
  1995年   4602篇
  1994年   4007篇
  1993年   3689篇
  1992年   4997篇
  1991年   5224篇
  1990年   5026篇
  1989年   5026篇
  1988年   4445篇
  1987年   4478篇
  1986年   4338篇
  1985年   4522篇
  1984年   4111篇
  1983年   3818篇
  1982年   3059篇
  1981年   2911篇
  1980年   2860篇
  1979年   3488篇
  1978年   3042篇
  1977年   2812篇
  1976年   2629篇
  1975年   2503篇
  1974年   2672篇
  1973年   2754篇
  1972年   2447篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
996.
997.
998.
999.
1. The growth of three distinct adipose tissue depots around the abdomen, neck and thigh was measured in a commercial strain of broiler, and related to the changes in activity of lipoprotein lipase within each depot.

2. At 10 d of age there was no significant difference between the weights of the depots. Thereafter the abdominal fat pad exhibited a much greater rate of growth than the other two depots so that by 55 d of age the abdominal fat pad was 4 times the size of the leg depot and 3.4 times the size of the neck depot.

3. Changes in total lipoprotein lipase activity for all three depots showed a similar pattern to the changes in their weight.

4. When [14C]‐VLDL was injected intravenously into birds at 15 and 57 d of age the percentage taken up into the abdominal fat pad was greater than that into the other two depots at both ages. At 57 d of age the abdominal fat pad had a 2.3‐fold greater uptake than at 15 d whereas the other two depots showed no significant differences at the two ages.

5. These results provide further evidence for a key role of lipoprotein lipase in regulating adipose tissue growth in broilers. They also demonstrate that although the abdominal fat pad has been used in a number of studies of adipose tissue metabolism it is not necessarily representative of other depots.  相似文献   

1000.
Alleviation of postanesthetic hypoxemia in the horse   总被引:1,自引:0,他引:1       下载免费PDF全文
This study was designed to investigate the effect of the nasotracheal insufflation of oxygen at a flow rate of 15 L/min on the arterial partial pressure of oxygen during the recovery period following inhalation anesthesia in the horse. It has been stated that this is a suitable flow rate to prevent postoperative hypoxemia but without any experimental evidence to support those statements. Horses being used for the study of healing of cartilage were anesthetized on two separate occasions. Following one period of anesthesia they were allowed to recover breathing room air, and following the other period of anesthesia oxygen was insufflated into the trachea at 15 L/min throughout the recovery period. This permitted each horse to act as its own control and allowed statistical analysis using Student's t-test for paired samples.

The insufflated horses had a higher arterial partial pressure of oxygen during the recovery period than did the noninsufflated horses (p < 0.05).

  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