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   7128篇
  免费   3384篇
  国内免费   34篇
林业   208篇
农学   508篇
基础科学   40篇
  1391篇
综合类   168篇
农作物   226篇
水产渔业   2522篇
畜牧兽医   4188篇
园艺   14篇
植物保护   1281篇
  2024年   2篇
  2023年   4篇
  2022年   34篇
  2021年   156篇
  2020年   490篇
  2019年   1054篇
  2018年   905篇
  2017年   954篇
  2016年   946篇
  2015年   855篇
  2014年   845篇
  2013年   998篇
  2012年   495篇
  2011年   512篇
  2010年   632篇
  2009年   288篇
  2008年   279篇
  2007年   131篇
  2006年   132篇
  2005年   116篇
  2004年   113篇
  2003年   103篇
  2002年   119篇
  2001年   96篇
  2000年   118篇
  1999年   22篇
  1998年   13篇
  1997年   18篇
  1996年   15篇
  1995年   7篇
  1994年   7篇
  1993年   13篇
  1992年   3篇
  1991年   5篇
  1990年   8篇
  1989年   3篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1983年   2篇
  1982年   3篇
  1978年   6篇
  1977年   5篇
  1975年   3篇
  1974年   3篇
  1970年   4篇
  1963年   1篇
  1908年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.

Background

Metabolic profile was initially designed as a presymptomatic diagnostic aid based on statistical analyses of blood metabolites to provide an early warning of certain types of metabolic disorder. However, there is little metabolic profile data available about Korean Hanwoo cows. Therefore, this study aimed to determine the reference intervals of metabolic profile for Korean Hanwoo cows.

Methods

Healthy animals (2,205) were selected and divided into early (day 1 to 95), middle (day 96 to 190) and late (day 191 to 285) period according to their gestating period. Metabolic profile including total protein (TP), albumin (Alb), urea (UREA), glucose (Glu), total cholesterol (T-Cho), long-chain fatty acid (LCFA), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), creatinine (Crea), calcium (Ca), inorganic phosphorous (iP) and magnesium (Mg) were analyzed using a TBA-40FR automatic biochemical analyzer. The data of Korean Hanwoo cows were then compared to those of the Japanese Wagyu cows.

Results

Most of the data of the Korean Hanwoo cows were relatively higher than those of Japanese Wagyu cows, with the exception of Glu and GGT. This may indicate that the nutritional level of feed for the Korean Hanwoo cows was higher than that of the Japanese Wagyu cows because of the different feeding system. In particular, relatively higher levels of UREA and LCFA were observed in the Korean Hanwoo cows, and this may also contribute to the low reproduction efficiency.

Conclusions

These findings may provide some theoretical basis for understanding the reproductive and feeding situation of Korean Hanwoo cows.  相似文献   
92.
93.
94.
95.
96.
97.
98.
99.
Kaempferol (KAE) is a natural flavonoid present in different plant species and exhibits anti‐inflammatory, antioxidant, and anticancer therapeutic properties. In the present study, we investigated the influence and underlying mechanisms of KAE supplementation on porcine oocytes during in vitro aging. The results show that KAE treatment can alleviate the aging‐related reduction of developmental competence. We observed that the blastocyst production rate in aged oocytes treated with 0.1 μM KAE was significantly higher than in untreated aging oocytes (36.78 ± 0.86% vs. 27.55 ± 2.60%, respectively, p < .05). The KAE‐treated aging oocytes had significantly reduced levels of reactive oxygen species (p < .05). Furthermore, the mRNA levels of the embryonic pluripotency‐related genes Oct4, NANOG, and ITGA5 were significantly increased in blastocysts derived from KAE‐treated oocytes (p < .05). During excessive oocyte culture, KAE treatment maintained the mitochondrial membrane potential and reduced apoptosis; however, this was not observed in untreated aging oocytes. In conclusion, our results suggest that KAE treatment can alleviate the aging of porcine oocytes by reducing oxidative stress and improving mitochondrial function.  相似文献   
100.
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