收费全文 | 915篇 |
免费 | 45篇 |
国内免费 | 91篇 |
农学 | 12篇 |
基础科学 | 1篇 |
14篇 | |
综合类 | 190篇 |
农作物 | 8篇 |
水产渔业 | 34篇 |
畜牧兽医 | 790篇 |
园艺 | 1篇 |
植物保护 | 1篇 |
2023年 | 5篇 |
2022年 | 39篇 |
2021年 | 55篇 |
2020年 | 43篇 |
2019年 | 62篇 |
2018年 | 30篇 |
2017年 | 34篇 |
2016年 | 33篇 |
2015年 | 35篇 |
2014年 | 52篇 |
2013年 | 51篇 |
2012年 | 58篇 |
2011年 | 80篇 |
2010年 | 53篇 |
2009年 | 60篇 |
2008年 | 39篇 |
2007年 | 58篇 |
2006年 | 41篇 |
2005年 | 42篇 |
2004年 | 25篇 |
2003年 | 24篇 |
2002年 | 15篇 |
2001年 | 23篇 |
2000年 | 17篇 |
1999年 | 12篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 9篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
2. A total of 72 chickens from each of these breeds were randomly distributed to 4 pens to provide equal numbers of two replicate pens maintained as infected and control (uninfected). All chickens in infected groups were inoculated orally with 1 × 108 CFU (1 ml dose) of a field isolate of S. gallinarum, at the age of 8 and 16 weeks given over 5 consecutive days. Growth performance, clinical signs, gross pathological lesions and antibody responses were measured.
3. A significantly higher mortality was observed in the brown layers compared with the white layers, and clinical signs and mortality were absent in village chickens. However, a large number of birds with gross lesions and high antibody titres were detected in village chickens, indicating that birds had the disease subclinically. Commercial breeds had a significantly higher body weight, feed intake and feed conversion efficiency.
4. There was a significantly lower proportion of positive reactors in village chickens in the whole-blood agglutination test (35%) compared to brown (100%) and white (90%) layers even after the second inoculation. Uninfected birds were negative in all groups. The indirect enzyme-linked immunosorbent assay confirmed these observations.
5. These results suggest that the indigenous breed had superior natural resistance to S. gallinarum than the commercial breeds. 相似文献
2. Using a 5 × 2 factorial arrangement of treatments, 800 1-d-old male Cobb 500 broilers were used to study the effects of feed additives (without additive or with zinc bacitracin, B. subtilis, YCW, and the combination of B. subtilis and YCW), pathogen challenge (without or with Clostridium perfringens challenge), and their interactive effects.
3. C. perfringens infection increased intestinal lesions scores, damaged intestinal histomorphology, increased serum endotoxin concentration, cytokine mRNA expression and intestinal population of C. perfringens and Escherichia coli and decreased ileal bifidobacteria numbers. The 4 additives decreased serum endotoxin. Zinc bacitracin tended to decrease cytokine mRNA expression and the intestinal number of C. perfringens and E. coli. B. subtilis, YCW and their combination increased cytokine mRNA expression. B. subtilis and YCW decreased the number of C. perfringens and E. coli in the ileum, and their combination decreased pathogens numbers in the ileum and caecum.
4. In conclusion, B. subtilis, YCW and their combination improved the intestinal health of NE-infected broilers, and could be potential alternatives to antibiotics. 相似文献
2. Tissue-specific expression analysis of NOD1, receptor-interacting serine-threonine kinase 2 (RIPK2), nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase 11 (MAPK11 or p38) by quantitative real-time PCR (qRT-PCR) revealed their wide distribution in various organs and tissues.
3. Salmonella pullorum infection activated NOD1 receptor signalling in vivo and in vitro, resulting in significant induction of downstream signalling molecules RIPK2, NF-κB/p65, MAPK11/p38 and the effector molecules IL-1b and IL-8.
4. Activation of NOD1 by its agonist bacterial γ-D-glutamyl-meso-diaminopimelic acid (iE-DAP) in HD11 cells induced the adapter molecular RIPK2 and activated the NF-κB/p65 and MAPK11/p38 pathways, resulting in an increase in IL-8 but not IL-1β. Additionally, inhibition of NOD1 using NOD1-shRNA resulted in downregulation of RIPK2, MAPK11 and IL-8, while NF-κB/p65 and IL-1β were unaltered.
5. These results highlight the important role of NOD1 receptors in eliciting the innate immune response following pathogenic invasion in chicken. 相似文献