全文获取类型
收费全文 | 401篇 |
免费 | 36篇 |
专业分类
林业 | 15篇 |
农学 | 3篇 |
46篇 | |
综合类 | 51篇 |
农作物 | 10篇 |
水产渔业 | 24篇 |
畜牧兽医 | 245篇 |
园艺 | 27篇 |
植物保护 | 16篇 |
出版年
2024年 | 2篇 |
2023年 | 3篇 |
2022年 | 15篇 |
2021年 | 21篇 |
2020年 | 34篇 |
2019年 | 23篇 |
2018年 | 24篇 |
2017年 | 8篇 |
2016年 | 23篇 |
2015年 | 9篇 |
2014年 | 16篇 |
2013年 | 18篇 |
2012年 | 25篇 |
2011年 | 33篇 |
2010年 | 16篇 |
2009年 | 13篇 |
2008年 | 34篇 |
2007年 | 21篇 |
2006年 | 19篇 |
2005年 | 26篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 4篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1973年 | 1篇 |
1969年 | 2篇 |
1963年 | 1篇 |
排序方式: 共有437条查询结果,搜索用时 328 毫秒
131.
Wu GD Chen J Hoffmann C Bittinger K Chen YY Keilbaugh SA Bewtra M Knights D Walters WA Knight R Sinha R Gilroy E Gupta K Baldassano R Nessel L Li H Bushman FD Lewis JD 《Science (New York, N.Y.)》2011,334(6052):105-108
Diet strongly affects human health, partly by modulating gut microbiome composition. We used diet inventories and 16S rDNA sequencing to characterize fecal samples from 98 individuals. Fecal communities clustered into enterotypes distinguished primarily by levels of Bacteroides and Prevotella. Enterotypes were strongly associated with long-term diets, particularly protein and animal fat (Bacteroides) versus carbohydrates (Prevotella). A controlled-feeding study of 10 subjects showed that microbiome composition changed detectably within 24 hours of initiating a high-fat/low-fiber or low-fat/high-fiber diet, but that enterotype identity remained stable during the 10-day study. Thus, alternative enterotype states are associated with long-term diet. 相似文献
132.
133.
134.
OBJECTIVE: To determine the effect of oral hydrocortisone on intraocular pressure (IOP) in ocular normotensive dogs. ANIMALS STUDIED: Seventeen ocular normotensive dogs. Procedures Dogs were randomly assigned to treatment (n = 9) and control (n = 8) groups. Dogs in the treatment group received hydrocortisone, 3.3 mg/kg PO every 8 h, and dogs in the control group received gelatin capsule placebo PO every 8 h for 5 weeks. Applanation tonometry was performed on both eyes of all dogs prior to treatment and then once weekly for 5 weeks during hydrocortisone treatment. RESULTS: No significant effect of treatment was noted for right (P = 0.1013) or left (P = 0.1157) eyes during the treatment period, nor was there significant interaction of treatment by week for the right (P = 0.9456) or left (P = 0.3577) eyes. A significant rise in IOP over the treatment period was noted in both right (P < 0.0001) and left (P = 0.0006) eyes of both groups, but was unrelated to treatment. CONCLUSION: Orally administered hydrocortisone does not significantly increase IOP in nonglaucomatous dogs when administered over a 5-week period. 相似文献
135.
Erin E. McCandless Catherine A. Rugg Gregory J. Fici James E. Messamore Michelle M. Aleo Andrea J. Gonzales 《Veterinary immunology and immunopathology》2014,157(1-2):42-48
The canine cytokine IL-31 induces pruritus in dogs and can be detected in dogs with atopic dermatitis; however very little is understood around its interactions with specific canine cells. We hypothesize that IL-31 is involved in the progression of allergic skin disease by coordinating the interaction between the immune system with skin and neuronal systems. The goal of the following work was to identify cells that produce IL-31 as well as cells that may respond to this cytokine. Peripheral blood mononuclear cells (PBMCs) were collected from naïve and house dust mite (HDM) allergen-sensitized beagle dogs and used for ex vivo characterization of cytokine production assessed using ELISpot and quantitative immunoassay. Sensitization to HDM allergen induced a T-helper type 2 (Th2) cell phenotype characterized by an increase in the production of IL-4 protein. Interestingly, repeated allergen challenge over time also resulted in an increase in IFN-γ. Further evaluation showed that co-stimulation of Th2 polarized cells with antigen and the bacterial component Staphylococcus enterotoxin B (SEB) produced higher levels of IL-31 compared to either stimulant alone. Production of IL-31 when PBMCs were stimulated by T cell mitogens suggests T cells as a source of IL-31. Quantitative real-time PCR was utilized to determine expression of the IL-31 receptor alpha chain in canine cell lines and tissue. Canine monocytic cells, keratinocytes, and dorsal root ganglia were shown to express the IL-31 receptor alpha chain mRNA. In a multifaceted disease such as canine atopic dermatitis, the combination of Th2 polarization and microbial presence may lead to IL-31 mediated effects driving inflammation and pruritus by immune cells, keratinocytes, and direct neuronal stimulation. 相似文献
136.
Kovacs JJ Whalen EJ Liu R Xiao K Kim J Chen M Wang J Chen W Lefkowitz RJ 《Science (New York, N.Y.)》2008,320(5884):1777-1781
137.
Purines are synthesized de novo in 10 chemical steps that are catalyzed by six enzymes in eukaryotes. Studies in vitro have provided little evidence of anticipated protein-protein interactions that would enable substrate channeling and regulation of the metabolic flux. We applied fluorescence microscopy to HeLa cells and discovered that all six enzymes colocalize to form clusters in the cellular cytoplasm. The association and dissociation of these enzyme clusters can be regulated dynamically, by either changing the purine levels of or adding exogenous agents to the culture media. Collectively, the data provide strong evidence for the formation of a multi-enzyme complex, the "purinosome," to carry out de novo purine biosynthesis in cells. 相似文献
138.
139.
Sina Marsilio Shelley J. Newman James Scot Estep Paula R. Giaretta Jonathan A. Lidbury Emma Warry Andi Flory Paul S. Morley Katy Smoot Erin H. Seeley Matthew J. Powell Jan S. Suchodolski Jörg M. Steiner 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(2):669-677