全文获取类型
收费全文 | 3717篇 |
免费 | 282篇 |
专业分类
林业 | 105篇 |
农学 | 28篇 |
基础科学 | 12篇 |
218篇 | |
综合类 | 243篇 |
农作物 | 43篇 |
水产渔业 | 132篇 |
畜牧兽医 | 3129篇 |
园艺 | 27篇 |
植物保护 | 62篇 |
出版年
2023年 | 55篇 |
2021年 | 20篇 |
2020年 | 118篇 |
2019年 | 21篇 |
2018年 | 85篇 |
2017年 | 84篇 |
2016年 | 61篇 |
2015年 | 81篇 |
2014年 | 125篇 |
2013年 | 152篇 |
2012年 | 137篇 |
2011年 | 158篇 |
2010年 | 121篇 |
2009年 | 129篇 |
2008年 | 140篇 |
2007年 | 148篇 |
2006年 | 123篇 |
2005年 | 116篇 |
2004年 | 122篇 |
2003年 | 127篇 |
2002年 | 147篇 |
2001年 | 78篇 |
2000年 | 76篇 |
1999年 | 86篇 |
1998年 | 115篇 |
1997年 | 110篇 |
1996年 | 89篇 |
1995年 | 94篇 |
1994年 | 90篇 |
1993年 | 101篇 |
1992年 | 113篇 |
1991年 | 90篇 |
1990年 | 107篇 |
1989年 | 93篇 |
1988年 | 82篇 |
1987年 | 86篇 |
1986年 | 46篇 |
1985年 | 54篇 |
1984年 | 46篇 |
1983年 | 53篇 |
1982年 | 26篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1976年 | 5篇 |
1975年 | 5篇 |
1974年 | 5篇 |
1973年 | 7篇 |
1972年 | 8篇 |
1970年 | 9篇 |
排序方式: 共有3999条查询结果,搜索用时 15 毫秒
61.
62.
63.
Rachel J Sorensen James S Drouillard Teresa L Douthit Qinghong Ran Douglas G Marthaler Qing Kang Christopher I Vahl James M Lattimer 《Journal of animal science》2021,99(1)
The effect of hay type on the microbiome of the equine gastrointestinal tract is relatively unexplored. Our objective was to characterize the cecal and fecal microbiome of mature horses consuming alfalfa or Smooth Bromegrass (brome) hay. Six cecally cannulated horses were used in a split-plot design run as a crossover in two periods. The whole plot treatment was ad libitum access to brome or alfalfa hay fed over two 21-d acclimation periods with subplots of sampling location (cecum and rectum) and sampling hour. Each acclimation period was followed by a 24-h collection period where cecal and fecal samples were collected every 3 h for analysis of pH and volatile fatty acids (VFA). Fecal and cecal samples were pooled and sent to a commercial lab (MR DNA, Shallowater, TX) for the amplification of the V4 region of the 16S rRNA gene and sequenced using Illumina HiSeq. The main effects of hay on VFA, pH, and taxonomic abundances were analyzed using the MIXED procedure of SAS 9.4 with fixed effects of hay, hour, location, period, and all possible interactions and random effect of horse. Alpha and beta diversities were analyzed using the R Dame package. Horses fed alfalfa had greater fecal than cecal pH (P ≤ 0.05), whereas horses fed brome had greater cecal than fecal pH (P ≤ 0.05). Regardless of hay type, total VFA concentrations were greater (P ≤ 0.05) in the cecum than in feces, and alfalfa resulted in greater (P ≤ 0.05) VFA concentrations than brome in both sampling locations. Alpha diversity was greater (P ≤ 0.05) in fecal compared with cecal samples. Microbial community structure within each sampling location and hay type differed from one another (P ≤ 0.05). Bacteroidetes were greater (P ≤ 0.05) in the cecum compared with the rectum, regardless of hay type. Firmicutes and Firmicutes:Bacteroidetes were greater (P ≤ 0.05) in the feces compared with cecal samples of alfalfa-fed horses. In all, fermentation parameters and bacterial abundances were impacted by hay type and sampling location in the hindgut. 相似文献
64.
65.
66.
Rita M. Hanel DVM DACVIM DACVECC Lee Palmer DVM MS DACVECC NREMT‐T WEMT CCRP Janice Baker DVM DACVPM Jo‐Anne Brenner BA EMT‐I EMT‐T David Dorman DVM PhD DABVT John C. Gicking DVM DACVECC Brian Gilger DVM MS DACVO DABT Cynthia M. Otto DVM PhD DACVECC DACVSMR Elizabeth Rozanski DVM DACVECC DACVIM Brian Trumpatori DVM 《Journal of Veterinary Emergency and Critical Care》2016,26(2):166-233
67.
Nutritional analysis and microbiological evaluation of commercially available enteral diets for cats 下载免费PDF全文
68.
69.
Thromboelastographic evidence of inhibition of fibrinolysis after ε‐aminocaproic acid administration in a dog with suspected acute traumatic coagulopathy 下载免费PDF全文
70.
Comparison of 4 point‐of‐care blood gas analyzers for arterial blood gas analysis in healthy dogs and dogs with cardiopulmonary disease 下载免费PDF全文