全文获取类型
收费全文 | 182篇 |
免费 | 15篇 |
专业分类
林业 | 8篇 |
农学 | 1篇 |
9篇 | |
综合类 | 13篇 |
农作物 | 4篇 |
水产渔业 | 10篇 |
畜牧兽医 | 146篇 |
植物保护 | 6篇 |
出版年
2020年 | 5篇 |
2019年 | 3篇 |
2018年 | 10篇 |
2017年 | 2篇 |
2016年 | 3篇 |
2015年 | 4篇 |
2013年 | 7篇 |
2012年 | 5篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 6篇 |
2008年 | 10篇 |
2007年 | 6篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 9篇 |
2001年 | 8篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 5篇 |
1996年 | 6篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 3篇 |
1968年 | 3篇 |
1966年 | 1篇 |
1958年 | 1篇 |
1956年 | 2篇 |
1945年 | 1篇 |
1863年 | 1篇 |
排序方式: 共有197条查询结果,搜索用时 15 毫秒
1.
ABSTRACTAims: To determine if an ELISA for measurement of IgA in equine serum could be used to measure concentrations of IgA in foal faeces and to determine correlations with concentrations in the milk of the dam.Methods: Faeces from 20 Welsh Cob and Welsh Pony foals and milk from their dams were collected within 12?hours (Day 0) and at 6 days after parturition (Day 6). On Day 6, faeces could not be collected from 2/20 foals, and milk samples could not be collected from 3/20 mares. An equine IgA ELISA validated for serum and plasma was used to measure concentrations of IgA in all samples in triplicate. The precision of the assay for each sample type was determined using modified CV.Results: IgA was not detectable in 7/20 Day 0 faecal samples and in 2/18 Day 6 faecal samples. For samples with detectable IgA, the mean modified CV was 10.5 (95% CI?=?6.0–15.0)% for Day 0 faecal samples, and was 6.8 (95% CI?=?4.3–9.4)% for Day 6 faecal samples. Median concentrations of IgA in faeces on Day 0 were lower than concentrations on Day 6 (0.7?mg/g vs. 37?mg/g dry matter; p?=?0.003). Concentrations of IgA in milk and faeces on Day 6 were statistically correlated (r?=?0.59; p?=?0.006).Conclusions and clinical relevance: The IgA ELISA showed acceptable precision when used to estimate concentrations of IgA in foal faeces during the first week of life, but IgA could not be detected in 37% of meconium samples collected on Day 0. This assay may be useful for investigation of the role of maternal milk IgA in the gastrointestinal tract of neonatal foals, but further assessment of both accuracy and precision of the ELISA is required. 相似文献
2.
H. Bartels 《Forstwissenschaftliches Centralblatt》1956,75(3-4):124-128
Ohne ZusammenfassungMit 4 Abbildungen 相似文献
3.
Peat properties and unsaturated hydraulic conductivity of peat soils . Drainage of organic soils is closely connected with water supply of plants by the capillary fringe of the groundwater. Unsaturated flow of water was measured by the double-membrane apparatus described by Vetterlein, which was modified for experiments with undisturbed peat samples. The influence of decomposition, nature of peat, ash content, bulk density (consolidation) and flux direction on unsaturated flow of water in peat soils was determined. The correlation to unsaturated water conductivity decreased in the sequence: decomposition, flux direction, ash content, bulk density. A dependence on bulk density exists only below pF 2. 相似文献
4.
5.
6.
7.
8.
9.
T. Bartels K. Cramer P. Wolf M. Hässig A. Boos 《Anatomia, histologia, embryologia》2009,38(4):262-269
The aims of this study were to examine the skeleton of domesticated budgerigars of phenotypically different breeding types, to describe the expression of skeletal changes and to discuss the results with special reference to the causes and effects of breed-conditioned alterations. Complete skeletons of 39 adult budgerigars of both sexes were the object of our research. The examinations demonstrated that almost all metrically sized skeleton dimensions of budgerigars of the exhibition type were increased significantly, compared with those of the non-exhibition type. Only for the scapula significant length differences between the budgerigars of both breeding types could not be verified. It can be stated that the measuring parameters 'occipital width', 'maxilla length', 'skull length' and 'prefrontal width' are suitable for the characterization of exhibition budgerigars. However, sexual dimorphisms could be verified in only three parameters (width of the pars symphysialis mandibulae, height of the skull, width of the skull within the range of the occiput). It has to be clarified in future studies to what extent the changes in the skeleton of budgerigars of the exhibition type have already had consequences for their flying ability, metabolism, health and well-being. 相似文献
10.
S W Lee G H Hankes R C Purohit J E Bartels R E Cartee L Pablo J C Conti 《American journal of veterinary research》1990,51(1):109-113
The carotid artery of clinically normal goats was examined, using duplex ultrasonography and arteriography. The diameter of the carotid artery was measured by use of two-dimensional ultrasonography and Doppler ultrasonography, respectively, before and after xylazine administration. The diameter of the artery was also measured by use of an arteriography technique in halothane-anesthetized goats. There was no significant difference between the mean diameter of the carotid artery measured by ultrasonography in conscious nonsedated goats and that determined by arteriography in goats under halothane anesthesia. On the other hand, ultrasonography of xylazine-sedated goats revealed an increase of carotid artery diameter of 20 to 30%. There was no change in the velocity of blood flow after xylazine administration. 相似文献