全文获取类型
收费全文 | 52篇 |
免费 | 1篇 |
专业分类
林业 | 13篇 |
农学 | 1篇 |
10篇 | |
综合类 | 3篇 |
农作物 | 6篇 |
水产渔业 | 4篇 |
畜牧兽医 | 15篇 |
植物保护 | 1篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 2篇 |
2007年 | 3篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 3篇 |
2001年 | 2篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1968年 | 2篇 |
排序方式: 共有53条查询结果,搜索用时 15 毫秒
31.
This paper describes the use of hormone analysis in the diagnosis of adrenal cortex dysfunction in the dog, cat and horse. Analytical problems concerning the determination of corticosteroid levels are discussed and the pathology of adrenal dysfunction is briefly presented. The paper focuses on the problems in establishing physiological norms for adrenal function based on the established assays. Own experiences and other reported data are referred to. 相似文献
32.
33.
Summary Morphological and biochemical parameters that could be involved in resistance to late blight were studied in non-infected
and in infected potato hybrids resulting from a cross betweenSolanum phureja, resistant toPhytophthora infestans, and a susceptibleSolanum tuberosum.
Some morphological differences between resistant and susceptible hybrids, indicating a positive correlation between stem diameter
and phloem thickness in the stem and resistance toP. infestans, were observed. The lignin content in the leaves of the resistant hybrid rose upon infection byP. infestans. In the leaves of the susceptible hybrid, a diminution of the lignin content could be observed upon infection byP. infestans. In the same context, peroxidasic activity raised upon infection byP. infestans in both resistant and susceptible hybrids. Further characterization of the hybrid clones based on the polymorphism of peroxidases
was attempted using isoelectric focusing. 相似文献
34.
By a 4 weeks old being laid up calf the possibilities of the clinician's neurologic examination and further diagnostic aids (radiography, tomography and myelography) are presented. 相似文献
35.
Effect of furaltadone on strangles in horses 总被引:1,自引:0,他引:1
W D Evers 《Journal of the American Veterinary Medical Association》1968,152(9):1394-1398
36.
37.
Keirith A. Snyder Louisa Evers Jeanne C. Chambers Jason Dunham John B. Bradford Michael E. Loik 《Strength and Conditioning Journal》2019,72(1):1-12
Climate change is already resulting in changes in cold desert ecosystems, lending urgency to the need to understand climate change effects and develop effective adaptation strategies. In this review, we synthesize information on changes in climate and hydrologic processes during the past century for the Great Basin and Columbia Plateau and discuss future projections for the 21st century. We develop midcentury projections of temperature and climate for the Great Basin and Columbia Plateau at timescales relevant to managers (2020 ? 2050) and discuss concepts and strategies for adapting to the projected changes. For the instrumented record in the Great Basin and Columbia Plateau (1985 ? 2011), a temperature increase of 0.7 ? 1.4°C has been documented, but changes in precipitation have been relatively minor with no clear trends. Climate projections for 2020 ? 2050 indicate that temperatures will continue to increase, especially in winter and during the night. Precipitation is more difficult to project, and estimates range from an 11% decrease to 25% increase depending on location. Recent records indicate that the Great Basin and Columbia Plateau are becoming more arid, a trend that is projected to continue. Droughts are likely to become more frequent and last longer, invasive annual grasses are likely to continue to expand, and the duration and severity of wildfire seasons are likely to increase. Climate projections can help in developing adaptive management strategies for actual or expected changes in climate. Strategies include reducing the risks of nonnative invasive plant spread and wildfires that result in undesirable transitions, planning for drought, and where necessary, facilitating the transition of populations, communities, and ecosystems to new climatic conditions. A proactive approach to planning for and adapting to climate change is needed, and publicly available Internet-based resources on climate data and planning strategies are available to help meet that need. 相似文献
38.
39.
Small fruits such as berries have low energy contents, but high contents of vitamins, micronutrients, and dietary fibers and constitute a good source of natural antioxidant compounds that are important constituents of the human diet. This study identified a large number of compounds in an extract of black currant showing high antioxidant activity and compared their profile in various parts of the plants (leaves, buds, and berries). If it was known that berries contained very high levels of natural phenolic compounds, this study showed that leaves and buds could also be considered good sources of natural antioxidants. Indeed, they contained high amounts of phenolic acids, flavonoids, and carotenoids. An acetone mixture can extract several classes of phenolic compounds with a good yield of flavonols, flavan-3-ols, and anthocyanins. 相似文献
40.
In central Europe and to some degree in North America, the so called “new type” forest damages occur over large areas. Various studies indicate the declines are more or less frequently associated with nutritional disturbances that have developed within rather short time periods. The most common disorder is a Mg deficiency that produces specific discoloration symptoms such as tip-yellowing in Norway spruce. But also K deficiencies and other disturbances exist in coniferous as well as in deciduous forests. Good correlations between the site specific substrate chemistry and the actual nutritional status of the trees and stands were found. To explain the sudden and widespread development of the forest declines adverse anthropogenic influences such as increased N and H+ deposition, land use and forestry mismanagement as well as natural stresses are discussed. The hypothesized causal mechanisms are multiple, but include generally soil degradation processes associated with losses of alkaline nutrient ions from the rooted solum. Recent and previous fertilization (and liming) experiments have shown that a fast and sustained revitalization and restabilization of declining forest ecosystems marked by nutrient deficiencies can be achieved. This was demonstrated by chemical and histological foliar analyses and the visible improvement of the trees. Soil analyses also revealed a positive change of the chemical soil status when site and stand specific fertilizer applications were utilized in the appropriate amounts. However, under certain site and stand conditions risks and limitations exist that have to be evaluated when fertilization practices are discussed.To overcome or minimize these influences the treatments. must be adapted to the site, and stand specific fertilization needs as indicated by soil and foliar analysis, humus form, hydrologic parameter and atmospheric deposition rates. 相似文献