全文获取类型
收费全文 | 60篇 |
免费 | 1篇 |
国内免费 | 5篇 |
出版年
2013年 | 1篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2009年 | 2篇 |
2003年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1968年 | 1篇 |
1965年 | 1篇 |
1962年 | 1篇 |
1960年 | 2篇 |
1959年 | 1篇 |
1958年 | 2篇 |
1957年 | 1篇 |
1956年 | 2篇 |
1955年 | 1篇 |
1954年 | 4篇 |
1953年 | 2篇 |
1952年 | 2篇 |
1950年 | 1篇 |
1945年 | 1篇 |
1917年 | 1篇 |
排序方式: 共有66条查询结果,搜索用时 234 毫秒
61.
M. J. CULLEN 《Physiological Entomology》1974,49(1):17-41
Certain ultrastructural features of insect flight muscle are described and their value as criteria for differentiating between synchronous and asynchronous muscle is assessed. The distribution of asynchronous muscle in the Pterygota as a whole and the Hemiptera in particular is investigated and the evolutionary implications of the results are discussed. 相似文献
62.
63.
IT is well established that in the chicken humoral antibody formation depends on the bursa of Fabricius, whereas delayed hypersensitivity and other manifestations of cellular immunity depend on the thymus for their development1,2. Surgical bursectomy3,4 and the administration of testosterone5–7, cortisone acetate8 or cyclophosphamide9–11 have been found to limit the bursa-dependent antibody system. Infectious bursal disease (IBD), formerly known as Gumboro disease, is a naturally occurring virus disease of young chickens12, characterized by the destruction of the lymphoid tissue in the bursa without repopulation13. The disease has been reported from many countries in Europe and in North America. The effect of IBD on the course of other infections in the chicken is therefore of interest. We report here that the primary and secondary serological responses to Newcastle disease vaccine were reduced significantly in chickens which were experimentally inoculated with the infectious bursal agent (IBA) at one day of age. 相似文献
64.
An assessment of the performance of a wetland dominated by opportunistic weeds in removing nutrients from a secondary sewage effluent was carried out at Thredbo in Kosciusko National Park. Water quality sampling of the inflow and outflow showed a reduction in turbidity, pH and conductivity with passage through the wetland. Dissolved oxygen levels also decreased. In summer 1982, the phosphorus toad of 1.8 kg P day-1 was reduced by 44% as wastewater moved through the wetland, and the nitrogen load of 6.4 kg N day-1 by 65%. Winter retentions were 10% and 14% of inflowing loads, respectively. In 1983 there was a net release of phosphorus and reduced retention of nitrogen. This was regarded as being a result of physical disturbance of the wetland. Vegetation downstream of the effluent inflow was dominated by the opportunistic weeds Epilobium sarmantaceum and Rumex crispus. Upstream, Carex gaudichaudiana and Baeckea gunniana dominated. Marked seasonal changes in vigour and biomass were recorded. Plants, but not sediments, downstream of the inflow contained more nutrients than those upstream. Seed bank analysis showed more seeds downstream than upstream. A moist treatment promoted more seed germination than a flooded treatment. E. sarmantaceum and to a lesser extent R. crispus dominated in each treatment. In an effort to promote greater water retention and replacement of the weed species, channels in the wetland have been blocked with gravel and planted with Phragmites australis and Schoenoplectus validus. 相似文献
65.
66.