全文获取类型
收费全文 | 40篇 |
免费 | 9篇 |
专业分类
49篇 |
出版年
2021年 | 2篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2005年 | 1篇 |
1998年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1982年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1967年 | 1篇 |
1965年 | 2篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1954年 | 2篇 |
1929年 | 1篇 |
1928年 | 1篇 |
排序方式: 共有49条查询结果,搜索用时 7 毫秒
1.
Plasmalogenase activity in normal and demyelinating tissue of the central nervous system 总被引:4,自引:1,他引:3 下载免费PDF全文
1. The plasmalogenase activity of brain was found to be associated with the white matter but was absent from myelin fractions. 2. Increased enzyme activity was found in demyelinating spinal cords from vitamin B12-deficient monkeys and in white matter from a patient with multiple sclerosis. 相似文献
2.
THE METABOLISM OF LABELLED ETHANOLAMINE IN THE BRAIN OF THE RAT IN VIVO 总被引:13,自引:1,他引:12
3.
4.
5.
Summary The sieve plate pores of Salix caprea in preparations fixed in glutaraldehyde are normally found to be occupied by slime fibrils showing periodic banding such as occur in a number of other species. Arguments are put forward to suggest that the occurence of fibrils in this position is natural and not an artefact of preparation. The sieve tubes further possess prominent and persistent nucleoli showing a radiating structure of tubules. The endoplasmic reticulum often occurs in parietal stacks reminiscent of other species.This evidence is discussed in relation to the electroosmotic theory of translocation.This work formed part of that submitted for the degree of Ph. D. of the University of London by U. Mishra. 相似文献
6.
1. The phospholipase C of Bacillus cereus attacks the ethanolamine plasmalogen of brain to yield a plasmalogenic diglyceride (2-acyl-1-alkenylglycerol). 2. This plasmalogenic diglyceride is analogous to the material obtained by the action of the phospholipase C of Clostridium welchii on the choline plasmalogen of heart. 相似文献
7.
Summary When radioactive tracer is applied locally to the stolon of Saxifraga its long-distance movement after 18 hours is found to be strongly polarised; there is in addition a short-distance movement which is unpolarised. With caesium, the long-distance movement is predominantly in the phloem; with strontium in the xylem. These interpretations, a priori probable, were confirmed by artifically reversing, separately, the xylem and the phloem currents. With long pieces of excised stolon only the unpolarised short-distance movement is observed. These results constitute evidence against simultaneous bidirectional translocation in the same sieve tube, and are consistent with either the Münch or the electro-osmotic theory. 相似文献
8.
The effect of nitrogen on the movement of tracers down the stolon of Saxifraga sarmentosa,with some observations on the influence of light 总被引:1,自引:0,他引:1
Summary The movement of applied 137Cs and of naturally-assimilated 14C down the long stolon of Saxifraga is strongly inhibited by confining a length of 10 to 30 cm of the stolon in an atmosphere of nitrogen. The inhibition is reversible, normal transport being restored after less then 4 h when the stolon is returned to air from 5 h in nitrogen. Callose formation does not seem to be involved. There is evidence that local darkness has a similar adverse effect on phloem transport.These findings are considered antagonistic to the pressure-flow hypothesis, but favourable to the active mass-flow theories.This work formed part of that submitted for the degree of Ph.D. of the University of London. 相似文献
9.
10.
Summary The sieve tube wall possesses a broad inner layer often with pronounced radial striations. The plasmalemma of the sieve tube appears to penetrate this wall in the form of a brush border of irregular microvilli, greatly increasing its surface area. It is suggested that this is the site of active transport of potassium, which circulates electroosmotically through the sieve plate pores and back through the thick wall. The function of the companion cells is the care and maintenance of the active brush border sites; in conjunction with their activity in supplying high-energy intermediates movement in the column acts regeneratively and fully polarises the plates. Many of the lamellar stacks and curvilinear membrane aggregates hitherto regarded as endoplasmic reticulum are, it is suggested, plasmalemma displaced from the wall. These findings have important consequences for the electroosmotic theory. 相似文献