全文获取类型
收费全文 | 118篇 |
免费 | 0篇 |
专业分类
系统科学 | 1篇 |
理论与方法论 | 1篇 |
现状及发展 | 33篇 |
研究方法 | 11篇 |
综合类 | 70篇 |
自然研究 | 2篇 |
出版年
2012年 | 3篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 3篇 |
2008年 | 8篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1992年 | 3篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 5篇 |
1969年 | 5篇 |
1968年 | 4篇 |
1967年 | 5篇 |
1965年 | 2篇 |
1964年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有118条查询结果,搜索用时 15 毫秒
51.
J. H. Duffus C. S. Penman N. W. C. Webb 《Cellular and molecular life sciences : CMLS》1973,29(5):632-633
Résumé Protéines ont été extraites de l'algue rougeRhodymenia palmata, par les méthodes normalement utilisées pour les histones. Ces protéines diffèrent des histones du thymus de veau d'une façon marquée, mais elles ont des similarités fonctionelles. 相似文献
52.
Myosin Va transports intracellular cargoes along actin filaments in cells. This processive, two-headed motor takes multiple 36-nm steps in which the two heads swing forward alternately towards the barbed end of actin driven by ATP hydrolysis. The ability of myosin Va to move processively is a function of its long lever arm, the high duty ratio of its kinetic cycle and the gating of the kinetics between the two heads such that ADP release from the lead head is greatly retarded. Mechanical studies at the multiple- and the single-molecule level suggest that there is tight coupling (that is, one ATP is hydrolysed per power stroke), but this has not been directly demonstrated. We therefore investigated the coordination between the ATPase mechanism of the two heads of myosin Va and directly visualized the binding and dissociation of single fluorescently labelled nucleotide molecules, while simultaneously observing the stepping motion of the fluorescently labelled myosin Va as it moved along an actin filament. Here we show that preferential ADP dissociation from the trail head of mouse myosin Va is followed by ATP binding and a synchronous 36-nm step. Even at low ATP concentrations, the myosin Va molecule retained at least one nucleotide (ADP in the lead head position) when moving. Thus, we directly demonstrate tight coupling between myosin Va movement and the binding and dissociation of nucleotide by simultaneously imaging with near nanometre precision. 相似文献
53.
54.
Sleep in normal and pathological aging 总被引:2,自引:0,他引:2
55.
Three-dimensional Fourier synthesis of horse oxyhaemoglobin at 2.8 A resolution: (1) x-ray analysis 总被引:6,自引:0,他引:6
M F Perutz H Miurhead J M Cox L C Goaman F S Mathews E L McGandy L E Webb 《Nature》1968,219(5149):29-32
56.
57.
Andrew R. Webb 《Journal of Classification》1997,14(2):249-267
This paper considers the use of radial basis functions for exploratory data analysis. These are used to model a transformation
from a high-dimensional observation space to a low-dimensional one. The parameters of the model are determined by optimising
a loss function defined to be the stress function in multidimensional scaling. The metric for the low-dimensional space is
taken to be the Minkowski metric with order parameter 1<-p<-2. A scheme based on iterative majorisation is proposed. 相似文献
58.
59.
Invasion and the evolution of speed in toads 总被引:1,自引:0,他引:1
Cane toads (Bufo marinus) are large anurans (weighing up to 2 kg) that were introduced to Australia 70 years ago to control insect pests in sugar-cane fields. But the result has been disastrous because the toads are toxic and highly invasive. Here we show that the annual rate of progress of the toad invasion front has increased about fivefold since the toads first arrived; we find that toads with longer legs can not only move faster and are the first to arrive in new areas, but also that those at the front have longer legs than toads in older (long-established) populations. The disaster looks set to turn into an ecological nightmare because of the negative effects invasive species can have on native ecosystems; over many generations, rates of invasion will be accelerated owing to rapid adaptive change in the invader, with continual 'spatial selection' at the expanding front favouring traits that increase the toads' dispersal. 相似文献
60.