全文获取类型
收费全文 | 118篇 |
免费 | 2篇 |
专业分类
120篇 |
出版年
2015年 | 2篇 |
2014年 | 1篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 4篇 |
2007年 | 8篇 |
2006年 | 4篇 |
2005年 | 4篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1996年 | 9篇 |
1994年 | 2篇 |
1992年 | 2篇 |
1985年 | 1篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1963年 | 1篇 |
1958年 | 6篇 |
1957年 | 3篇 |
1956年 | 1篇 |
1955年 | 2篇 |
1954年 | 8篇 |
1953年 | 3篇 |
1952年 | 7篇 |
1951年 | 6篇 |
1950年 | 7篇 |
1935年 | 1篇 |
排序方式: 共有120条查询结果,搜索用时 0 毫秒
1.
2.
3.
IAN J. JACKSON PETER BUDD JACQUELINE M. HORN RUTH JOHNSON SOPHIE RAYMOND KAREN STEEL 《Pigment cell & melanoma research》1994,7(2):73-80
The formation of mouse coat color is a relatively complex developmental process that is affected by a large number of mutations, both naturally occurring and induced. The cloning of the genes in which these mutations occur and the elucidation of the mechanisms by which these mutations disrupt the normal pigmentation pattern is leading to an understanding of the way interactions between gene products lead to a final phenotype. 相似文献
4.
5.
6.
Both sexes of Ameira hyalina (Noodt, 1952) and A. parasimulans Lang, 1965 are redescribed. The genus Psammameira Noodt, 1952 previously regarded as a junior subjective synonym of Ameira. is reinstated to accommodate these two species and a revised diagnosis for the genus is presented. Examination of the type material of Psammameira reducta Wells, 1967 and P. gradis (Nicholls, 1939) revealed that they should be removed from the genus. The possible relationships of two species of doubtful affinity, A. esigun T. Scott, 1894 and A. simulans T. Scott, 1912 are reconsidered. The phylogenetic position of Psammameira within the Ameiridae is briefly discussed. 相似文献
7.
DAVID J. S. MONTAGNES JOHN ALLEN LOUISE BROWN CELIA BULIT RUSSELL DAVIDSON CARLOS DÍAZ‐ÁVALOS SOPHIE FIELDING MIKE HEATH NAOMI P. HOLLIDAY JENS RASMUSSEN RICHARD SANDERS JOANNA J. WANIEK DAVID WILSON 《The Journal of eukaryotic microbiology》2008,55(5):457-465
ABSTRACT. Myrionecta rubra, a ubiquitous planktonic ciliate, has received much attention due to its wide distribution, occurrence as a red tide organism, and unusual cryptophyte endosymbiont. Although well studied in coastal waters, M. rubra is poorly examined in the open ocean. In the Irminger Basin, North Atlantic, the abundance of M. rubra was 0–5 cells/ml, which is low compared with that found in coastal areas. Distinct patchiness (100 km) was revealed by geostatistical analysis. Multiple regression indicated there was little relationship between M. rubra abundance and a number of environmental factors, with the exception of temperature and phytoplankton biomass, which influenced abundance in the spring. We also improve on studies that indicate distinct size classes of M. rubra; we statistically recognise four significantly distinct width classes (5–16, 12–23, 18–27, 21–33 μm), which decrease in abundance with increasing size. A multinomial logistic regression revealed the main variable correlated with this size distribution was ambient nitrate concentration. Finally, we propose a hypothesis for the distribution of sizes, involving nutrients, feeding, and dividing of the endosymbiont. 相似文献
8.
DAVID P. HUGHES HARRY C. EVANS NIGEL HYWEL‐JONES JACOBUS J. BOOMSMA SOPHIE A. O. ARMITAGE 《Ecological Entomology》2009,34(2):214-220
Abstract 1. The leaf‐cutting ants practise an advanced system of mycophagy where they grow a fungus as a food source. As a consequence of parasite threats to their crops, they have evolved a system of morphological, behavioural, and chemical defences, particularly against fungal pathogens (mycopathogens). 2. Specific fungal diseases of the leaf‐cutting ants themselves have not been described, possibly because broad spectrum anti‐fungal defences against mycopathogens have reduced their susceptibility to entomopathogens. 3. Using morphological and molecular tools, the present study documents three rare infection events of Acromyrmex and Atta leaf‐cutting ants by Ophiocordyceps fungi, agenus of entomopathogens that is normally highly specific in its host choice. 4. As leaf‐cutting ants have been intensively studied, the absence of prior records of Ophiocordyceps suggests that these infections may be a novel event and that switching from one host to another is possible. To test the likelihood of this hypothesis, host switching was experimentally induced, and successfully achieved, among five distinct genera of ants, one of which was in a different sub‐family than the leaf‐cutter ants. 5. Given the substantial differences among the five host ants, the ability of Ophiocordyceps to shift between such distant hosts is remarkable; the results are discussed in the context of ant ecological immunology and fungal invasion strategies. 相似文献
9.
10.