全文获取类型
收费全文 | 499篇 |
免费 | 50篇 |
国内免费 | 200篇 |
出版年
2024年 | 5篇 |
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 14篇 |
2019年 | 22篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 16篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 25篇 |
2012年 | 56篇 |
2011年 | 44篇 |
2010年 | 45篇 |
2009年 | 40篇 |
2008年 | 41篇 |
2007年 | 40篇 |
2006年 | 26篇 |
2005年 | 28篇 |
2004年 | 24篇 |
2003年 | 18篇 |
2002年 | 28篇 |
2001年 | 22篇 |
2000年 | 15篇 |
1999年 | 13篇 |
1998年 | 14篇 |
1997年 | 3篇 |
1996年 | 7篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 4篇 |
1989年 | 8篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1976年 | 2篇 |
1971年 | 2篇 |
1957年 | 2篇 |
1956年 | 3篇 |
排序方式: 共有749条查询结果,搜索用时 15 毫秒
1.
作者在广东省梅县市发现四个吸虫新种:1.鼠丽色吸虫,新种Reesella ratta sp. nov., 2.后囊蛙蠕吸虫,新种Batrachotrema optstosacca sp. nov., 3.梅县后平睾吸虫,新种Opisthioparorchis meixianensis sp. nov., 4.大卵后平睾吸虫,新种Opisthioparorchis megaloonos sp. nov.,它们分别归隶于蹲茎科Cathaemasiidae及蛙蠕科Bstrachotrematidae。模式标本保存于中山医科大学寄生虫学研究所。 相似文献
2.
对我国52种微茎类吸虫的18项成虫形态学特征进行主成分分析,结果表明:卵巢位置、子宫延伸位置等7项性状对第一主成分贡献较大,提示描述器官位置的指标是重要的分类依据。52个虫种在前三个主成分上的排序图显示应将其划分成4个亚科。 相似文献
3.
Pulmonary microcirculatory kinetics of neutrophils deficient in leukocyte adhesion-promoting glycoproteins 总被引:2,自引:0,他引:2
M C Yoder L L Checkley U Giger W L Hanson K R Kirk R L Capen W W Wagner 《Journal of applied physiology》1990,69(1):207-213
The mechanism that causes neutrophils to sequester in the pulmonary circulation is unknown. Because the CD11/CD18 glycoprotein family on the surface membrane of neutrophils participates in many adhesive interactions with the endothelium, we investigated the role of these proteins in the intravascular sequestration of pulmonary neutrophils. Neutrophils were isolated from normal dogs and from the only living dog known to have leukocyte adhesion deficiency disease, an inherited deficiency of the CD11/CD18 adhesion family. The neutrophils were labeled with fluorescein dye, injected into normal recipient dogs, and their passage through the pulmonary microcirculation was recorded by in vivo videofluorescence microscopy through a transparent thoracic window. Transit times for normal and deficient neutrophils were similar over a wide range of hemo-dynamic conditions. Activation by zymosan-activated plasma, which increases the surface membrane expression of CD11/CD18, prolonged the transit of normal neutrophils but did not alter the transit time of the deficient neutrophils. These results indicate that neutrophil CD11/CD18 adhesion-promoting glycoproteins are not involved in the normal pulmonary sequestration of neutrophils but have a significant role in the arrest of activated neutrophils in the pulmonary capillaries. 相似文献
4.
A. D. Giger M. V. Srinivasan 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1996,178(6):763-769
The spectral properties of the discrimination of pattern orientation in freely flying honeybees (Apis mellifera) were examined. Bees were trained to discriminate between two random black/white gratings oriented perpendicularly to each other, one of which was associated with a reward. Subsequently the bees were tested on two-colour gratings or gratings consisting of grey and coloured stripes, providing a range of different chromatic contrasts, luminance contrasts and specific channel contrasts. The results of these experiments indicate that orientation analysis in the honeybee is mediated almost exclusively by the green receptor channel, although the bee's visual system as a whole is endowed with excellent trichromatic colour vision. 相似文献
5.
Implications for the domain arrangement of axonin-1 derived from the mapping of its NgCAM binding site. 总被引:7,自引:0,他引:7
下载免费PDF全文
![点击此处可从《The EMBO journal》网站下载免费的PDF全文](/ch/ext_images/free.gif)
C Rader B Kunz R Lierheimer R J Giger P Berger P Tittmann H Gross P Sonderegger 《The EMBO journal》1996,15(9):2056-2068
The neuronal cell adhesion molecule axonin-1 is composed of six immunoglobulin and four fibronectin type III domains. Axonin-1 promotes neurite outgrowth, when presented as a substratum for neurons in vitro, via a neuronal receptor that has been identified as the neuron-glia cell adhesion molecule, NgCAM, based on the blocking effect of polyclonal antibodies directed to NgCAM. Here we report the identification of axonin-1 domains involved in NgCAM binding. NgCAM-conjugated microspheres were tested for binding to COS cells expressing domain deletion mutants of axonin-1. In addition, monoclonal antibodies directed to axonin-1 were assessed for their ability to block the axonin-1-NgCAM interaction, and their epitopes were mapped using the domain deletion mutants. The results suggest that the four amino-terminal immunoglobulin domains of axonin-1 form a domain conglomerate which is necessary and sufficient for NgCAM binding. Surprisingly, NgCAM binding to membrane-bound axonin-1 was increased strongly by deletion of the fifth or sixth immunoglobulin domains of axonin-1. Based on these results and on negative staining electron microscopy, we propose a horseshoe-shaped domain arrangement of axonin-1 that obscures the NgCAM binding site. Neurite outgrowth studies with truncated forms of axonin-1 show that axonin-1 is a neurite outgrowth-promoting substratum in the absence of the NgCAM binding site. 相似文献
6.
本文就萤叶甲亚科中柱萤叶甲属鞘翅具黑色刻点的种类进行研究,共记述4种,我国已记录3种,其中1种为新种。 相似文献
7.
8.
维生素C·Cu·菲咯啉系统对DNA的定位损伤 总被引:4,自引:0,他引:4
维生素C·Cu·菲咯啉系统对DNA的定位损伤柯德森,王爱国,罗广华(中国科学院华南植物研究所,广州510650)关键词活性氧;DNA;定位损伤活性氧对DNA的损伤已经被很多工作所证实”””,这种伤害是由0B”直接作用于DNA所引起的”’“。但是OH’... 相似文献
9.
本文报道在湛江市附近海域海鸟体内获得的两种吸虫,经鉴定为新种,命名为巨口类茎吸虫,新种Microphalloides macrostonrs sp.nov.,珊瑚多黄吸虫,新种Multivitellus coralius sp.nov. 相似文献
10.