全文获取类型
收费全文 | 292篇 |
免费 | 21篇 |
出版年
2023年 | 2篇 |
2022年 | 7篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 12篇 |
2018年 | 8篇 |
2017年 | 2篇 |
2016年 | 9篇 |
2015年 | 17篇 |
2014年 | 11篇 |
2013年 | 15篇 |
2012年 | 20篇 |
2011年 | 32篇 |
2010年 | 20篇 |
2009年 | 14篇 |
2008年 | 20篇 |
2007年 | 17篇 |
2006年 | 17篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 12篇 |
2002年 | 13篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 5篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1966年 | 2篇 |
1964年 | 1篇 |
1962年 | 1篇 |
排序方式: 共有313条查询结果,搜索用时 15 毫秒
71.
Alzheimer's disease (AD) is accompanied by oxidative stress in the brain. Because the brain tissue is rich in polyunsaturated fatty acids, it is prone to the free radical attack resulting in lipid peroxidation. Intermediates of lipid peroxidation may diffuse from the primary site, cross the blood-brain barrier and modify erythrocyte membranes in the bloodstream. We exposed isolated erythrocyte membranes from patients with AD and the control group to in vitro free radical damage and monitored the accumulation of the end products of lipid peroxidation, lipofuscin-like pigments (LFPs), by fluorescence spectroscopy. LFPs were analyzed by means of tridimensional and synchronous fluorescence spectroscopy. The levels of LFP formed during in vitro peroxidation were significantly higher in erythrocyte membranes from patients with AD compared with the control group. Furthermore, the chemical composition of LFP in AD was different from the control group. The analysis of the specific modifications of erythrocyte membranes in AD is of great medical importance regarding the need of a diagnostic blood biomarker. 相似文献
72.
73.
74.
75.
Peter Wenzl Pavla Suchánková Jason Carling Hana Šimková Eric Huttner Marie Kubaláková Pierre Sourdille Edie Paul Catherine Feuillet Andrzej Kilian Jaroslav Doležel 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2010,121(3):465-474
We describe how the diversity arrays technology (DArT) can be coupled with chromosome sorting to increase the density of genetic maps in specific genome regions. Chromosome 3B and the short arm of chromosome 1B (1BS) of wheat were isolated by flow cytometric sorting and used to develop chromosome- and chromosome arm-enriched genotyping arrays containing 2,688 3B clones and 384 1BS clones. Linkage analysis showed that 553 of the 711 polymorphic 3B-derived markers (78%) mapped to chromosome 3B, and 59 of the 68 polymorphic 1BS-derived markers (87%) mapped to chromosome 1BS, confirming the efficiency of the chromosome-sorting approach. To demonstrate the potential for saturation of genetic maps, we constructed a consensus map of chromosome 3B using 19 mapping populations, including some that were genotyped with the 3B-enriched array. The 3B-derived DArT markers doubled the number of genetic loci covered. The resulting consensus map, probably the densest genetic map of 3B available to this date, contains 939 markers (779 DArTs and 160 other markers) that segregate on 304 genetically distinct loci. Importantly, only 2,688 3B-derived clones (probes) had to be screened to obtain almost twice as many polymorphic 3B markers (510) as identified by screening approximately 70,000 whole genome-derived clones (269). Since an enriched DArT array can be developed from less than 5 ng of chromosomal DNA, a quantity which can be obtained within 1 h of sorting, this approach can be readily applied to any crop for which chromosome sorting is available. 相似文献
76.
β-N-Acetylhexosaminidases (EC 3.2.1.52, belonging to CAZy GH families 3, 20 and 84) have recently gained a lot of attention, not only due to their implication in human physiology and disease, but also due to their great potential in the enzymatic synthesis of carbohydrates and glycomimetics. GH family 20 β-N-acetylhexosaminidases, and GH family 3 and 84 β-N-acetylglucosaminidases from all kinds of organisms have been intensively studied from the point of view of their physiological roles, reaction mechanisms, structure and inhibition. Thanks to their outstanding substrate promiscuity, extracellular β-N-acetylhexosaminidases from filamentous fungi are able to cleave and transfer substrates bearing various functionalities, ranging from carboxylates, sulfates, acylations to azides, and even 4-deoxy glycosides. Thus, they have proved to be versatile biosynthetic tools for the preparation of both natural and modified hexosaminides under mild conditions with good yields. 相似文献
77.
Klára Hofštetrová Pavla T?mová Staffan G. Svärd Eva Nohýnková 《Experimental parasitology》2010,124(2):159-166
This study is a thorough examination of the effects of the DNA polymerase inhibitor aphidicolin on the nuclear cycle and cell cycle progression characteristics, as well as their reversibility, in Giardia intestinalis. Giardia trophozoites are arrested in the G1/S-junction after aphidicolin treatment according to their DNA content. However, cell growth continues and trophozoites arrested with aphidicolin resemble cells in the G2 phase and trophozoites in ageing cultures. Extensive treatment with aphidicolin causes side effects and we detected positive signals for phosphorylated histone H2A, which, in mammalian cells, is involved in a signalling pathway triggered as a reaction to double stranded DNA breaks. These results suggest that aphidicolin causes dissociation of the nuclear and cytoplasmic cycles, a phenomenon that has also been described for other inhibitors in mammalian cell lines. Thus, if aphidicolin is used for synchronization of Giardia trophozoites, this fact must be accounted for, and treatment with aphidicolin must be minimal. 相似文献
78.
79.
Pavla Hublarova Kristina Greplova Jitka Holcakova Borivoj Vojtesek Roman Hrstka 《Cellular & molecular biology letters》2010,15(3):473-484
Cisplatin and doxorubicin are widely used anticancer drugs that cause DNA damage, which activates the ATM-Chk2-p53 pathway
in cancer cells. This activation leads to cell cycle block or apoptosis, depending on the nature of the DNA damage. In an
attempt to enhance the effects of these agents, we inhibited ATM/ATR and Chk2, which are known upstream regulators of p53.
The cancer cell lines A2780 and ARN8, bearing the wild-type p53 protein, were used to study changes in p53 activation and
trans-activation. Our results suggest that the G1-checkpoint, normally activated by DNA damage, is functionally overcome by the action of kinase inhibitors that sensitize
cells to apoptosis. Both inhibitors show these effects, albeit with variable intensity in different cell lines, which is promising
for other studies and theoretically for use in clinical practice. 相似文献
80.
Gamma-tubulin is essential for acentrosomal microtubule nucleation and coordination of late mitotic events in Arabidopsis
下载免费PDF全文
![点击此处可从《The Plant cell》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Binarová P Cenklová V Procházková J Doskocilová A Volc J Vrlík M Bögre L 《The Plant cell》2006,18(5):1199-1212
Gamma-tubulin is required for microtubule (MT) nucleation at MT organizing centers such as centrosomes or spindle pole bodies, but little is known about its noncentrosomal functions. We conditionally downregulated gamma-tubulin by inducible expression of RNA interference (RNAi) constructs in Arabidopsis thaliana. Almost complete RNAi depletion of gamma-tubulin led to the absence of MTs and was lethal at the cotyledon stage. After induction of RNAi expression, gamma-tubulin was gradually depleted from both cytoplasmic and microsomal fractions. In RNAi plants with partial loss of gamma-tubulin, MT recovery after drug-induced depolymerization was impaired. Similarly, immunodepletion of gamma-tubulin from Arabidopsis extracts severely compromised in vitro polymerization of MTs. Reduction of gamma-tubulin protein levels led to randomization and bundling of cortical MTs. This finding indicates that MT-bound gamma-tubulin is part of a cortical template guiding the microtubular network and is essential for MT nucleation. Furthermore, we found that cells with decreased levels of gamma-tubulin could progress through mitosis, but cytokinesis was strongly affected. Stepwise diminution of gamma-tubulin allowed us to reveal roles for MT nucleation in plant development, such as organization of cell files, anisotropic and polar tip growth, and stomatal patterning. Some of these functions of gamma-tubulin might be independent of MT nucleation. 相似文献