首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   106篇
  免费   6篇
  112篇
  2021年   2篇
  2018年   1篇
  2017年   2篇
  2016年   3篇
  2015年   3篇
  2014年   1篇
  2013年   7篇
  2012年   12篇
  2011年   9篇
  2010年   11篇
  2009年   5篇
  2008年   2篇
  2007年   11篇
  2006年   5篇
  2005年   8篇
  2004年   8篇
  2003年   2篇
  2002年   5篇
  2001年   3篇
  1998年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1990年   2篇
  1986年   1篇
  1984年   1篇
  1975年   1篇
  1972年   1篇
排序方式: 共有112条查询结果,搜索用时 31 毫秒
71.
72.
Red wine is a beverage that can exert a broad spectrum of health-promoting actions both in humans and laboratory animal models if consumed moderately. However, information about its effect on body weight is scarce. We have evaluated the effect of moderate red wine consumption on body weight and energy intake in male Zucker lean rats fed a hypercaloric diet for 8 weeks. For this purpose, we used three 5-animal groups: a high-fat diet group (HFD), a high-fat-diet red-wine-drinking group (HFRWD), and a standard diet group (SD). After 8 weeks, the HFRWD group had a lower body weight gain (175.66 +/- 2.78% vs 188.22 +/- 4.83%; P<.05) and lower energy intake (269.45 +/- 4.02 KJ/animal.day vs day vs 300.81 +/- 4.52 KJ/animal.day; P<.05) and had less fat mass at epididymal location respect to the whole body weight (0.014 +/- 0.001 vs 0.017 +/- 0.001; P<.05) than the HFD group. However, the red wine didn't modified the fed efficiency 0.012 +/- 0.001 g/KJ for HFRWD group versus 0.013 +/- 0.001 g/KJ for the HFD one (P=.080). These findings, though preliminary, show that moderate red wine intake can prevent the increase of body weight by modulating energy intake in a rat diet-induced model of obesity.  相似文献   
73.
The interaction between Glomus intraradices and the root-lesion nematode Pratylenchus vulnus was studied on micropropagated BA-29 quince rootstock during one growing season. Inoculation with G. intraradices significantly increased growth of plants in low P soil and was more effective than P fertilization at increasing top-plant development. In the presence of the nematode, mycorrhizal plants achieved higher values in all growth parameters measured. P. vulnus caused a significant decrease in the percentage of root length colonized by G. intraradices and fewer internal vesicles were formed within the host roots. Enhanced root mass production accounted for the twofold increase in final nematode population recovered from plants with combined inoculations of pathogen and symbiont. Low levels were found of Al, Fe, Mn and Zn in nonmycorrhizal nematode-infected plants in low P soil. G. intraradices-inoculated plants reached the highest foliar levels of N, Ca, Mg, Mn, Cu and Zn. Mycorrhizal plants infected with P. vulnus maintained normal to high levels of Mn, Cu, and Zn. Inoculation with G. intraradices favours quince growth and confers protection against P. vulnus by improving plant nutrition.  相似文献   
74.
This paper describes an open-field host-specificity test conducted to make a preliminary evaluation of the safety of four candidate agents for the biological control of Heliotropium amplexicaule, an invasive weed of South American origin. These agents were a leaf-eating beetle, Deuterocampta quadrijuga, a flea-beetle, Longitarsus sp., that feeds on leaves as an adult and roots as a larva, a shoot-feeding thrips, Haplothrips heliotropica, and a cell-sucking bug, Dictyla sp. During the first phase of the experiment, the four agents were given a choice between the target weed and six species of nontarget plant of varying degrees of phylogenetic relatedness. All four species were found to feed and reproduce on only H. amplexicaule and the closely related H. nicotianaefolium (a member of the same section of the genus Heliotropium). No plants outside this genus were attacked. For the second “no-choice” phase, the host-plants used in Phase 1 were cut, forcing the insects to use either other plant species within the plots, emigrate, or die of starvation. Heliothrips heliotropica disappeared rapidly from the plot, while D. quadrijuga persisted for several days on Heliotropium arborescens with some exploratory nibbling and then disappeared. Host-choice behavior of these species therefore remained unchanged, even in the absence of the primary host-plants. In contrast, adults of Longitarsus sp. rapidly colonized and fed on H. arborescens when the preferred hosts were removed. It therefore demonstrated a wider host-range under these more extreme conditions. In fact, on some plots, feeding commenced on H. arborescens before the “no-choice” phase, once the two preferred Heliotropium species were heavily damaged by these insects. The two-phase test is shown here to be a useful way of measuring host-choice behavior under “normal” conditions of choice and under more extreme conditions, such as it might occur were an agent to locally destroy the target weed following its release. It therefore provides a more refined assessment of the risk that would be posed to nontarget plants by the release of weed biological control agents.  相似文献   
75.
76.

Background

Gut is the major source of endogenous bacteria causing infections in advanced cirrhosis. Intestinal barrier dysfunction has been described in cirrhosis and account for an increased bacterial translocation rate.

Hypothesis and Aims

We hypothesize that microbiota composition may be affected and change along with the induction of experimental cirrhosis, affecting the inflammatory response.

Animals and Methods

Progressive liver damage was induced in Balb/c mice by weight-controlled oral administration of carbon tetrachloride. Laparotomies were performed at weeks 6, 10, 13 and 16 in a subgroup of treated mice (n = 6/week) and control animals (n = 4/week). Liver tissue specimens, mesenteric lymph nodes, intestinal content and blood were collected at laparotomies. Fibrosis grade, pro-fibrogenic genes expression, gut bacterial composition, bacterial translocation, host''s specific butyrate-receptor GPR-43 and serum cytokine levels were measured.

Results

Expression of pro-fibrogenic markers was significantly increased compared with control animals and correlated with the accumulated dose of carbon tetrachloride. Bacterial translocation episodes were less frequent in control mice than in treated animals. Gram-positive anaerobic Clostridia spp count was decreased in treated mice compared with control animals and with other gut common bacterial species, altering the aerobic/anaerobic ratio. This fact was associated with a decreased gene expression of GPR43 in neutrophils of treated mice and inversely correlated with TNF-alpha and IL-6 up-regulation in serum of treated mice along the study protocol. This pro-inflammatory scenario favoured blood bacterial translocation in treated animals, showing the highest bacterial translocation rate and aerobic/anaerobic ratio at the same weeks.

Conclusions

Gut microbiota alterations are associated with the development of an inflammatory environment, fibrosis progression and bacterial translocation in carbon tetrachloride-treated mice.  相似文献   
77.

Background

Plants rely on the root system for anchorage to the ground and the acquisition and absorption of nutrients critical to sustaining productivity. A genome wide association analysis enables one to analyze allelic diversity of complex traits and identify superior alleles. 384 inbred lines from the Ames panel were genotyped with 681,257 single nucleotide polymorphism markers using Genotyping-by-Sequencing technology and 22 seedling root architecture traits were phenotyped.

Results

Utilizing both a general linear model and mixed linear model, a GWAS study was conducted identifying 268 marker trait associations (p ≤ 5.3×10-7). Analysis of significant SNP markers for multiple traits showed that several were located within gene models with some SNP markers localized within regions of previously identified root quantitative trait loci. Gene model GRMZM2G153722 located on chromosome 4 contained nine significant markers. This predicted gene is expressed in roots and shoots.

Conclusion

This study identifies putatively associated SNP markers associated with root traits at the seedling stage. Some SNPs were located within or near (<1 kb) gene models. These gene models identify possible candidate genes involved in root development at the seedling stage. These and respective linked or functional markers could be targets for breeders for marker assisted selection of seedling root traits.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1226-9) contains supplementary material, which is available to authorized users.  相似文献   
78.
79.
Ancient asymmetries in the evolution of flowers   总被引:1,自引:0,他引:1  
Dorsoventral asymmetry in flowers is thought to have evolved many times independently as a specialized adaptation to animal pollinators. To understand how such a complex trait could have arisen repeatedly, we have compared the expression of a gene controlling dorsoventral asymmetry in Antirrhinum with its counterpart in Arabidopsis, a distantly related species with radially symmetrical flowers. We found that the Arabidopsis gene is expressed asymmetrically in floral meristems, even though they are destined to form symmetrical flowers. This suggests that, although the flowers of the common ancestor were probably radially symmetrical, they may have had an incipient asymmetry, evident at the level of early gene activity, which could have been recruited many times during evolution to generate asymmetric flowers.  相似文献   
80.

Background

Bacterial translocation is a frequent event in cirrhosis leading to an increased inflammatory response. Splanchnic adrenergic system hyperactivation has been related with increased bacterial translocation. We aim at evaluating the interacting mechanism between hepatic norepinephrine and inflammation during liver damage in the presence of bacterial-DNA.

Animals and Methods

Forty-six mice were included in a 16-week protocol of CCl4-induced cirrhosis. Laparotomies were performed at weeks 6, 10, 13 and 16. A second set of forty mice injected with a single intraperitoneal dose of CCl4 was treated with saline, 6-hydroxidopamine, Nebivolol or Butoxamine. After 5 days, mice received E. coli-DNA intraperitoneally. Laparotomies were performed 24 hours later. Liver bacterial-DNA, norepinephrine, TNF-alpha, IL-6 and beta-adrenergic receptor levels were measured.

Results

Bacterial-DNA translocation was more frequent in CCl4-treated animals compared with controls, and increased as fibrosis progressed. Liver norepinephrine and pro-inflammatory cytokines were significantly higher in mice with vs without bacterial-DNA (319.7±120.6 vs 120.7±68.6 pg/g for norepinephrine, 38.4±6.1 vs 29.7±4.2 pg/g for TNF-alpha, 41.8±7.4 vs 28.7±4.3 pg/g for IL-6). Only beta-adrenergic receptor-1 was significantly increased in treated vs control animals (34.6±7.3 vs 12.5±5.3, p = 0.01) and correlated with TNF-alpha, IL-6 and norepinephrine hepatic levels in animals with bacterial-DNA. In the second set of mice, cytokine levels were increased in 6-hydroxidopamine and Nebivolol (beta-adrenergic receptor-1 antagonist) treated mice compared with saline. Butoxamine (beta-adrenergic receptor-2 antagonist) didn’t inhibit liver norepinephrine modulation of pro-inflammatory cytokines.

Conclusions

Beta-adrenergic receptor-1 mediates liver norepinephrine modulation of the pro-inflammatory response in CCl4-treated mice with bacterial-DNA.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号