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   585篇
  免费   32篇
  2021年   9篇
  2020年   2篇
  2019年   12篇
  2018年   14篇
  2017年   9篇
  2016年   18篇
  2015年   17篇
  2014年   22篇
  2013年   38篇
  2012年   25篇
  2011年   30篇
  2010年   24篇
  2009年   26篇
  2008年   36篇
  2007年   43篇
  2006年   34篇
  2005年   27篇
  2004年   32篇
  2003年   35篇
  2002年   27篇
  2001年   8篇
  2000年   7篇
  1999年   5篇
  1998年   6篇
  1997年   10篇
  1996年   4篇
  1995年   8篇
  1994年   6篇
  1993年   6篇
  1992年   4篇
  1991年   5篇
  1990年   5篇
  1989年   10篇
  1988年   5篇
  1987年   6篇
  1986年   3篇
  1985年   4篇
  1984年   3篇
  1983年   4篇
  1982年   5篇
  1981年   3篇
  1979年   2篇
  1978年   5篇
  1976年   4篇
  1975年   1篇
  1974年   1篇
  1973年   2篇
  1972年   1篇
  1970年   1篇
  1969年   1篇
排序方式: 共有617条查询结果,搜索用时 375 毫秒
551.

Objective

Human toxocariasis is a zoonotic infection caused by the larval stages of Toxocara canis (T. canis) and less frequently Toxocara cati (T. cati). A relationship between toxocariasis and epilepsy has been hypothesized. We conducted a systematic review and a meta-analysis of available data to evaluate the strength of association between epilepsy and Toxocara spp. seropositivity and to propose some guidelines for future surveys.

Data Sources

Electronic databases, the database from the Institute of Neuroepidemiology and Tropical Neurology of the University of Limoges (http://www-ient.unilim.fr/) and the reference lists of all relevant papers and books were screened up to October 2011.

Methods

We performed a systematic review of literature on toxocariasis (the exposure) and epilepsy (the outcome). Two authors independently assessed eligibility and study quality and extracted data. A common odds ratio (OR) was estimated using a random-effects meta-analysis model of aggregated published data.

Results

Seven case-control studies met the inclusion criteria, for a total of 1867 participants (850 cases and 1017 controls). The percentage of seropositivity (presence of anti-Toxocara spp. antibodies) was higher among people with epilepsy (PWE) in all the included studies even if the association between epilepsy and Toxocara spp. seropositivity was statistically significant in only 4 studies, with crude ORs ranging 2.04–2.85. Another study bordered statistical significance, while in 2 of the included studies no significant association was found. A significant (p<0.001) common OR of 1.92 [95% confidence interval (CI) 1.50–2.44] was estimated. Similar results were found when meta-analysis was restricted to the studies considering an exclusively juvenile population and to surveys using Western Blot as confirmatory or diagnostic serological assay.

Conclusion

Our results support the existence of a positive association between Toxocara spp. seropositivity and epilepsy. Further studies, possibly including incident cases, should be performed to better investigate the relationship between toxocariasis and epilepsy.  相似文献   
552.
553.
Arbuscular mycorrhizal (AM) fungi establish a mutualistic symbiosis with the roots of most plant species. While receiving photosynthates, they improve the mineral nutrition of the plant and can also increase its tolerance towards some pollutants, like heavy metals. Although the fungal symbionts exclusively colonize the plant roots, some plant responses can be systemic. Therefore, in this work a clone of Populus alba L., previously selected for its tolerance to copper and zinc, was used to investigate the effects of the symbiosis with the AM fungus Glomus intraradices on the leaf protein expression. Poplar leaf samples were collected from plants maintained in a glasshouse on polluted (copper and zinc contaminated) or unpolluted soil, after four, six and sixteen months of growth. For each harvest, about 450 proteins were reproducibly separated on 2DE maps. At the first harvest the most relevant effect on protein modulation was exerted by the AM fungi, at the second one by the metals, and at the last one by both treatments. This work demonstrates how importantly the time of sampling affects the proteome responses in perennial plants. In addition, it underlines the ability of a proteomic approach, targeted on protein identification, to depict changes in a specific pattern of protein expression, while being still far from elucidating the biological function of each protein.  相似文献   
554.
The ovine POU1F1 gene is localized on chromosome 1 and it contains five introns and six exons. In different mammalian species some mutations in different exons are associated with different production traits. The aim of our research was to study the POU1F1 gene nucleotide sequence to detect possible polymorphisms and their relationships with milk productive traits in Sarda breed sheep. The study had been conducted on 140 ewes, 4 or 5 years old coming from a farm located in Sardinia. All the animals were multiparous, lactating and in their third to fifth lactation. Individual milk yield had been recorded monthly and for each sample fat, protein, casein, lactose, and somatic cell count values were analysed. A jugular blood sample was collected from each ewe to perform genomic DNA extraction. PCR, SSCP and sequencing analysis were carried out to examine the six exons to highlight possible SNPs. One-way ANOVA was used to analyse association of variants with milk yield and/or its composition. Two novel SNP were found: 121 C>T in the 5′UTR of the fourth intron fragment and 249 G>A in the 3′UTR of the sixth exon fragment. The statistical analysis did not shown association between milk productive traits and the found polymorphisms. However, further investigations about the promoter region or the prophet genes, like the PROP-1, could clarify its exact role in regulating the productive traits in sheep.  相似文献   
555.
The serine/threonine specific protein kinase B-Raf is part of the MAPK pathway and is an interesting oncology target. We have identified thieno[2,3-d]pyrimidines as a core scaffold of small molecule B-Raf inhibitors. The SAR of analogs in this series will be described.  相似文献   
556.
Here we report the cDNA nucleotide sequences of a calmodulin-binding catalase and an antiquitin from the latex of the Mediterranean shrub Euphorbia characias. Present findings suggest that catalase and antiquitin might represent additional nodes in the Euphorbia defense systems, and a multi-enzymatic interaction contributing to plant's protection against biotic and abiotic stresses is proposed to occur in E. characias laticifers.  相似文献   
557.
558.
Proteolytic cleavage of translation initiation factors is a means to interfere with mRNA circularization and to induce translation arrest during picornaviral replication or apoptosis. It was shown that the regulated cleavages of eukaryotic initiation factor (eIF) 4G and poly(A)-binding protein (PABP) by viral proteinases correlated with early and late arrest of host cap-dependent and viral internal ribosome entry site (IRES)-dependent translation, respectively. Here we show that in contrast to coxsackievirus, eIF4G is not a substrate of proteinase 3C of hepatitis A virus (HAV 3Cpro). However, PABP is cleaved by HAV 3Cpro in vitro and in vivo, separating the N-terminal RNA-binding domain (NTD) of PABP from the C-terminal protein-interaction domain. In vitro, NTD has a dominant negative effect on HAV IRES-dependent translation and an enhanced binding affinity to the RNA structural element pY1 in the 5′ nontranslated region of the HAV RNA that is essential for viral genome replication. The results point to a regulatory role of PABP cleavage in RNA template switching of viral translation to RNA synthesis.  相似文献   
559.
560.
The biological implication of protein tyrosine nitration in signaling pathways triggered by nitric oxide is recently emerging. Here we report for the first time that nitrotyrosination occurs in the neural intermediate filament protein peripherin. In neuron-like PC12 cells, nitrated peripherin is associated with the cytoskeleton fraction, its level increases during the progression of NGF-induced differentiation and the nitrated protein remains closely associated with stable microtubules. Tyr 17 and Tyr 376 were identified by MALDI-TOF analyses as two specific residues endogenously nitrated. Finally, peripherin nitration is not restricted to PC12 cells but it is also present in vivo in rat brain. Gabriella Tedeschi and Graziella Cappelletti contributed equally to this work.  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