全文获取类型
收费全文 | 302篇 |
免费 | 23篇 |
专业分类
325篇 |
出版年
2023年 | 2篇 |
2022年 | 8篇 |
2021年 | 21篇 |
2020年 | 7篇 |
2019年 | 7篇 |
2018年 | 11篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 19篇 |
2014年 | 25篇 |
2013年 | 35篇 |
2012年 | 30篇 |
2011年 | 18篇 |
2010年 | 7篇 |
2009年 | 16篇 |
2008年 | 13篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 16篇 |
2003年 | 3篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1996年 | 3篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有325条查询结果,搜索用时 0 毫秒
71.
Vito A. G. Ricigliano Renato Umeton Lorenzo Germinario Eleonora Alma Martina Briani Noemi Di Segni Dalma Montesanti Giorgia Pierelli Fabiana Cancrini Cristiano Lomonaco Francesca Grassi Gabriella Palmieri Marco Salvetti 《PloS one》2013,8(8)
The factual value of genome-wide association studies (GWAS) for the understanding of multifactorial diseases is a matter of intense debate. Practical consequences for the development of more effective therapies do not seem to be around the corner. Here we propose a pragmatic and objective evaluation of how much new biology is arising from these studies, with particular attention to the information that can help prioritize therapeutic targets. We chose multiple sclerosis (MS) as a paradigm disease and assumed that, in pre-GWAS candidate-gene studies, the knowledge behind the choice of each gene reflected the understanding of the disease prior to the advent of GWAS. Importantly, this knowledge was based mainly on non-genetic, phenotypic grounds. We performed single-gene and pathway-oriented comparisons of old and new knowledge in MS by confronting an unbiased list of candidate genes in pre-GWAS association studies with those genes exceeding the genome-wide significance threshold in GWAS published from 2007 on. At the single gene level, the majority (94 out of 125) of GWAS-discovered variants had never been contemplated as plausible candidates in pre-GWAS association studies. The 31 genes that were present in both pre- and post-GWAS lists may be of particular interest in that they represent disease-associated variants whose pathogenetic relevance is supported at the phenotypic level (i.e. the phenotypic information that steered their selection as candidate genes in pre-GWAS association studies). As such they represent attractive therapeutic targets. Interestingly, our analysis shows that some of these variants are targets of pharmacologically active compounds, including drugs that are already registered for human use. Compared with the above single-gene analysis, at the pathway level GWAS results appear more coherent with previous knowledge, reinforcing some of the current views on MS pathogenesis and related therapeutic research. This study presents a pragmatic approach that helps interpret and exploit GWAS knowledge. 相似文献
72.
Piccoli G Verpelli C Tonna N Romorini S Alessio M Nairn AC Bachi A Sala C 《Journal of proteome research》2007,6(8):3203-3215
Following long-term treatment with bicuculline and tetrodotoxin (TTX) aimed at modifying synaptic activity in cultured neurons, we used a proteomic approach to identify the associated changes in protein expression. The neurons were left untreated, or treated with bicuculline or TTX, and fractionated by means of differential detergent extraction, after which the proteins in each fraction were separated by means of two-dimensional (2D) gel electrophoresis, and 57 proteins of interest were identified by mass spectrometry. The proteins that showed altered expression and/or post-translational modifications include proteins or enzymes involved in regulating cell and protein metabolism, the cytoskeleton, or mitochondrial activity. These results suggest that extensive alterations in neuronal protein expression take place as a result of increased or decreased synaptic activity. 相似文献
73.
Biosynthesis of 5,15-dihydroxyeicosatetraenoic acid (5,15-diHETE) in leukocytes involves consecutive oxygenation of arachidonic acid by 5-lipoxygenase (LOX) and 15-LOX in either order. Here, we analyzed the contribution of cyclooxygenase (COX)-2 to the biosynthesis of 5,15-diHETE and 5,11-diHETE in isolated human leukocytes activated with lipopolysaccharide and calcium ionophore A23187. Transformation of arachidonic acid was initiated by 5-LOX providing 5S-HETE as a substrate for COX-2 forming 5S,15S-diHETE, 5S,15R-diHETE, and 5S,11R-diHETE as shown by LC/MS and chiral phase HPLC analyses. The levels of 5,15-diHETE were 0.45 ± 0.2 ng/106 cells (mean ± SEM, n = 6), reaching about half the level of LTB4 (1.3 ± 0.5 ng/106 cells, n = 6). The COX-2 specific inhibitor NS-398 reduced the levels of 5,15-diHETE to below 0.02 ng/106 cells in four of six samples. Similar reduction was achieved by MK-886, an inhibitor of 5-LOX activating protein but the above differences were not statistically significant. Aspirin treatment of the activated cells allowed formation of 5,15-diHETE (0.1 ± 0.05 ng/106 cells, n = 6) but, as expected, abolished formation of 5,11-diHETE. The mixture of activated cells also produced 5S,12S-diHETE with the unusual 6E,8Z,10E double bond configuration, implicating biosynthesis by 5-LOX and 12-LOX activity rather than by hydrolysis of the leukotriene A4-epoxide. Exogenous octadeuterated 5S-HETE and 15S-HETE were converted to 5,15-diHETE, implicating that multiple oxygenation pathways of arachidonic acid occur in activated leukocytes. The contribution of COX-2 to the biosynthesis of dihydroxylated derivatives of arachidonic acid provides evidence for functional coupling with 5-LOX in activated human leukocytes. 相似文献
74.
Parra A Veraldi N Locatelli M Fini M Martini L Torri G Sangiorgi L Bisio A 《Glycobiology》2012,22(2):248-257
Glycosaminoglycans were extracted from both young rabbit growth plate (GRP) and articular (ART) cartilage tissues and enzymatically treated to selectively eliminate chondroitin sulfates and hyaluronic acid. The procedure avoided any fractionation step that could enrich the extract with over- or under-sulfated species. Isolated heparan sulfate (HS) was characterized by mono- and bidimensional nuclear magnetic resonance (NMR) spectroscopy to quantify their specific structural features and/or by mass spectrometry to establish the disaccharide composition. Both GRP and ART HSs, despite differing in their yield (GRP at least 100 times greater than ART), exhibited a surprisingly high degree of sulfation. Quantitative two-dimensional heteronuclear single-quantum coherence-NMR analysis of GRP HS revealed unusually high N-sulfated glucosamine and 2-O-sulfated iduronic acid contents, similar to heparin. The unique pentasaccharide sequence of the binding site for antithrombin was also detected in a significant amount. High-performance liquid chromatography mass spectrometry analysis of the enzymatic digests with a cocktail of heparin lyases of both cartilaginous HSs confirmed the NMR results. As well as the discovery of an unusual HS structure in the two different types of rabbit cartilage, the feasibility of the analytical method adopted here has been demonstrated within this study. Such a method can be used to isolate and analyze HS from both normal and pathologic tissues. Characterization of healthy and pathological HS structures will contribute to improve the understanding of diseases related to malfunctions of HS biosynthesis and/or metabolism. 相似文献
75.
Cerovska N Hoffmeisterova H Moravec T Plchova H Folwarczna J Synkova H Ryslava H Ludvikova V Smahel M 《Journal of biosciences》2012,37(1):125-133
Transient expression of foreign genes based on plant viral vectors is a suitable system for the production of relevant immunogens
that can be used for the development of a new generation of vaccines against a variety of infectious diseases. In the present
study the epitope derived from HPV-16 L2 minor capsid protein (amino acids 108–120) was expressed from Potato virus X (PVX)-based vector pGR106 as N- or C-terminal fusion with the PVX coat protein (PVX CP) in transgenic Nicotiana benthamiana plants. The fusion protein L2108-120-PVX CP was successfully expressed in plants at a level of 170 mg/kg of fresh leaf tissue. The C-terminal fusion protein PVX
CP- L2108-120 was expressed using mutated vector sequence to avoid homologous recombination at a level of 8 mg/kg of fresh leaf tissue.
Immunogenicity of L2108-120-PVX CP virus-like particles was tested after immunization of mice by subcutaneous injection or tattoo administration. In
animal sera the antibodies against the PVX CP and the L2108-120 epitope were found after both methods of vaccine delivery. 相似文献
76.
Noemi Ruiz-López Richard P. Haslam Mónica Venegas-Calerón Tianbi Li Joerg Bauer Johnathan A. Napier Olga Sayanova 《Transgenic research》2012,21(6):1233-1243
The synthesis and accumulation of long chain polyunsaturated fatty acids such as eicosapentaenoic acid has previously been demonstrated in the seeds of transgenic plants. However, the obtained levels are relatively low, indicating the need for further studies and the better definition of the interplay between endogenous lipid synthesis and the non-native transgene-encoded activities. In this study we have systematically compared three different transgenic configurations of the biosynthetic pathway for eicosapentaenoic acid, using lipidomic profiling to identify metabolic bottlenecks. We have also used genetic crossing to stack up to ten transgenes in Arabidopsis. These studies indicate several potential approaches to optimize the accumulation of target fatty acids in transgenic plants. Our data show the unexpected channeling of heterologous C20 polyunsaturated fatty acids into minor phospholipid species, and also the apparent negative metabolic regulation of phospholipid-dependent ??6-desaturases. Collectively, this study confirms the benefits of iterative approaches to metabolic engineering of plant lipid synthesis. 相似文献
77.
Denise O. Guimarães Warley S. Borges Noemi J. Vieira Laiani F. de Oliveira Carlos H.T.P. da Silva Norberto P. Lopes Luis G. Dias Rosa Durán-Patrón Isidro G. Collado Mônica T. Pupo 《Phytochemistry》2010,71(11-12):1423-1429
Diketopiperazine (DKP) derivatives, named colletopiperazine, fusaperazine C and E as well as four known DKPs were isolated from cultures of Colletotrichum gloeosporioides, Penicillium crustosum, both endophytic fungi isolated from Viguiera robusta, and a Fusarium spp., an endophyte of Viguiera arenaria, respectively. Their structures were established on the basis of their spectroscopic data. Conformational analysis of two known DKPs showed that folded conformations were as energetically stable as the extended one. 相似文献
78.
79.
Noemi Cifani Barbara Pompili Marco Anile Miriam Patella Daniele Diso Federico Venuta Giuseppe Cimino Serena Quattrucci Enea Gino Di Domenico Fiorentina Ascenzioni Paola Del Porto 《PloS one》2013,8(8)
Pseudomonas aeruginosa is the most common pathogen for chronic lung infection in cystic fibrosis (CF) patients. About 80% of adult CF patients have chronic P. aeruginosa infection, which accounts for much of the morbidity and most of the mortality. Both bacterial genetic adaptations and defective innate immune responses contribute to the bacteria persistence. It is well accepted that CF transmembrane conductance regulator (CFTR) dysfunction impairs the airways-epithelium-mediated lung defence; however, other innate immune cells also appear to be affected, such as neutrophils and macrophages, which thus contribute to this infectious pathology in the CF lung. In macrophages, the absence of CFTR has been linked to defective P. aeruginosa killing, increased pro-inflammatory cytokine secretion, and reduced reactive oxygen species (ROS) production. To learn more about macrophage dysfunction in CF patients, we investigated the generation of the oxidative burst and its impact on bacterial killing in CF macrophages isolated from peripheral blood or lung parenchyma of CF patients, after P. aeruginosa infection. Our data demonstrate that CF macrophages show an oxidative response of similar intensity to that of non-CF macrophages. Intracellular ROS are recognized as one of the earliest microbicidal mechanisms against engulfed pathogens that are activated by macrophages. Accordingly, NADPH inhibition resulted in a significant increase in the intracellular bacteria survival in CF and non-CF macrophages, both as monocyte-derived macrophages and as lung macrophages. These data strongly suggest that the contribution of ROS to P. aeruginosa killing is not affected by CFTR mutations. 相似文献
80.
Caruggi Noemi Lucisano Mara Feyissa Aberham Hailu Rahimi Yazdi Saeed Mohammadifar Mohammad Amin 《Food biophysics》2019,14(3):249-259
Food Biophysics - This study aimed to describe the effects of ohmic heat treatment (OHT) of milk on the formation and properties of acid milk gels. The influence of voltage gradient (25, 40,... 相似文献