全文获取类型
收费全文 | 1286篇 |
免费 | 96篇 |
专业分类
1382篇 |
出版年
2023年 | 14篇 |
2022年 | 27篇 |
2021年 | 32篇 |
2020年 | 26篇 |
2019年 | 32篇 |
2018年 | 51篇 |
2017年 | 38篇 |
2016年 | 59篇 |
2015年 | 74篇 |
2014年 | 94篇 |
2013年 | 86篇 |
2012年 | 135篇 |
2011年 | 103篇 |
2010年 | 70篇 |
2009年 | 52篇 |
2008年 | 83篇 |
2007年 | 65篇 |
2006年 | 57篇 |
2005年 | 47篇 |
2004年 | 58篇 |
2003年 | 43篇 |
2002年 | 34篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 8篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1987年 | 3篇 |
1985年 | 4篇 |
1981年 | 1篇 |
1979年 | 3篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 3篇 |
1966年 | 1篇 |
1964年 | 1篇 |
1960年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有1382条查询结果,搜索用时 0 毫秒
71.
72.
Devendra Bansal Fabien Herbert Pharath Lim Prakash Deshpande Christophe Bécavin Vincent Guiyedi Ilaria de Maria Jean Claude Rousselle Abdelkader Namane Rajendra Jain Pierre-André Cazenave Gyan Chandra Mishra Cristiano Ferlini Constantin Fesel Arndt Benecke Sylviane Pied 《PloS one》2009,4(12)
Background
The main processes in the pathogenesis of cerebral malaria caused by Plasmodium falciparum involved sequestration of parasitized red blood cells and immunopathological responses. Among immune factors, IgG autoantibodies to brain antigens are increased in P. falciparum infected patients and correlate with disease severity in African children. Nevertheless, their role in the pathophysiology of cerebral malaria (CM) is not fully defined. We extended our analysis to an Indian population with genetic backgrounds and endemic and environmental status different from Africa to determine if these autoantibodies could be either a biomarker or a risk factor of developing CM.Methods/Principal Findings
We investigated the significance of these self-reactive antibodies in clinically well-defined groups of P. falciparum infected patients manifesting mild malaria (MM), severe non-cerebral malaria (SM), or cerebral malaria (CM) and in control subjects from Gondia, a malaria epidemic site in central India using quantitative immunoprinting and multivariate statistical analyses. A two-fold complete-linkage hierarchical clustering allows classifying the different patient groups and to distinguish the CM from the others on the basis of their profile of IgG reactivity to brain proteins defined by PANAMA Blot. We identified beta tubulin III (TBB3) as a novel discriminant brain antigen in the prevalence of CM. In addition, circulating IgG from CM patients highly react with recombinant TBB3. Overall, correspondence analyses based on singular value decomposition show a strong correlation between IgG anti-TBB3 and elevated concentration of cluster-II cytokine (IFNγ, IL1β, TNFα, TGFβ) previously demonstrated to be a predictor of CM in the same population.Conclusions/Significance
Collectively, these findings validate the relationship between antibody response to brain induced by P. falciparum infection and plasma cytokine patterns with clinical outcome of malaria. They also provide significant insight into the immune mechanisms associated to CM by the identification of TBB3 as a new disease-specific marker and potential therapeutic target. 相似文献73.
74.
Ilaria Guarniero Flavio Garoia Raffaele Di Placido Andreja Ramsak Piero Mannini Fausto Tinti 《Molecular ecology resources》2003,3(2):312-313
A microsatellite dinucleotide‐enriched library was obtained from the European squid (Loligo vulgaris) and five species‐specific dinucleotide markers were optimized. These markers are highly polymorphic with average expected heterozygosity ranging from 0.706 to 0.927 and allele number ranging from 7 to 17. This set of primers is suitable for population genetic studies. 相似文献
75.
Genetic relationships and clonal identity in a collection of commercially relevant poplar cultivars assessed by AFLP and SSR 总被引:2,自引:0,他引:2
Tiziana?Fossati Ilaria?Zapelli Stefano?Bisoffi Alessandra?Micheletti Lorenzo?Vietto Francesco?Sala Stefano?CastiglioneEmail author 《Tree Genetics & Genomes》2005,1(1):11-20
A collection of 66 poplar commercial clones widely cultivated in Italy, China and in other countries of southern Europe and belonging to various poplar species and hybrids, have been fingerprinted using both amplified fragment length polymorphism (AFLP) and simple sequence repeats (SSR) techniques. Three AFLP primer combinations and six SSRs unambiguously genotyped the analysed poplar collection, with the exception of three groups of six, four and two individuals, which turned out to be indistinguishable even if they met the standards currently applied for distinctness, uniformity and stability (DUS) testing when registered. High levels of variation were detected with both molecular techniques; a total of 201 AFLP bands were amplified of which 96% turned out to be polymorphic and up to 15 SSR alleles were identified at a single locus, with a mean of 9.3 alleles per locus in the case of Populus × canadensis. The probability of matching fortuitously any two genotypes at all the SSR loci in the case of P. × canadensis was less then 7.5×10–9. The AFLP-derived dendrogram and principal coordinate analysis (PCOORDA) clustered the clones with respect to their taxonomic classification, and allowed their genetic interrelationships to be established. Correct identification of poplar varieties is essential for ensuring the effective correspondence between the real and the declared identity of a clone, to avoid commercial frauds, and to establish breeding programmes. Molecular markers may play a major role to satisfy all these needs. 相似文献
76.
Finore Ilaria Kasavi Ceyda Poli Annarita Romano Ida Oner Ebru Toksoy Kirdar Betul Dipasquale Laura Nicolaus Barbara Lama Licia 《World journal of microbiology & biotechnology》2011,27(10):2425-2433
This study reports the purification and biochemical characterization of a raw starch-digesting α-amylase from Geobacillus thermoleovorans subsp. stromboliensis subsp. nov. (strain PizzoT). The molecular weight was estimated to be 58 kDa by SDS–PAGE. The enzyme was highly active over a wide range of pH from
4.0–10.0. The optimum temperature of the enzyme was 70°C. It showed extreme thermostability in the presence of Ca2+, retaining 50% of its initial activity after 90 h at 70°C. The enzyme efficiently hydrolyzed 20% (w/v) of raw starches, concentration
normally used in starch industries. The α-amylase showed an high stability in presence of many organic solvents. In particular
the residual activity was of 73% in presence of 15% (v/v) ethyl alcohol, which corresponds to ethanol yield in yeast fermentation
process. By analyzing its complete amyA gene sequence (1,542 bp), the enzyme was proposed to be a new α-amylase. 相似文献
77.
Tommasini I Cerioni L Guidarelli A Cantoni O 《Biochemical and biophysical research communications》2005,329(4):1282-1287
A short-term growth of U937 cells in serum-free medium causes a prompt, mitochondrial permeability transition (MPT)-dependent necrotic response after exposure to an otherwise non-toxic concentration of peroxynitrite. This event is mediated by inhibition of extracellular signal-regulated kinase 1 and 2 (ERK1/2) phosphorylation, essential for the cytosolic phospholipase A(2)-dependent arachidonic acid (AA) release evoked by peroxynitrite. Reduced availability of the lipid messenger would therefore limit the efficiency of the AA-dependent survival signalling and cause an MPT-based necrosis. Since peroxynitrite further reduces the extent of ERK1/2 phosphorylation, regardless of whether cells had been grown in serum-free or -containing medium, it appears that basal ERK1/2 phosphorylation is a critical determinant for the survival response of U937 cells to a non-toxic, but nevertheless MPT-committing, concentration of peroxynitrite. 相似文献
78.
Maria Angela Orsi Margarida Maria H. Zaroni Luciano Doretto Júnior Soraya Cecilia Albieri Camillo Simone Alves Mendes Ribeiro Fernando Rosado Spilki Maria da Glria Buzinaro Clarice Weis Arns 《Biologicals》2009,37(4):252-258
The thermostability (TS) and efficacy offered by live vaccines against Newcastle disease strains B1, La Sota, VG-GA and Ulster, produced or imported by four Brazilian laboratories, were evaluated during their validity period. Kinetic profiles were obtained from samples conserved in refrigerators during 0, 4, 8, 12, 16, 20 and 24 months after their manufacturing. The statistical analysis of the vaccine titre effect obtained by the fresh air (FA) method showed that the vaccine profiles were parallel and coincident, presenting a significant descending trend. The vaccine titres and efficiency proofs at the end of the validity period were above the level of legislation requirements and showed an average loss in titre of 0.40 and 0.66 log10, within the first and second validity years, respectively. The titre obtained by TS, within the month after manufacturing, had no significant difference from the titre obtained by FA within 24 months after manufacturing, being their pairs of observations positively correlated (r = 0.49, p = 0.0003), showing that the TS method, which anticipates the vaccines' performance at the end of the validity period, can substitute the FA method 24 months after manufacturing. 相似文献
79.
80.
Paola Elisa Corneo Alberto Pellegrini Luca Cappellin Cesare Gessler Ilaria Pertot 《Microbial ecology》2014,67(3):659-670
Changes in the soil microbial community structure can lead to dramatic changes in the soil ecosystem. Temperature, which is projected to increase with climate change, is commonly assumed to affect microbial communities, but its effects on agricultural soils are not fully understood. We collected soil samples from six vineyards characterised by a difference of about 2 °C in daily soil temperature over the year and simulated in a microcosm experiment different temperature regimes over a period of 1 year: seasonal fluctuations in soil temperature based on the average daily soil temperature measured in the field; soil temperature warming (2 °C above the normal seasonal temperatures); and constant temperatures normally registered in these temperate soils in winter (3 °C) and in summer (20 °C). Changes in the soil bacterial and fungal community structures were analysed by automated ribosomal intergenic spacer analysis (ARISA). We did not find any effect of warming on soil bacterial and fungal communities, while stable temperatures affected the fungal more than the bacterial communities, although this effect was soil dependent. The soil bacterial community exhibited soil-dependent seasonal fluctuations, while the fungal community was mainly stable. Each soil harbours different microbial communities that respond differently to seasonal temperature fluctuations; therefore, any generalization regarding the effect of climate change on soil communities should be made carefully. 相似文献