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911.
Anthony Klein Hervé Houtin Céline Rond Pascal Marget Françoise Jacquin Karen Boucherot Myriam Huart Nathalie Rivière Gilles Boutet Isabelle Lejeune-Hénaut Judith Burstin 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2014,127(6):1319-1330
Key message
Avoidance mechanisms and intrinsic resistance are complementary strategies to improve winter frost tolerance and yield potential in field pea.Abstract
The development of the winter pea crop represents a major challenge to expand plant protein production in temperate areas. Breeding winter cultivars requires the combination of freezing tolerance as well as high seed productivity and quality. In this context, we investigated the genetic determinism of winter frost tolerance and assessed its genetic relationship with yield and developmental traits. Using a newly identified source of frost resistance, we developed a population of recombinant inbred lines and evaluated it in six environments in Dijon and Clermont-Ferrand between 2005 and 2010. We developed a genetic map comprising 679 markers distributed over seven linkage groups and covering 947.1 cM. One hundred sixty-one quantitative trait loci (QTL) explaining 9–71 % of the phenotypic variation were detected across the six environments for all traits measured. Two clusters of QTL mapped on the linkage groups III and one cluster on LGVI reveal the genetic links between phenology, morphology, yield-related traits and frost tolerance in winter pea. QTL clusters on LGIII highlighted major developmental gene loci (Hr and Le) and the QTL cluster on LGVI explained up to 71 % of the winter frost damage variation. This suggests that a specific architecture and flowering ideotype defines frost tolerance in winter pea. However, two consistent frost tolerance QTL on LGV were independent of phenology and morphology traits, showing that different protective mechanisms are involved in frost tolerance. Finally, these results suggest that frost tolerance can be bred independently to seed productivity and quality. 相似文献912.
913.
The Ma gene for complete-spectrum resistance to Meloidogyne species in Prunus is a TNL with a huge repeated C-terminal post-LRR region 总被引:1,自引:0,他引:1
Claverie M Dirlewanger E Bosselut N Van Ghelder C Voisin R Kleinhentz M Lafargue B Abad P Rosso MN Chalhoub B Esmenjaud D 《Plant physiology》2011,156(2):779-792
Root-knot nematode (RKN) Meloidogyne species are major polyphagous pests of most crops worldwide, and cultivars with durable resistance are urgently needed because of nematicide bans. The Ma gene from the Myrobalan plum (Prunus cerasifera) confers complete-spectrum, heat-stable, and high-level resistance to RKN, which is remarkable in comparison with the Mi-1 gene from tomato (Solanum lycopersicum), the sole RKN resistance gene cloned. We report here the positional cloning and the functional validation of the Ma locus present at the heterozygous state in the P.2175 accession. High-resolution mapping totaling over 3,000 segregants reduced the Ma locus interval to a 32-kb cluster of three Toll/Interleukin1 Receptor-Nucleotide Binding Site-Leucine-Rich Repeat (LRR) genes (TNL1-TNL3), including a pseudogene (TNL2) and a truncated gene (TNL3). The sole complete gene in this interval (TNL1) was validated as Ma, as it conferred the same complete-spectrum and high-level resistance (as in P.2175) using its genomic sequence and native promoter region in Agrobacterium rhizogenes-transformed hairy roots and composite plants. The full-length cDNA (2,048 amino acids) of Ma is the longest of all Resistance genes cloned to date. Its TNL structure is completed by a huge post-LRR (PL) sequence (1,088 amino acids) comprising five repeated carboxyl-terminal PL exons with two conserved motifs. The amino-terminal region (213 amino acids) of the LRR exon is conserved between alleles and contrasts with the high interallelic polymorphisms of its distal region (111 amino acids) and of PL domains. The Ma gene highlights the importance of these uncharacterized PL domains, which may be involved in pathogen recognition through the decoy hypothesis or in nuclear signaling. 相似文献
914.
Both predation and individual variation in life history traits influence population dynamics. Recent results from laboratory
predator–prey systems suggest that differences between individuals can also influence predator–prey dynamics when different
genotypes experience different predation-associated mortalities. Despite the growing number of studies in this field, there
is no synthesis identifying the overall importance of the interactions between predation and individual heterogeneity and
their role in shaping the dynamics of free-ranging populations of vertebrates. We aim to fill this gap with a review that
examines how individual variability in prey susceptibility, in predation costs, in predator selectivity, and in predatory
performance, might influence prey population dynamics. Based on this review, it is clear that (1) predation risk and costs
experienced by free-ranging prey are associated with their phenotypic attributes, (2) many generalist predator populations
consist of individual specialists with part of the specialization associated with their phenotypes, and (3) a complete understanding
of the population dynamic consequences of predation may require information on individual variability in prey selection and
prey vulnerability. Altogether, this work (1) highlights the importance of maintaining long-term, detailed studies of individuals
of both predators and prey in contrasting ecological conditions, and (2) advocates for a better use of available information
to account for interactive effects between predators and their prey when modelling prey population dynamics. 相似文献
915.
Ladeuze S Lentz N Delbrassinne L Hu X Mahillon J 《Applied and environmental microbiology》2011,77(7):2555-2558
In this study, the fungistatic activity of Bacillus cereus cereulide-producing strains was demonstrated against nine fungal species. The role of cereulide was confirmed using plasmid-cured derivatives and ces knockout mutants. The fungistatic spectra of cereulide and valinomycin, a chemically related cyclododecadepsipeptide, were also compared and found to be similar but distinct. 相似文献
916.
Rogel A Vignard V Bobinet M Labarriere N Lang F 《Cancer immunology, immunotherapy : CII》2011,60(3):327-337
CD4+ T cells contribute importantly to the antitumor T cell response, and thus, long peptides comprising CD4 and CD8 epitopes
may be efficient cancer vaccines. We have previously identified an overexpressed antigen in melanoma, MELOE-1, presenting
a CD8+ T cell epitope, MELOE-136–44, in the HLA-A*0201 context. A T cell repertoire against this epitope is present in HLA-A*0201+ healthy subjects and melanoma
patients and the adjuvant injection of TIL containing MELOE-1 specific CD8+ T cells to melanoma patients was shown to be beneficial. In this study, we looked for CD4+ T cell epitopes in the vicinity of the HLA-A*0201 epitope. Stimulation of PBMC from healthy subjects with MELOE-126–46 revealed CD4 responses in multiple HLA contexts and by cloning responsive CD4+ T cells, we identified one HLA-DRβ1*1101-restricted and one HLA-DQβ1*0603-restricted epitope. We showed that the two epitopes
could be efficiently presented to CD4+ T cells by MELOE-1-loaded dendritic cells but not by MELOE-1+ melanoma cell-lines. Finally, we showed that the long peptide
MELOE-122–46, containing the two optimal class II epitopes and the HLA-A*0201 epitope, was efficiently processed by DC to stimulate CD4+ and CD8+ T cell responses in vitro, making it a potential candidate for melanoma vaccination. 相似文献
917.
Sébastien Gogo Fatima Laggoun-Défarge Frédéric Delarue Nathalie Lottier 《Biogeochemistry》2011,106(1):53-69
Peatlands act as a sink of carbon (C) through the accumulation of dead remains of plants. Under global changes triggered by
human activities, it is not only the sink capacity of peatland that is in danger, but also the C already stored. Invasion
of Sphagnum peatlands, mainly by Molinia caerulea and Betula spp, is a growing preoccupation. This study aims to assess the extent of the influence of this invasion on the biochemical
characteristics of the peat. Elemental analysis, sugar and Rock–Eval pyrolysis parameters were measured in 50 cm profiles
collected in invaded and intact plots. The results show that oxygen index ratios (OICO2/OICO) can be used to detect new C substrate injection as invading plants have a lower ratio than Sphagnum spp and Sphagnum peat. Total hemicellulosic sugar contents and organic matter (OM) degradation indices (R400, PPI) suggest that the invading
plants promote a faster OM decomposition probably through a faster degradability and a relatively higher nutrient content
of their litter. Differences in terms of nutrient status between areas of the peatland are suggested to be of great importance
in determining the extent of OM transformation likely due to stoichiometric constraints. 相似文献
918.
Bedia C Casas J Andrieu-Abadie N Fabriàs G Levade T 《The Journal of biological chemistry》2011,286(32):28200-28209
Dacarbazine (DTIC) is the treatment of choice for metastatic melanoma, but its response in patients remains very poor. Ceramide has been shown to be a death effector and to play an important role in regulating cancer cell growth upon chemotherapy. Among ceramidases, the enzymes that catabolize ceramide, acid ceramidase (aCDase) has been implicated in cancer progression. Here we show that DTIC elicits a time- and dose-dependent decrease of aCDase activity and an increase of intracellular ceramide levels in human A375 melanoma cells. The loss of enzyme activity occurred as a consequence of reactive oxygen species-dependent activation of cathepsin B-mediated degradation of aCDase. These events preceded autophagic features and loss of cell viability. Down-regulation of acid but not neutral or alkaline ceramidase 2 resulted in elevated levels of ceramide and sensitization to the toxic effects of DTIC. Conversely, inducible overexpression of acid but not neutral ceramidase reduced ceramide levels and conferred resistance to DTIC. In conclusion, we report that increased levels of ceramide, due to enhanced degradation of aCDase, are in part responsible for the cell death effects of DTIC. These results suggest that down-regulation of aCDase alone or in combination with DTIC may represent a useful tool in the treatment of metastatic melanoma. 相似文献
919.
True stress and Poisson's ratio of tendons during loading 总被引:1,自引:0,他引:1
Vergari C Pourcelot P Holden L Ravary-Plumioën B Gerard G Laugier P Mitton D Crevier-Denoix N 《Journal of biomechanics》2011,44(4):719-724
Excessive axial tension is very likely involved in the aetiology of tendon lesions, and the most appropriate indicator of tendon stress state is the true stress, the ratio of instantaneous load to instantaneous cross-sectional area (CSA). Difficulties to measure tendon CSA during tension often led to approximate true stress by assuming that CSA is constant during loading (i.e. by the engineering stress) or that tendon is incompressible, implying a Poisson's ratio of 0.5, although these hypotheses have never been tested. The objective of this study was to measure tendon CSA variation during quasi-static tensile loading, in order to assess the true stress to which the tendon is subjected and its Poisson's ratio. Eight equine superficial digital flexor tendons (SDFT, about 30cm long) were tested in tension until failure while the CSA of each tendon was measured in its metacarpal part by means of a linear laser scanner. Axial elongation and load were synchronously recorded during the test. CSA was found to linearly decrease with strain, with a mean decrease at failure of -10.7±2.8% (mean±standard deviation). True stress at failure was 7.1-13.6% higher than engineering stress, while stress estimation under the hypothesis of incompressibility differed from true stress of -6.6 to 2.3%. Average Poisson's ratio was 0.55±0.12 and did not significantly vary with load. From these results on equine SDFT it was demonstrated that tendon in axial quasi-static tension can be considered, at first approximation, as an incompressible material. 相似文献
920.
Nathalie T. Reichmann Carolina Piçarra Cassona João M. Monteiro Amy L. Bottomley Rebecca M. Corrigan Simon J. Foster Mariana G. Pinho Angelika Gründling 《Molecular microbiology》2014,92(2):273-286
Lipoteichoic acid (LTA) is an important cell wall component of Gram‐positive bacteria. In Staphylococcus aureus it consists of a polyglycerolphosphate‐chain that is retained within the membrane via a glycolipid. Using an immunofluorescence approach, we show here that the LTA polymer is not surface exposed in S. aureus, as it can only be detected after digestion of the peptidoglycan layer. S. aureus mutants lacking LTA are enlarged and show aberrant positioning of septa, suggesting a link between LTA synthesis and the cell division process. Using a bacterial two‐hybrid approach, we show that the three key LTA synthesis proteins, YpfP and LtaA, involved in glycolipid production, and LtaS, required for LTA backbone synthesis, interact with one another. All three proteins also interacted with numerous cell division and peptidoglycan synthesis proteins, suggesting the formation of a multi‐enzyme complex and providing further evidence for the co‐ordination of these processes. When assessed by fluorescence microscopy, YpfP and LtaA fluorescent protein fusions localized to the membrane while the LtaS enzyme accumulated at the cell division site. These data support a model whereby LTA backbone synthesis proceeds in S. aureus at the division site in co‐ordination with cell division, while glycolipid synthesis takes place throughout the membrane. 相似文献