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161.
Ribeiro AF Laroche E Hanin G Fournier M Quillet L Dupont JP Pawlak B 《FEMS microbiology ecology》2012,81(1):267-280
Occurrences of antibiotic-resistant Escherichia coli in two springs of a karstic system (NW France) providing drinking water were determined to study the role of aquifers in the dissemination of the resistance genes. Water samples were collected during wet and dry periods and after a heavy rainfall event to investigate E. coli density, antibiotic resistance patterns, and occurrences of class 1, 2, and 3 integrons. By observing patterns of the resistant isolates (i.e. number and type of resistances) and their occurrences, we were able to define two resistant subpopulations, introduced in the aquifer via surface water: (1) R1-2, characterized by one or two resistance(s), essentially to chloramphenicol and/or tetracycline (96.5%), was always found during the heavy rainfall event; (2) R3-10, characterized by three or more resistances, mostly resistant to tetracycline (94.1%) and beta-lactams (86%), was found transiently. Class 1 and 2 integrons were detected, mostly in the R3-10 subpopulation for class 1 integrons. The characteristics of these two subpopulations strongly suggest that the contamination originates from pasture runoff for the R1-2 subpopulation and from wastewater treatment plant effluents for the R3-10 subpopulation. These two subpopulations of E. coli could be used as biological indicators to determine the origin of groundwater contamination. 相似文献
162.
The present study reports the evolution of environmental conditions and seawater temperatures during the establishment of a marine hotspot of paleobiodiversity that took place in the Paris Basin during the Lutetian. The stable isotope compositions (δ18O and δ13C) of three species of molluscs (two bivalves: Cubitostrea plicata and Venericardia imbricata, and one gastropod: Sigmesalia multisulcata) collected along the reference section of Grignon (Falunière) are used for paleoenvironmental and paleoclimatic reconstructions. Additional high-resolution analyses on one specimen of Haustator imbricatarius allow the documentation of seasonal changes for temperature. The high-resolution profiles of the δ18O signatures of S. multisulcata reveal that these gastropods mineralized their shell during the warm months of the year, as did V. imbricata, which probably had a short life span (less than 1?year). These two species thus only yield temperatures for the summer period, from 22 to 30?°C. The δ18O of C. plicata shells indicate mean annual sea surface temperatures ranging between 15 and 23?°C during the Middle Lutetian, with minimal temperatures probably reflecting greater depth at the base of the section. The seasonal contrasts reconstructed in the upper part of the section, from the large gastropod H. imbricatarius, ranged between 18 and 30?°C. Comparison of the isotopic values of the species indicates that the δ13C of the three taxa seems to be mostly influenced by ecological features, leading to differences between endobenthic (V. imbricata) and epibenthic species (C. plicata); or the food habits. The paleoclimatic reconstructions show that the Lutetian climate was relatively stable in the Paris Basin with long-term cooling of the mean annual sea-surface temperatures. Nevertheless, this study shows that despite a context of colder conditions compared to the Early Eocene, the climate provided a favorable context for the increase of marine biodiversity in the Paris Basin during the Middle Lutetian. 相似文献
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166.
Emilie E. L. Muller Nicolás Pinel John D. Gillece James M. Schupp Lance B. Price David M. Engelthaler Caterina Levantesi Valter Tandoi Khai Luong Nitin S. Baliga Jonas Korlach Paul S. Keim Paul Wilmes 《Journal of bacteriology》2012,194(23):6670-6671
“Candidatus Microthrix” bacteria are deeply branching filamentous actinobacteria which occur at the water-air interface of biological wastewater treatment plants, where they are often responsible for foaming and bulking. Here, we report the first draft genome sequence of a strain from this genus: “Candidatus Microthrix parvicella” strain Bio17-1. 相似文献
167.
Sylvaine Simon Karine Morel Emilie Durand Géraldine Brevalle Thierry Girard Pierre-Éric Lauri 《Trees - Structure and Function》2012,26(1):273-282
Plant architecture highly constrains pest infestation but is rarely considered in studies on plant–insect interactions. We
analysed the relationships between apple tree architectural traits manipulated by tree training and within-branch development
of Dysaphis plantaginea (rosy apple aphid, RAA), a major apple pest, during its multiplication wingless phase in spring. We hypothesised that the
degree of branching had an effect on RAA within-branch infestation. In an experimental apple orchard, the infestation by aphid
wingless forms was surveyed in two consecutive spring seasons within branches manipulated to design contrasted architectures
differing in shoot numbers, shoot density and branching orders. Whatever the branch management system, aphid infestation was
higher on long versus short, fruiting versus vegetative, and growing versus non-growing shoots. Either less infested shoots
or less severe infestation were observed in the most branched system. A pattern of within-branch short-distance infestation
was confirmed. Moreover, the number of branching points between two shoots exerted a high constraint on this infestation pattern.
Beside possible trophic effects due to plant growth patterns already documented in the literature, a high degree of branching
is likely to be a key-architectural trait to constrain within-branch aphid infestation. This opens new perspectives on the
manipulation of branch architecture as a mean giving partial control of pests towards sustainable fruit production. 相似文献
168.
Vazeille E Slimani L Claustre A Magne H Labas R Béchet D Taillandier D Dardevet D Astruc T Attaix D Combaret L 《The Journal of nutritional biochemistry》2012,23(3):245-251
Immobilization is characterized by activation of the ubiquitin (Ub)-proteasome-dependent proteolytic system (UPS) and of the mitochondrial apoptotic pathway. Increased oxidative stress and inflammatory response occur in immobilized skeletal muscles. Curcumin exhibits antioxidant and anti-inflammatory properties, blocked proteasome activation in intact animals, and may favor skeletal muscle regeneration. We therefore measured the effects of curcumin on immobilization-induced muscle atrophy and subsequent recovery. Rats were subjected to hindlimb immobilization for 8 days (I8) and allowed to recover for 10 days (R10). Fifty percent of the rats were injected daily with either curcumin or vehicle. Proteolytic and apoptotic pathways were studied in gastrocnemius muscles. Curcumin treatment prevented the enhanced proteasome chymotrypsin-like activity and the trend toward increased caspase-9-associated apoptosome activity at I8 in immobilized muscles. By contrast, the increase of these two activities was blunted by curcumin at R10. Curcumin did not reduce muscle atrophy at I8 but improved muscle recovery at R10 and the cross-sectional area of muscle fibers of immobilized muscles. Curcumin reduced the increased protein levels of Smac/DIABLO induced by immobilization and enhanced the elevation of X-linked inhibitory apoptotic protein levels at R10. Ub-conjugate levels and caspase-3 activity increased at I8 and were normalized at R10 without being affected by curcumin treatment. Altogether, the data show that curcumin treatment improved recovery during reloading. The effect of curcumin during the atrophic phase on proteasome activities may facilitate the initiation of muscle recovery after reloading. These data also suggest that this compound may favor the initial steps of muscle regeneration. 相似文献
169.
R Marchetti L Malinovska E Lameignère L Adamova C de Castro G Cioci C Stanetty P Kosma A Molinaro M Wimmerova A Imberty A Silipo 《Glycobiology》2012,22(10):1387-1398
Bacteria from the Burkholderia cepacia complex (Bcc) cause highly contagious pneumonia among cystic fibrosis (CF) patients. Among them, Burkholderia cenocepacia is one of the most dangerous in the Bcc and is the most frequent cause of morbidity and mortality in CF patients. Indeed, it is responsible of "cepacia syndrome", a deadly exacerbation of infection, that is the main cause of poor outcomes in lung transplantation. Burkholderia cenocepacia produces several soluble lectins with specificity for fucosylated and mannosylated glycoconjugates. These lectins are present on the bacterial cell surface and it has been proposed that they bind to lipopolysaccharide epitopes. In this work, we report on the interaction of one B. cenocepacia lectin, BC2L-A, with heptose and other manno configured sugar residues. Saturation transfer difference NMR spectroscopy studies of BC2L-A with different mono- and disaccharides demonstrated the requirement of manno configuration with the hydroxyl or glycol group at C6 for the binding process. The crystal structure of BC2L-A complexed with the methyl-heptoside confirmed the location of the carbohydrate ring in the binding site and elucidated the orientation of the glycol tail, in agreement with NMR data. Titration calorimetry performed on monosaccharides, heptose disaccharides and bacterial heptose-containing oligosaccharides and polysaccharides confirmed that bacterial cell wall contains carbohydrate epitopes that can bind to BC2L-A. Additionally, the specific binding of fluorescent BC2L-A lectin on B. cenocepacia bacterial surface was demonstrated by microscopy. 相似文献
170.
Origin of strigolactones in the green lineage 总被引:1,自引:0,他引:1
Delaux PM Xie X Timme RE Puech-Pages V Dunand C Lecompte E Delwiche CF Yoneyama K Bécard G Séjalon-Delmas N 《The New phytologist》2012,195(4):857-871
? The aims of this study were to investigate the appearance of strigolactones in the green lineage and to determine the primitive function of these molecules. ? We measured the strigolactone content of several isolated liverworts, mosses, charophyte and chlorophyte green algae using a sensitive biological assay and LC-MS/MS analyses. In parallel, sequence comparison of strigolactone-related genes and phylogenetic analyses were performed using available genomic data and newly sequenced expressed sequence tags. The primitive function of strigolactones was determined by exogenous application of the synthetic strigolactone analog, GR24, and by mutant phenotyping. ? Liverworts, the most basal Embryophytes and Charales, one of the closest green algal relatives to Embryophytes, produce strigolactones, whereas several other species of green algae do not. We showed that GR24 stimulates rhizoid elongation of Charales, liverworts and mosses, and rescues the phenotype of the strigolactone-deficient Ppccd8 mutant of Physcomitrella patens. ? These findings demonstrate that the first function of strigolactones was not to promote arbuscular mycorrhizal symbiosis. Rather, they suggest that the strigolactones appeared earlier in the streptophyte lineage to control rhizoid elongation. They may have been conserved in basal Embryophytes for this role and then recruited for the stimulation of colonization by glomeromycotan fungi. 相似文献