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排序方式: 共有511条查询结果,搜索用时 15 毫秒
471.
Vívian D’Afonseca Francisco Prosdocimi Fernanda A. Dorella Luis Gustavo C. Pacheco Pablo M. Moraes Izabela Pena Josè Miguel Ortega Santuza Teixeira Sérgio Costa Oliveira Elisângela Monteiro Coser Luciana Márcia Oliveira Guilherme Corrêa de Oliveira Roberto Meyer Anderson Miyoshi Vasco Azevedo 《Microbiological research》2010,165(4):312-320
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The recombinant G glycoprotein from the surface of the rabies virus (RVGP) is a promising candidate as a rabies vaccine component and also for diagnostic purposes. In this study, RVGP production by transfected Drosophila melanogaster S2 cells cultivated in a serum-free medium (supplemented IPL-41 medium) was carried out. The effects of pH and pO2 were evaluated in batch culture in parallel spinner flasks. The use of a pH equal to 6.3 and a pO2 of 40% air saturation resulted in the highest RVGP content. These conditions were also used in fed-batch mode, yielding a RVGP content level of 98 g/107 cells. The main nutrients consumed were glucose, glutamine, asparagine, serine and proline and the major metabolites produced were alanine and ammonia, according to the metabolism studies performed. Since RVGP is a transmembrane protein, two different methods for protein recovery were assessed and compared. Detergent-based cell disruption showed to be more effective than mechanical disruption with glass beads for glycoprotein recovery. 相似文献
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Jaqueline Cabral Vilas Boas Wellington Santos Fava Sebastião Laroca Maria Rosângela Sigrist 《Flora》2013,208(5-6):360-369
Sympatric and taxonomically related species may present pre- and/or postzygotic mechanisms for reproductive isolation. We compared the phenology and reproductive biology of Byrsonima intermedia and B. pachyphylla, two sympatric Malpighiaceae species, growing in a remnant of Cerrado in Central Brazil. Both species are evergreens and do not have an overlapping flowering period. In both species, dispersal occurs during the rainy season with low and intermediate overlap in the production of immature and mature fruits, respectively. Both species exhibit self-incompatibility (SI), or, in the case of B. intermedia, facultative SI, and, hence, depend on pollinators to compensate for the lack of spontaneous self-pollination. The flowers of the Byrsonima species were visited by fifteen species of bees that collected pollen and/or oil. Based on their more appropriate intrafloral posture, Epicharis flava and Centris varia were the main pollinators of both species, presenting more frequent visits and/or exhibiting trapline foraging behavior, tending to promote outcrossing. Temporal variation in flowering period and total or partial self-incompatibility seem to function as prezygotic isolation mechanisms that form barriers to gene flow between the studied species and probably avoid competition among pollinators. Both species make oil and pollen available to flower visitors and pollinators almost the entire year, but since Byrsonima intermedia has a long flowering time and is very abundant in the study area, it seems to be more important in maintaining flower-visiting bees. 相似文献
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Moure María Candela Pérez Torrado Roberto Garmendia Gabriela Vero Silvana Querol Amparo Alconada Teresa León Peláez Ángela 《International microbiology》2023,26(2):361-370
International Microbiology - Kefir is a fermented probiotic drink obtained by placing kefir granules in a suitable substrate. The kefir granules are a consortium of bacteria and yeasts embedded in... 相似文献
477.
Esther Molina-Menor Kristie Tanner Àngela Vidal-Verdú Juli Peretó Manuel Porcar 《Microbial biotechnology》2019,12(6):1359-1370
Microbial communities from harsh environments hold great promise as sources of biotechnologically relevant strains and compounds. In the present work, we have characterized the microorganisms from the supralittoral and splash zone in three different rocky locations of the Western Mediterranean coast, a tough environment characterized by high levels of irradiation and large temperature and salinity fluctuations. We have retrieved a complete view of the ecology and functional aspects of these communities and assessed the biotechnological potential of the cultivable microorganisms. All three locations displayed very similar taxonomic profiles, with the genus Rubrobacter and the families Xenococcaceae, Flammeovirgaceae, Phyllobacteriaceae, Rhodobacteraceae and Trueperaceae being the most abundant taxa; and Ascomycota and halotolerant archaea as members of the eukaryotic and archaeal community respectively. In parallel, the culture-dependent approach yielded a 100-isolates collection, out of which 12 displayed high antioxidant activities, as evidenced by two in vitro (hydrogen peroxide and DPPH) and confirmed in vivo with Caenorhabditis elegans assays, in which two isolates, CR22 and CR24, resulted in extended survival rates of the nematodes. This work is the first complete characterization of the Mediterranean splash-zone coastal microbiome, and our results indicate that this microbial niche is home of an extremophilic community that holds biotechnological potential. 相似文献
478.
Jorge Castro Craig D. Allen Mercedes Molina‐Morales Sara Marañón‐Jiménez Ángela Sánchez‐Miranda Regino Zamora 《Restoration Ecology》2011,19(4):537-544
Intense debate surrounds the effects of post‐fire salvage logging (SL) versus nonintervention policies on forest regeneration, but scant support is available from experimental studies. We analyze the effect of three post‐fire management treatments on the recruitment of a serotinous pine (Pinus pinaster) at a Mediterranean mountain. Treatments were applied 7 months after the fire and differ in the degree of intervention, ranging from “no intervention” (NI, all trees left standing) to “partial cut plus lopping” (PCL, felling most of the trees, cutting the main branches, and leaving all the biomass in situ without mastication), and “SL” (felling and piling the logs, and masticating the woody debris). Seedling survival after 3 years was the highest in PCL (47.3% versus 38.7% in SL). This was associated with the amelioration of microclimatic conditions under the scattered branches, which reduced radiation and soil temperature while increasing soil moisture. Seedling density after 2 years was approximately 5.5 times higher in PCL than in SL, as in SL a large fraction of seedlings was lost as a consequence of mechanized mastication. The NI treatment showed the lowest seedling survival (17.3%). Nevertheless, seedling density was similar to SL. Seedling growth scarcely differed among treatments. Our results show that branches left onsite acted as nurse objects that improved key microclimatic conditions for seedling recruitment. This creates a facilitative interaction ideal for seedling establishment in moisture‐deficient ecosystems, as it provides the benefit of a shading overstory but without underground competition. 相似文献
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David Reigada Rosa María Navarro-Ruiz Marcos Javier Caballero-López Ángela Del Águila Teresa Muñoz-Galdeano Rodrigo M. Maza Manuel Nieto-Díaz 《Purinergic signalling》2017,13(1):75-87
Reducing cell death during the secondary injury is a major priority in the development of a cure for traumatic spinal cord injury (SCI). One of the earliest processes that follow SCI is the excitotoxicity resulting from the massive release of excitotoxicity mediators, including ATP, which induce an excessive and/or prolonged activation of their receptors and a deregulation of the calcium homeostasis. Diadenosine tetraphosphate (Ap4A) is an endogenous purinergic agonist, present in both extracellular and intracellular fluids, with promising cytoprotective effects in different diseases including neurodegenerative processes. In a search for efficient neuroprotective strategies for SCI, we have tested the capability of Ap4A to reduce the excitotoxic death mediated by the ATP-induced deregulation of calcium homeostasis and its consequences on tissue preservation and functional recovery in a mouse model of moderate contusive SCI. Our analyses with the murine neural cell line Neuro2a demonstrate that treatment with Ap4A reduces ATP-dependent excitotoxic death by both lowering the intracellular calcium response and decreasing the expression of specific purinergic receptors. Follow-up analyses in a mouse model of contusive SCI showed that acute administration of Ap4A following SCI reduces tissue damage and improves motor function recovery. These results suggest that Ap4A cytoprotection results from a decrease of the purinergic tone preventing the effects of a massive release of ATP after SCI, probably together with a direct induction of anti-apoptotic and pro-survival pathways via activation of P2Y2 proposed in previous studies. In conclusion, Ap4A may be a good candidate for an SCI therapy, particularly to reduce excitotoxicity in combination with other modulators and/or inhibitors of the excitotoxic process that are being tested. 相似文献