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排序方式: 共有119条查询结果,搜索用时 765 毫秒
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M. G. Pellegrini A. R. Garbuglia S. Guerrazzi P. Bogani P. Bettini E. Storti C. Simeti M. Buiatti M. Broggio G. Nascari 《Journal of Phytopathology》1990,130(2):137-146
In a preliminary study on the interaction between an Alternaria alternata pathotype and Solanum tuberosum a series of parameters, indicative of active and passive defence processes, was investigated in vitro using tolerant (Chiquita) and susceptible (Superior) cultivars. Ion leakage experiments along with growth of suspension cultures and plating efficiencies in the presence of fungal culture filtrates suggest that toxin tolerance is a valuable character in distinguishing between resistant and susceptible genotypes. As far as active defence was concerned, although TLC patterns suggested the synthesis of different fluorescent compounds, probably phenolic acid, when fungal elicitors were applied to Chiquita or susceptible tissue,cultures, no consistent pattern suggesting a relationship with defence could be observed. On the other hand, peroxidase isozyme analysis after different dual culture periods showed the activation of ionically and covalently bound peroxidases in the prese,nce of the pathogen only in cv. Chiquita. 相似文献
113.
Hypersensitive browning, host cell death and phytoalexins (rishitin) synthesis in both callus cultures and cotyledons have been observed in a susceptible tomato cultivar following treatment with high molecular weight cell wall components from Phytophthora infestans race 1B. The growth of the pathogen was restricted on both elicited differentiated and undifferentiated tomato tissues. Subtance(s) released by germinating sporangia, but not by the mycelium, suppressed the hypersensitive reaction. 相似文献
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JOHANNES STÖKL PHILIPP M. SCHLÜTER TOD F. STUESSY HANNES F. PAULUS RAPHAELO FRABERGER DIRK ERDMANN CLAUDIA SCHULZ WITTKO FRANCKE GÜNTER ASSUM MANFRED AYASSE 《Biological journal of the Linnean Society. Linnean Society of London》2009,98(2):439-451
Ophrys orchids mimic the female sex pheromones of their pollinator species to attract males for pollination. Reproductive isolation in Ophrys is based on the selective attraction of only a single pollinator species. A change of floral odour can result in the attraction of a new pollinator species that acts as an isolation barrier towards other sympatrically occurring Ophrys species. Ophrys lupercalis, Ophrys bilunulata, and Ophrys fabrella grow sympatrically and bloom consecutively on Majorca and are pollinated by three species of Andrena. We investigated variation of phenotypic and genotypic flower traits, aiming to study the role of the floral odour for reproductive isolation and speciation. Using chemical and electrophysiology (gas chromatography coupled with an electroantennographic detector) methods, we show that the three Ophrys species use the same odour compounds for pollinator attraction, but in different proportions. A comparison of the floral odour bouquets in a multivariate analysis revealed a clear grouping of plants from the same species, although with an overlap between species. A comparison of the same plants using molecular markers gave a contrasting result. Although O. lupercalis and O. fabrella were genetically well separated, plants of O. bilunulata did not form a distinct group but were similar to either O. lupercalis or O. fabrella. Our data indicate gene flow and hybridization to occur between O. bilunulata and O. lupercalis as well as between O. bilunulata and O. fabrella. All plants of O. bilunulata, despite having different genotypes, showed a very similar floral odour. This reflects a strong selective pressure by the pollinating males. The overlap of genotypes of O. bilunulata and O. fabrella supports our hypothesis that O. fabrella diverged from O. bilunulata by scent variation and the attraction of a new pollinator species, Andrena fabrella. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 439–451. 相似文献
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R Marra L Pagano D R Liene S Storti M Girasoli G Leone 《Folia haematologica (Leipzig, Germany : 1928)》1989,116(2):187-191
Sixteen elderly patients affected by acute non lymphoblastic leukaemia (ANLL) with a preexisting severe internal disease were treated with a low systemic toxicity drugs combination: OAP (Vincristine, Cytarabine and Prednisone). Complete remission was achieved in 5 patients (31%) after 2 OAP courses. The mean duration of remission was 18 weeks. Six patients were resistant to the therapy. Six patients died during the treatment: 5 in induction phase and 1 in consolidation phase. Even though the duration of remission was short we retain that OAP combination may be still considered a good therapeutical approach in elderly ANLL patients with associated severe internal disease. 相似文献
118.
Bioactive compounds produced by cyanobacteria 总被引:7,自引:0,他引:7
Cyanobacteria produce a large number of compounds with varying bioactivities. Prominent among these are toxins: hepatotoxins such as microcystins and nodularins and neurotoxins such as anatoxins and saxitoxins. Cytotoxicity to tumor cells has been demonstrated for other cyanobacterial products, including 9-deazaadenosine, dolastatin 13 and analogs. A number of compounds in cyanobacteria are inhibitors of proteases — micropeptins, cyanopeptolins, oscillapeptin, microviridin, aeruginosins- and other enzymes, while still other compounds have no recognized biological activities. In general cyclic peptides and depsipeptides are the most common structural types, but a wide variety of other types are also found: linear peptides, guanidines, phosphonates, purines and macrolides. The close similarity or identity in structures between cyanobacterial products and compounds isolated from sponges, tunicates and other marine invertebrates suggests the latter compounds may be derived from dietary or symbiotic blue-green algae. 相似文献
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