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Abstract: A new fossil microfungus, Kryphiomyces catenulatus gen. et sp. nov., occurs as an endobiotic mycelial thallus in a large spore of a glomeromycotan fungus from the Lower Devonian Rhynie chert. The thallus consists of branched (?pseudo‐)septate hyphae with numerous catenulate swellings. Some hyphal tips produce spherical reproductive structures or propagules. Hyphal morphology in K. catenulatus is reminiscent of that in certain extant Hyphochytridiomycota, Chytridiomycota, and even Ascomycota, but specific diagnostic features that allow assignment of the fossil to modern groups are absent. The discovery of this interfungal association broadens our knowledge about the diversity of microfungi and their intricate associations in early continental ecosystems.  相似文献   
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Discrimination amongst Alliums using an electronic nose   总被引:1,自引:0,他引:1  
Pyruvic acid content determination and, to lesser extents, thiosulphinates determination and organoleptic tests are used for assessing the eating characteristics of onions and other Allium spp. Each of these methods has inherent limitations, especially when large numbers of samples are to be evaluated. With a view to developing a more convenient quality evaluation method, an electronic nose was used to discriminate flavour and aroma characteristics amongst garlic, leek, shallot, bulb onion and spring onion. Differences in relative sensor response to headspace volatiles over macerated samples of these five different Allium types were recorded. Principal Component Analysis (PCA) showed some separation among the five types. PCA and Mahalanobis' D2 statistic suggested similarities in headspace volatiles for shallot, spring and bulb onions and differences for leek and, especially, garlic. Multiple linear regression analyses (Y =α+β1X11X2; N(x, Y)=5) of the first two principal component values (PCA 1 [X1] and PCA 2 [X2]) accounted for not less than 90% of the total variation in pyruvic acid concentration (Y1), total soluble solids content (Y2) and percentage dry matter content (Y3) of the Allium types. These relationships suggest that electronic nose discrimination was on the basis of quality characteristics that relate to Allium flavour. This work has shown that the electronic nose has potential for flavour characteristic‐based discrimination amongst Allium types. Future work will explore this potential within a single Allium spp.  相似文献   
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THE PRODUCTION OF ANTIBIOTICS IN SOIL   总被引:1,自引:0,他引:1  
Antibiotic production in and around particles of plant debris in soil was studied. High yields of an antibiotic, shown by bioassay methods to be similar to gliotoxin, were obtained from wheat straws buried in a normal, unautoclaved; acid podsoc from Wareham Heath which had been inoculated with a strain of Trichoderma viride known to produce gliotoxin in culture media. Only a little of the antibiotic was produced in the soil immediately surrounding the straws. Much less was produced in straws buried in John Innes potting compost and none at all in straws buried in a Kettering loam. In no case was an antibiotic detected in straws from un-inoculated soils.
If, however, the Kettering loam was acidified or, alternatively, the straws themselves were acidified and then buried in untreated Kettering loam, good yields of the antibiotic were obtained from straw extracts. Conversely, when the pH of Wareham Heath soil was raised by addition of calcium hydroxide to the soil no antibiotic activity could be detected in the straws. This suggests that the pH of the soil and of the food substrate has a profound effect on production of an antibiotic, assumed to be gliotoxin, by T. viride. The results obtained suggested that increased production of gliotoxin after autoclaving the straws was due to a decrease in the pH of the straws rather than to a release of nutrients.  相似文献   
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A field experiment has been conducted to control blowflies which fell as mature larvae from railway wagons carrying domestic refuse and infested the soil at the sidings of a refuse collecting and sorting depot.
The surface of the soil was treated so that the insects were exposed to insecticide both as migrating larvae and newly emerged adults. Dusts and emulsions of DDT and BHC were compared on the basis of equal cost. A method was evolved for obtaining quantitative measurements of the effectiveness of the treatments by trapping flies emerging from the soil.
DDT was more effective than BHC, dusts were more effective than emulsions, and small quantities applied twice weekly were more effective than a correspondingly heavy dose applied monthly. DDT dust applied twice weekly was estimated to have killed 79.7% of larvae and pupae and 95.7% of emerging adults: overall control was 99.1%. Equally high control was maintained when the method was adopted as a routine measure by the local authority.  相似文献   
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SUCCINEA PUTRIS: A TERRESTRIAL OPISTHOBRANCH MOLLUSC   总被引:1,自引:0,他引:1  
An account of the histology and functional morphology of the alimentary system (excluding the musculature of the buccal mass) and of the reproductive system is pressented. The path of the sperm prior to, and after, copulation is traced. Comparison is made with other gasteropods and it is concluded that the Succineidae should be placed among the tectibranch opisthobranchs.  相似文献   
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PATIENTS with haemophilia A have recently been divided into two groups; one characterized by a functionally defective factor VIII (AHG) molecule in the plasma, which is immunologically similar to normal factor VIII but lacks procoagulant activity1–3, while the other seems to represent a true deficiency of factor VIII, for both procoagulant and immunological properties of factor VIII are absent. These conclusions are based on the ability of normal and some haemophiliac plasma to neutralize human antibodies from patients with spontaneously occurring inhibitors against factor VIII or from multi-transfuscd haemophiliacs who have developed circulating inhibitors directed against factor VIII. These studies have divided haemophilia A into those with cross reactive material (CRM +) and those without (CRM ?). Other methods of characterizing this genetic polymorphism in haemophilia have not been reported. We have used immunoelectrophoresis and antibody neutralization with a heterologous antibody to show a similar division of haemophilia A into a small group of CRM+ (15%) and a larger group of CRM? (85%). Immunoelectrophoresis and antibody neutralization studies have also been described in factor X polymorphism4.  相似文献   
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