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1.
High levels of mutagenic activity in chlorinated drinking water in Finland   总被引:4,自引:0,他引:4  
The organic extract from the drinking water of Kuopio, Eastern Finland, turned out to be highly mutagenic in the Ames test. The direct mutagenic activities of the acid/neutral fractions of 48 drinking water samples were on an average 1700 net revertants/l in strain TA100. The highest activities were more than 6000 net revertants/l, and one drinking water sample exceeded 10 000 net revertants/l. The drinking water of Kuopio is produced from lake water which has a relatively high content of humic substances. Water processing involved two chlorination phases. The organic constituents of the water samples were isolated either by continuous liquid-liquid extraction or by absorption on XAD 8 resin.  相似文献   
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The attractiveness and the mating success of fertile (normal and brownie, br) and sterile (rudimentary testis, rt) Drosophila montana males were studied in female-choice experiments (one female + two males). The normal males courted the sterile rt males nearly as much as they courted the females, while they courted other males less frequently. The females required a long courtship with the rt males and accepted them as their mating partner less often than normal males. The courtship behaviour of normal, br and rt males was recorded in single pair situations with a normal female. The courtships of the males of all types proceeded in a similar manner, but the successful courtships of the rt males included more licking and touching than those of the normal and br males. The licking and touching periods are probably the critical phases at which the females are able to detect differences in male fertility.  相似文献   
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The red species of Cortinarius subgenus Dermocybe in Europe were studied based on morphological and molecular data. Three completely red species were recognized: C. sanguineus (syn. C. sanguineus var. aurantiovaginatus), C. puniceus (syn. C. cruentus, C. rubrosanguineus) and C. vitiosus comb. nov. Cortinarius sanguineus has dusky red to red pileus, reddish yellow mycelium and lacking or with only slightly encrusted hyphae in pileipellis. It occurs in mesic to damp forests with Picea, often on rich soil in the boreal and montane areas of Europe, presumably also in eastern Canada. Cortinarius puniceus differs from C. sanguineus by its stronger purplish red, narrower spores and spot-like encrusted hyphae in pileipellis. It grows with deciduous trees in the temperate zone of Europe. Cortinarius vitiosus is known only from Fennoscandia and occurs in dry to mesic coniferous forests. It has fairly thin, often zonate, dark red to dark reddish brown pileus, pale red mycelium, small spores and encrusted lamellar trama and pileipellis hyphae. In addition to these three species C. fervidus and C. phoeniceus occasionally have red basidiomes. The relationships of the species were inferred by analysis of ITS sequences. Our study suggests that the section Sanguinei, as earlier defined, is polyphyletic. Here the section is limited to include C. sanguineus, C. puniceus and North American D. sierraensis. The relationships with other red species were not determined. Section Dermocybe, including C. cinnamomeus, C. croceus and C. uliginosus, formed a monophyletic group, and the section Malicoriae had some support. A total of 34 new sequences are published including nine from type specimens.  相似文献   
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Cortinarius is one of the most species-rich genera of mushroom-forming fungi. Based on phylogenetic and morphological evidence, Cortinarius, sect. Riederi, is introduced at sectional level (= subsect. Riederi sensu Brandrud & Melot). The taxonomy, phylogeny, ecology and distribution of not only mainly European but also including some North American taxa of this section are treated, which includes nine species and two varieties. Of these, three taxa are described as new (C. burlinghamiae, C. pallidoriederi and C. argenteolilacinus var. dovrensis). The sect. Riederi species possess morphological features similar to Phlegmacium group(s) and forms a phylogenetically isolated lineage, with no supported affinity to other phlegmacioid groups. Three taxa are known from both Europe and North America, two species are known only from North America and five only from Europe. Altogether, eight of the ten taxa are associated with conifers or northern (boreal-subalpine) deciduous trees (Betula spp.). Only two species occur in more temperate forests (Fagus forests), and no species have so far been found in thermophilous Quercus forests  相似文献   
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Synopsis The emergence chronology of brook charr alevins in the Chikanishing River, Ontario, Canada and the concurrent changes in stream chemistry resulting from acidic snowmelt runoff were examined during the spring, 1986–1988. Emergence patterns were similar among years with the most intense emergence (> 70%) occurring during the declining stream discharge following the spring flood. This period coincided with stream pH depressions (minimum pH 5.2) in 2 of 3 years, suggesting emergence behaviour frequently subjects the earliest free-swimming life interval of brook charr to episodic acidification events.  相似文献   
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This letter presents a novel identification and analysis of mobile cholesterol compounds in an experimental glioma model by (1)H MRS in vivo. The cholesterol compounds turned out to comprise as much as 17 mol% of MRS visible total lipids. The results also imply partly associated accumulation of (1)H MRS detectable cholesterol compounds and unsaturated lipids during gene therapy-induced apoptosis, and indicate that the contribution of cholesterol compounds cannot be bypassed in spectral lipid analysis. The introduced (1)H MRS approach facilitates a non-invasive follow-up of mobile cholesterol compounds, paving way for studies of tumour cholesterol metabolism in vivo.  相似文献   
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Four species of the Drosophila virilis group, D. montana, D. littoralis, D. lummei, and D. ezoana, occur sympatrically in several locations in northern Europe. Courtship interactions between the flies of the three first-mentioned species were observed at malt baits in Kemi, northern Finland, to find out how the flies of different species recognize conspecific individuals and how interspecific courtships differ from intraspecific ones in the wild. Intraspecific courtships (including females of different reproductive stages) and interspecific courtships were also videotaped and analyzed in laboratory. In the wild the males courted both conspecific and allospecific females, even though the species varied in how much the males were attracted to females of different species. Interspecific courtships usually broke off when the male touched the female or when the male and/or the female vibrated his/her wings, producing acoustic cues. In the laboratory males courted conspecific females irrespective of the reproductive stage of the female, even though the courtships directed toward immature and fertilized females usually included only orienting and touching (no licking and singing). D. littoralis, and very rarely D. montana and D. lummei, males courted also allospecific females. In the few interspecific courtships between these three species, where the male proceeded to singing, females responded to male singing by vibrating their wings. This ended the courtship. It is suggested that both the chemical cues affecting female attractivity and the acoustic signals of males and females, which are produced by wing vibration, function in maintaining sexual isolation between these three species.  相似文献   
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