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121.
A semiparametric additive regression model for longitudinal data 总被引:2,自引:0,他引:2
122.
The impact of flowers on the population growth of Frankliniella occidentalis was characterized on waxflower plants, Impatiens walleriana . In the presence of flowers, the populations grew exponentially while in their absence, the thrips populations only maintained themselves and showed no growth The difference in number and in size of thrips reared in both conditions suggested that the flowers were essential for the success of thrips development. In the presence of flowers, the distribution of females between the leaves and the flowers varied strongly according to the availability of flowers. By contrast, the proportion of first larvae in the flowers increased up to the last day of the experiment. 相似文献
123.
A 'polarisation sun-dial' dictates the optimal time of day for dispersal by flying aquatic insects 总被引:2,自引:0,他引:2
ZOLTÁN CSABAI PÁL BODA BALÁZS BERNÁTH GYÖRGY KRISKA GÁBOR HORVÁTH 《Freshwater Biology》2006,51(7):1341-1350
1. Daily changes in the flight activity of aquatic insects have been investigated in only a few water beetles and bugs. The diel flight periodicity of aquatic insects and the environmental factors governing it are poorly understood. 2. We found that primary aquatic insects belonging to 99 taxa (78 Coleoptera, 21 Heteroptera) fly predominantly in mid‐morning, and/or around noon and/or at nightfall. There appears to be at least four different types of diurnal flight activity rhythm in aquatic insects, characterised by peak(s): (i) in mid‐morning; (ii) in the evening; (iii) both in mid‐morning and the evening; (iv) around noon and again in the evening. These activity maxima are quite general and cannot be explained exclusively by daily fluctuations of air temperature, humidity, wind speed and risks of predation, which are all somewhat stochastic. 3. We found experimental evidence that the proportion (%) P(θ) of reflecting surfaces detectable polarotactically as ‘water’ is always maximal at the lowest (dawn and dusk) and highest (noon) angles of solar elevation (θ) for dark reflectors while P(θ) is maximal at dawn and dusk (low solar elevations) for bright reflectors under clear or partly cloudy skies. 4. From the temporal coincidence between peaks in the diel flight activity of primary aquatic insects and the polarotactic detectability P(θ) of water surfaces we conclude that the optimal times of day for aquatic insects to disperse are the periods of low and high solar elevations θ. The θ‐dependent reflection–polarisation patterns, combined with an appropriate air temperature, clearly explain why polarotactic aquatic insects disperse to new habitats in mid‐morning, and/or around noon and/or at dusk. We call this phenomenon the ‘polarisation sun‐dial’ of dispersing aquatic insects. 相似文献
124.
M. P. PENER A. Th. M. Van den BROEK W. J. A. Van MARREWIJK J. M. Van DOORN D. J. Van der HORST A. M. TH. BEENAKKERS 《Physiological Entomology》1989,14(1):67-76
Abstract. Adipokinetic responses to injection of synthetic adipokinetic hormone I (sAKH) were investigated in precocene-induced fifth-instar adultiforms and in chemically allatectomized but morphogenetically normal adults of Locusta migratoria (L.). The results were compared with data on normal fifth (=last)-instar nymphs and normal adults. Chemical allatectomy did not affect the resting level of lipid in the haemolymph, nor the slight decrease of haemolymph carbohydrate concentration induced by sAKH. The effects of chemical allatectomy on sAKH-induced hyperlipaemia, the resting level of haemolymph carbohydrate, total glycogen phosphorylase specific activity, as well as sAKH-induced phosphorylase activation in the fat body, were mostly minor and probably indirect. The concentrations of lipid and carbohydrate in the haemolymph, and sAKH-induced activation of fat body glycogen phosphorylase were more or less similar in normal fifth-instar nymphs, normal adults and fifth-instar adultiforms. Thus, precocious metamorphosis did not affect markedly those parameters which show no or slight changes during normal metamorphosis. In contrast, parameters which change substantially during normal metamorphosis (sAKH-induced hyperlipaemia, sAKH-induced changes in haemolymph carbohydrate level and total glycogen phosphorylase activity) showed similar changes in the course of precocious metamorphosis; the values for fifth-instar adultiforms were similar to those obtained for normal adults, but differed markedly from those found in normal fifth-instar nymphs. Thus, accelerated (precocious) morphological adult development is strongly correlated with accelerated imaginal target competence to AKH and with relevant physiological development. 相似文献
125.
Two phases are distinguished in the α-amylase production in barley (Hordeum vulgare) grains. There is an increase in activity extended to the third or fourth day of germination, then a slight decrease follows. This decrease is accelerated by kinetin while it is prevented by IAA applied at the top of the embryo coleoptile. IAA reverses partially the kinetin action. IAA applied in the germination medium has practically no effect. Removal of the coleoptile stops further increase in α-amylase activity and induces complete insensitivity to hormone treatment. The results indicate that auxin metabolism in the coleoptile participates in the control of α-amylase evolution in the barley grain and that kinetin could act through auxin metabolism in this coleoptile. 相似文献
126.
Zusammenfassung Die Ergebnisse wurden mit Bodenfallen in Getreidefeldern erarbeitet. Fenitrothion beeinflußte bei Flugzeugausbringung in normaler Dosierung (600 g/ha in 40 1 Wasser) nur die Populationsdichte von Pterostichus vulgaris und P. niger vorübergehend. Eine Spritzung mit erhöhter Dosierung (900 g/ha in 350 1 Wasser) wirkte sehr stark auf die fünf häufigsten Carabidenarten ein. Parathion-äthyl beeinflußte in normaler Dosierung (125 g/ha in 300 1 Wasser) bei einer Behandlung Anfang Juni besonders einschneidend die Frühlingstiere, Ende Juni stark die Frühlings- und die Herbsttiere. In doppelter Dosierung reduzierte es alle wichtigen Prädatorengruppen sehr deutlich. Parathion-methyl (Staub) wirkte bei Ausbringung auf feuchte Pflanzen (200 g/ha) nicht stark auf die epigäischen Räuber. Nur kletternde Arten (Staphyliniden und Agonum dorsale) wurden geschädigt. Methoxychlor wirkte als Spritzmittel (600 g/ha in 300 1 Wasser) stark auf die großen Carabiden, während die kleinen Laufkäferarten, die Staphyliniden und Spinnen nicht beeinflußt wurden. Methoxychlor-Staub, auf die feuchten Pflanzen ausgebracht (1000 g/ha), beeinflußte die epigäischen Räuber nicht. Eine Randbehandlung eines Winterrapsfeldes mit Methoxychlor-Staub störte die Besiedlung des Feldes durch Carabiden und Staphyliniden nicht.
Summary The influence of some insecticides often used in agriculture upon the terrestrial predaceous arthropods was investigated by pitfall trapping on cereal fields of about 10 hectares each, half the area of which was treated.Fenitrothion, sprayed by aeroplane at the normal dosage (600 g/ha in 40 1 water) influenced the abundance of Pterostichus vulgaris and P. niger only, for a short period. Spraying fenitrothion at a higher dosage (900 g/ha in 350 1 water) killed a high percentage of the five most common carabid species.Parathion-ethyl at the normal dosage (125 g/ha in 300 1 water), sprayed at the beginning of June reduced numbers of spring breeders especially (e.g. Pterostichus cupreus). Sprayed at the end of June, it influenced both spring and autumn breeders (e.g. P. vulgaris). Rain, falling one day after the insecticide treatment, did not alter its effect upon the terrestrial predators. At a higher dosage (250 g/ha) parathion-ethyl reduced numbers of all predators to a large extent, but not very much more than at the normal dosage.Parathion-methyl dust, applied to moist plants (200 g a.i./ha), did not influence all terrestrial predators, but only those species which also climb up the plants (some staphylinids and Agonum dorsale).Methoxychlor emulsion, sprayed at a dosage of 600 g/ha in 300 1 water, killed the bigger ground beetles only (Carabus spp. and P. vulgaris), but not the smaller ones (Agonum dorsale and Bembidion lampros), the staphylinids and the spiders. Methoxychlor, dust, applied to moist plants (1000 g a.i./ha) did not influence the terrestrial predators. Treating the edge only (ca. 20 m) of a winter-rape field with methoxychlor dust did not prevent the colonization of the field by carabids and staphylinids. It is recommended, therefore, to treat the field edges only, which should control most cereal pests.相似文献