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21.
CHRISTER LARSSON 《Physiologia plantarum》1979,46(3):221-226
The Compartmentation of 14CO2 fixation and concomitant metabolism of l4C-iabelled products in a recombined system, composed of isolated intact spinach (Spinacia oleracea) chloroplasls and a ‘cytoplasm’ fraction, has been studied. Addition of ‘cytoplasm’ to chloroplasts fixing 14CO2 increased the label in hexoae monophosphates outside the chloroplasts at the expense of excreted dihydroxyacetone phosphate. The label in ammo acids was increased both inside and outside the chloroplasts. The results support the view that chloroplasls are not able to make 2-oxoacids for amino acid synthesis directly from fixed CO2, but have to co-operate with the cytoplasm and other organelles. The results also show that recombined systems can be useful for studies on the compartmen tation of carbon metabolism in pholosynthesizing plant tissues. 相似文献
22.
Inanidrilus bulbosus gen. et sp.n., a Marine Tubificid (Oligochaeta) from Florida, USA 总被引:1,自引:0,他引:1
CHRISTER ERSéUS 《Zoologica scripta》1979,8(1-4):209-210
Inanidrilus bulbosus gen. et sp.n. is described from subtidal sands near Miami, Florida. The species lacks alimentary canal, but it possesses highly modified penial setae and an unpaired dorsal spermatheca. It appears closely related to Phallodrilus Pierantoni, but since it is devoid of anterior prostate glands, which are attached to the ental ends of the atria in Phallodrilus , a new monotypic genus, Inanidrilus gen.n., is established. 相似文献
23.
CHRISTER ERSÉUS 《Zoologica scripta》1982,11(3):195-197
Parakaketio longiprostatus sp.n. is described from shallow marine water in S.E. Florida. The male ducts of the new genus Parakaketio resemble those of Kaketio Righi & Kanner, 1979, but do not end as voluminous, eversible pseudopenes, rather as simple tubes opening directly to the exterior through simple pores. 相似文献
24.
A new oligochaete family, Randiellidae, is established for R. multitheca sp.n. (from the continental shelf off the east coast of the U.S.A.), R. litoralis sp.n. (from Oregon, U.S.A.), R. caribaea sp.n. and R. minuta sp.n. (both from Guadeloupe and Martinique), all members of a new marine genus Randiella. The species are characterized by small single-pointed and somewhat sigmoid somatic setae, slender (generally hair-like) modified genital setae in segment X, sperm funnels in X (if one pair), or in X and XI (if two pairs), very simple male ducts lacking atria, clitellum over XII-XIII, and multiple spermathecae in VII and/or VIII. 相似文献
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27.
Pine sawfly defence and variation in host plant resin acids: a trade-off with growth 总被引:2,自引:0,他引:2
Abstract.
- 1 The defence capability of pine sawfly larvae reared on Scots pines with low or high concentrations of resin acids was determined in a field experiment, where larvae were exposed to predatory ants, and in a laboratory experiment in which the rate of defence droplet replenishment was measured.
- 2 Larvae on low resin-acid shoots disappeared faster than larvae on high resin-acid shoots when exposed to predatory ants.
- 3 Larvae fed high resin-acid needles produced 50% larger defence droplets than larvae fed low resin-acid needles.
- 4 In an additional experiment high predation pressure was simulated by repeatedly removing defence droplets. Larvae responded by feeding more on tissue rich in resin acids, but at the cost of a reduction in growth rate.
- 5 Based on these data and earlier findings that survival and development of sawfly larvae are negatively affected by high resin-acid concentrations, we conclude that pine sawflies face a dilemma of conflicting demands, i.e. although high needle resin-acid concentrations enhance defence capability, they also reduce growth and survival. Our data also suggest that it is not necessarily the ovipositing female that has to balance this trade-off: plasticity in larval feeding behaviour provides larvae with a means to at least partly solve the dilemma.
28.
GLENN P. SVENSSON HONG‐LEI WANG JEAN‐MARC LASSANCE OLLE ANDERBRANT GUO‐FA CHEN BERIT GREGORSSON CLAUDE GUERTIN EEVAMARIA HARALA ERLING V. JIRLE ILME LIBLIKAS VLADIMIR PETKO ALAIN ROQUES OLLE ROSENBERG WARD STRONG KALJO VOOLMA TIINA YLIOJA YAN‐JUN WANG XIAO‐MING ZHOU CHRISTER LÖFSTEDT 《Systematic Entomology》2013,38(2):305-315
Combining pheromone trapping and genetic analyses can be useful when trying to resolve complexes of closely related insect taxa that are difficult to distinguish based on morphological characters. Nearctic and Palearctic populations of the spruce seed moth, Cydia strobilella L., have been considered taxonomically synonymous since 1983, but more recent work revealing distinct sex pheromones for Canadian and Swedish moths suggest that populations in the two regions belong to different species. In order to test this hypothesis, we performed field trapping using different pheromone lures at ten sites in North America, Europe and Asia, and reconstructed phylogenetic relationships among trapped moths using mitochondrial (cytochrome oxidase subunit I) and nuclear (elongation factor 1 alpha) DNA sequence data. Trapping data and tree topologies for both genes revealed distinct pherotypes in North America and Eurasia. A genetically distinct population from China was investigated further with respect to its sex pheromone. Electrophysiological data indicated that Chinese females produce a deviant ratio of the sex pheromone components (dienic acetates) compared to Swedish females. However, trapping experiments in both areas revealed a similar broad response profile in males to a wide range of acetate ratios, and these populations should be considered taxonomically synonymous. A previous suggestion of an agonistic effect on the attraction of C. strobilella males in Sweden when adding the corresponding alcohols to the binary acetate blend was also tested in Sweden as well as in China, with no observed effect on attraction of males. In conclusion, our study demonstrates the great potential of using pheromone trapping as a tool for identification and delimitation of taxa within cryptic species complexes. Based on our data, Nearctic and Palearctic populations of C. strobilella should be considered different species, and C. youngana Kearfott stat. rev. is resurrected here as valid name for North American populations, which was the case before the revision in 1983. 相似文献
29.
Epiphyton-feeding snails are often a conspicuous feature ofthe invertebrate fauna associated with submerged freshwatermacrophytes. In this paper I review the different interactionstaking place between snails, epiphyton and macrophytes. Studies on grazing by freshwater snails show that snails havea great impact on the biomass, productivity and species compositionof epiphytic communities. Direct effects of grazing on livingmacrophytes are probably of minor importance, but snails havea significant indirect effect on macrophytes by reducing thedetrimental impact of epiphyton (e.g. shading and competitionfor nutrients). Predators of snails can have a mediating effecton snail-epiphyton-macrophyte interactions, both through a directpredatorprey relationship (reducing the density of snails) andby inducing a habitat displacement of the snails. In a studyon the effects of predation by the pumpkinseed sunfish (a specializedsnail predator) it was found that predation indirectly affectsthe biomass and species composition of epiphytic algae by regulatingthe density of snails. 相似文献