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Microfungal species composition and fungal biomass in a coniferous forest soil polluted by alkaline deposition 总被引:3,自引:0,他引:3
Isolations of soil microfungi from the humus (F/H-layer) of a coniferous forest soil which was either unpolluted (pH 4.1) or polluted (pH 6.6) for 25 years by deposition of alkaline dust, were made by soil washing and spore plating. Both techniques revealed similar changes in species composition. Alkaline dust exposure caused a reduction in overall species numbers, but led to higher relative isolation frequencies of Mortierella alpina, Oidiodendron tenuissimum, Penicillium montanese, Sagenomella verticillata, and Trichosporiella sporotrichioides. The incidence of M. isabellina, O. cf. clamydosporium, P. spinulosum, Penicillium sp. 1, P. sclerotiorum, Trichoderma viride, and Verticillium bulbillosum was reduced on polluted sites. The amount of the mainly fungal-derived phospholipid fatty acid 18 : 26 decreased by 23%, while the amount of ergosterol increased by 9% in the polluted soil.
Offprint requests to: H. Fritze. 相似文献
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Tree decline and deaths have been observed among 15 to 20-year-old Scots pines (Pinus sylvestris L.) in a dry heath forest in southwestern Finland. The sudden decline in height growth, the dieback of leading shoots and the yellowing of needles in young shoots in the upper part of the tree are typical symptoms of the decline of these young pines. Needle ultrastructure and chemical composition of Scots pines with or without decline and fluctuations of them in different seasons were studied. Afflicted trees were found to suffer from a deficiency in calcium and magnesium with low concentration of foliar nitrogen and phosphorus observed in all the trees studied. Ultrastructural study revealed changes characteristic of different seasons and measured nutrient status of needles. A clear reduction of membrane system in chloroplasts, especially related to Mg deficiency, was observed in most samples. The symptoms related to N deficiency, the translucent appearance of the cytoplasm and chloroplast stroma, and the elongated chloroplasts, as well as swelling of mitochondria, indicating P deficiency, were also found in the needles sampled from this forest decline area. The present study showed that it is possible to detect specific nutrient deficiency symptoms in needle ultrastructure in field samples and for use as sensitive indicators of unbalanced nutrient status. 相似文献
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Hannu K. Penttinen 《Analytical biochemistry》1980,102(2):353-357
A sensitive and accurate method for the determination of inorganic phosphate is described. The method enables the estimation of 10 nanomoles of inorganic phosphate with a coefficient of variation of 3.6% for ten replicates. The method is suitable for the estimation of the activities of thiamine triphosphatase, adenosine triphosphatase, and alkaline and acid phosphatase by a continuous flow system. 相似文献
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Merritt R. Turetsky Agnieszka Kotowska Jill Bubier Nancy B. Dise Patrick Crill Ed R. C. Hornibrook Kari Minkkinen Tim R. Moore Isla H. Myers‐Smith Hannu Nykänen David Olefeldt Janne Rinne Sanna Saarnio Narasinha Shurpali Eeva‐Stiina Tuittila J. Michael Waddington Jeffrey R. White Kimberly P. Wickland Martin Wilmking 《Global Change Biology》2014,20(7):2183-2197
Wetlands are the largest natural source of atmospheric methane. Here, we assess controls on methane flux using a database of approximately 19 000 instantaneous measurements from 71 wetland sites located across subtropical, temperate, and northern high latitude regions. Our analyses confirm general controls on wetland methane emissions from soil temperature, water table, and vegetation, but also show that these relationships are modified depending on wetland type (bog, fen, or swamp), region (subarctic to temperate), and disturbance. Fen methane flux was more sensitive to vegetation and less sensitive to temperature than bog or swamp fluxes. The optimal water table for methane flux was consistently below the peat surface in bogs, close to the peat surface in poor fens, and above the peat surface in rich fens. However, the largest flux in bogs occurred when dry 30‐day averaged antecedent conditions were followed by wet conditions, while in fens and swamps, the largest flux occurred when both 30‐day averaged antecedent and current conditions were wet. Drained wetlands exhibited distinct characteristics, e.g. the absence of large flux following wet and warm conditions, suggesting that the same functional relationships between methane flux and environmental conditions cannot be used across pristine and disturbed wetlands. Together, our results suggest that water table and temperature are dominant controls on methane flux in pristine bogs and swamps, while other processes, such as vascular transport in pristine fens, have the potential to partially override the effect of these controls in other wetland types. Because wetland types vary in methane emissions and have distinct controls, these ecosystems need to be considered separately to yield reliable estimates of global wetland methane release. 相似文献
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Suppressed breeding in the field vole (Microtus agrestis): an adaptation to cyclically fluctuating predation risk 总被引:6,自引:0,他引:6
The densities of microtine rodents and their main predators,small mustelids, fluctuate synchronously in 35-year cyclesin central and northern Fennoscandia. Predation by small mustelidshas been suggested as one of the driving forces in microtinecyclicity, causing deep synchronous declines of several volespecies. We studied experimentally the effects of small mustelidson mating behavior, foraging, and breeding in nonwintered fieldvoles (Microtus agrestis) originating from a cyclic population.By using mustelid odors, we simulated a crash phase environmentwith high predation risk for breeding pairs of voles. In ourexperiments, 87% of the female field voles suppressed breedingwhen exposed to mustelid odors. Both female and male behaviorchanged, and no mating behaviors were observed under the simulatedpredation risk. Weights of both sexes decreased when exposedto mustelid odor, probably due to decreased foraging; weightsof the control females increased due to pregnancy; and no weightchanges occurred in control males. Decreased breeding and foragingpossibilities under high predation pressure may form the basisfor the ultimate explanation for breeding suppression. Thereare at least two different mechanisms for breeding suppression:either mating does not take place or malnutrition in femalesdoes not' allow breeding to occur. Delayed breeding under highrisk of predation, for whatever reason, could increase the probabilityof individuals, especially that of the females, to survive overthe crash to the next, safer breeding season when their youngwould have better possibilities to survive. 相似文献
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Mitochondrial DNA polymorphism in Finnish families with Leber's hereditary optic neuroretinopathy 总被引:5,自引:0,他引:5
Johanna Vilkki Marja-Liisa Savontaus Hannu Kalinmo Eeva K. Nikoskelainen 《Human genetics》1989,82(3):208-212
Summary Leukocyte mitochondrial DNA (mtDNA) from 17 Finnish families iwth Leber's hereditary optic neuroretinopathy and 70 maternally unrelated controls as well as skeletal muscle mtDNA from four of the Leber families and three controls was analyzed with 30 restriction enzymes. By this means, over 10% of the nucleotides of mtDNA were screened. No major deletion or insertion was found in any of the mtDNAs studied. The restriction fragment patterns of mtDNA showed no evidence of mtDNA heteroplasmy (mixture of different mtDNA types) in either blood or muscle cells. In all, 24 mtDNA types were observed in the material. In the maternal lines of Leber families, 11 mtDNA types were found, indicating no recent common maternal ancestor for the Finnish Leber families. In spite of several previously unknown polymorphisms, no mutation of mtDNA could be found exclusively in families with Leber's disease. However, a couple of mutations leading to amino acid replacements of mitochondrially encoded proteins were observed in certain Leber families only. These mutations have occurred in genes coding for subunits of NADH dehydrogenase, suggesting that a defect of the respiratory chain complex I may cause Leber's disease. 相似文献