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61.
ANTONIO DIAZ‐ESPEJO MAGDALENA TOMÀS HIPÓLITO MEDRANO 《Plant, cell & environment》2014,37(12):2707-2721
Crown carbon gain is maximized for a given total water loss if stomatal conductance (gs) varies such that the marginal carbon product of water (?A/?E) remains invariant both over time and among leaves in a plant crown, provided the curvature of assimilation rate (A) versus transpiration rate (E) is negative. We tested this prediction across distinct crown positions in situ for the first time by parameterizing a biophysical model across 14 positions in four grapevine crowns (Vitis vinifera), computing optimal patterns of gs and E over a day and comparing these to the observed patterns. Observed water use was higher than optimal for leaves in the crown interior, but lower than optimal in most other positions. Crown carbon gain was 18% lower under measured gs than under optimal gs. Positive curvature occurred in 39.6% of cases due to low boundary layer conductance (gbw), and optimal gs was zero in 11% of cases because ?A/?E was below the target value at all gs. Some conclusions changed if we assumed infinite gbw, but optimal and measured E still diverged systematically in time and space. We conclude that the theory's spatial dimension and assumption of positive curvature require further experimental testing. 相似文献
62.
VS Cerqueira EB Hollenbach F Maboni FA Camargo Mdo C Peralba FM Bento 《World journal of microbiology & biotechnology》2012,28(3):1203-1222
The use of microorganisms with hydrocarbon degrading capability and biosurfactant producers have emerged as an alternative
for sustainable treatment of environmental passives. In this study 45 bacteria were isolated from samples contaminated with
petrochemical residues, from which 21 were obtained from Landfarming soil contaminated with oily sludge, 11 were obtained from petrochemical industry effluents and 13 were originated directly
from oily sludge. The metabolization capability of different carbon sources, growth capacity and tolerance, biosurfactant
production and enzymes detection were determined. A preliminary selection carried out through the analysis of capability for
degrading hydrocarbons showed that 22% of the isolates were able to degrade all carbon sources employed. On the other hand,
in 36% of the isolates, the degradation of the oily sludge started within 18–48 h. Those isolates were considered as the most
efficient ones. Twenty isolates, identified based on partial sequencing of the 16S rRNA gene, were pre-selected. These isolates
showed ability for growing in a medium containing 1% of oily sludge as the sole carbon source, tolerance in a medium containing
up to 30% of oily sludge, ability for biosurfactant production, and expression of enzymes involved in degradation of aliphatic
and aromatic compounds. Five bacteria, identified as Stenotrophomonas
acidaminiphila BB5, Bacillus megaterium BB6, Bacillus cibi, Pseudomonas aeruginosa, and Bacillus cereus BS20 were shown to be promising for use as inoculum in bioremediation processes (bioaugmentation) of areas contaminated with
petrochemical residues since they can use oily sludge as the sole carbon source and produce biosurfactants. 相似文献
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64.
A hierarchically structured population model with a dependence of the vital rates on a function of the population density
(environment) is considered. The existence, uniqueness and the asymptotic behaviour of the solutions is obtained transforming the original
non-local PDE of the model into a local one. Under natural conditions, the global asymptotical stability of a nontrivial equilibrium
is proved. Finally, if the environment is a function of the biomass distribution, the existence of a positive total biomass
equilibrium without a nontrivial population equilibrium is shown.
Received 16 February 1996; received in revised form 16 September 1996 相似文献
65.
Abstract: A third fossil attributable to the crustacean peracarid order Spelaeogriphacea is described from an Upper Barremian (125 Ma) lacustrine environment in Central Spain. Neither the new taxon, Spinogriphus ibericus gen. et sp. nov., nor the two already described fossil forms can be identified with certainty as crown‐group spelaeogriphaceans. We consider that Schram’s 1974 family Acadiocarididae represents stem‐lineage spelaeogriphaceans and should accommodate these fossil taxa that display very generalised peracaridan features and lack any conspicuous autapomorphies, except for a short carapace, undifferentiated pereiopods, foliaceous pleopods and a tail fan‐like (uropods + telson) caudal structure where the unsegmented uropodal endopod lacks annulation. The zoogeography of the Acadiocarididae is Laurasian in contrast to the modern, crown‐group spelaeogriphaceans (Spelaeogriphidae), which are limited to Gondwanan territories. 相似文献
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67.
Margarida A. Ferreira A.Correia Alves M.Áurea Cruz Costa M.Isabel Paul 《Phytochemistry》1977,16(1):117-120
The naphthoquinone dimers natalenone, 8′-hydroxydiospyrin and euclanone and the trimers galpinone and a compound with MW 562 were isolated from E. natalensis roots. Natalenone is a dehydrodimer of 7-methyl- juglone with the two moieties linked by two CC bonds to give a fused tetracyclic structure, one ring bearing a methylene bridge. Galpinone is a 7-methyljuglone linear trimer, the three units probably being linked C-8-C-6′and C-3′-C-3″. Euclanone is a new dimer of 7-methyljuglone and methylnaphthazarin, isomeric with 8′-hydroxydiospyrin. 相似文献
68.