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91.
Katrin Strauss Holger Scharpenberg Robin M. Crewe Felix Glahn Heidi Foth Robin F. A. Moritz 《Behavioral ecology and sociobiology》2008,62(9):1523-1531
Queen pheromones interfere with worker reproduction in social insects. However, there is still an unresolved question as to
whether this pheromone acts as an “honest” signal for workers, giving a reliable indication of the queen’s reproductive value,
or as a suppressive agent, inhibiting worker reproduction independent of the queen’s reproductive capacity. In honeybees (Apis mellifera), the queen’s mandibular gland secretion, a mix of fatty acids and some aromatic compounds, is crucial for regulating the
reproductive division of labor in the colony inhibiting ovary development in workers. We quantified the mandibular gland secretions
of virgin, drone-laying, and naturally mated queens using gas chromatography to test whether the queens’ mating, ovary activation,
or the reproductive value for workers correlated with the composition of the secretion. Although the absolute amounts of the
“queen substance” 9-oxo-2(E)-decenoic acid (9-ODA) were similar among the three groups, the proportions of 9-ODA decreased
with increasing reproductive quality. Furthermore, the ratios of queen to worker compounds were similar in all three treatment
groups, irrespective of the reproductive capacity. A multivariate analysis including all six compounds could not separate
drone-laying queens from naturally mated ones, both with active ovaries but only the latter ensuring colony survival. We suggest
that the mandibular gland pheromones are unlikely to function as reliable indicators of queen reproductive value and rather
operate as an agent to suppress worker reproduction. This does not exclude the possibility that other “honest” pheromone signals
exist in the honeybee colony, but these would have to arise from other semiochemicals, which could be produced by both the
queen and the brood. 相似文献
92.
93.
Evolutionary divergence among lineages of the ocean sunfish family,Molidae (Tetraodontiformes) 总被引:1,自引:0,他引:1
Anna?L.?Bass Heidi?Dewar Tierney?Thys J.?Todd.?Streelman Stephen?A.?KarlEmail author 《Marine Biology》2005,148(2):405-414
Ocean sunfish, family Molidae, are enigmatic members of the epipelagic fauna of all tropical and temperate oceans. A study, begun in 1998, initially focused on the population genetics of Mola mola Linnaeus 1758 immediately indicated high levels of genetic divergence in the d-loop and cytochrome b mitochondrial genes. This preliminary effort was expanded to include Masturus lanceolatus Liénard 1840, Ranzania laevis Pennant 1776, and representative sequences of other Tetraodontiformes. Analysis of the sequence data confirms that there are two species in the genus Mola, Mola mola and M. ramsayi Giglioli 1883, with the latter presumed to be limited to the southern hemisphere. There is an indication of inter-ocean subdivision within both species originating 0.05–0.32 and 1.55–4.10 million years ago, respectively. Given limited sample sizes, however, the divergence estimates are minimums and the isolating mechanisms remain speculative. The systematic analysis provided strong support for the sister taxa relationship between genera Masturus and Mola and the basal position of the genus Ranzania within the family, as well as the sister group relationship of the Tetraodontiform families Tetraodontidae + Diodontidae to the Molidae. 相似文献
94.
Keith H. Nislow Francis J. Magilligan Heidi Fassnacht Doug Bechtel Ana Ruesink 《Journal of the American Water Resources Association》2002,38(6):1533-1548
ABSTRACT: Understanding the effects of dams on the inundation regime of natural floodplain communities is critical for effective decision making on dam management or dam removal. To test the implications of hydrologic alteration by dams for floodplain natural communities, we conducted a combined field and modeling study along two reaches in the Connecticut River Rapids Macrosite (CRRM), one of the last remaining flowing water sections of the Upper Connecticut River. We surveyed multiple channel cross sections at both locations and concurrently identified and surveyed the elevations of important natural communities, native species of concern, and nonnative invasive species. Using a hydrologic model, HEC‐RAS, we routed estimated pre‐and post‐impoundment discharges of different design recurrence intervals (two year through 100 year floods) through each reach to establish corresponding reductions in elevation and effective wetted perimeter following post‐dam discharge reductions. By comparing (1) the frequency and duration of flooding of these surfaces before and after impoundment and (2) the total area flooded at different recurrence intervals, our goal was to derive a spatially explicit assessment of hydrologic alteration, directly relevant to natural floodplain communities. Post‐impoundment hydrologic alteration profoundly affected the subsequent inundation regime, and this impact was particularly true of higher floodplain terraces. These riparian communities, which were flooded, on average, every 20 to 100 years pre‐impoundment, were predicted to flood at 100 ? 100 year intervals, essentially isolating them completely from riverine influence. At the pre‐dam five to ten year floodplain elevations, we observed smaller differences in predicted flood frequency but substantial differences in the total area flooded and in the average flood duration. For floodplain forests in the Upper Connecticut River, this alteration by impoundment suggests that even if other stresses facing these communities (human development, invasive exotics) were alleviated, this may not be sufficient to restore intact natural communities. More generally, our approach provides a way to combine site specific variables with long term gage records in assessing the restorative potential of dam removal. 相似文献
95.
Here we use sexual selection theory to develop a logistically simple, yet effective, method for the manipulation of female reproductive behavior for conservation goals. Mate choice leading to nonrandom mating patterns can exacerbate the loss of genetic diversity in small populations. On theoretical grounds, females should choose high-quality mates. A prediction stemming from chemical communication theory is that competitive males will be better able to saturate an area with scent marks. If this is true, females should mate preferentially with males whose odors they encounter most frequently. We tested this hypothesis with the pygmy loris, Nycticebus pygmaeus, a threatened and poorly studied nocturnal prosimian. For several weeks females were exposed repeatedly to the urine from a particular male, and were then allowed to choose between a male whose odors were familiar and one whose odors were novel. Females showed an unusually strong preference for the familiar-odor male, as indicated by several behavioral measures of mate preference. Conservation managers can use this method as a tool to obtain reproductive pairings that will maximize genetic compatibility and diversity. For example, unsuccessful males may be given the opportunity to reproduce. In captive populations, studbook managers often select pairs in order to optimize outbreeding, but these selected pairings may not coincide with the preferences of the individual animals involved. Although several authors have made theoretical arguments for manipulating mate choice for conservation, this is a novel test of a proximate mechanism that can be manipulated, cultivating applications rather than mere implications. 相似文献
96.
97.
Hartmut Koehler Tobias Frische Ingo Dobner Peter Behrend Maike Schaefer Heidi Taubner Bernd Jastorff Jürgen Warrelmann und Ulrich Walter 《Umweltwissenschaften und Schadstoff-Forschung》2001,13(5):291-300
Zusammenfassung Die Befunde des in seiner Konzeption in Teil I dargestellten Freilandexperimentes dokumentieren die TNT-Abreicherung und Erholung
des Standortes im Laufe der Phytoremediation. Das Monitoring umfasst Erhebungen im Feld (Nitroaromatengehalte in Boden, Sickerwasser
und Pflanzen; Erfassung von Bodenorganismen und Streuabbau) und den Einsatz einer Biotestbatterie mit 6 Einzeltests. Die Daten
belegen die hohe Heterogenit?t der TNT-Kontamination, eine rasche initiale Abreicherung und eine geringe Verlagerung von Nitroaromaten
in Pflanzen und Sickerwasser. Die anf?nglich rasche Transformation des TNT zu Aminodinitrotoluolen l?sst nach 3 Monaten deutlich
nach. Mit Hilfe der Biotestbatterie wird die Toxizit?t des Bodens differenziert beurteilbar; die boden-biologischen Befunde
lassen Langzeitwirkungen der TNT-Belastung wahrscheinlich werden. Eine Gesamtbeurteilung des Projekts wird im dritten Teil
der Artikelserie erfolgen.
OnlineFirst: 10. 09. 2001 相似文献
98.
Tuan Xu Heidi Q. Xie Yunping Li Yingjie Xi Rui Sh Lingyun Wang Yangsheng Chen Li Xu Bin Zhao 《环境科学学报(英文版)》2018,30(1):260-267
Dioxin can cause a series of neural toxicological effects. Micro RNAs(mi Rs) play important roles in regulating nervous system function and mediating cellular responses to environmental pollutants, such as dioxin. Hsa-mi R-146 b-5 p appears to be involved in neurodegenerative diseases and brain tumors. However, little is known about effects of dioxin on the expression of hsa-mi R-146 b-5 p. We found that the hsa-mi R-146 b-5 p expression and its promoter activity were significantly increased in dioxin treated SK-N-SH cells, a human-derived neuroblastoma cell line. Potential roles of hsa-mi R-146 b-5 p in mediating neural toxicological effects of dioxin may be due to the regulation of certain target genes. We further confirmed that hsa-mi R-146 b-5 p significantly suppressed acetylcholinesterase(ACh E) activity and targeted the3′-untranslated region of the ACh E T subunit, which has been down-regulated in dioxin treated SK-N-SH cells. Functional bioinformatic analysis showed that the known and predicted target genes of hsa-mi R-146 b-5 p were involved in some brain functions or cyto-toxicities related to known dioxin effects, including synapse transmission, in which ACh E may serve as a responsive gene for mediating the effect. 相似文献
99.
Movements and site fidelity of the giant manta ray, <Emphasis Type="Italic">Manta birostris,</Emphasis> in the Komodo Marine Park,Indonesia 总被引:2,自引:1,他引:1
Heidi Dewar Peter Mous Michael Domeier Andreas Muljadi Jos Pet Jeff Whitty 《Marine Biology》2008,155(2):121-133
Despite their large size and frequent occurrence in near-shore tropical habitats, little published information is available
on the movements and behaviors of the giant manta ray, Manta birostris, and what factors influence visitation patterns. To examine the movements of manta rays in the Komodo Marine Park, Indonesia,
an acoustic array was installed at up to seven sites in the park between 2000 and 2003. A total of 41 acoustic tags were deployed
in three separate deployments in 2000, 2001 and 2002. Mantas were recorded in the park for up to 526 days with an average
duration of 183 ± 136 days, when mantas made from 3 to 303 individual visits to different sites (median 58 visits). There
was a clear preference for three sites that comprised over 90% of manta activity. The most popular site (German Flag) was
off the southern tip of Komodo Island in an area with a high degree of bathymetric structure. Examination of the longest records
suggests some site preference with 5 of 7 individuals spending greater than 90% of their time at the location where they were
tagged. Using a general linear model it was possible to examine the effects of daytime, lunar phase, aggregation site, season
and tidal phase on visitation patterns. The vast majority of visits were recorded during daylight hours at all sites. The
strongest effects of both the lunar and tidal phase were apparent in the northern sites with the most visits occurring when
tidal intensity was the greatest during full and new moons. The strongest seasonal pattern was observed in the south where
no mantas were recorded during the first quarter in any year. This coincides with an increase in temperature and reduction
of productivity in this region associated with monsoonal shifts. The long-term fidelity indicates that marine-protected areas
centered around aggregation sites could help protect this species from overexploitation. 相似文献
100.
Heidi Van den Broeck Karin Breugelmans Hans De Wolf Thierry Backeljau 《Marine Biology》2008,153(3):421-429
Planktonic developing organisms are generally assumed to be good dispersers showing little genetic structuring in neutral
markers. At first glance, this also applies to the planktonic developing periwinkle Tectarius striatus, an endemic gastropod from Macaronesia (i.e. Azores, Madeira, Canary Islands and Cape Verde Islands), where the only sign
of genetic structuring hitherto is provided by a non-significant allozyme/RAPD heterogeneity between the Cape Verde Islands
and the other archipelagos. However, partial sequences of the mitochondrial cytochrome b and cytochrome oxidase I genes now show that the Cape Verde Islands and the three other archipelagos have no haplotypes in
common, whereas the latter three do share several haplotypes. Nevertheless, this highly disjunct haplotype distribution does
not entail a phylogeographic break separating the haplotypes of both areas in two reciprocally monophyletic groups. This remarkable
geographic and phylogenetic structuring may be explained by assuming that T. striatus colonized the Macaronesian archipelagos in periods when sea levels were lower (and/or volcanic activity was higher), so that
seamounts peaked above sea level and could act as stepping-stones. Yet, after the last glacial period seamounts submerged,
thus preventing further stepping-stones mediated dispersal of T. striatus between the Cape Verde Islands and the other archipelagos, while not affecting dispersal among the latter because of their
closer proximity and connectivity. Hence, these contrasting patterns of neutral genetic variation in T. striatus show that genetic structuring in planktonic developing species may be far more complex than is usually assumed. 相似文献