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281.
Symbion americanus was recently described as the second species in the phylum Cycliophora, living commensally on the American commercial lobster
Homarus americanus. A previous genetic analysis of American and European populations of cycliophorans suggested that haplotype divergence in
S. americanus was much greater than in its European counterpart S. pandora. This study examined the population structure and demographics of 169 individuals thought to belong to S. americanus collected from lobsters over 13 North American localities (Nova Scotia, Canada to Maryland, USA) between October 2003 and
January 2006. Cytochrome c oxidase subunit I sequence data clearly suggested the presence of three cryptic lineages in a species complex, often co-occurring
in the same lobster specimens. One of these lineages, named the “G” lineage, was represented by very few individuals and therefore
was excluded from subsequent statistical analyses. The other two sympatric lineages, named the “T” and “C” lineages, showed
different population structure and demography. Although limited geographic structure was found in the T lineage, the C lineage
showed higher nucleotide and haplotype diversity values, as well as more variation between localities. The data also indicated
that the T lineage underwent a recent population expansion, suggesting that the C and T lineages may have speciated in allopatry
but a subsequent population expansion may have been responsible for their current sympatric distribution. Studies on the anatomy
and ecology of the sympatric lineages of this species complex should provide further information on the identity of the holotype
of S. americanus, which currently cannot be ascribed to any of the three cryptic lineages. 相似文献
282.
Borth Priscila Liane Biesdorf Perin Jessica Klarosk Helenas Torrecilhas Arthur Ribeiro Pan Nicole Caldas Kuroda Emília Kiyomi Fernandes Fernando 《Journal of Material Cycles and Waste Management》2021,23(5):1974-1983
Journal of Material Cycles and Waste Management - The objective of this study is to evaluate the influence of the addition of garden waste (GW) on the performance of food waste (FW) anaerobic... 相似文献
283.
Linkages between detritus-based ("brown") food webs and producer-based ("green") food webs are critical components of ecosystem functionality, but these linkages are hard to study because it is difficult to measure release of nutrients by brown food webs and their subsequent uptake by plants. In a three-month greenhouse experiment, we examined how the detritus-based food web inhabiting rain-filled leaves of the pitcher plant Sarracenia purpurea affects nitrogen transformation and its subsequent uptake by the plant itself. We used isotopically enriched prey (detritus) and soluble inorganic nitrogen, and manipulated food web structure to determine whether the presence of a complete brown web influences uptake efficiency of nitrogen by the plant. Uptake efficiency of soluble inorganic nitrogen was greater than that of nitrogen derived from mineralized prey. Contrary to expectation, there was no effect of the presence in the food web of macroinvertebrates on uptake efficiency of either form of nitrogen. Further, uptake efficiency of prey-derived nitrogen did not differ significantly among S. purpurea and two congeneric species (S. flava and S. alata) that lack associated food webs. Although upper trophic levels of this brown food web actively process detritus, it is the activity of the microbial component of this web that ultimately determines nitrogen availability for S. purpurea. 相似文献
284.
Along the west coast of North America, the invasive mussel Mytilus galloprovincialis and a native congener M. trossulus overlap in range and compete for habitat in an extensive hybrid zone along central California. The two species have been
shown to exhibit differential abiotic tolerances in laboratory studies, yet little is known about how such tolerances affect
spatial and temporal patterns of geographic distribution, particularly in areas of competition. We examined distributions
of the two congeners and their hybrids in neighboring intertidal and subtidal habitats in Bodega Bay, CA over 2 years, and
compared shell length and seasonal ubiquitin (Ub) conjugates to estimate protein turnover and physiological stress for the
species at each site. The two species were spatially segregated, with M. galloprovincialis dominating the subtidal habitat, and M. trossulus constituting a majority of the intertidal mussel population. Hybrid individuals appeared in low numbers at both sites. For
each habitat, there was no statistical difference between shell lengths of M. galloprovincialis and hybrids but M. trossulus mussels were statistically smaller than the other two. In regards to physiological performance, ubiquitin conjugate values
showed different seasonal cycles for the two species, suggesting different periods of peak environmental stress. The highest
levels of Ub-conjugated proteins were observed in winter for M. galloprovincialis and in summer for M. trossulus, consistent with the respective range edges for their distributions since Bodega Bay is near the northern range edge of the
invader and the southern edge of the native species. These findings suggest that future assessments of Mytilus populations along the California coast may need to consider vertical distributions and seasonal cycles as part of monitoring
and research activities. 相似文献
285.
Jessica?PurcellEmail author Timothée?Brütsch Michel?Chapuisat 《Behavioral ecology and sociobiology》2012,66(3):467-474
The phenotype of social animals can be influenced by genetic, maternal and environmental effects, which include social interactions
during development. In social insects, the social environment and genetic origin of brood can each influence a whole suite
of traits, from individual size to caste differentiation. Here, we investigate to which degree the social environment during
development affects the survival and fungal resistance of ant brood of known maternal origin. We manipulated one component
of the social environment, the worker/brood ratio, of brood originating from single queens of Formica selysi. We monitored the survival of brood and measured the head size and ability to resist the entomopathogenic fungus Beauveria bassiana of the resulting callow workers. The worker/brood ratio and origin of eggs affected the survival and maturation time of the
brood and the size of the resulting callow workers. The survival of the callow workers varied greatly according to their origin,
both in controls and when challenged with B. bassiana. However, there was no interaction between the fungal challenge and either the worker/brood ratio or origin of eggs, suggesting
that these factors did not affect parasite resistance in the conditions tested. Overall, the social conditions during brood
rearing and the origin of eggs had a strong impact on brood traits that are important for fitness. We detected a surprisingly
large amount of variation among queens in the survival of their brood reared in standard queenless conditions, which calls
for further studies on genetic, maternal and social effects influencing brood development in the social insects. 相似文献
286.
Michael D. Arendt Albert L. Segars Julia I. Byrd Jessica Boynton Jeffrey A. Schwenter J. David Whitaker Lindsey Parker 《Marine Biology》2012,159(1):113-125
Sixteen satellite-tagged adult male loggerhead sea turtles (Caretta caretta) dispersed widely from an aggregation near Port Canaveral, Florida, USA (28°23′N, −80°32′W) after breeding. Northbound males
migrated further (990 ± 303 km) than southbound males (577 ± 168 km) and transited more rapidly (median initial dive duration = 6
(IQR = 4–16) versus 19 (IQR = 10–31) min, respectively).. Migration occurred along a depth corridor (20–40 m) except where
constricted by a narrow continental shelf width. Males foraged in areas 27 ± 41 km2 day−1 at locations <1–80 km from shore for 100.1 ± 60.6 days, with variability in foraging patterns not explained by turtle size
or geography. Post-breeding dispersal patterns were similar to patterns reported for adult female loggerhead sea turtles in
this region and adult male loggerhead sea turtles elsewhere in the northern hemisphere; however, foraging ground distributions
were most similar to adult female loggerhead sea turtles in this region. 相似文献
287.
Effects of extreme variation in female morph frequencies on the mating behaviour of male damselflies
Janice J. Ting Jessica Bots Felipe Pérez Jvostov Hans van Gossum Thomas N. Sherratt 《Behavioral ecology and sociobiology》2009,64(2):225-236
Female-limited polymorphism is often attributed to selection to avoid excessive male mating attempts. It is encountered in
various taxonomic groups, but is particularly common in damselflies, where one female morph (andromorph) typically resembles
the conspecific male in colour pattern, while the other(s) (gynomorph(s)) do not. Two sets of theories have been proposed
to explain the phenomenon in damselflies, which can be classified as the learned mate recognition (LMR) and male mimicry (MM)
hypotheses. To test predictions of these hypotheses, we evaluated the rate of male sexual response towards female morphs and
conspecific males in the damselfly Nehalennia irene. The LMR hypothesis predicts that males should respond sexually to andromorphs at greater rates in populations containing
a higher relative frequency of andromorphs. The MM hypothesis predicts that males respond more often sexually to both andromorphs
and males as the ratio of andromorphs to males increases. While LMR predicts that the rate of mating attempts towards gynomorphs
should vary, the MM predicts that it should be relatively fixed. On experimentally presenting live specimens to focal males
in five different populations with extreme variation in female morph frequencies, we observed that as the andromorph frequency
and ratio of andromorphs to males increased, the proportion of male mating attempts increased on both andromorphs and males,
whereas it decreased on gynomorphs. While the simplest form of the MM hypothesis is rejected, the results support specific
predictions of both hypotheses and suggest that future studies should not treat these hypotheses as mutually exclusive. 相似文献
288.
Jessica Haapkylä Adrian S. Seymour Orit Barneah Itzchak Brickner Sebastian Hennige David Suggett David Smith 《Marine Biology》2009,156(5):1021-1027
This is the first quantitative study on the prevalence of epizoic Waminoa sp. acoel worms and their association with corals in the Wakatobi Marine National Park (WMNP), South-East Sulawesi, Indonesia.
Three replicate transects were laid on the reef crest, flat and slope at six sites in 2006 and eight sites in 2007. Four of
the sites were common in both years. In total 69 transects were surveyed in 2006, and 87 transects in 2007. A total of 4.8%
of all observed hard corals were associated with acoel worms in 2006 and 2.6% of hard and soft corals in 2007. Acoels were
present on 16 and 21 of the coral taxa studied in 2006 and 2007 respectively. The worms were strongly associated with the
azooxanthellate coral Tubastrea spp. and were rare or absent on the most abundant coral genera Montipora and Porites. The mean number of corals having acoels was highest on reef slopes, whereas acoels were virtually absent on reef flats. Corals
that had a high and a medium cover of worms were more common in 2007 than in 2006. No significant trend in the adaptation
of the zooxanthellae of Waminoa sp. to different depths at different sites was revealed. The impact of the worm on the coral is unknown, but high numbers
may have a shading effect and a negative impact on the coral’s photophysiology. This acoel merits more study of its life cycle,
its photophysiology, and its impact on its host corals.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
289.
A survey of polycyclic musks in selected household commodities from the United States 总被引:9,自引:0,他引:9
Occurrence of the polycyclic musks, 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran (HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronapthalene (AHTN), in wastewater influent and effluent, as well as in surface waters, has been reported. HHCB and AHTN were also reported to occur in human and wildlife tissues. The major sources for HHCB and AHTN to wastewater are thought to be consumer products such as shampoos, deodorants, laundry detergents, and household surface cleaners. However, the levels of HHCB and AHTN in consumer products are not known. For evaluation of the sources of human and environmental exposures, characterization of levels of HHCB and AHTN in consumer products is needed. In this study, we measured concentrations of HHCB (Galaxolide), AHTN (Tonalide), and HHCB-lactone (Galaxolidone) from a variety of consumer products, including perfumes, body lotions, and deodorants. Concentrations of HHCB, AHTN, and HHCB-lactone in consumer products ranged from <5 ng/g to over 4000 microg/g, <5 ng/g to 451 microg/g, and <5 ng/g to 217 microg/g, respectively. The highest concentrations were found in perfumes, body creams and lotions, and deodorants. The results suggest that a wide variety of source materials exist for HHCB and AHTN, and that these materials are used on a daily basis. 相似文献
290.
Nation‐building policies in Timor‐Leste: disaster risk reduction,including climate change adaptation
Jessica Mercer Ilan Kelman Francisco do Rosario Abilio de Deus de Jesus Lima Augusto da Silva Anna‐Maija Beloff Alex McClean 《Disasters》2014,38(4):690-718
Few studies have explored the relationships between nation‐building, disaster risk reduction and climate change adaptation. Focusing on small island developing states, this paper examines nation‐building in Timor‐Leste, a small island developing state that recently achieved independence. Nation‐building in Timor‐Leste is explored in the context of disaster risk reduction, which necessarily includes climate change adaptation. The study presents a synopsis of Timor‐Leste's history and its nation‐building efforts as well as an overview of the state of knowledge of disaster risk reduction including climate change adaptation. It also offers an analysis of significant gaps and challenges in terms of vertical and horizontal governance, large donor presence, data availability and the integration of disaster risk reduction and climate change adaptation for nation‐building in Timor‐Leste. Relevant and applicable lessons are provided from other small island developing states to assist Timor‐Leste in identifying its own trajectory out of underdevelopment while it builds on existing strengths. 相似文献