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141.
Kátya?G.?AbrantesEmail author Jayson?M.?Semmens Jeremy?M.?Lyle Peter?D.?Nichols 《Marine Biology》2012,159(1):57-64
Stable isotope analysis is increasingly used in ecological studies. Because lipid content influences δ13C, lipids should be removed from lipid-rich samples before δ13C analysis. To account for differences in δ13C arising from differences in lipid content, relationships between lipid content, C:N ratio and Δδ13C with lipid removal can be used to normalise lipid content to uniform levels. We investigate these relationships for salmonid
muscle and evaluate the suitability of previously published normalisation equations for these fish. Salmonids with a wide
range of condition (muscle lipid content = 3–35% of dry weight) were considered. There were no consistent relationships between
lipid content or C:N ratio and Δδ15N. There were linear relationships between C:N ratio and lipid content (L = −16.53 + 6.27 × C:N); C:N ratio and Δδ13C (Δδ13C = −1.87 + 0.65 × C:N); and lipid content and Δδ13C (Δδ13C = 0.01 + 0.10 × L), which should be used on salmonid stable isotope studies. 相似文献
142.
I.?Calderón Lucía?Pita S.?Brusciotti C.?Palacín X.?TuronEmail author 《Marine Biology》2012,159(1):187-197
Spatio-temporal variability in settlement and recruitment, high mortality during the first life-history stages, and selection
may determine the genetic structure of cohorts of long-lived marine invertebrates at small scales. We conducted a spatial
and temporal analysis of the common Mediterranean Sea urchin Paracentrotus
lividus to determine the genetic structure of cohorts at different scales. In Tossa de Mar (NW Mediterranean), recruitment was followed
over 5 consecutive springs (2006–2010). In spring 2008, recruits and two-year-old individuals were collected at 6 locations
along East and South Iberian coasts separated from 200 to over 1,100 km. All cohorts presented a high genetic diversity based
on a fragment of mtCOI. Our results showed a marked genetic homogeneity in the temporal monitoring and a low degree of spatial
structure in 2006. In 2008, coupled with an abnormality in the usual circulation patterns in the area, the genetic structure
of the southern populations studied changed markedly, with arrival of many private haplotypes. This fact highlights the importance
of point events in renewing the genetic makeup of populations, which can only be detected through analysis of the cohort structure
coupling temporal and spatial perspectives. 相似文献
143.
Rosamond?GodwinEmail author Ian?Brown Steven?Montgomery Stewart?Frusher Timothy?Green Jennifer?Ovenden 《Marine Biology》2012,159(1):77-86
Telomere length has been purported as a biomarker for age and could offer a non-lethal method for determining the age of wild-caught
individuals. Molluscs, including oysters and abalone, are the basis of important fisheries globally and have been problematic
to accurately age. To determine whether telomere length could provide an alternative means of ageing molluscs, we evaluated
the relationship between telomere length and age using the commercially important Sydney rock oyster (Saccostrea glomerata). Telomere lengths were estimated from tissues of known age individuals from different age classes, locations and at different
sampling times. Telomere length tended to decrease with age only in young oysters less than 18 months old, but no decrease
was observed in older oysters aged 2–4 years. Regional and temporal differences in telomere attrition rates were also observed.
The relationship between telomere length and age was weak, however, with individuals of identical age varying significantly
in their telomere length making it an imprecise age biomarker in oysters. 相似文献
144.
Understanding physiological and environmental variables that initiate sexual maturity would provide fundamental information
on life history dynamics. The aim of this study was to test the usefulness of the common circumnuclear ring (CNR), an oocytic
structure similar to the Balbiani body, which appears just prior to oocyte development as a predictor of first maturation
in Atlantic herring (Clupea harengus). The relative roles of physiology (e.g. fat) and photoperiod as triggers of maturation were also investigated. Samples were
collected in May 2008 (72°26′–73°84′N/11°26′–18°40′E) and February 2009 (56°12′–59°45′N/00°25′–03°06′W). These data suggested
that thresholds in body size may influence the decision to mature. We also found that short days (winter solstice) may be
the photoperiod trigger for a first-decision window for both Norwegian spring-spawning (NSS) and North Sea autumn-spawning
(NSAS) herring. The second-decision window for NSAS herring maturation appears to be triggered by longer days (spring equinox),
while a decreasing rate of day lengthening may trigger NSS herring maturation. So, photoperiodic cycle is a key determinate
of the timing of maturation in Atlantic herring. 相似文献
145.
Michael?D.?ArendtEmail author Albert?L.?Segars Julia?I.?Byrd Jessica?Boynton J.?David?Whitaker Lindsey?Parker David?W.?Owens Ga?lle?Blanvillain Joseph?M.?Quattro Mark?A.?Roberts 《Marine Biology》2012,159(1):127-139
Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel
(32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which
they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of
juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south
in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained
south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored
during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged
extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely
to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with
juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground. 相似文献
146.
This study examines the composition and activity of the planktonic community during the polar night in the high Arctic Kongsfjord, Svalbard. Our results are the first published evidence of bioluminescence among zooplankton during the Arctic polar night. The observations were collected by a bathyphotometer detecting bioluminescence, integrated into an autonomous underwater vehicle, to determine the concentration and intensity of bioluminescent flashes as a function of time of day and depth. To further understand community dynamics and composition, plankton nets were used to collect organisms passing through the bathyphotometer along with traditional vertical net tows. Additionally, using a moored bathyphotometer closed to the sampling site, the bioluminescence potential itself was shown not to have a diurnal or circadian rhythm. Rather, our results provide evidence for a diel vertical migration of bioluminescent zooplankton that does not correspond to any externally detectable changes in illumination. 相似文献
147.
Ivan Viegas Sónia Cotrim Marques Filipa Bessa Ana Lígia Primo Filipe Martinho Ulisses Miranda Azeiteiro Miguel ?ngelo Pardal 《Marine Biology》2012,159(1):33-43
This study provides a comprehensive examination of the life cycle dynamics of the brown shrimp (Crangon crangon L.) in the Mondego estuary, Portugal, a habitat located near the southern edge of the range of this species in European waters.
The phenology of all life stages was documented (from the occurrence of ovigerous females, developing embryos, planktonic
larvae and benthic post-larvae), and migration patterns of larvae into and out of the estuary were examined. Temperature-dependent
functions of egg and larval development were combined with data on field abundance to predict the timing and magnitude of
occurrence of larvae and recruits. Compared to brown shrimp at higher latitudes, southern conspecifics grow slower, mature
earlier and have smaller brood sizes, and larvae have a more protracted settlement period. The Mondego estuary, besides acting
as nursery area, is a dynamic platform for C. crangon to use in different stages, sizes and seasons. 相似文献
148.
Judith?MoralesEmail author Roxana?Torres Alberto?Velando 《Behavioral ecology and sociobiology》2012,66(1):135-143
In evolutionary biology, whether parents should enhance or reduce parental care according to mate ornamentation is a subject
of great debate. However, the evolution of female ornaments can shed light on this question. In theory, female ornamentation
should be traded off against fecundity and thus cannot be wholly informative to males without a direct indication of fecundity.
Hence, direct cues of offspring quality should affect the relationship between male investment and female ornamentation. Under
this hypothesis, we manipulated two direct cues of offspring quality (egg size and color) after first egg laying in the blue-footed
booby and registered male incubation patterns. In this species, foot color is a dynamic signal of current condition and in
females is traded off with egg size. We found that males spent more time incubating when paired with dull females but only
in nests with large eggs. Males also spent less time incubating small dull eggs. Results indicate that egg size, a direct
cue of reproductive value, affected the relationship between male effort and female ornamentation. Males may be willing to
help females that have invested in offspring at the expense of ornamentation, which suggests compensation when females are
in low condition. Another possibility is that males relax their effort when paired with highly ornamented and fecund females
because they have high parenting abilities. Our findings suggest that the information conveyed by female ornaments may depend
on direct cues of fecundity. Results also highlight that parental decisions are complex, modulated by a combination of information
sources. 相似文献
149.
Time of departure and landing of nocturnal migrants are of great importance for understanding migratory strategy used by birds.
It allows us to estimate flying time and hence the distance that migrants cover during a single night. In this paper, I studied
the temporal schedule of nocturnal departures of European robins during spring migration. The study was done on the Courish
Spit on the Baltic Sea in 1998–2003 by retrapping 51 ringed birds in high mist nets during nocturnal migratory departure.
Take-offs of individual birds occurred between the first and tenth hour after sunset (median 176 min after sunset). Departure
time was not related to fuel stores at arrival and departure, stopover duration and progress of the season. The results suggest
that one reason for temporal variation in take-off time was differential response of European robins with high and low motivation
to depart to such triggers as air pressure and its trend. If these parameters reach a certain minimum threshold shortly before
sunset, robins with a high migratory motivation take off in the beginning of the night. When air pressure or its trend reaches
a maximum, it may trigger to take off later during the night birds with lower initial motivation for departure, including
those that have low refuelling efficiency. In regulation of timing of take-offs of robins, an important role is also played
by their individual endogenous circadian rhythm of activity which is related to the environment in a complex way. 相似文献
150.
Virginia?Gonzalez-JimenaEmail author Patrick?S.?Fitze 《Behavioral ecology and sociobiology》2012,66(2):305-315
Glucocorticoids affect physiology and behaviour, reproduction and potentially sexual selection as well. Short-term and moderate
glucocorticoid elevations are suggested to be adaptive, and prolonged and high elevations may be extremely harmful. This suggests
that optimal reproductive strategies, and thus sexual selection, may be dose dependent. Here, we investigate effects of moderate
and high elevations of blood corticosterone levels on intra- and intersexual behaviour and mating success of male common lizards
Lacerta vivipara. Females showed less interest and more aggressive behaviour towards high corticosterone males and blood corticosterone levels
affected male reproductive strategy. Males of moderate and high corticosterone elevations, compared with Control males, showed
increased interest (i.e., higher number of chases, tongue extrusions, and approaches) towards females and high corticosterone
males initiated more copulation attempts. However, neither increased male interest nor increased copulation attempts resulted
in more copulations. This provides evidence for a best-of-a-bad-job strategy, where males with higher corticosterone levels
compensated for reduced female interest and increased aggressive female behaviour directed towards them, by showing higher
interest and by conducting more copulation attempts. Blood corticosterone levels affected intrasexual selection as well since
moderate corticosterone levels positively affected male dominance, but dominance did not affect mating success. These findings
underline the importance of female mate choice and are in line with adaptive compensatory behaviours of males. They further
show that glucocorticoid effects on behaviour are dose dependent and that they have important implications for sexual selection
and social interactions, and might potentially affect Darwinian fitness. 相似文献