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991.
Ivonne?MeucheEmail author K.?Eduard?Linsenmair Heike?Pr?hl 《Behavioral ecology and sociobiology》2012,66(4):613-621
In many species male reproductive success is limited by access to females. Territoriality is one behavioural strategy which
helps to acquire females. In the present study, we investigated the correlation between territory size and (1) female availability
and (2) rate of intrusion by conspecific males in strawberry poison frogs, Oophaga pumilio. Males defended smaller territories in areas with a high female density and high rate of intrusion by conspecific males.
Only males with high body condition values were able to establish territories in areas of high female density probably due
to better fighting abilities. Moreover, dominant calling frequency was lower during agonistic interactions. Because only males
with high body condition values were able to produce very low dominant frequencies, the acoustic properties appear to be an
honest signal containing information about fighting abilities. Thus, the negative correlation between dominant frequency and
mating success of males found in previous studies seems to be in part the result of intrasexual competition between males. 相似文献
992.
Meeghan?E.?GrayEmail author Elissa?Z.?Cameron Mary?M.?Peacock David?S.?Thain Veronica?S.?Kirchoff 《Behavioral ecology and sociobiology》2012,66(4):529-537
A growing number of studies conducted on diverse taxa have shown that extra-pair/group paternity is higher than what would
be predicted from behavioral observations alone. While it may be beneficial for females to mate with multiple males, this
often results in offspring not sired by the behavioral father, which could influence offspring survival, especially in social
mammals. Feral horses (Equus caballus) maintain stable social relationships over several years, usually with one stallion defending a harem band of unrelated mares
against other males. Sneak copulations by subordinate males have been observed and mares sometimes change bands, both of which
can result in foals sired by males other than the dominant band stallion. We measured female fidelity in free-ranging feral
horses in 23 bands, with 51 foals over four foaling seasons and tested offspring paternity against parental behaviors. We
used 12 polymorphic microsatellite loci and the program CERVUS 2.0 to determine and exclude potential sires. The majority
of mares remained in the band with the sire of their foal resulting in most foals being sired by the band stallion. Most foals
that were not sired by the band stallion were born in the year after a round-up and we could not determine if they were the
result of band changing or sneak copulations. Foals born into a band without their sire had lower survival rates and mothers
were significantly more protective of foals not sired by the band stallion. These findings suggest that band stability increases
the reproductive success of mares and support the importance of infanticide risk in equid social structure. 相似文献
993.
Šmuc NR Dolenec T Serafimovski T Tasev G Dolenec M Vrhovnik P 《Environmental geochemistry and health》2012,34(4):513-526
Heavy metal contamination of soils is widespread and induces a long-term risk to ecosystem health. This research focuses on the heavy metal contamination, transfer values and risk assessment in the Ko?ani Field plant system (Republic of Macedonia). To identify the heavy metal concentrations in Ko?ani crops (rice and maize), the geochemical analysis was performed by inductive coupled plasma mass spectrometer and thereupon the transfer factor (TF) and estimated daily intake amount values were calculated. The highest As, Cd, Mo, Pb and Zn values were determined in the rice samples grown in the paddy fields near the Zletovska River. The highest Pb and Mo concentrations measured in the maize samples were from the maize fields near the Zletovska River and Ciflik city. High TF values for Mo, Zn, Cd and Cu revealed a strong accumulation of Mo, Zn and Cd by rice and Mo and Zn by maize crops. The results of the estimated daily intake showed that the regular consumption of rice and maize crops containing the highest Cd, Mo, Pb and Zn concentrations could pose a serious threat to human health, because the daily intake of Cd, Mo, Pb and Zn for crops grown in the fields around the Zletovska River exceeded the recommended provisional tolerable daily intake values. Taking into account the results, the area around Zletovska River is considered as the most anthropogenically impacted part of Ko?ani Field. 相似文献
994.
A theoretical model, based on linear stability analysis, is proposed to predict the onset of natural convection in lakes and
reservoirs due to night time cooling. To such purpose, the system was modelled as a initially quiescent deep Boussinesq fluid
reservoir, whose upper boundary temperature changes sinusoidally. From scaling analysis, it is found that critical onset times
for convection are proportional to R
−2/7, where R is a Rayleigh number including fluid properties and forcing frequency. The proportionality constant was found, from the solution
of an eigenvalue problem, as a function of the Prandtl number. The onset time for convection was easily observed from experiments
and quantitatively detected as a rapid increase of the RMS of the computed velocity field obtained using PIV. In this controlled
conditions, differences close to 10% between predicted and observed times for the start of the convective flow was found.
It is apparent from the present set of results that predictions are reasonable. 相似文献
995.
Diogo Rúben Neves Sara Rodrigues Concei??o Juana Fortes Maria Teresa Reis Jo?o Alfredo Santos Rui Capit?o 《Journal of Coastal Conservation》2012,16(4):489-501
This paper describes a first approach on the risk assessment in port navigation using GUIOMAR, an integrated system for port and coastal engineering modelling developed at the National Civil Engineering Laboratory (LNEC), Portugal, using a GIS software environment. A set of automatic procedures was designed to include a new methodology based on the amplitude of the wave-induced vertical movement of a ship along its trajectory. In this methodology, the risk in port navigation is assessed on the basis of a combination of the probability of exceedance of a pre-set threshold for the ship??s vertical movements and its consequences. To test the new procedures, a set of sea wave records obtained at the Sines wave-buoy from 1988 to 2002 was transferred into Sines Port using two numerical models of sea wave propagation and deformation (SWAN and DREAMS), included in the GUIOMAR system. The numerical model WAMIT was used for estimating the wave-induced ship??s vertical movements inside the port. By applying the new procedures, automatic generation of risk maps was carried out for navigation in the vicinity of the West breakwater of the Port of Sines. The recent developments contribute towards a more versatile and efficient GUIOMAR system, which results in a more adequate tool to support decision-making processes in port and coastal management. 相似文献
996.
The relative importance of chemical, nematocyst, and nutritional defenses was examined for 18 species of Caribbean sea anemones
(actinarians), zoanthids, and mushroom polyps (corallimorpharians) from the Florida Keys and the Bahamas Islands, 2008–2010.
Feeding assays were performed using the fish Thalassoma bifasciatum with artificial foods containing crude organic extracts of cnidarian tissues. A novel behavioral assay using brine shrimp
nauplii was used to assess nematocyst defenses. The nutritional quality of cnidarian tissues was examined using bomb calorimetry
and soluble protein assays. In general, actinarians invested in nematocyst defenses, zoanthids in either nematocyst or chemical
defenses, and corallimorpharians lacked both, except for 1 of 3 species that was chemically defended. Relative to other coral
reef invertebrates, cnidarian tissues had similar caloric values but lower soluble protein concentrations. Trade-offs between
chemical and nematocyst defenses were observed for 65% of species, while habitat and behavior provided a likely explanation
for undefended species. 相似文献
997.
Seung?Hyeon?Kim Young?Kyun?Kim Sang?Rul?Park Wen-Tao?Li Kun-Seop?LeeEmail author 《Marine Biology》2012,159(2):255-267
Seagrass species in the genus Halophila are usually distributed in tropical or subtropical areas, but a Halophila species identified as H. nipponica was first observed in temperate coastal regions of Korea in 2007. Since this species mainly occurs in warm temperate regions
influenced by warm currents, we hypothesized that H. nipponica may exhibit different growth patterns from those of other temperate seagrass species in Korea, instead showing similar growth
dynamics to tropical/subtropical species. The growth and morphology of H. nipponica in relation to coincident measurements of environmental factors were investigated from July 2008 to September 2009 to examine
the growth dynamics of this species. Water temperature at the study site ranged from 9.7°C in January to 25.1°C in August.
Shoot density, biomass, and productivity exhibited significant seasonal variation, increasing during summer and decreasing
during winter. Productivity was severely restricted to nearly ceasing at water temperatures less than 15°C, and winter minimum
growth lasted until May. The optimal temperature for H. nipponica growth was approximately 25°C, which was the maximum water temperature at the study site, and no growth reduction in high
summer water temperature was observed. Thus, H. nipponica on the temperate coast of Korea exhibited a distinctly different growth pattern from those of temperate seagrass species
in Korea, which have shown great reductions in growth at water temperatures higher than 20°C. Higher below- to above-ground
ratio and leaf burial into sediments with shorter leaf petioles during winter might be overwintering strategies in this species.
The growth patterns of H. nipponica at the study site imply that this species still possess the tropical characteristics of the genus Halophila. 相似文献
998.
This study developed an objective quantitative method for detecting small-scale temporal or spatial differences in gametogenesis
in echinoderms. The method was applied to conventional monthly samples of the planktotrophic brittle star, Ophiopholis aculeata, collected at a single site in Newfoundland (eastern Canada) at 10–15 m depth. The samples were analysed to determine gonad
index, oocyte size and gonadal stage using histology. The maturity stage index (MSI) was developed to integrate a measure
of brittle star size (disc diameter), oocyte size and oocyte density. The MSIs ranged from 0 to 800 and had significantly
different means among the four gametogenic stages (early growth, growth, mature and spent). The MSI was more sensitive in
revealing significant differences between consecutive stages than any of its individual constituents. The MSI was also applied
to gametogenic data from the lecithotrophic holothuroid, Mesothuria lactea, again revealing significant differences between successive oogenic stages. This method is expected to be useful in field
and experimental studies of gametogenesis in echinoderms (and possibly other taxa), where it is important to detect not just
the timing of annual peaks in reproduction but small differences in reproductive status among individuals or populations (e.g.
from different habitats or feeding regimes). 相似文献
999.
The fatty acid and alcohol composition of the pelagic amphipod, Themisto libellula, was monitored during the 5 first months of its life cycle (4–20 mm length) in an Arctic fjord, Kongsfjorden, Svalbard. Fatty
acids of the three major lipid classes, polar lipids (PL), triacylglycerol (TAG), and wax esters (WE), were analyzed to highlight
ontogenic changes in their diet and metabolism. The PL composition of T. libellula did not show any strong variations along their growth except during the first month where an important increase of 20:5(n-3)
(EPA) and 22:6(n-3) (DHA) was observed. The TAG composition revealed a clear gradient corresponding to a diet shift from omnivorous
juveniles toward carnivorous sub-adults and adults. Indeed, fatty acid trophic markers of diatoms were dominant in the juveniles,
whereas 20:1(n-9) and 22:1(n-11), the Calanus sp. trophic markers, overwhelmed in the older stages. The WE composition highlighted the same general trend, however, differences
were found with the TAG and are discussed as a result of differences in turnover rates and assimilation pathways between the
two lipid classes. 相似文献
1000.
The preference of the hermit crab, Calcinus
californiensis, among six species of shells, was tested by two different experiments. The first experiment used pair-wise trials, analyzing
the preference by Chi-square tests using two different constructions of the null hypothesis. One hypothesis was based on a
no-preference among shell species, the second on comparing the number of crabs changing for a particular shell species when
two options were given versus the changing when no options were offered. The second experiment was a multiple-alternative
test based on a rank ordering of the shell preference. This method has both statistical and resource-saving advantages over
the traditional pair-wise comparisons. The sequence of shell preference was similarly independent of the procedure used. The
preferred shell species are heavy and might be associated with hydrodynamic advantages and with the protection against predation.
The shell preference matches with the pattern of shell occupancy indicating that the shell use in nature is determined by
the crab’s preference. The information generated may be used for further research on shell preference as a methodological
alternative. 相似文献