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961.
Kirstin?Anderson?HansenEmail authorView authors OrcID profile Alyssa?Maxwell Ursula?Siebert Ole?N?sbye?Larsen Magnus?Wahlberg 《Die Naturwissenschaften》2017,104(5-6):45
In-air hearing in birds has been thoroughly investigated. Sound provides birds with auditory information for species and individual recognition from their complex vocalizations, as well as cues while foraging and for avoiding predators. Some 10% of existing species of birds obtain their food under the water surface. Whether some of these birds make use of acoustic cues while underwater is unknown. An interesting species in this respect is the great cormorant (Phalacrocorax carbo), being one of the most effective marine predators and relying on the aquatic environment for food year round. Here, its underwater hearing abilities were investigated using psychophysics, where the bird learned to detect the presence or absence of a tone while submerged. The greatest sensitivity was found at 2 kHz, with an underwater hearing threshold of 71 dB re 1 μPa rms. The great cormorant is better at hearing underwater than expected, and the hearing thresholds are comparable to seals and toothed whales in the frequency band 1–4 kHz. This opens up the possibility of cormorants and other aquatic birds having special adaptations for underwater hearing and making use of underwater acoustic cues from, e.g., conspecifics, their surroundings, as well as prey and predators. 相似文献
962.
Qian?Sun Kenneth?F.?Haynes Jordan?D.?Hampton Xuguo?ZhouEmail authorView authors OrcID profile 《Die Naturwissenschaften》2017,104(9-10):79
In social insects, the postembryonic development of individuals exhibits strong phenotypic plasticity in response to the environment, thus generating the caste system. Different from eusocial Hymenoptera, in which queens dominate reproduction and inhibit worker fertility, the primary reproductive caste in termites (kings and queens) can be replaced by neotenic reproductives derived from functionally sterile individuals. Feedback regulation of nestmate differentiation into reproductives has been suggested, but the sex specificity remains inconclusive. In the eastern subterranean termite, Reticulitermes flavipes, we tested the hypothesis that neotenic reproductives regulate worker-reproductive transition in a sex-specific manner. With this R. flavipes system, we demonstrate a sex-specific regulatory mechanism with both inhibitory and stimulatory functions. Neotenics inhibit workers of the same sex from differentiating into additional reproductives but stimulate workers of the opposite sex to undergo this transition. Furthermore, this process is not affected by the presence of soldiers. Our results highlight the reproductive plasticity of termites in response to social cues and provide insights into the regulation of reproductive division of labor in a hemimetabolous social insect. 相似文献
963.
Vázquez S Hevia A Moreno E Esteban E Peñalosa JM Carpena RO 《Journal of environmental management》2011,92(8):2069-2075
Non-amended soils affected by pyritic sludge residues were monitored for 7 years to assess the long-term natural attenuation ability of these soils. The decrease in both the total concentration of elements (particularly As) and (NH(4))(2)SO(4)-extractable fractions of Mn, and Zn, below the maximum permissible levels indicate a successful natural ability to attenuate soil pollution. Soil acidification by pyrite oxidation and rainfall-enhanced leaching were the largest contributors to the reduction of metals of high (Mn, Cu, Zn and Cd) and low (Fe, Al, and As) availability. Periodic use of correlation and spatial distribution analysis was useful in monitoring elemental dispersion and soil property/element relationships. 相似文献
964.
Alonso-Santurde R Andrés A Viguri JR Raimondo M Guarini G Zanelli C Dondi M 《Journal of environmental management》2011,92(3):994-1002
The feasibility of recycling spent foundry sand in clay bricks was assessed in laboratory, pilot line and industrial trials, using naturally occurring sand as a reference. Raw materials were analyzed by X-ray fluorescence, X-ray diffraction, particle size distribution, and leaching and combined to produce bodies containing up to 35% wt. sand. The extrusion, drying and firing behaviour (plasticity, drying sensitivity, mechanical strength, bulk density, water absorption, and shrinkage) were determined. The microstructure, phase composition, durability and leaching (EN 12457, granular materials, end-life step, European Waste Landfill Directive; NEN 7345, monolithic materials, use-life step, Dutch Building Material Decree) were evaluated for bricks manufactured at optimal firing temperature. These results demonstrate that spent foundry sand can be recycled in clay bricks. There are no relevant technological drawbacks, but the feasibility strongly depends on the properties of the raw materials. Spent foundry sand may be introduced into bricks up to 30% wt. Most of the hazardous elements from the spent foundry sand are inertized during firing and the concentrations of hazardous components in the leachates are below the standard threshold for inert waste category landfill excepting for chromium and lead; however, their environmental risk during their use-life step can be considered negligible. 相似文献
965.
Jaffrezic A Jardé E Pourcher AM Gourmelon M Caprais MP Heddadj D Cottinet P Bilal M Derrien M Marti R Mieszkin S 《Journal of environmental quality》2011,40(3):959-968
Fecal contamination of water resources is evaluated by the enumeration of the fecal coliforms and Enterococci. However, the enumeration of these indicators does not allow us to differentiate between the sources of fecal contamination. Therefore, it is important to use alternative indicators of fecal contamination to identify livestock contamination in surface waters. The concentration of fecal indicators (, enteroccoci, and F-specific bacteriophages), microbiological markers (Rum-2-bac, Pig-2-bac, and ), and chemical fingerprints (sterols and stanols and other chemical compounds analyzed by 3D-fluorescence excitation-matrix spectroscopy) were determined in runoff waters generated by an artificial rainfall simulator. Three replicate plot experiments were conducted with swine slurry and cattle manure at agronomic nitrogen application rates. Low amounts of bacterial indicators (1.9-4.7%) are released in runoff water from swine-slurry-amended soils, whereas greater amounts (1.1-28.3%) of these indicators are released in runoff water from cattle-manure-amended soils. Microbial and chemical markers from animal manure were transferred to runoff water, allowing discrimination between swine and cattle fecal contamination in the environment via runoff after manure spreading. Host-specific bacterial and chemical markers were quantified for the first time in runoff waters samples after the experimental spreading of swine slurry or cattle manure. 相似文献
966.
Sheng Fulai Gary Flomenhoft Timothy J. Downs MaÁngeles Grande‐Ortiz Dana Graef Bert Scholtens Arthur P.J. Mol David A. Sonnenfeld Gert Spaargaren Rajeev K. Goel Edward W.T. Hsieh Serban Scrieciu Reinhard Steurer Christine Polzin Genia Kostka Tiho Ancev Elke Pirgmaier Frank Boons Karl‐Henrik Robèrt Christopher Bryant Ke Zhou Surya Raj Acharya David Huberman Denis J. Sonwa Michelle Mycoo Dabo Guan Klaus Hubacek U. Rashid Sumaila Hector G. Lopez‐Ruiz G. Jason Jolley Michael L. Dougherty André Francisco Pilon Ravi Prakash Tulus Tambunan Sebastian Hermann 《Natural resources forum》2011,35(1):63-72
967.
Jesús M. Avilés Juan J. Soler Nathan S. Hart 《Behavioral ecology and sociobiology》2011,65(9):1721-1730
It has been proposed that the blue-green bird egg colourations of many avian species may constitute a sexually selected female
signal that males can use to modulate their parental investment. A fundamental untested assumption for the validation of this
hypothesis is that males can accurately assess differences in the colour of eggs. A recent review suggests that this could
be particularly problematic when egg clutches were located within a dimly lit nest cavity, due to limitations of the visual
system in low light conditions. Here, we first used a photoreceptor noise-limited model of colour discrimination ability that
accounts for visual performance under low light conditions to study whether a typical cavity-nesting passerine, the spotless
starling Sturnus unicolor, can discriminate their eggs under the ambient illumination in their nest-holes. Secondly, we tested the validity of model
predictions with behavioural data collected in two egg discrimination experiments performed in this species. Estimated egg
detectability depended entirely on model assumptions about visual limitations linked to light intensity. Starlings would not
be able to discriminate egg differences in their nests if the model was based on the assumption that light intensity limited
detectability, whereas they could potentially perceive as different many possible pairwise clutch comparisons if the model
assumption was that light intensity did not limit detectability. Results of behavioural experiments fitted the prediction
of the visual model where light intensity did not limit detectability. Our results suggest that photoreceptor noise-limited
colour models based on stimulation of single photoreceptors cannot, at present, be used to predict egg discrimination ability
in spotless starlings under low light conditions. Future studies aiming to test egg discrimination constraints in the frame
of the sexual selection hypothesis should therefore combine both modelling and behavioural experiments to determine which
are the components of the models that produce the mismatch with the behavioural conditions. 相似文献
968.
Paulina L. González-Gómez Natalia Ricote-Martinez Pablo Razeto-Barry Ivania S. Cotorás Francisco Bozinovic 《Behavioral ecology and sociobiology》2011,65(11):2141-2148
A common assumption in behavioral ecology is that the valuation of a resource by consumers depends on the energetic value
of the resource itself. Nevertheless, the value of a resource may be relative to the condition of the organism, which is in
turn related to the abiotic conditions such as ambient temperature. We developed a theoretical model—incorporating these untested
assumptions—to predict a functional relationship between territorial aggression and ambient temperature for individuals sensitive
to daily variations in energy availability. We evaluated our theoretical predictions against a field experiment carried out
with the hummingbird Sephanoides sephaniodes. The model predicted a quadratic relation between aggression intensity and ambient temperature. Field data were better explained
by a quadratic equation than a linear function, suggesting the existence of lower and upper thresholds of temperature which
determine the intensity of territorial defense. Ambient temperature affects energy expenditure for thermoregulation, and therefore,
it fixes the benefit level that must be produced by the territory to pay the costs of its defense. Our findings strongly suggest
that abiotic conditions can change an animal evaluation of the yield of a resource and in turn influence the behavioral strategy
which it adopts. 相似文献
969.
Poor-data and data-poor species stock assessment using a Bayesian hierarchical approach 总被引:4,自引:0,他引:4
Appropriate inference for stocks or species with low-quality data (poor data) or limited data (data poor) is extremely important. Hierarchical Bayesian methods are especially applicable to small-area, small-sample-size estimation problems because they allow poor-data species to borrow strength from species with good-quality data. We used a hammerhead shark complex as an example to investigate the advantages of using hierarchical Bayesian models in assessing the status of poor-data and data-poor exploited species. The hammerhead shark complex (Sphyrna spp.) along the Atlantic and Gulf of Mexico coasts of the United States is composed of three species: the scalloped hammerhead (S. lewini), the great hammerhead (S. mokarran), and the smooth hammerhead (S. zygaena) sharks. The scalloped hammerhead comprises 70-80% of the catch and has catch and relative abundance data of good quality, whereas great and smooth hammerheads have relative abundance indices that are both limited and of low quality presumably because of low stock density and limited sampling. Four hierarchical Bayesian state-space surplus production models were developed to simulate variability in population growth rates, carrying capacity, and catchability of the species. The results from the hierarchical Bayesian models were considerably more robust than those of the nonhierarchical models. The hierarchical Bayesian approach represents an intermediate strategy between traditional models that assume different population parameters for each species and those that assume all species share identical parameters. Use of the hierarchical Bayesian approach is suggested for future hammerhead shark stock assessments and for modeling fish complexes with species-specific data, because the poor-data species can borrow strength from the species with good data, making the estimation more stable and robust. 相似文献
970.
Multi-year monitoring of estuarine sediments as ultimate sink for DDT, HCH, and other organochlorinated pesticides in Argentina 总被引:3,自引:0,他引:3
Andr��s Hugo Arias Marcelo T. Pereyra Jorge E. Marcovecchio 《Environmental monitoring and assessment》2011,172(1-4):17-32
Forty-nine superficial sediment samples used in this study were collected from eight sites in the Bahia Blanca Estuary, located in the Buenos Aires Province southwest, Argentina, in a period between April 2005 and March 2009, to assess the concentration levels, spatial and seasonal distribution, and putative input sources of 18 selected organochlorine pesticides (OCs), following UNEP-IAEA procedures. Average concentration levels in sediments ranged between 3.54 and 63.79 ng g???1, d.w. (mean = 15.99 ng g???1, d.w.), for ??OCs, and from nondetectable to 8.03 ng g???1, d.w. (mean = 2.16 ng g???1, d.w.), and from nondetectable to 3.20 ng g???1 (mean = 0.97 ng g???1, d.w.) for hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs), respectively. Principal component analysis allowed the classification of sampling sites according to the main OCs inputs over the estuary. In comparison to other worldwide locations and to the world coastal sediment concentrations range, sediment DDTs and HCHs levels were in the low range; on the opposite, ??OCs average was in the medium range. OCs seasonal distribution was found to be highly correlated with the precipitations seasonality and sowing seasons in the adjacent agriculture fields. In addition, an ecotoxicological risk assessment pointed industrial and agriculture catchment zones with intermediate probability of adverse effects to biota, while the city sewage outfall was classified with none indication of an immediate threat. Data indicated that the estuary sediments were functioning as a sink for persistent OC pesticides (either in use or banned), however, it was found a declining trend on their environmental burden. 相似文献