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571.
Accident risk of foreign drivers in various road environments 总被引:1,自引:0,他引:1
INTRODUCTION: This paper reports on the accident risk of foreign and native drivers in various road environments in Greece. In particular, the analysis aims to determine the combined effect of driver nationality, area type (inside/outside urban area), junction (yes/no), and lighting conditions (day/night) on accident fault risk. METHODS: Data from the national accident database of Greece are used in a hierarchical log-linear analysis. The induced exposure technique is applied due to the lack of exposure data. Estimated and observed odds ratios are then examined for the quantification of the various effects in terms of relative risk. RESULTS: The initial examination of a saturated model leads to the rejection of all three- and higher-order effects within variables, without providing an adequate fit to the data. On the contrary, a non-saturated second-order model presents a very satisfactory overall fit. The examination of single and combined effects indicates that the most significant effect on accident risk rises from the presence of foreign drivers at junctions. CONCLUSIONS: Results confirm that foreign drivers in Greece are at increased risk. However, immigrant permanent residents appear to have a lower risk compared to tourists, regardless of the road environment. 相似文献
572.
Featured Collection Introduction: Synthesis and Analysis of Conservation Effects Assessment Projects for Improved Water Quality
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Richard Lawford Sushel Unninayar George J. Huffman Wolfgang Grabs Angélica Gutiérrez Toshio Koike 《Journal of the American Water Resources Association》2023,59(5):877-884
Given the wide diversity of data services provided to national water management agencies, the Group on Earth Observations (GEO) in collaboration with the Committee on Earth Observation Satellites (CEOS) developed the approach described in the report, Implementing the GEOSS Water Strategy—From Observations to Decisions to develop more coherent and equitable data services for water management through the use of Earth observations. Among other water resource issues, it recognized the need to enhance data-enriched water management services to support decision making related to drought monitoring, flood warning, tracking and improving sustainable development and monitoring and ameliorating the impacts of climate change. Needs associated with the Strategy's four themes: improved data acquisition for essential water variables, research and product development, interoperability and coordination, and capacity development and decision support, are reviewed. Responses to the recommendations have been undertaken by GEO, led by its Global Water Sustainability (GEOGloWS) initiative which includes NASA contributions, CEOS, and the Global Terrestrial Network for Hydrology (GTN-H). Progress on the themes is reviewed and benefits of these developments for international and US water management are identified. The commentary concludes with a summary of what has been achieved, what remains to be done, and the priority focus areas for implementation in the final year of the Strategy. 相似文献
576.
The chemical speciation of water solutions containing chromium oxyanions in various ratios is calculated (with the aid of available computer code Mineql Plus, Geochemist Workbench and Visual Minteq) and discussed. The effect of solution pH, total concentration of each species studied, and the presence of other species in solution are calculated and presented in the form of thermodynamic speciation diagrams. Electrochemical diagram (correlating pH to Eh) has been calculated as well. The conditions of Cr(VI) reduction to Cr(III) and the subsequent solid phase precipitation are given as a function of redox potential and pH. Surface reactions that might occur between the chromate ions in the solution and redox couples as Fe2+/Fe3+ on the surface of sorbents are also discussed. Moreover, experimental sorption data of hexavalent chromium onto synthetic magnetite are presented and discussed with the aid of the calculated diagrams. A mechanism is elucidated for the efficient removal of Cr(VI) from water streams at low pH values, and zeta potential data of synthetic magnetite with and without Cr(VI) are presented, which agree well with the mechanism proposed. 相似文献
577.
Milani Chaloupka Thierry M. Work George H. Balazs Shawn K. K. Murakawa Robert Morris 《Marine Biology》2008,154(5):887-898
We investigated cause-specific temporal and spatial trends in sea turtle strandings in the Hawaiian Archipelago. Five species
of sea turtle were recorded in 3,861 strandings over a 22-year period (1982–2003). Green turtles comprised 97% of these strandings
with size and gender composition reflecting the demographic structure of the resident green turtle population and relative
green turtle abundance in Hawaiian waters. The cause of strandings was determined by necropsy based on a complete gross external
and internal examination. Totally 75% of the 3,732 green turtle strandings were from Oahu where strandings occur year-round.
The most common known cause of the green turtle strandings was the tumour-forming disease, fibropapillomatosis (28%) followed
by hook-and-line fishing gear-induced trauma (7%), gillnet fishing gear-induced trauma (5%), boat strike (2.5%), and shark
attack (2.7%). Miscellaneous causes comprised 5.4% of strandings whereas 49% of green turtle strandings could not be attributed
to any known cause. Green turtle strandings attributable to boat strike were more likely from Kauai and Oahu while fibropapilloma
strandings were more likely from Oahu and Maui. Hook-and-line gear strandings were more likely from Oahu due to higher per
capita inshore fishing effort. The specific mortality rate (conditional probability) for fibropapillomatosis was 88%, 69%
for gillnet gear and 52% for hook-and-line gear. The probability of a dead green turtle stranding increased from 1982 but
levelled off by the mid-1990s. The declining mortality risk was because the prevalence and severity of fibropapillomatosis
has decreased recently and so has the mortality risk attributable to gillnet gear. Despite exposure to disease and inshore
fishing gears, the Hawaiian green turtle stock continues to recover following protection since the late 1970s. Nevertheless,
measures to reduce incidental capture of sea turtles in coastal Hawaiian fisheries would be prudent, especially since strandings
attributable to hook-and-line fishing gear have increased steadily since 1982. 相似文献
578.
Competition–colonization models can address the population dynamics of remnants following habitat destruction. Spatially explicit versions have produced qualifications of the extinction debt issue and limited hyperdynamism in populations following habitat destruction. Although spatially explicit, these efforts examined few indicators of the spatial structure of the landscape. An existing model is modified here to represent a difference in niche adaptations as well as the competition–colonization tradeoff. Several landscape metrics are calculated at each iteration. Although the addition of niche differentiation did not change the qualitative outcome of the model, the spatial metrics show that some aspects of landscape structure, i.e., average patch area and proximity, become hyperdynamic and remain so. Small fluctuations in species populations are magnified in their spatial expression because the landscape is simplified. 相似文献
579.
David W. Pfennig George R. HarperJr Abel F. Brumo William R. Harcombe Karin S. Pfennig 《Behavioral ecology and sociobiology》2007,61(4):505-511
Batesian mimicry evolves when a palatable species, the “mimic,” resembles a dangerous species, the “model,” because both receive
protection from predation. Yet, this protection should break down where the model is absent, because predators in such areas
would not be under selection to avoid the model. Here, we test this prediction in a coral snake mimicry complex. We exposed
plasticine replicas of milk snakes that closely mimic coral snakes to natural predators to determine if good mimetic milk
snakes are preferentially attacked in allopatry with their model. Moreover, we evaluated whether attack rates on these replicas
varied among three different allopatric regions that differed in the type of mimic found locally (i.e., good mimic, poor mimic,
or no mimic). When all three regions were considered together, mimics were not preferentially attacked. When regions were
analyzed separately, however, attacks on mimics were significantly greater than randomness only where good mimics were found.
These variable levels of predation on good mimics might reflect frequency-dependent (i.e., apostatic) predation. In allopatric
regions where good mimics are present, predators might have learned or evolved preferences for conspicuous, palatable prey
that they encounter frequently. By contrast, in allopatric regions where good mimics are absent, predators might not have
learned or evolved preferences for novel phenotypes. Thus, when predation is frequency-dependent, as long as good mimics are
rare, they might not experience elevated levels of predation in allopatry with their model as predicted by the Batesian mimicry
hypothesis. 相似文献
580.
Jean Vernin Hervé Trinquet George Jumper Edmund Murphy Anthony Ratkowski 《Environmental Fluid Mechanics》2007,7(5):371-382
Herein we present a campaign dedicated to the detection and the characterization of Gravity Waves (GW) in the Earth’s atmosphere
in relation to the generation of Optical Turbulence (OT). The observations took place in France from 17 to 24 July 2002 at
the Haute Provence Observatory (OHP) and simultaneously at the Sirene Observatory, some 20 km apart. From both sites, several
balloons were launched that measured the classical PTU-Wind profiles and additionally the structure constant of the temperature
field vertical profiles. A Generalized Scidar (GS) technique was implemented at the 1.93 m-diameter OHP telescope, providing profiles every minute. From our observations, a significant amount of GW activity was observed at both sites, but without
clear evidence of correlation between the two sites. It seems from our observations that a wide spectrum of GW is present
at a given altitude and that this could result in a lack of correlation between observations made from two sites 20 km apart.
Most GW are non-stationary with long horizontal wavelengths (λ ∼ 100–200 km), kilometric vertical wavelengths (λ ~ 0.5–2 km)
and long intrinsic period (T ~ 2–15 h). They belong in the category of “hydrostatic rotating or non-rotating waves”. Layers of optical turbulence detected
by balloons and the Scidar technique correlate well with regions of GW activity.
The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. 相似文献