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631.
Reliability of Elasticity Analysis: Reply to Mills et al. 总被引:2,自引:0,他引:2
632.
Direct Perturbation Analysis for Better Conservation 总被引:6,自引:1,他引:5
633.
Agrochemical spray drift; assessment and mitigation--a review 总被引:1,自引:0,他引:1
Felsot AS Unsworth JB Linders JB Roberts G Rautman D Harris C Carazo E 《Journal of environmental science and health. Part. B》2011,46(1):1-23
During application of agrochemicals spray droplets can drift beyond the intended target to non-target receptors, including water, plants and animals. Factors affecting this spray drift include mode of application, droplet size, which can be modified by the nozzle types, formulation adjuvants, wind direction, wind speed, air stability, relative humidity, temperature and height of released spray relative to the crop canopy. The rate of fall of spray droplets depends upon the size of the droplets but is modified by entrainment in a mobile air mass and is also influenced by the rate of evaporation of the liquid constituting the aerosol. The longer the aerosol remains in the air before falling to the ground (or alternatively striking an object above ground) the greater the opportunity for it to be carried away from its intended target. In general, all size classes of droplets are capable of movement off target, but the smallest are likely to move the farthest before depositing on the ground or a non-target receptor. It is not possible to avoid spray drift completely but it can be minimized by using best-management practices. These include using appropriate nozzle types, shields, spray pressure, volumes per area sprayed, tractor speed and only spraying when climatic conditions are suitable. Field layout can also influence spray drift, whilst crop-free and spray-free buffer zones and windbreak crops can also have a mitigating effect. Various models are available to estimate the environmental exposure from spray drift at the time of application. 相似文献
634.
Eulaers I Covaci A Herzke D Eens M Sonne C Moum T Schnug L Hanssen SA Johnsen TV Bustnes JO Jaspers VL 《Environment international》2011,37(3):622-630
In previous studies, feathers of adult predatory birds have been evaluated as valid non-destructive biomonitor matrices for persistent organic pollutants (POPs). In this study, we assessed for the first time the usefulness of nestling raptor feathers for non-destructive biomonitoring of POPs. For this purpose, we collected body feathers and blood of nestlings from three avian top predators from northern Norway: northern goshawks (Accipiter gentilis), white-tailed eagles (Haliaeetus albicilla) and golden eagles (Aquila chrysaetos). We were able to detect a broad spectrum of legacy POPs in the nestling feathers of all three species (Σ PCBs: 6.78-140ng g(-1); DDE: 3.15-145ng g(-1); Σ PBDEs: 0.538-7.56ng g(-1)). However, these concentrations were lower compared to other studies on raptor species, probably due to the aspect of monitoring of nestlings instead of adults. Besides their analytical suitability, nestling feathers also appear to be biologically informative: concentrations of most POPs in nestling feathers showed strong and significant correlations with blood plasma concentrations in all species (p<0.050; 0.775相似文献
635.
Leat EH Bourgeon S Borgå K Strøm H Hanssen SA Gabrielsen GW Petersen A Olafsdottir K Magnusdottir E Fisk AT Ellis S Bustnes JO Furness RW 《Environmental pollution (Barking, Essex : 1987)》2011,159(5):1222-1228
Concentrations of POPs in Great skua eggs from Shetland are among the highest in North Atlantic seabirds, with up to 11,600 μg/kg (ww) DDE and up to 17,900 μg/kg ww ∑PCB. Concentrations of legacy POPs were significantly lower in 2008 than 1980. Decreases were greatest for least persistent compounds. Median ∑PBDEs increased from 99 μg/kg ww in 1980 to 173 μg/kg ww in 2008. There were changes in Great skua breeding season diet, with more adult Herring and Mackerel and less Sandeel. These changes increase exposure to POPs, since Herring and Mackerel accumulate more POPs than Sandeels. In both years, eggs with higher δ15N had higher POP concentrations. In 1980, birds feeding more on demersal discard fish from trawl fisheries and less on Sandeels, had higher POP levels in eggs. In 2008, individuals feeding more on Herring and Mackerel, and less on discards, had higher POP levels in eggs. 相似文献
636.
Effect of dissolved oxygen on biological nutrient removal by denitrifying phosphorus-accumulating organisms in a continuous-flow system 总被引:1,自引:0,他引:1
A laboratory-scale continuous-flow system with an anaerobic/anoxic/aerobic configuration was set up to study the effect of oxygen in the internal recycle stream; of particular interest was its performance of denitrifying phosphorus-accumulating organisms (DPAOs). It was found that, by using a degas device, the dissolved oxygen in the nitrate recycle stream was effectively decreased from 0.1 +/- 0.02 to 0.01 +/- 0.01 mg/L. This provided a favorable condition for DPAOs to grow under an anoxic condition and thus be sustained successfully in the system. When the degas device was removed from the system, the dissolved oxygen concentration in the anoxic reactor increased to 0.1 +/- 0.02 mg/L. The proliferation of the denitrifying glycogen-accumulating organisms (DGAOs) population and deterioration of DPAOs performance was observed. The increased population of DGAO/GAOs, which competed for the carbon source with DPAO/ PAOs, resulted in a poor performance of biological phosphorus removal. 相似文献
637.
Mark Thompson Jan Vlok Mathieu Rouget M. T. Hoffman Andrew Balmford R. M. Cowling 《Environmental management》2009,43(4):585-596
Improved techniques for measuring and monitoring the state of biodiversity are required for reporting on national obligations
to international and regional conservation institutions. Measuring the extent of grazing-related degradation in semi-arid
ecosystems has proved difficult. Here we present an accurate and cost-effective method for doing this, and apply it in a South
African semi-arid region that forms part of a globally significant biodiversity hotspot. We grouped structurally and functionally
similar vegetation units, which were expert-mapped at the 1:50,000 scale, into four habitat types, and developed habitat-specific
degradation models. We quantified degradation into three categories, using differences between dry and wet season values of
the Normalized Difference Vegetation Index (NDVI) for the three succulent karoo habitats, and the difference between maximum
and mean NDVI values for the subtropical thicket habitat. Field evaluation revealed an accuracy of 86%. Overall, degradation
was high: 24% of the study area was modeled as severely degraded, and only 9% as intact. Levels of degradation were highest
for bottomland habitats that were most exposed to grazing impacts. In sharp contrast to our methods, a widely used, broad-scale
and snapshot assessment of land cover in South Africa was only 33% accurate, and it considerably underestimated the extent
of severely degraded habitat in the study area. While our approach requires a multidisciplinary team, and in particular expert
knowledge on the characteristics and spatial delimitation of vegetation types, it is repeatable, rapid, and relatively inexpensive.
Consequently, it holds great promise for monitoring and evaluation programs in semi-arid ecosystems, in Africa, and beyond. 相似文献
638.
639.
Sami Mynttinen Author Vitae Author Vitae Jan Vissers Author Vitae Author Vitae Kari Hakuli Author Vitae Author Vitae 《Journal of Safety Research》2009,40(4):301-309
Problem
This study examined novice drivers’ overconfidence by comparing their self-assessed driver competence with the assessments made by driving examiners.Method
A Finnish (n = 2,739) and a Dutch sample (n = 239) of drivers license candidates assessed their driver competence in six areas and took the driving test.Result and Discussion
In contrast to previous studies where drivers have assessed their skill in comparison to the average driver, a smaller proportion overestimated and a larger proportion made realistic self-assessments of their driver competence in the present study, where self-assessments were compared with examiner assessments. Between 40% and 50% of the candidates in both samples made realistic assessments and 30% to 40% overestimated their competence. The proportion of overestimation was greater in the Dutch than in the Finnish sample, which might be explained by greater possibilities for practicing self-assessment in the Finnish driver education system. Similar to other self-assessment studies that indicate that incompetence is related to overestimation, a larger proportion of candidates that failed the test overestimated their skill compared to those who passed. In contrast to other studies, males did not overestimate their skills more than females, and younger driver candidates were not more overconfident than older drivers.Impact on traffic safety
Although a great proportion of the candidates made a realistic assessment of their own driver competence, overestimation is still a problem that needs to be dealt with. To improve the accuracy of novice drivers’ self-assessment, methods for self-assessment training should be developed and implemented in the driver licensing process. 相似文献640.
Hansen M Krogh KA Brandt A Christensen JH Halling-Sørensen B 《Environmental pollution (Barking, Essex : 1987)》2009,157(2):474-480
The antibacterial potency of eight anticoccidial drugs was tested in a soil bacteria bioassay (pour plate method), EC50-values between 2.4 and 19.6 μM were obtained; however, one compound, nicarbazin exhibited an EC50-value above the maximum tested concentration (21 μM, 9.1 mg L−1). The potency of mixtures of two of the compounds, narasin and nicarbazin, was synergistic (more than additive) with 10-fold greater antibacterial potency of the mixture than can be explained by their individual EC50-values. The influence of pH, temperature, oxygen concentration and light on the transformation of robenidine and salinomycin was investigated. Robenidine was transformed by photolysis (DT50 of 4.1 days) and was unstable at low pH (DT50 of approximately 4 days); salinomycin was merely transformed at low pH, the latter into an unknown number of products. The antibacterial potency of the mixtures of transformation products of robenidine after photolysis and at low pH was comparable with that of the parent compound. Finally five photo-transformation products of robenidine were structural elucidated by accurate mass measurements, i-FIT values (isotopic pattern fit) and MS/MS fragmentation patterns. 相似文献