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391.
Thomas Bauer 《Behavioral ecology and sociobiology》1981,8(2):91-97
Summary The carabid beetle Notiophilus biguttatus hunts springtails and mites by visual cues. The preycapture behaviour of the beetle and the escape behaviour of the springtails were analysed by means of highspeed films.
N. biguttatus has between 900 and 1250 ommatidia in each compound eye. The visual space covers ca. 200° in the horizontal plane, with a binocular overlap of no more than 74°. The fovea, the part of the eye where the pseudopupil is largest, points straight ahead of a beetle in its normal posture.The structure of the visual space was determined from measurements of the optical axes in the horizontal plane (plane of fixation) over the middle of the eye. Because of the slanted position of the ommatidia under the cornea, the optical axes point more towards the front or the back of the animal than do the anatomical axes.The optical axes were used to construct the binocular visual space in the horizontal plane. The point E
, to which an estimation of distance is possible, lies on the midline 42.6 mm away from the front edges of the eyes. Resolution rapidly decreases with increasing distance, particularly depth resolution.At a distance corresponding to that from which the beetle attacks its prey, depth and width resolution correspond roughly to the dimensions of the smallest prey animals. The smallest measured directional corrections made by the beetle prior to attack (2°–3°) correspond approximately to the divergence angles in the fovea (
h=2.2°), and the smallest measured distance correction prior to attack (0.2 mm) corresponds approximately to the depth resolution at attack distance.Supported by the Deutsche Forschungsgemeinschaft (SFB 4) 相似文献
392.
Trine Lund Hansen Thomas H?jlund Christensen Sonia Schmidt 《Waste management & research》2006,24(2):141-152
Modelling of environmental impacts from the application of treated organic municipal solid waste (MSW) in agriculture differs widely between different models for environmental assessment of waste systems. In this comparative study five models were examined concerning quantification and impact assessment of environmental effects from land application of treated organic MSW: DST (Decision Support Tool, USA), IWM (Integrated Waste Management, U.K.), THE IFEU PROJECT (Germany), ORWARE (ORganic WAste REsearch, Sweden) and EASEWASTE (Environmental Assessment of Solid Waste Systems and Technologies, Denmark). DST and IWM are life cycle inventory (LCI) models, thus not performing actual impact assessment. The DST model includes only one water emission (biological oxygen demand) from compost leaching in the results and IWM considers only air emissions from avoided production of commercial fertilizers. THE IFEU PROJECT, ORWARE and EASEWASTE are life cycle assessment (LCA) models containing more detailed land application modules. A case study estimating the environmental impacts from land application of 1 ton of composted source sorted organic household waste was performed to compare the results from the different models and investigate the origin of any difference in type or magnitude of the results. The contributions from the LCI models were limited and did not depend on waste composition or local agricultural conditions. The three LCA models use the same overall approach for quantifying the impacts of the system. However, due to slightly different assumptions, quantification methods and environmental impact assessment, the obtained results varied clearly between the models. Furthermore, local conditions (e.g. soil type, farm type, climate and legal regulation) and waste composition strongly influenced the results of the environmental assessment. 相似文献
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Thomas A. O'Neil Robert J. Steidl W. Daniel Edge Blair Csuti 《Conservation biology》1995,9(6):1482-1491
Determining which vegetation types organisms perceive similarly and classifying these types into groups that function as similar habitats are necessary steps toward expanding the focus of conservation strategies from single species to ecosystems. Therefore, the methods used to determine these habitat classifications are crucial to the successful design and implementation of these conservation strategies. Typically, this process has been accomplished through best professional judgement. We used quantitative techniques to group vegetation types into habitats based on the occurrence of breeding wildlife species ( n = 420) in Oregon. After calculating faunal similarities among all regional vegetation types ( n = 130), we used cluster analysis to group vegetation types into wildlife habitats. We classified the original 130 vegetation types into 30 wildlife habitat types that we believe function similarly. We tested this classification to assess whether vegetation types could be correctly classified into habitat types based on wildlife species composition. Discriminant analysis correctly classified 95% of the vegetation types into their wildlife habitat types, strengthening our confidence in this approach. This approach for classifying habitat types allows consistent development of conservation strategies at coarse resolutions and aids in identifying vegetation types where additional biodiversity surveys are needed. Finally, this approach can be refined continuously as the precision of vegetation mapping and our understanding of organism-habitat associations improve. 相似文献
395.
Fresh water, a fundamental element of all estuarine ecosystems, is South Africa’s most limited natural resource. Recent projections
indicate that by the year 2020 the country will be utilizing all its exploitable freshwater sources. Steeply increasing demands
by a rapidly growing population on this limited commodity have already resulted in a severe reduction of water supplies to
natural users such as estuaries-this trend is predicted to increase in the future. Concurrent with excesive water abstraction,
poor land husbandry (e.g. soil erosion) in many catchment basins and pollution (e.g. salinization) in return flows have led
to a serious deterioration in water quality. In contrast, a review of estuarine responses to varying flow regimes stresses
the strong dependence of local systems on riverine fresh water inputs of adequate quantity and quality. Freshwater dependence
is i.a. expressed in: flooding events that scour accumulated sediments, riverine nutrient input to drive estuarine phyto-
and zooplankton production, axial salinity gradients that increase habitat and species diversity, and maintenance of open
tidal inlets that prevent salinity and temperature extremes and facilitate larval exchange, fish migrations and tidal flushing
of salt marshes. Thus, estuarine conservation will have to encompass management of rivers and watersheds and play an increasingly
political role in decision processes concerning water allocations among ‘human’ and ‘natural’ users. 相似文献
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398.
Howard M. Prichard Thomas F. Gesell Charles T. Hess Conrad V. Weiffenbach Philip Nyberg 《Environment international》1982,8(1-6)
Radon concentrations were measured in several locations in each of approximately 100 dwellings in central Maine and in Houston, TX. Integrated samples were taken during the heating (or cooling) seasons with commercially available passive alpha track devices, while grab samples were taken at the time of integrated sampler deployment. It was found that both indoor and outdoor measurements in both areas were distributed log normally, and that the geometric mean of indoor measurements in Maine was three times higher than that of corresponding measurements in the Houston area. It was also noted that the mean of the indoor grab sample measurements was not significantly different from the mean of the indoor integrated measurements, and that the degree of correlation between the grab samples and a given indoor integrated sample was nearly as good as between integrated samples taken at different living area locations. 相似文献
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