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411.
Identification of copper sources in urban surface waters using the principal component analysis based on aquatic parameters 总被引:2,自引:0,他引:2
Sodre FF dos Anjos VE Prestes EC Grassi MT 《Journal of environmental monitoring : JEM》2005,7(6):581-585
The goal of this work was to identify the sources of copper loads in surface urban waters using principal component analysis under the aquatic parameters data evaluation approach. Water samples from the Irai and Iguacu rivers were collected monthly during a 12-month period at two points located upstream and downstream of a metropolitan region. pH, total alkalinity, dissolved chloride, total suspended solids, dissolved organic matter, total recoverable copper, temperature, and precipitation data provided some reliable information concerning the characteristics and water quality of both rivers. Principal component analysis indicated seasonal and spatial effects on copper concentration and loads in both environments. During the rainy season, non-point sources such as urban run-off are believed to be the major source of copper in both cases. In contrast, during the lower precipitation period, the discharge of raw sewage seems to be the primary source of copper to the Iguacu River, which also exhibited higher total metal concentrations. 相似文献
412.
413.
Magalhães JM Silva JE Castro FP Labrincha JA 《Journal of environmental management》2005,75(2):157-166
In EU countries approximately 150,000 tons/year of galvanic sludges are generated by 4000 industrial units from the corresponding wastewater treatment plants. These sludges are generally classified as hazardous (European Waste Catalogue as adopted in Council Decision 2000/532/CE and as amended by Decisions 2001/118/EC, 2001/119/EC and 2001/573/CE), basically due to the presence of heavy metals. This work attempts to better understand the physical and chemical characteristics of these sludges, by studying 39 samples collected in different Portuguese industries that should represent all kinds of similar wastes independent of their place of generation. Chemical composition and leaching characteristics are given, together with density, grain size distribution, and specific surface area values. Statistical analysis was used for grouping the wastes according to chemical parameters, which might be useful to predict potential reuse as raw materials for different applications. 相似文献
414.
Mark K. Goldstein Salvador R. Bozzo Robert Malone Fernando Galdos Walter Sevian Donald Goellner 《Environmental management》1979,3(5):447-460
The data base for each process of the nuclear fuel cycle has been updated as a part of the Committee on Nuclear and Alternative Energy Systems (CONAES) at Brookhaven National Laboratory (BNL). The BNL Energy System Network Simulator (ESNS) was modified to accommodate the new data, and methodology was developed for estimating population dose and health effects resulting from atmosphere releases of radioactive materials from the nuclear fuel cycle.Estimates of population dose and health effects were made using these new CONAES emission data and the new model for three scenarios out to the year 2000: (1) no reprocessing; (2) reprocessing, 1-year cooling; and (3) reprocessing, 5-year cooling. Results indicate that radon emissions from mining and milling of uranium bearing ores will have greater impacts than any other component in the open nuclear fuel cycle. The estimated number of health effects will depend, to a large extent, on the lung model mechanism assumed to induce cancer; i.e., either the smeared or the unsmeared model. The smear model and the linear relationship predict for scenario 1, 630; for scenario 2, 949; and for scenario 3, 854 lung cancers, respectively, using the new CONAES data.Epidemiologic data from six United States counties were correlated using a new statistical model (described in the text) in order to test the validity of the lung model and the linear relationship. Results do not support the high lung cancer correlations expected from the unsmear model and the linear relationship; therefore, it is concluded that low-dose mechanisms may be different from those developed from high-dose data. The best place to look for effects of low-dose radiation may be the less developed countries because of a reduction in the noise level caused by chemical pollutants. 相似文献
415.
Fernando G. Brun Fabio Cummaudo Irene Olivé Juan José Vergara José Lucas Pérez-Lloréns 《Marine Biology》2007,151(5):1917-1927
Disaggregating seagrass meadows and studying its components separately (clones, ramets, shoots) can provide us insights on
meadow dynamics and growth patterns. The clonal growth, dependent upon clonal rules may regulate and impose constraints to
plant architecture and, therefore, determine how individual clones evolve into the environment. In order to investigate the
relationship between clonal growth rules and clone architecture, the belowground network architecture of single-clones of
the seagrass Zostera noltii was studied. Networks were traced in situ after washing out the overlying sediment, and network characteristics were measured
using digital analysis: area covered by clone, total rhizome length, type of rhizomatic axes (main, secondary, tertiary, quaternary),
number and length of the internodes, branching angles and branching frequencies. This approach revealed that Z. noltii is able to develop into large clones integrating up to 300 internodes, 676 cm of rhizome, 208 shoots and 4,300 cm2 of plant area. Internodal length depended on both, the distance to the apical shoot (time effect) and the axes type (apical
dominance effect). However, average branching angle was independent of axis type (average 58.3 ± 0.75), but varied significantly
depending on the distance from the apical shoot. This average branching angle allows Z. noltii maximize the rate of centrifugal expansion, maintaining a high density in colonized areas to produce close stands but also
minimizing the investment in belowground biomass and ramets overlapping. The clonal architecture of Z. noltii seems to be regulated by the interaction of both, apical dominance strength and clonal integration distance. Moreover, clonal
growth rules and growth pattern seem to constrain clonality through (clonal) plant architecture regulations (i.e. branching
is restricted in secondary axes, similar average branching angles regardless the axes, the higher the distance to the apex
the higher the number of internodes in secondary axes, shorter internodes in secondary and tertiary axes). Future research
efforts should focus on how these complex relationships between apical dominance and clonal integration interact to elucidate
the temporal (seasonal) and spatial scales of both processes and the outcome at the plant architectural level. 相似文献
416.
Fabio de Oliveira Lucas Igor Jos Chaves de Oliveira Fernando Brenha Ribeiro 《Journal of environmental radioactivity》2009,100(10):875-883
The assembling of a system for field sampling and activity concentration measurement of radon dissolved in groundwater is described. Special attention is given in presenting the calibration procedure to obtain the radon activity concentration in groundwater from the raw counting rate registered in a portable scintillation detector and in establishing the precision of the activity concentration measurements. A field procedure was established and the system tested during one year of monthly observations of 222Rn activity concentration in groundwater drawn from two wells drilled on metamorphic rocks exposed at Eastern São Paulo State, Brazil. The observed mean 222Rn activity concentrations are 374 Bq/dm3 in one well and about 1275 Bq/dm3 in the other one. In both wells the 222Rn activity concentrations showed a seasonal variation similar to variations previously reported in the literature for the same region. 相似文献
417.
418.
MM5-SMOKE-CMAQ as a modeling tool for 8-h ozone regulatory enforcement: application to the state of Arizona 总被引:1,自引:0,他引:1
Sang-Mi Lee H. J. S. Fernando S. Grossman-Clarke 《Environmental Modeling and Assessment》2007,12(1):63-74
The Penn State/NCAR Mesoscale Meteorological Model 5 (MM5), Sparse Matrix Operator Kernal Emissions (SMOKE), and Community
Multiscale Air Quality (CMAQ) modeling systems were employed to simulate ozone concentration distribution within the State
of Arizona, in particular, Phoenix air basin, as supporting information to designate nonattainment areas of the U.S. Environmental
Protection Agency's new 8-h ozone standard. In general, based on statistical comparisons between predictions and available
(sparsely distributed) observations, the modeling system performed reasonably well for the Phoenix basin, thus proving it
to be a useful tool for both regulatory as well as research applications. Detailed inspection, however, revealed a serious
problem with respect to the details of the ozone distribution in that for some days the transition from downslope flow to
upslope flow in the Phoenix basin was delayed in the model, causing the ozone distribution to show an unrealistic high-ozone
bias toward the west valley. Implementation of a modified subgrid parameterization improved the time of transition, and hence
the prediction of ozone and its precursor distributions. This study points to possible inadequacies of commonly used subgrid
parameterizations in dealing with rapidly changing flow conditions such as morning (and evening) transitions. 相似文献
419.
420.