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961.
Antimony (Sb) emissions to the environment are increasing, and there is a dearth of knowledge regarding Sb fate and behaviour in natural systems. In particular, there is a lack of understanding of sorption of the oxidised Sb(V) species onto soils and soil phases. In this study sorption of Sb(V) by two organic rich soils with high levels of oxalate extractable Fe was examined over the pH range of 2.5-7. Furthermore, the sorption behaviour of Sb(V) was examined in two phases mimicking those dominant in the experimental soils, namely a solid humic acid and an amorphous Fe(OH)3, across the same pH range. Sorption of Sb by the soils and the humic acid fitted a Freundlich type isotherm, with the equation parameters reflecting changes in bonding affinity corresponding to pH changes. The soils sorbed >75% of the added Sb in all trials, and 80-100% at pH values less than approximately 6.5. The Fe(OH)3 retained >95% of the added Sb in all experiments. The humic acid sorbed up to 60% of the added Sb at acidic pH values, but sorption decreased to zero at higher pH values. Further adsorption studies are recommended, such as examining the effects of ion competition and changes in ionic strength. 相似文献
962.
Löflund M Kasper-Giebl A Stopper S Urban H Biebl P Kirchner M Braeutigam S Puxbaum H 《Journal of environmental monitoring : JEM》2002,4(2):205-209
Passive samplers were used to monitor ammonia concentrations at rural inner alpine and pre-alpine, as well as urban, sites in Austria and Bavaria. Elevated concentrations were measured both at farms (up to 36 microg NH3 m(-3)) and at urban locations (up to 28 microg NH3 m(-3)). At urban locations a linear relationship between the traffic density and the NH3 concentration was found, but there was no marked seasonal trend. The highest ammonia concentrations were measured in a traffic tunnel (up to 78 microg NH3 m(-3)). The presence of livestock breeding or small scale alpine pastures resulted in elevated concentrations at the rural sites (8.1-12 and 2.5-4.6 microg NH3 m(-3), respectively), compared to the surrounding areas (3.1 and 0.9 microg NH3 m(-3)). Agriculture related sources are usually limited either spatially or seasonally. As the emissions were moderate in our case, a rapid removal and dilution of ammonia was possible and therefore the NH3 burden was only local. Sources related to traffic are more evenly distributed both geographically and seasonally. The WHO guideline, annual average concentration of 8 microg m(-3) for the protection of vegetation, was only exceeded at farms, at the urban station with the heaviest traffic and in the Tauerntunnel. 相似文献
963.
Peter W. Abrahams Trevor D. Davies Timothy D. Jickells Martyn Tranter 《Environmental monitoring and assessment》1993,27(3):159-174
This paper records the concentrations of major and trace elements determined from snow samples collected during a comprehensive survey undertaken in the Scottish Highlands during the winter and spring period of 1987. The configuration of calculated back-trajectories allowed the samples to be categorized into one of five geographical sectors. Discriminant analysis was used to check the validity of these calculations, to isolate potentially deviant samples, and to predict the possible source of one sample whose back-trajectory could not be computed with confidence. Limitations of the statistical method are discussed, but we conclude that the technique justifies more use by environmental scientists involved in the evaluation of data. 相似文献
964.
The US Environmental Protection Agency recently completed two regulatory negotiation demonstrations. These demonstrations suggest that the current EPA rule-making process could be improved through the introduction of face-to-face negotiation at the earliest stages of rulemaking. In the demonstrations, EPA (1) relied on a consensus building process to forestall litigation after the promulgation of the final rule; (2) Used a nonpartisan facilitator to convene the negotiations; (3) Defined criteria to determine which parties should be represented in the negotiation. From the perspective of participants, the negotiating consensus version of a draft regulation is a successful alternative to the traditional rulemaking process. It is still too soon to say negotiated rulemaking significantly reduces the likelihood of ligitation. The results of the demonstration indicate that it is possible for either an agency employee or a neutral outsider to facilitate the sessions. A successful negotiation also requires top level agency support as well as the confidence of the environmental community. The single most important outcome of the negotiations was that the participants developed a greater understanding of the interests of the other parties. The demonstrations also suggest possible changes in future regulatory negotiations. 相似文献
965.
Dedecker AP Goethals PL D'heygere T Gevrey M Lek S De Pauw N 《Environmental monitoring and assessment》2005,111(1-3):223-241
This study aimed at analysing the relationship between river characteristics and abundance of Gammarus pulex. To this end, four methods which can identify the relative contribution and/or the contribution profile of the input variables
in neural networks describing the habitat preferences of this species were compared: (i) the ‘PaD‘ (‘Partial Derivatives‘)
method consists of a calculation of the partial derivatives of the output in relation to the input variables; (ii) the ‘Weights‘method
is a computation using the connection weights of the backpropagation Artificial Neural Networks; (iii) the ‘Perturb‘method
analyses the effect of a perturbation of the input variables on the output variable; (iv) the ‘Profile‘ method is a successive
variation of one input variable while the others are kept constant at a fixed set of values. The dataset consisted of 179
samples, collected over a three-year period in the Zwalm river basin in Flanders, Belgium. Twenty-four environmental variables
as well as the log-transformed abundance of Gammarus pulex were used in this study. The different contribution methods gave similar results concerning the order of importance of the
input variables. Moreover, the stability of the methods was confirmed by gradually removing variables. Only in a limited number
of cases a shift in the relative importance of the remaining input variables could be observed. Nevertheless, differences
in sensitivity and stability of the methods were detected, probably as a result of the different calculation procedures. In
this respect, the ‘PaD‘method made a more severe discrimination between minor and major contributing environmental variables
in comparison to the ‘Weights‘, ‘Profile‘ and ‘Perturb‘ methods. From an ecological point of view, the input variables ‘Ammonium‘
and to a smaller extent ‘COD‘, were selected by these methods as dominant river characteristics for the prediction of the
abundance of Gammarus pulex in this study area. 相似文献
966.
Soeroes C Goessler W Francesconi KA Schmeisser E Raml R Kienzl N Kahn M Fodor P Kuehnelt D 《Journal of environmental monitoring : JEM》2005,7(7):688-692
In contrast to the large body of data on naturally-occurring arsenic compounds in marine organisms, relatively little is known about arsenic speciation in freshwater biota. We report an investigation using HPLC-ICPMS into the arsenic compounds in five species of freshwater mussels collected from five sites from the Danube in Hungary. Total arsenic concentrations in the mussels ranged from 3.8-12.8 mg As kg(-1). The arsenic speciation patterns were broadly similar for mussels representing each of the five species and five sites, but quite different from those reported for marine mussels. The major extractable arsenicals were two oxo arsenosugars (glycerol sugar and phosphate sugar), and their thio analogues (thio glycerol sugar and thio phosphate sugar). Arsenobetaine, usually the major arsenical in marine organisms, was not a significant compound in the freshwater mussels and was detected in only three of the 11 samples. This is the first report of thio arsenosugars in freshwater biota and suggests that these compounds may be common and widespread naturally-occurring arsenicals. 相似文献
967.
Tedesco M Bohlen WF Howard-Strobel MM Cohen DR Tebeau PA 《Environmental monitoring and assessment》2003,81(1-3):35-42
A network of five water quality monitoring stations has been established in Long Island Sound, measuring temperature, salinity, and dissolved oxygen since 1999. The stations are located in areas of extreme water quality degradation (western Long Island Sound) as well as in pristine areas (eastern Long Island Sound). The data from these stations are collected every 15 minutes and posted to the project web site in real time as provisional data. After subsequent quality assurance procedures, the data are archived to the project File Transfer Protocol (FSP) site for downloading by the user community. The network of stations is in part supported logistically by a number of partners, including state and local agencies, schools, and non-governmental organizations. Data from the monitoring programs of some of these partners are also published to the project website providing a more comprehensive and complete picture of the status of the Sound than can be provided independently. This repository of information is used by marine educators, resource managers, scientists, and the general public, each with a different end purpose. We use the data from two of the stations to show that these high frequency time series measurements can be used to complement and enhance other monitoring programs within the Sound, documenting in greater detail the occurrence and duration of hypoxic events. 相似文献
968.
Klaus Eisenack Juergen Scheffran Juergen Peter Kropp 《Environmental Modeling and Assessment》2006,11(1):69-79
The pressure on marine renewable resources has rapidly increased over past decades. The resulting scarcity has led to a variety
of different control and surveillance instruments. Often they have not improved the current situation, mainly due to institutional
failure and intrinsic uncertainties about the state of stocks. This contribution presents an assessment of different management
schemes with respect to predefined constraints by utilizing viability theory. Our analysis is based on a bio-economic model
which is examined as a dynamic control system in continuous time. Feasible development paths are discussed in detail. It is
shown that participatory management may lead to serious problems if a purely resource-based management strategy is employed.
The analysis suggests that a less risky management strategy can be implemented if limited data are available. 相似文献
969.
Bowden M Sequiera M Krog JP Gravesen P Diamond D 《Journal of environmental monitoring : JEM》2002,4(5):767-771
The application of a phosphorus monitoring device based on microsystems technology (MST) to the analysis of river water is presented. An alternative to the standard molybdenum blue method known as the yellow vanadomolybdophosphoric acid method has been very effectively implemented. The method is simple, a reagent and sample are mixed in a 1:1 ratio forming a yellow complex that absorbs strongly below 400 nm in the UV spectrum. The kinetics of the reaction are rapid and sample turnaround is typically 3 min at room temperature. Therefore a very uncomplicated microfluidic design can be adopted. The working wavelength was chosen as 380 nm to coincide with the peak output of a UV-LED narrow bandwidth light source recently developed by Nichia. The limit of detection for the yellow method in the microfluidic system is 0.2 ppm with a dynamic linear range from 0-50 ppm. The method was applied to a measurement of phosphorus in a local river at specific sampling points along its course. 相似文献
970.
Surveys were completed on Tutuila Island, American Samoa, to characterize reef development and assess the impacts of non-point source pollution on adjacent coral reefs at six sites. Multivariate analyses of benthic and coral community data found similar modern reef development at three locations; Aoa, Alofau, and Leone. These sites are situated in isolated bays with gentle sloping foundations. Aoa reefs had the highest estimates of crustose coralline algae cover and coral species richness, while Leone and Alofau showed high abundances of macroalgae and Porites corals. Aoa has the largest reef flat between watershed discharge and the reef slope, and the lowest human population density. Masefau and Fagaalu have a different geomorphology consisting of cemented staghorn coral fragments and steep slopes, however, benthic and coral communities were not similar. Benthic data suggest Fagaalu is heavily impacted compared with all other sites. Reef communities were assessed as bio-criteria indicators for waterbody health, using the EPA aquatic life use support designations of (1) fully supportive, (2) partially supportive, and (3) non-supportive for aquatic life. All sites resulted in a partially supportive ranking except Fagaalu, which was non-supportive. The results of this rapid assessment based upon relative benthic community measures are less desirable than long-term dataset analyses from monitoring programs, however it fills an important role for regulatory agencies required to report annual waterbody assessments. Future monitoring sites should be established to increase the number of replicates within each geological and physical setting to allow for meaningful comparisons along a gradient of hypothesized pollution levels. 相似文献