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81.
Are R. Berentsen William C. Pitt John D. Eisemann Richard M. Engeman 《Environmental science and pollution research international》2014,21(3):2283-2288
Invasive rodents (primarily Rattus spp.) are responsible for loss of biodiversity in island ecosystems worldwide. Large-scale rodenticide applications are typically used to eradicate rats and restore ecological communities. In tropical ecosystems, environmental conditions rapidly degrade baits and competition for baits by non-target animals can result in eradication failure. Our objective was to evaluate persistence of rodenticide baits during a rat eradication program on Palmyra Atoll; a remote tropical atoll with intense competition for resources by land crabs. Following aerial application, bait condition was monitored in four terrestrial environments and in the canopy foliage of coconut palms. Ten circular PVC hoops were fixed in place in each of Palmyra’s four primary terrestrial habitats and five rodenticide pellets were placed in each hoop. Five coconut palms were selected in three distinct regions of the atoll. One rodenticide pellet was placed on each of five palm fronds in each coconut palm. Fresh baits were placed in all monitoring locations after each broadcast bait application. Bait condition and survival was monitored for 7 days after the first bait application and 6 days after second application. Bait survival curves differed between applications at most monitoring sites, suggesting a decrease in overall rat activity as a result of rodenticide treatment. One terrestrial site showed near 100 % bait survival after both applications, likely due to low localized rat and crab densities. Median days to pellet disappearance were one and two days for the first and second application, respectively. Differences in survival curves were not detected in canopy sites between bait applications. Median days to pellet disappearance in canopy sites were 2 and 4 days for the first and second application, respectively. Frequent rainfall likely contributed to rapid degradation of bait pellets in coconut palm fronds. 相似文献
82.
Richard L. Skaggs Larry W. Mays Lance W. Vail 《Journal of the American Water Resources Association》2001,37(4):867-875
ABSTRACT: A methodology for ground water remediation design has been developed that interfaces ground water simulation models with an enhanced annealing optimizer. The ground water flow and transport simulators provide the ability to consider site‐specific contamination and geohydrologic conditions directly in the assessment of alternative remediation system designs. The optimizer facilitates analysis of tradeoffs between technical, environmental, regulatory, and financial risks for alternative design and operation scenarios. A ground water management model using an optimization method referred to as “enhanced annealing” (simulated annealing enhanced to include “directional search” and “memory” mechanisms) has been developed and successfully applied to an actual restoration problem. The demonstration site is the contaminated unconfined aquifer referred to as N‐Springs located at Han‐ford, Washington. Results of the demonstration show the potential for improving groundwater restoration system performance while reducing overall system cost. 相似文献
83.
Richard Dennis John E. Wilder Dale L. Harmon 《Journal of the Air & Waste Management Association (1995)》2013,63(9):987-992
The analysis of pressure loss characteristics for pulse jet filters suggests that the relationship between dust adhesion to the fabric and the opposing force generated by pulse jet action plays a major role in dust removal. Hence, fabric cleanability is examined in terms of the adhesion-cohesion forces bonding the dust to the fabric vs. the intensity and frequency of the dust dislodgement forces produced by the high energy air pulses. The effect of jet size and location, jet air volume, and the intensity (pressure) and duration of the jet pulses is related to operating pressure loss. The mechanics of energy transfer from the jet pulse to the dustladen fabric are explored in terms of jet pressure, solenoid valve action, the ratio of delivered pulse air volume to bag (tube) volume, and the elastic and flex properties of the felt bags. Effective and actual fabric dust holdings before and after cleaning are discussed with respect to steady-state dust deposition and removal rates, and operating pressure losses. Finally, predictive equations are proposed for estimating pressure loss over a broad range of design and operating parameters. 相似文献
84.
85.
Richard H. McCuen 《Journal of the American Water Resources Association》2011,47(6):1364-1371
86.
Richard Shearman 《Environmental management》1990,14(1):1-8
Some have argued that the meaning of sustainability varies according to context, forcing us to be as explicit as possible when defining our terms. An argument is offered that disputes this conclusion by maintaining that it is not the meaning of sustainability that changes with respect to context, but rather our understanding of the context itself. This is frequently apparent in contradictions that arise when conceiving each context in terms of sustainability. If this argument is correct, then we should be concerned not with the “meaning” of sustainability but rather the implications of sustainability as they affect the status quo. And in order to do this we must be prepared to answer the question: Why is sustainability desirable? This approach is illustrated through a preliminary conceptual and ethical analysis of ecologically sustainable development. 相似文献
87.
The land evaluation and site assessment (LESA) method has been used extensively in the United States to assess agricultural
land suitability for different localities. Despite widespread use, LESA models rarely have been evaluated in a systematic,
comprehensive manner. This article discusses development of a LESA system for Hawaii, the first statewide application of the
LESA methodology. The empirical model was implemented with a computerized geographic information system (GIS). The system's
efficiency, ability to discriminate among land parcels, and robustness to subjective model parameter values are evaluated
with statistical analyses and map overlays of GIS data. Results show great potential to simplify the original model specification,
primarily through deletion of marginal site assessment factors. System output was generally insensitive to the numeric values
selected for model parameters, with exception of the ratio used to combine the land evaluation (LE) and site assessment (SA)
component scores. Relative supplies of the differing land attributes measured by the two components must be considered in
determining an appropriate LE:SA ratio for a given area. 相似文献
88.
William F. Porter Nancy E. Mathews H. Brian Underwood Richard W. Sage Jr. Donald F. Behrend 《Environmental management》1991,15(6):809-814
Populations of white-tailed deer (Odocoileus virginianus) inhabiting many state and national parks and suburban areas have grown to the point that they conflict with human activities.
Conflicts range from destruction of vegetation through browsing to public perception that diseases carried by deer pose threats
to human health. Traditional modes of hunting to control populations are inappropriate in many of these areas because of intense
human development and activity. This article explores an alternative approach for population reduction based on deer social
organization. Female white-tailed deer are highly philopatric and female offspring remain near their dams for life. This suggests
that a population expands slowly as a series of overlapping home ranges in a form analogous to the petals on a rose. Incorporating
the rose petal concept into a model of population growth shows that removal of deer by family unit can potentially alleviate
conflicts in localized areas for as many as 10–15 yr. 相似文献
89.
In Hawaii, trace concentrations of pesticides used in the production of pineapple were found in the groundwater supplies of
Mililani Town in the Pearl Harbor Basin on the island of Oahu. Groundwater serves as the major source of drinking water and
residents pay for wellhead treatment of the contaminated water, via their monthly water bill. The agricultural chemical users
within the Pearl Harbor Basin do not include these wellhead treatment costs in their production costs. The agricultural industry
benefits from using pesticides but does not pay the entire societal cost of using these chemicals. In this study we evaluate
the specific financial cost of wellhead treatment, and not the economic value of groundwater. While wellhead treatment costs
could conceivably be shared by several parties, this study focuses on the financial impact of the pineapple industry alone.
This study factors annual wellhead treatment costs into annual pineapple production costs to measure the effect on annual
financial return from pineapple production. Wellhead treatment costs are calculated from the existing granulated activated
carbon (GAC) water treatment facility for Millilani Wells I and II. Pineapple production costs are estimated from previous
cost of production studies. The inclusion of wellhead treatment costs produces different production-cost results, depending
on the scale of analysis. At the local scale, the Mililani wellhead treatment costs can be factored into the production costs
of the pineapple fields, which were probably responsible for contamination of the Mililani Wells, without causing a deficit
in economic return. At the larger regional scale, however, the return from all of the pineapple grown in the Pearl Harbor
Basin can not sustain the cost of wellhead treatmentfor the entire water supply of the basin. Recommendations point to the
prevention of groundwater contamination as more cost-effective measure than wellhead treatment. 相似文献
90.
The United States Soil Conservation Service (SCS) conducts a survey for the purpose of establishing an agricultural land use database. This survey is called the National Resources Inventory (NRI) database. The complex NRI land classification system, in conjunction with the quantitative information gathered by the survey, has numerous applications. The current paper uses the wetland area data gathered by the NRI in 1982 and 1987 to examine empirically the factors that generate wetland loss in the United States. The cross-section regression models listed here use the quantity of wetlands, the stock of drainage capital, the realty value of farmland and drainage costs to explain most of the cross-state variation in wetland loss rates. Wetlands preservation efforts by federal agencies assume that pecuniary economic factors play a decisive role in wetland drainage. The empirical models tested in the present paper validate this assumption. 相似文献