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71.
72.
Normative models of choice predict no preference when unequally priced options of identical quality are temporarily offered
for the same low price, yet several studies using nonhuman subjects have found a preference in this context. Paradoxically,
subjects have preferred the stimulus associated with typically higher acquisition cost. Here, preference tests were conducted for gray jays (Perisoreus canadensis) choosing between temporarily identical options, which were color coded to represent typical conditions. During no-choice
trials, subjects were offered either a cheap or an expensive food reward, by positioning the reward either 1.9 or 60 cm into
a tunnel. During intermittent free-choice trials, subjects chose between color-coded but otherwise identical options (same
reward, both cheap). Jays preferred the stimulus associated with lower cost, unlike subjects in previous studies. To reconcile these conflicting findings, we model choice as a trade-off between
state and predation. We explore how alternative mechanisms of valuation may lead to preference in either direction (i.e.,
for greater workload vs lower predation risk). Our models accommodate observed paradoxical preferences in both directions. 相似文献
73.
The Washington State Environmental Policy Act (SEPA) promotes the conservation of natural resources through procedural review of proposed actions which may impact natural systems. There are, however, many actions specifically exempt from the SEPA review process. Since many exempt actions could have significant adverse effects on natural resources at one location and not another, the SEPA statute contains a provision that enables local governments to designate Environmentally Sensitive Areas (ESAs). Within the ESAs, these potentially adverse activities are subject to SEPA review. Local governments have complete control over the exact definition of the ESA criteria and the types of local projects exempt from SEPA. Whitman County, the most productive wheat-producing county in Washington, has recognized the need for conservation of its natural resources in its comprehensive plan but has not implemented the ESA provision. A representative watershed within Whitman County was used as a case study to identify areas which would qualify for ESA status. In these areas, specific soil, water, and biological characteristics or resources were identified as sensitive to certain common land uses. Significant differences were found between state and county policies regarding ESAs and actual conditions within the watershed. It may be more effective for the state to manage ESAs on a consistent and regional basis. 相似文献
74.
There is increasing international pressure to ensure that mining development is aligned with local and national development objectives. In South Africa, legislation requires mining companies to produce Social and Labour Plans, which are aimed at addressing local developmental concerns. Against the background of the new mining legislation in South Africa, this paper evaluates attempts to address mine downscaling in the Free State Goldfields over the past two decades. The analysis shows that despite an improved legislative environment, the outcomes in respect of integrated planning are disappointing, owing mainly to a lack of trust and government incapacity to enact the new legislation. It is argued that legislative changes and a national response in respect of mine downscaling are required. 相似文献
75.
Air protection agencies in the United States increasingly confront non-attainment of air quality standards for multiple pollutants
sharing interrelated emission origins. Traditional approaches to attainment planning face important limitations that are magnified
in the multipollutant context. Recognizing those limitations, the Georgia Environmental Protection Division has adopted an
integrated framework to address ozone, fine particulate matter, and regional haze in the state. Rather than applying atmospheric
modeling merely as a final check of an overall strategy, photochemical sensitivity analysis is conducted upfront to compare
the effectiveness of controlling various precursor emission species and source regions. Emerging software enables the modeling
of health benefits and associated economic valuations resulting from air pollution control. Photochemical sensitivity and
health benefits analyses, applied together with traditional cost and feasibility assessments, provide a more comprehensive
characterization of the implications of various control options. The fuller characterization both informs the selection of
control options and facilitates the communication of impacts to affected stakeholders and the public. Although the integrated
framework represents a clear improvement over previous attainment-planning efforts, key remaining shortcomings are also discussed. 相似文献
76.
Application and sensitivity testing of a eutrophication assessment method on coastal systems in the United States and European Union 总被引:5,自引:0,他引:5
The Assessment of Estuarine Trophic Status (ASSETS) screening model has been extended to allow its application to both estuarine and coastal systems. The model, which combines elements of pressure, state and response, was tested on four systems: Maryland Coastal Bays and Long Island Sound in the United States and The Firth of Clyde (Scotland) and Tagus Estuary (Portugal) in the European Union. The overall scores were: Maryland Coastal Bays: Bad; Firth of Clyde: Poor; Tagus Estuary: Good. Long Island Sound was modelled along a timeline, using 1991 data (score: Bad) and 2002 data (score: Moderate). The improvement registered for Long Island Sound is a consequence of the reduction in nutrient loading, and the ASSETS score changed accordingly. The two main areas where developments are needed are (a) In the definition of type-specific ranges for eutrophication parameters, due to the recognition that natural or pristine conditions may vary widely, and the use of a uniform set of thresholds artificially penalizes some systems and potentially leads to misclassification; (b) In the definition and quantification of measures which will result in an improved state through a change in pressures, as well as in the definition of appropriate metrics through which response may be assessed. One possibility is the use of detailed research models where different response scenarios potentially produce changes in pressure and state. These outputs may be used to drive screening models and analyze the suitability of candidate metrics for evaluating management options. 相似文献
77.
Depleting Fish Resources,Declining Fishing Communities,and the State Revitalization Project in Korea
Cheong SM 《Environmental management》2003,32(3):382-390
This paper reviews recent declines in fish resources and fishing communities in Korea, evaluates major factors of declines, and examines a subsequent community-based revitalization project. Factors leading to depleting fish resources include global regulations, technological advances in fishing, national economic development policies, land reclamation projects, and pollution. The negative economic and societal impact of depleting fish resources is addressed using demographic and income levels of the communities. In response, the state initiated revitalization projects and invested in local fishing cooperatives promoting community-based management. The result has been less than effective as it led to mismanagement of investment and created an attitude of dependence on the government for financial assistance. 相似文献
78.
79.
Michael R. Patsfall Nickolaus R. Feimer Gregory J. Buhyoff J. Douglas Wellman 《Journal of environmental psychology》1984,4(1):7-26
Two studies were conducted to examine distance classes of vegetation (foreground, middleground and background) and scene composition (presence of vegetation in left, center or right section of the image) as predictors of perceived scenic beauty. In study one, 41 students rated 63 landscape scenes with regard to scenic beauty. The Scenic Beauty Estimation Method was used to derive interval scale beauty values (SBEs). For each landscape image, areal measures of vegetation in each distance class and for each vertical section were taken and used as predictors. Presence of haze, clouds and human impacts were also recorded. Among the most important contributors to scenic beauty were amount of center middleground vegetation, and center background vegetation. Left foreground vegetation and right foreground vegetation were found to have significant and opposing regression weight signs—negative for the left and positive for the right. Study two was conducted to determine whether these opposing regression weight signs for foreground vegetation were due to a perceptual right-left bias or to some specific content in the image itself. In the second study, the photographic slides used to present landscape scenes to subjects were reversed so that the content which was previously on the right was now left, and vice versa. Thirty-nine students rated the reversed slides with regard to their scenic beauty. The signs of the regression weights in study two shifted such that left foreground was now positively valued and right foreground was negatively valued. This finding suggests that viewers are sensitive to foreground content and its placement in the image, and not simply to one side of the field of vision. 相似文献
80.
R. Thomas. James Kim O'Dell Val H. Smith 《Journal of the American Water Resources Association》1994,30(3):531-546
ABSTRACT: Water quality in eutrophic Lake Tohopekaliga, Florida, improved markedly from 1982 to 1992 as a result of reductions in phosphorus and nitrogen loading to the lake. Annual budgets of water, chloride, phosphorus and nitrogen were constructed for the lake, and indicate it is a sink for phosphorus and a source for nitrogen. Water column concentrations of total phosphorus, soluble reactive phosphorus, total nitrogen, dissolved inorganic nitrogen, and chlorophyll a all declined as external inputs of nutrients decreased. Water column nitrogen: phosphorus ratios have increased, suggesting a probable shift from nitrogen- to phosphorus-limitation. This apparent shift in nutrient limitation status also is supported by comparisons of the mean Trophic State Indices for phosphorus, nitrogen, and chlorophyll a. These improvements in water quality are attributed to the diversion of wastewater treatment plant effluent from the lake, and the increased use of wet retention ponds for stormwater runoff. 相似文献