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431.
432.
Development and evaluation of a Macroinvertebrate Biotic Integrity Index (MBII) for regionally assessing Mid-Atlantic Highlands Streams 总被引:5,自引:0,他引:5
Klemm DJ Blocksom KA Fulk FA Herlihy AT Hughes RM Kaufmann PR Peck DV Stoddard JL Thoeny WT Griffith MB Davis WS 《Environmental management》2003,31(5):0656-0669
The Macroinvertebrate Biotic Integrity Index (MBII) was developed from data collected at 574 wadeable stream reaches in the
Mid-Atlantic Highlands region (MAHR) by the U.S. Environmental Protection Agency's (USEPA) Environmental Monitoring and Assessment
Program (EMAP). Over 100 candidate metrics were evaluated for range, precision, responsiveness to various disturbances, relationship
to catchment area, and redundancy. Seven metrics were selected, representing taxa richness (Ephemeroptera richness, Plecoptera
richness, Trichoptera richness), assemblage composition (percent non-insect individuals, percent 5 dominant taxa), pollution
tolerance [Macroinvertebrate Tolerance Index (MTI)], and one functional feeding group (collector-filterer richness). We scored
metrics and summed them, then ranked the resulting index through use of independently evaluated reference stream reaches.
Although sites were classified into lowland and upland ecoregional groups, we did not need to develop separate scoring criteria
for each ecoregional group. We were able to use the same metrics for pool and riffle composite samples, but we had to score
them differently. Using the EMAP probability design, we inferred the results, with known confidence bounds, to the 167,797
kilometers of wadeable streams in the Mid-Atlantic Highlands. We classified 17% of the target stream length in the MAHR as
good, 57% as fair, and 26% as poor. Pool-dominated reaches were relatively rare in the MAHR, and the usefulness of the MBII
was more difficult to assess in these reaches. The process used for developing the MBII is widely applicable and resulted
in an index effective in evaluating region-wide conditions and distinguishing good and impaired reaches among both upland
and lowland streams dominated by riffle habitat. 相似文献
433.
The regulation of the emissions of 'traditional' primary air pollutants (fluorides, sulfur dioxide) has changed the pattern of exposure of ecological systems, with greatly reduced exposure close to sources, but with a smaller effect in some remote areas. Measurements show that recovery is occurring at some sites, in fresh water chemistry (reduced acidity) and in sensitive biota (sustainable fish populations). However, the pattern of change in exposure has not always been simply related to emission reductions. An understanding of responses to recent changes will improve our predictions of the response to future emission changes, both locally and globally. As exposure to 'traditional' pollutants is reduced, the potential for other pollutants to have effects becomes more evident. In the aqueous phase, we need to understand the role of soluble and suspended organics, but this also means explicit recognition of the possibility of phase exchange, and the role of photolytic reactions on plant, soil, and water surfaces. Do highly reactive free radicals in the atmosphere, formed by the action of sunlight on volatile organic compounds, have direct effects on plants? Organic compounds and heavy metals may be bioactive as gases and particles, but for many potentially toxic compounds, the experimental evidence for biotic response is very limited. To evaluate the potential effects of pollutants, we need to understand the pathways by which airborne pollutants enter and react within ecosystems. For vegetation, we have to consider bidirectional fluxes, and distinguish among uptake through stomata, through leaf surfaces, or through roots. There are several challenges for the future. (1) Can we devise experiments that permit exposure of vegetation to gases, particles, and/or aqueous pollutants at 'realistic' concentrations? (2) Can we include the potential interactions with photolytically derived free radicals, and the dynamics of exchange? (3) How do we allow for responses to pollutant mixtures, or the simultaneous exposure to pollutants in gas, particle, and aqueous phases? The recognition of the importance of the dynamic exchange of pollutants between phases will be the key to the development of effective experimental approaches to evaluating cause-effect relationships between pollutant mixtures and ecosystem responses. 相似文献
434.
Water, Air, &; Soil Pollution: Focus - The mountain ecosystems of the Hindu Kush Himalayas are generally considered to be pristine despite little available data to confirm it. Is there any... 相似文献
435.
Management of natural environment sites is becoming increasingly complex because of the influx of urbanized society into wildland areas. This worldwide phenomenon impacts a wide range of countries. In southern California ethnicity is often a major factor influencing recreation site use and behavior at sites in the wildland-urban interface. This study investigated the role of ethnicity and race on the use patterns, perception of environment, and recreation behaviors at an outdoor recreation site visited by an ethnically diverse population. Two research questions were asked: (1) What ethnic groups engage in outdoor recreation at this site, and (2) what differences can be assigned to these various groups? Data were collected from 250 recreationists during 1991. Three major ethnic groups were identified, and statistically significant differences were found in the importance of site attributes, activity participation, and in preferred and actual communication channels. Management implications and strategies based on group differences are discussed. 相似文献
436.
Alan Miller 《Environmental management》1993,17(5):563-574
There is a continuing debate about the proper role of analytical (positivist) science in natural resource decision making.
Two diametrically opposed views are evident, arguing for and against a more extended role for scientific information. The
debate takes on a different complexion if one recognizes that certain kinds of problem, referred to here as “wicked” or “trans-science”
problems, may not be amenable to the analytical process. Indeed, the mistaken application of analytical methods to trans-science
problems may not only be a waste of time and money but also serve to hinder policy development. Since many environmental issues
are trans-science in nature, then it follows that alternatives to analytical science need to be developed. In this article,
the issues involved in the debate are clarified by examining the impact of the use of analytical methods in a particular case,
the spruce budworm controversy in New Brunswick. The article ends with some suggestions about a “holistic” approach to the
problem. 相似文献
437.
Alan Miller 《The Environmentalist》1993,13(1):47-59
Summary An increased role for citizen participation in natural resource decision-making has been advocated by, amongst others, the United Nations (Brundtland Commission) as a means of initiating fundamental changes in the way we exploit natural resources. However, attempts at meaningful participation by the public are met with resistance, commonly by the dominant elites who control environmental and economic policies. Citizen groups press for involvement, only to be dismissed by local establishments as ill-informed amateurs. The resulting conflicts seldom lead to innovations in policy or to constructive cooperation in the face of new environmental problems. This leads the author to feelings of pessimism about prospects for genuine public participation in the absence of political change. In arguing in support of such change, a case study is offered which illustrates the unfortunate consequences that ensue when participation is sought and rejected. The paper closes with recommendations for the way in which citizen groups could contribute in a meaningful way to natural resource decision-making, were they to be given the opportunity.Dr Alan Miller is currently Professor of Psychology at the University of New Brunswick. He has published previously in this journal on the topic of Ideology and Environmental Risk Management (The Environmentalist,5(1), 21–30.) 相似文献
438.
Prior research on employees' views of various criteria for obtaining a desirable intrafirm transfer has conceptualized these perceptions on an individual level of analysis (i.e. has examined psychological transfer climates). It is argued that the identification of aggregate transfer climate dimensions on an organizational (subsystem) level of analysis is important for improving the effectiveness of R&D via better transfer policies. Factor analyses of questionnaire data obtained from 729 R&D professionals in 11 FRG industrial firms and 141 R&D professionals in three U.K. industrial firms revealed that both FRG and U.K. subjects perceived three broad means (overall task performance, publication and patent productivity, favouritism) for obtaining a desirable job transfer. Empirically the idea was supported that, for certain transfer criteria (overall task performance, manifest professional output, educational level, luck), individuals' scores can be meaningfully aggregated to obtain organizational transfer climate measures. Remarkable differences in the importance of company tenure and educational level as criteria for transfers in R&D were found between FRG and U.K. organizations. Using the FRG data set differences in the performance responsiveness of organizational transfer climates were shown to be significantly related to work-related outcome variables. Implications are sketched for R&D transfer policies and for explaining U.K./FRG differences in the corporate treatment of R&D activities. 相似文献
439.
ABSTRACT: Using data from 80 Oregon watersheds that ranged in size from 0.54 km2 to 27.45 km2, equations were developed to predict peak flows for use in culvert design on forest roads. Oregon was divided into six physiographic regions based on previous studies of flood frequency. In each region, data on annual peak flow from gaging stations with more than 20 years of record were analyzed using four flood frequency distributions: type 1 extremal, two parameter-log normal, three parameter-log normal, and log-Pearson type III. The log-Pearson type III distribution was found to be suitable for use in all regions of the State, based on the chi-square goodness-of-fit-test. Flood magnitudes having recurrence intervals of 10, 25, 50, and 100 years were related to physical and climatic characteristics of drainage basins by multiple regression. Drainage basin size was the most important variable in explaining the variation of flood peaks in all regions. Mean basin elevation and mean annual precipitation were also significantly related to flood peaks in two regions of western Oregon. The standard error of the estimate for the regression relationships ranged from 26 to 84 percent. 相似文献
440.
Alan Mair Ali Fares Aly El‐Kadi 《Journal of the American Water Resources Association》2007,43(1):148-159
Abstract: Land‐use/land‐cover changes in Mākaha valley have included the development of agriculture, residential dwellings, golf courses, potable water supply facilities, and the introduction of alien species. The impact of these changes on surface water and ground water resources in the valley is of concern. In this study, streamflow, rainfall, and ground‐water pumping data for the upper part of the Mākaha valley watershed were evaluated to identify corresponding trends and relationships. The results of this study indicate that streamflow declined during the ground‐water pumping period. Mean and median annual streamflow have declined by 42% (135 mm) and 56% (175 mm), respectively, and the mean number of dry stream days per year has increased from 8 to 125. Rainfall across the study area appears to have also declined though it is not clear whether the reduction in rainfall is responsible for all or part of the observed streamflow decline. Mean annual rainfall at one location in the study area declined by 14% (179 mm) and increased by 2% (48 mm) at a second location. Further study is needed to assess the effect of ground‐water pumping and to characterize the hydrologic cycle with respect to rainfall, infiltration, ground‐water recharge and flow in the study area, and stream base flow and storm flow. 相似文献