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731.
Lynn A. Mandarano Jeffrey P. Featherstone Kurt Paulsen 《Journal of the American Water Resources Association》2008,44(1):136-147
Abstract: This paper evaluates alternative approaches to management of interstate water resources in the United States (U.S.), including interstate compacts, interstate associations, federal‐state partnerships, and federal‐interstate compacts. These governance structures provide alternatives to traditional federalism or U.S. Supreme Court litigation for addressing problems that transcend political boundaries and functional responsibilities. Interstate compacts can provide a forum for ongoing collaboration and are popular mechanisms for allocating water rights among the states. Federal‐interstate compacts, such as the Delaware River Basin Compact and federal‐state partnerships, such as the National Estuary Program, are also effective and complementary approaches to managing water resources. However, all of these approaches can only make modest improvements in managing water resources given the complicated and fragmented nature of our federalist system of government. 相似文献
732.
Empirically derived relationships associating sediment metal concentrations with degraded ecological conditions provide important information to assess estuarine condition. Resources limit the number, magnitude, and frequency of monitoring activities to acquire these data. Models that use available information and simple statistical relationships to predict sediment metal concentrations could provide an important tool for environmental assessment. We developed 45 predictive models for the total concentrations of copper, lead, mercury, and cadmium in estuarine sediments along the Southern New England and Mid-Atlantic regions of the United States. Using information theoretic model-averaging approaches, we found total developed land and percent silt/clay of estuarine sediment were the most important variables for predicting the presence of all four metals. Estuary area, river flow, tidal range, and total agricultural land varied in their importance. The model-averaged predictions explained 78.4, 70.5, 56.4, and 50.3% of the variation for copper, lead, mercury, and cadmium, respectively. Overall prediction accuracies of selected sediment benchmark values (i.e., effects ranges) were 83.9, 84.8, 78.6, and 92.0% for copper, lead, mercury, and cadmium, respectively. Our results further support the generally accepted conclusion that sediment metal concentrations are best described by the physical characteristics of the estuarine sediment and the total amount of urban land in the contributing watershed. We demonstrated that broad-scale predictive models built from existing monitoring data with information theoretic model-averaging approaches provide valuable predictions of estuarine sediment metal concentrations and show promise for future environmental modeling efforts in other regions. 相似文献
733.
A critical review of the theory and application of social learning in participatory natural resource management processes 总被引:1,自引:0,他引:1
Social learning is increasingly cited as an essential component of sustainable natural resource management and the promotion of desirable behavioural change. This paper attempts to contribute to the current debate about social learning and public participation by reviewing the many perspectives on social learning and associated claims and benefits. Based on this analysis the paper identifies conceptual and practical weaknesses of the concept of social learning and their implications for the design of participatory processes in natural resource management. 相似文献
734.
This paper presents a practical risk assessment methodology to provide drinking water infrastructure (DWI) decision-makers with an objective risk assessment tool. The purpose of this risk assessment tool is to maintain the desired level-of-service or systems reliability [r(f)], while managing the financial uncertainty of the expected budgetary impact within the capital improvement program (CIP). The goal of this paper is to demonstrate the value of an objective risk assessment tool for estimating the DWI decision-maker's sensitivity to the risk of systems failure (R). The objectives are to: (1) incorporate probability of systems failure [p(f)] into the CIP budgetary analysis process and (2) evaluate the affects of p(f) on the expected CIP budgetary outcome. The magnitude of the expected budgetary impact is managed through the DWI decision-maker's sensitivity to R, which is represented by the level of the rate of reinvestment (RR). The expected result of the proposed risk assessment tool demonstrates that by proactively managing R to maintain a desired r(f) will effectively manage the impact of uncertainty on the expected budgetary outcome within the CIP. The expected contribution of the practical risk assessment methodology is to provide DWI decision-makers with the ability to reduce budgetary uncertainty when allocating limited financial resources among competing operational, repair, maintenance, and expansion activities within the CIP. The conclusions of the paper reveal that if DWI decision-makers assume risk-avoidance positions through proactive asset management (AM) strategies, they will achieve positive affects on expected budgetary outcomes. 相似文献
735.
Elevated nitrate concentrations in streamwater are a major environmental management problem. While land use exerts a large control on stream nitrate, hydrology often plays an equally important role. To date, predictions of low-flow nitrate in ungauged watersheds have been poor because of the difficulty in describing the uniqueness of watershed hydrology over large areas. Clearly, hydrologic response varies depending on the states and stocks of water, flow pathways, and residence times. How to capture the dominant hydrological controls that combine with land use to define streamwater nitrate concentration is a major research challenge. This paper tests the new Hydrologic Landscape Regions (HLRs) watershed classification scheme of Wolock and others (Environmental Management 34:S71-S88, 2004) to address the question: Can HLRs be used as a way to predict low-flow nitrate? We also test a number of other indexes including inverse-distance weighting of land use and the well-known topographic index (TI) to address the question: How do other terrain and land use measures compare to HLR in terms of their ability to predict low-flow nitrate concentration? We test this for 76 watersheds in western Oregon using the U.S. Environmental Protection Agency’s Environmental Monitoring and Assessment Program and Regional Environmental Monitoring and Assessment Program data. We found that HLRs did not significantly improve nitrate predictions beyond the standard TI and land-use metrics. Using TI and inverse-distance weighting did not improve nitrate predictions; the best models were the percentage land use—elevation models. We did, however, see an improvement of chloride predictions using HLRs, TI, and inverse-distance weighting; adding HLRs and TI significantly improved model predictions and the best models used inverse-distance weighting and elevation. One interesting result of this study is elevation consistently predicted nitrate better than TI or the hydrologic classification scheme. 相似文献
736.
Jeffrey L. Jordan 《Journal of the American Water Resources Association》1999,35(5):1007-1013
Discussing, estimating or analyzing the value of water is a difficult task. In addressing the value of water as reflected in its price — either as charged by a water utility, as the price of a water transfer, or a water sale in some market — this paper will examine three propositions regarding water pricing. The paper will consider the marginal scarcity rent of water, estimates of externalities, the full cost pricing of water and the consequences of these considerations on water prices, transfers and the efficiency of water use. 相似文献
737.
There is a long and rich history of research on the concept of leader emergence. Much of this research positions leader emergence alongside leadership effectiveness as an epiphenomenal criterion in leadership research. Although this view has enhanced our understanding of factors that influence leader emergence and leadership effectiveness individually, our understanding of the potential alignment or misalignment of these concepts remains opaque. Following from this, we are left with unanswered questions concerning how, why, and under what conditions do the right or wrong leaders emerge or fail to emerge. Theory that develops insights into these questions is needed to advance our understanding of leadership and to cope with challenges of identifying and developing effective leaders and maximizing leadership potential in organizations. By integrating theories of leader emergence and leadership effectiveness—and considering their implications jointly—we provide a conceptual basis for identifying and understanding a more complete range of leader emergence than has been suggested in the literature. Importantly, our theoretical frame explains how our leader emergence types—over-emergence, under-emergence, congruent emergence, and congruent non-emergence—are differentially associated with a common set of factors. In doing so, we illuminate tradeoffs that might accompany different interventions intended to enhance leadership in organizations. 相似文献
738.
Protected area management involves balancing environmental and social objectives. This is particularly difficult at high-use/high-impact
recreation sites, because resource protection objectives may require substantial site management or visitor regulation. This
study examined visitors’ reactions to both of these types of actions at Annapolis Rocks, Maryland, a popular Appalachian Trail
camping area. We surveyed visitors before and after implementation of camping policies that included shifting camping to designated
newly constructed campsites and prohibiting campfires. Survey results reveal that visitors were more satisfied with all social
and environmental indicators after the changes were enacted. An Importance-Performance analysis also determined that management
actions improved conditions for factors of greatest concern to campers prior to the changes. Posttreatment visitors were least
satisfied with factors related to reduced freedom and to some characteristics of the constructed campsites. Although there
was evidence of visitor displacement, the camping changes met management goals by protecting the camping area’s natural resources
and improving social conditions. 相似文献
739.
740.
To better understand the role of herbivory and fire as potential disturbance processes in sagebrush communities, we examined
responses of a grazing ungulate, elk (Cervus elaphus), following prescribed burning of sagebrush (Artemisia
tridentata ssp. vaseyana) in south-central Montana (USA.) with concurrent monitoring of changes in plant production, nutritional quality, and community
diversity from 1989–1999. Burning transformed low-diversity, sagebrush-dominated communities into high-diversity, graminoid-forb
communities that persisted for 10 years without significant reestablishment of sagebrush. Elk increased use of burned sites
one year after burning, but elk use returned to pre-burn levels over the next two to nine years. Forage biomass and nutritional
quality declined after initial increases that coincided with increased elk use. Increases in elk use appeared to be influenced
by increases in combined graminoid and forb production and changes in structural vegetation characteristics that permitted
greater foraging efficiency. Declines in use were associated with loss of nutritional enhancement and declines in combined
graminoid and forb production. Managers may observe only short-term responses from grazing ungulates to prescribed fire in
sagebrush communities, but can expect longer-term increases in plant diversity and establishment of graminoid-forb communities. 相似文献