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951.
Brian D. Richter Stephen Andrews Rhaude Dahlinghaus Gabriella Freckmann Sam Ganis James Green Ian Hardman Marissa Palmer Jessica Shalvey 《Journal of the American Water Resources Association》2020,56(1):1-15
In recent decades, public and private environmental entities have been purchasing or leasing water rights across the Western United States (U.S.) in efforts to restore river flows and aquatic ecosystems. The need to pay for flow restoration arises from the fact that state governments did not begin to reserve water for instream purposes until the 1970s, long after water rights had become over‐appropriated and flows were substantially depleted in most rivers. As a consequence, flow depletion has become the leading cause of fish endangerment in the U.S., including the imperilment of two‐thirds of all native fish species in the Colorado River system. This paper takes stock of the progress made in buying water for the environment, specifically by reviewing and analyzing more than 50 transactions executed by public and private entities and the sources of funding underpinning these transactions. We conclude that nongovernmental actors — such as environmental organizations and state water trusts — are integral to regional efforts to restore river flows; these nongovernmental actors executed more than two‐thirds of the transactions we documented. However, we also conclude that the long‐term success of these nongovernmental actors depends upon the availability of sustained public funding that enables them to build capacity and engage in the large number of transactions needed to restore flows across each state. 相似文献
952.
Numerous reports have indicated that hydrophobic organic compound bioaccessibility in sediment and soil can be determined by extraction using aqueous hydroxypropyl-β-cyclodextrin (HPCD) solutions. This study establishes the compatibility of HPCD with Selenastrum capricornutum and assesses whether its presence influences the toxicity of reference toxicants. Algal growth inhibition (72 h) showed no significant (P > 0.05) difference at HPCD concentrations up to and including 20 mM. HPCD presence did not influence the toxicity of the inorganic reference toxicant (ZnSO4), with IC50 values of 0.82 μM and 0.85 μM, in the presence and absence of HPCD (20 mM), respectively. However, HPCD presence (20 mM) reduced the toxicity of 2,4-dichlorophenol and the herbicides diuron and isoproturon. These reductions were attributed to inclusion complex formation between the toxicants and the HPCD cavity. Liberation of complexed toxicants, by sample manipulation prior to toxicity assessment, is proposed to provide a sensitive, high throughput, bioassay that reflects compound bioaccessibility. 相似文献
953.
Willis SG Hole DG Collingham YC Hilton G Rahbek C Huntley B 《Environmental management》2009,43(5):836-845
Global climate change, along with continued habitat loss and fragmentation, is now recognized as being a major threat to future
biodiversity. There is a very real threat to species, arising from the need to shift their ranges in the future to track regions
of suitable climate. The Important Bird Area (IBA) network is a series of sites designed to conserve avian diversity in the
face of current threats from factors such as habitat loss and fragmentation. However, in common with other networks, the IBA
network is based on the assumption that the climate will remain unchanged in the future. In this article, we provide a method
to simulate the occurrence of species of conservation concern in protected areas, which could be used as a first-step approach
to assess the potential impacts of climate change upon such species in protected areas. We use species-climate response surface
models to relate the occurrence of 12 biome-restricted African species to climate data at a coarse (quarter degree-degree
latitude-longitude) resolution and then intersect the grid model output with IBA outlines to simulate the occurrence of the
species in South African IBAs. Our results demonstrate that this relatively simple technique provides good simulations of
current species' occurrence in protected areas. We then use basic habitat data for IBAs along with habitat preference data
for the species to reduce over-prediction and further improve predictive ability. This approach can be used with future climate
change scenarios to highlight vulnerable species in IBAs in the future and allow practical recommendations to be made to enhance
the IBA network and minimize the predicted impacts of climate change. 相似文献
954.
Brad Griffith J. Michael Scott Robert Adamcik Daniel Ashe Brian Czech Robert Fischman Patrick Gonzalez Joshua Lawler A. David McGuire Anna Pidgorna 《Environmental management》2009,44(6):1043-1052
Since its establishment in 1903, the National Wildlife Refuge System (NWRS) has grown to 635 units and 37 Wetland Management
Districts in the United States and its territories. These units provide the seasonal habitats necessary for migratory waterfowl
and other species to complete their annual life cycles. Habitat conversion and fragmentation, invasive species, pollution,
and competition for water have stressed refuges for decades, but the interaction of climate change with these stressors presents
the most recent, pervasive, and complex conservation challenge to the NWRS. Geographic isolation and small unit size compound
the challenges of climate change, but a combined emphasis on species that refuges were established to conserve and on maintaining
biological integrity, diversity, and environmental health provides the NWRS with substantial latitude to respond. Individual
symptoms of climate change can be addressed at the refuge level, but the strategic response requires system-wide planning.
A dynamic vision of the NWRS in a changing climate, an explicit national strategic plan to implement that vision, and an assessment
of representation, redundancy, size, and total number of units in relation to conservation targets are the first steps toward
adaptation. This adaptation must begin immediately and be built on more closely integrated research and management. Rigorous
projections of possible futures are required to facilitate adaptation to change. Furthermore, the effective conservation footprint
of the NWRS must be increased through land acquisition, creative partnerships, and educational programs in order for the NWRS
to meet its legal mandate to maintain the biological integrity, diversity, and environmental health of the system and the
species and ecosystems that it supports. 相似文献
955.
Jordan M. West Susan H. Julius Peter Kareiva Carolyn Enquist Joshua J. Lawler Brian Petersen Ayana E. Johnson M. Rebecca Shaw 《Environmental management》2009,44(6):1001-1021
Public lands and waters in the United States traditionally have been managed using frameworks and objectives that were established
under an implicit assumption of stable climatic conditions. However, projected climatic changes render this assumption invalid.
Here, we summarize general principles for management adaptations that have emerged from a major literature review. These general
principles cover many topics including: (1) how to assess climate impacts to ecosystem processes that are key to management
goals; (2) using management practices to support ecosystem resilience; (3) converting barriers that may inhibit management
responses into opportunities for successful implementation; and (4) promoting flexible decision making that takes into account
challenges of scale and thresholds. To date, the literature on management adaptations to climate change has mostly focused
on strategies for bolstering the resilience of ecosystems to persist in their current states. Yet in the longer term, it is
anticipated that climate change will push certain ecosystems and species beyond their capacity to recover. When managing to
support resilience becomes infeasible, adaptation may require more than simply changing management practices—it may require
changing management goals and managing transitions to new ecosystem states. After transitions have occurred, management will
again support resilience—this time for a new ecosystem state. Thus, successful management of natural resources in the context
of climate change will require recognition on the part of managers and decisions makers of the need to cycle between “managing
for resilience” and “managing for change.” 相似文献
956.
Brian S. Helms Jon E. Schoonover Jack W. Feminella 《Journal of the American Water Resources Association》2009,45(1):157-169
Abstract: We evaluated the impact of land cover on fish assemblages by examining relationships between stream hydrology, physicochemistry, and instream habitat and their association with fish responses in streams draining 18 watersheds of the Lower Piedmont of western Georgia. Several important relationships between land use and physicochemical, hydrological, and habitat parameters were observed, particularly higher frequency of spate flows, water temperatures, and lower dissolved oxygen (DO) with percentage impervious surface (IS) cover, higher habitat quality with percentage forest cover, and elevated suspended solid concentrations with percentage pasture cover. Fish assemblages were largely explained by physicochemical and hydrological rather than habitat variables. Specifically, fish species diversity, richness, and biotic integrity were lower in streams that received high frequency of spate flows. Also, overall fish assemblage structure as determined by nonmetric multidimensional scaling was best described by total dissolved solids (TDS) and DO, with high TDS and low DO streams containing sunfish‐based assemblages and low TDS and high DO streams containing minnow‐based assemblages. Our results suggest that altered hydrological and physicochemical conditions, induced largely by IS, may be a strong determinant of fish assemblage structure in these lowland streams and allow for a more mechanistic understanding of how land use ultimately affects these systems. 相似文献
957.
Brian G. Katz A. Alejandro Sepulveda Richard J. Verdi 《Journal of the American Water Resources Association》2009,45(3):607-627
Abstract: A nitrogen (N) mass‐balance budget was developed to assess the sources of N affecting increasing ground‐water nitrate concentrations in the 960‐km2 karstic Ichetucknee Springs basin. This budget included direct measurements of N species in rainfall, ground water, and spring waters, along with estimates of N loading from fertilizers, septic tanks, animal wastes, and the land application of treated municipal wastewater and residual solids. Based on a range of N leaching estimates, N loads to ground water ranged from 262,000 to 1.3 million kg/year; and were similar to N export from the basin in spring waters (266,000 kg/year) when 80‐90% N losses were assumed. Fertilizers applied to cropland, lawns, and pine stands contributed about 51% of the estimated total annual N load to ground water in the basin. Other sources contributed the following percentages of total N load to ground water: animal wastes, 27%; septic tanks, 12%; atmospheric deposition, 8%; and the land application of treated wastewater and biosolids, 2%. Due to below normal rainfall (97.3 cm) during the 12‐month rainfall collection period, N inputs from rainfall likely were about 30% lower than estimates for normal annual rainfall (136 cm). Low N‐isotope values for six spring waters (δ15N‐NO3 = 3.3 to 6.3‰) and elevated potassium concentrations in ground water and spring waters were consistent with the large N contribution from fertilizers. Given ground‐water residence times on the order of decades for spring waters, possible sinks for excess N inputs to the basin include N storage in the unsaturated zone and parts of the aquifer with relatively sluggish ground‐water movement and denitrification. A geographical‐based model of spatial loading from fertilizers indicated that areas most vulnerable to nitrate contamination were located in closed depressions containing sinkholes and other dissolution features in the southern half of the basin. 相似文献
958.
The North Fork of Clear Creek (NFCC), Colorado, is an acid‐mine‐drainage‐impacted stream typical of many mountain surface waters affected by historic metal mining in the western United States. The stream is devoid of fish primarily because of high metal concentrations in the water (e.g., copper and zinc) and has large amounts of settled iron oxyhydroxide solids that coat the streambed. The NFCC is part of the Central City/Clear Creek Superfund site, and remediation plans are being implemented that include treatment of three of the main point‐source inputs and cleanup of some tailings and waste rock piles. This article examines dissolved (0.45‐μm filterable) concentrations of cadmium, copper, and zinc following several potential remediation scenarios, simulated using a reactive transport model (WASP4/META4). Results from modeling indicate that for cadmium, remediation of the primary point‐source adit discharges should be sufficient to achieve acute and chronic water‐quality standards under both high‐ and low‐flow conditions. To achieve standards for copper and zinc, however, the modeling scenarios suggest that it may be necessary to treat or remove contaminated streambed sediments in downstream reaches, as well as identify and treat nonpoint sources of metals. Recommendations for improvements to the model for metal transport in acid‐mine drainage impacted streams are made. These recommendations are being implemented by the U.S. Environmental Protection Agency. © 2009 Wiley Periodicals, Inc. 相似文献
959.
Brian S. Caruso Timothy J. Cox 《Journal of the American Water Resources Association》2008,44(3):535-551
Abstract: The effects of natural flow restoration on metals fate and transport in the Upper Tenmile Creek Watershed, Montana, were modeled using the Water Quality Analysis Simulation Program developed by the U.S. Environmental Protection Agency (USEPA). This 50‐km2 watershed has over 150 historic abandoned mines, including mine waste rock and tailings, as well as adits discharging acid mine drainage, and is the primary drinking water supply for the City of Helena. Water supply diversions almost completely dewater some stream reaches during summer low flows, but the city is considering a new drinking water source and restoration of natural flows in Tenmile Creek as part of acid mine drainage remediation and broader aquatic habitat restoration. One dimensional steady‐state simulation of total recoverable cadmium, copper, lead, and zinc in the mainstem was performed, and the model was calibrated to June 2000 base‐flow data. Representative low‐flows in August and high‐flow snowmelt conditions in June were modeled using mean monthly natural flow estimates from the U.S. Geological Survey and representative USEPA metals concentrations data. The modeling showed that total recoverable metals concentrations, and especially loads, can vary significantly among input locations and over time in the watershed. Some data gaps limit evaluation of variability and increase uncertainty in several locations. Model results indicated, however, that natural low‐ and high‐flow restoration by itself can reduce some metals concentrations in the mainstem compared to June 2000 values, which were influenced by significant water diversion. Some values (such as Zn) may still exceed standards during natural August low flow due to the remaining high concentrations and loads in the primary inputs to the mainstem. Others (such as Cu) can increase during high flow due to remaining mine waste sources and loading of particulate Cu associated with erosion and transport of solids. Greater than 50% reduction in concentrations and loads from some of the main tributaries may be necessary to meet all standards, especially for potential particulate loads with higher flows in June. 相似文献
960.
Wernham CV Etheridge B Holling M Riddle G Riley HT Stirling-Aird PK Stroud D Thompson DB Wilson JD 《Ambio》2008,37(6):460-465
The Scottish Raptor Monitoring Scheme (SRMS) comprises 7 partner organizations and was established in 2002 after i) the publication of the UK Government's Raptor Working Group Report that made recommendations for enhanced monitoring, ii) increased applied data needs (e.g., for site designation), and iii) concerns for the status of some species. The SRMS has 3 major objectives: i) to facilitate cooperation between parties; ii) to provide robust information on Scottish raptor populations by determining trends in numbers, range, survival, and productivity and understanding the causes of change; and iii) to maintain high and uniform standards for the collection, collation, auditing, and analysis of data and reporting of information. Data are collected for 19 species: 14 diurnal raptors, 4 owls, and 1 corvid, the Common Raven. Here we describe the development of the scheme, challenges, and achievements during its first 4 y, the nature and value of the data collected, and plans for the future. 相似文献