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251.
252.
/ Mechanized military maneuvers are an intensive form of disturbance to plant communities in large areas throughout the world. Tracking by heavy vehicles can cause direct mortality and indirectly affect plant communities through soil compaction and by altering competitive relationships. We assessed the long-term condition of structural attributes of open woodland, grassland, and shrubland communities at Fort Carson, Colorado, in relation to levels of disturbance and soil texture. Covariate analyses were used to help separate the directional forcings by the chronic disturbance from the regenerative capacities in order to assess the relative resistance and resilience of the communities and to determine whether the continual disturbance-recovery processes balanced under current levels of utilization. All three communities responded differently to disturbance. In open woodlands, altered understory/overstory relationships were suggested by increased grass, forb, shrub, and total vegetation cover and smaller decreases in shorter than taller woody species with increasing levels of disturbance. Grassland communities generally displayed greater responses to disturbance than other communities, but temporal dynamics were often similar, indicating relatively less resistance but greater resilience of this community. Weed and exotic species increased both temporally and in relation to levels of disturbance in all three community types. Temporal trends in community-level indices of dissimilarity and diversity also indicate that rates of disturbance were greater than rates of recovery. Few variables were related to within-community differences in soil texture. While total aerial cover was temporally stable, changes in species composition and in basal cover in grasslands and shrublands suggest increasing erosion potential. 相似文献
253.
Understanding the processes that determine the solid-liquid partitioning (K(d) value) of Se is of fundamental importance in assessing the risk associated with the disposal of radio-selenium-containing waste. Using a mini-column (rather than batch) approach, K(d) values for (75)Se were determined over time in relation to soil moisture content (field capacity or saturated), redox potential and methyl bromide fumigation (used to disrupt the soil microbial population) in three contrasting soil types: clay loam, organic and sandy loam. The K(d) values were generally in the range 50-500 L kg(-1), with mean soil K(d) increasing with increasing organic matter content. Saturation with water lowered the measured redox potentials in the soils. However, only in the sandy loam soil did redox potential become negative, and this led to an increase in (75)Se K(d) value in this soil. Comparison of the data with the Eh-pH stability diagram for Se suggested that such strong reduction may have been consistent with the formation of the insoluble Se species, selenide. These findings, coupled with the fact that methyl bromide fumigation had no discernible effect on (75)Se K(d) value in the sandy loam soil, suggest that geochemical, rather than microbial, processes controlled (75)Se partitioning. The inter-relations between soil moisture content, redox potential and Se speciation should be considered in the modelling and assessment of radioactive Se fate and transport in the environment. 相似文献
254.
Increased education of consumers can be an effective tool for conservation of commercially harvested marine species when product labeling is accurate and allows an informed choice. However, generic labeling (e.g., as white fish or surimi) and mislabeling of seafood prevents this and may erode consumer confidence in seafood product labels in general. We used DNA barcoding to identify the species composition of two types of convenience seafood (i.e., products processed for ease of consumption): fish fingers (long pieces of fish covered with bread crumbs or batter, n = 241) and seafood sticks (long pieces of cooked fish, n = 30). In products labeled as either white fish or surimi, four teleost species were present. Less than 1.5% of fish fingers with species-specific information were mislabeled. Results of other studies show substantially more mislabeling (e.g., >25%) of teleost products, which likely reflects the lower economic gains associated with mislabeling of convenience seafood compared with whole fillets. In addition to species identification, seafood product labels should be required to contain information about, for example, harvesting practices, and our data indicate that consumers can have reasonable confidence in the accuracy of the labels of convenience seafood and thus select brands on the basis of information about current fisheries practice. 相似文献
255.
Conservation of biologically diverse regions has thus far been accomplished largely through the establishment and maintenance of protected areas. Climate change is expected to shift climate space of many species outside existing reserve boundaries. We used climate-envelope models to examine shifts in climate space of 11 species that are representative of the Mount Hamilton Project area (MHPA) (California, U.S.A.), which includes areas within Alameda, Santa Clara, San Joaquin, Stanislaus, Merced, and San Benito counties and is in the state's Central Coast ecoregion. We used Marxan site-selection software to determine the minimum area required as climate changes to achieve a baseline conservation goal equal to 80% of existing climate space for all species in the MHPA through 2050 and 2100. Additionally, we assessed the costs associated with use of existing conservation strategies (land acquisition and management actions such as species translocation, monitoring, and captive breeding) necessary to meet current species-conservation goals as climate changes. Meeting conservation goals as climate changes through 2050 required an additional 256,000 ha (332%) of protected area, primarily to the south and west of the MHPA. Through 2050 the total cost of land acquisition and management was estimated at US$1.67-1.79 billion, or 139-149% of the cost of achieving the same conservation goals with no climate change. To maintain 80% of climate space through 2100 required nearly 380,000 additional hectares that would cost $2.46-2.62 billion, or 209-219% of the cost of achieving the same conservation goals with no climate change. Furthermore, maintaining 80% of existing climate space within California for 27% of the focal species was not possible by 2100 because climate space for these species did not exist in the state. The high costs of conserving species as the climate changes-that we found in an assessment of one conservation project-highlights the need for tools that will aid in iterative goal setting given the uncertainty of the effects of climate change and adaptive management that includes new conservation strategies and consideration of the long-term economic costs of conservation. 相似文献
256.
There is a general lack of knowledge as regards the effects of climate change on pollutant behavior. This is particularly true of the Asia-Pacific Region (APR). This region has major significance in terms of global pollutant emission and also displays a wide variety of environments. This review presents the authors’ opinions on possible implications of climate change for pollutant behavior in the APR. Although differing responses can be expected across the region, there are clear implications as regards the short- and long-term behavior of pollutants. Effects can be predicted through modeling, but further data are required for model calibration. Nevertheless, it can be predicted that climate change will affect processes including global distillation of persistent organic pollutants, airborne transport of heavy metals, half-life of readily degradable pollutants, and eutrophication in water bodies. Particulates are expected to play a central role in mediating the effects of climate change, and successful predictive models will need to be based on particulate-mediated transport and behavior. Climate change also has the potential to cause an increase in the intensity and frequency of harmful algal blooms in aquatic environments throughout the region, with significant implications for supply of both food and drinking water. 相似文献
257.
Disasters and environmental degradation create serious problems all around the world. They are inherently linked, but little attention is paid to their interaction, particularly at local levels. The degree of integration of disaster management and risk analysis with environmental management programs in relation to human vulnerability has been examined in Thua Thien Hue Province, Central Viet Nam. Unsustainable agricultural practices, and inappropriate development programs have contributed substantially to the increase of disaster risks. On the other hand, disasters damage natural resources and reduce environmental quality, indirectly contributing to increasing poverty which in turn, adds to the vulnerability of both natural and human systems, so further increasing disaster losses. Notwithstanding, in Viet Nam, there is a big gap between disaster and environment management policies and programs. In order to bridge the gap, an integrated approach in which environment-disaster linkage, rural—urban linkage, and poverty are brought into focus as core aspects of disaster management. 相似文献
258.
J. O’Reilly M. J. Watts R. A. Shaw A. L. Marcilla N. I. Ward 《Environmental geochemistry and health》2010,32(6):491-515
Arsenic (As) speciation in surface and groundwater from two provinces in Argentina (San Juan and La Pampa) was investigated using solid phase extraction (SPE) cartridge methodology with comparison to total arsenic concentrations. A third province, Río Negro, was used as a control to the study. Strong cation exchange (SCX) and strong anion exchange (SAX) cartridges were utilised in series for the separation and preservation of arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MAV) and dimethylarsinic acid (DMAV). Samples were collected from a range of water outlets (rivers/streams, wells, untreated domestic taps, well water treatment works) to assess the relationship between total arsenic and arsenic species, water type and water parameters (pH, conductivity and total dissolved solids, TDS). Analysis of the waters for arsenic (total and species) was performed by inductively coupled plasma mass spectrometry (ICP-MS) in collision cell mode. Total arsenic concentrations in the surface and groundwater from Encon and the San José de Jáchal region of San Juan (north-west Argentina within the Cuyo region) ranged from 9 to 357 μg l?1 As. Groundwater from Eduardo Castex (EC) and Ingeniero Luiggi (LU) in La Pampa (central Argentina within the Chaco-Pampean Plain) ranged from 3 to 1326 μg l?1 As. The pH range for the provinces of San Juan (7.2–9.7) and La Pampa (7.0–9.9) are in agreement with other published literature. The highest total arsenic concentrations were found in La Pampa well waters (both rural farms and pre-treated urban sources), particularly where there was high pH (typically > 8.2), conductivity (>2,600 μS cm?1) and TDS (>1,400 mg l?1). Reverse osmosis (RO) treatment of well waters in La Pampa for domestic drinking water in EC and LU significantly reduced total arsenic concentrations from a range of 216–224 μg l?1 As to 0.3–0.8 μg l?1 As. Arsenic species for both provinces were predominantly AsIII and AsV. AsIII and AsV concentrations in San Juan ranged from 4–138 μg l?1 to <0.02–22 μg l?1 for surface waters (in the San José de Jáchal region) and 23–346 μg l?1 and 0.04–76 μg l?1 for groundwater, respectively. This translates to a relative AsIII abundance of 69–100% of the total arsenic in surface waters and 32–100% in groundwater. This is unexpected because it is typically thought that in oxidising conditions (surface waters), the dominant arsenic species is AsV. However, data from the SPE methodology suggests that AsIII is the prevalent species in San Juan, indicating a greater influence from reductive processes. La Pampa groundwater had AsIII and AsV concentrations of 5–1,332 μg l?1 and 0.09–592 μg l?1 for EC and 32–242 μg l?1 and 30–277 μg l?1 As for LU, respectively. Detectable levels of MAV were reported in both provinces up to a concentration of 79 μg l?1 (equating to up to 33% of the total arsenic). Previously published literature has focused primarily on the inorganic arsenic species, however this study highlights the potentially significant concentrations of organoarsenicals present in natural waters. The potential for separating and preserving individual arsenic species in the field to avoid transformation during transport to the laboratory, enabling an accurate assessment of in situ arsenic speciation in water supplies is discussed. 相似文献
259.
Casey Stevens 《国际发展与全球生态学杂志》2018,25(1):1-8
Efforts at integration are central in the Sustainable Development Goals and the wider Post-2015 Sustainable Development Agenda. While integration forms a major focus of this agenda, there are fundamental limitations on pursuing this focus. The global governance discussions on integration lack a clear conceptualization of what it is, do not have any tools for measurement or assessment, and are narrowly focused around policy integration between global institutions. This article develops a framework for conceptualizing cross-level and cross-scale integration which addresses these problems and introduces the opportunities and challenges of pursuing different types of integration in global governance. Cross-level integration involves governance efforts which seek to bridge similar institutions with one another (for example, bringing together efforts by environmental ministries and development ministries). Cross-scale integration, in contrast, deals with governance efforts that bring together institutions which have distinct scopes, jurisdictions, and epistemologies. With this important distinction, the article explores the opportunities for cross-scale integration as part of the global sustainable development efforts and particularly expanding the policy integration focus with spatial and temporal integration as well. The conclusion uses the Earth System Governance perspective to focus on the trade-offs that are likely as wider forms of institutional integration are pursued beyond environmental mainstreaming and policy integration. 相似文献
260.
Several researchers have examined the role of microfinance institutions (MFIs) in poverty alleviation, but the part that they play in disaster risk reduction remains unaddressed. Through an empirical study of Hatiya Island, one of the most vulnerable coastal communities of Bangladesh, this research evaluates perceptions of MFI support for the disaster risk reduction, response, and recovery process. The findings reveal no change in relation to risk reduction and income and occupation aspects for more than one‐half of the clients of MFIs. In addition, only 26 per cent of them have witnessed less damage as a result of being members of MFIs. One can argue, though, that the longer the membership time period the better the disaster preparedness, response, and recovery process. The outcomes of this study could help to guide the current efforts of MFIs to enhance the ability of coastal communities to prepare for and to recover from disasters efficiently and effectively. 相似文献