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731.
Downscaling climate change scenarios in an urban land use change model 总被引:10,自引:0,他引:10
The objective of this paper is to describe the process through which climate change scenarios were downscaled in an urban land use model and the results of this experimentation. The land use models (Urban Growth Model [UGM] and the Land Cover Deltatron Model [LCDM]) utilized in the project are part of the SLEUTH program which uses a probabilistic cellular automata protocol. The land use change scenario experiments were developed for the 31-county New York Metropolitan Region (NYMR) of the US Mid-Atlantic Region. The Intergovernmental Panel on Climate Change (IPCC), regional greenhouse gas (GHG) emissions scenarios (Special Report on Emissions Scenarios (SRES) A2 and B2 scenarios) were used to define the narrative scenario conditions of future land use change. The specific research objectives of the land use modeling work involving the SLEUTH program were threefold: (1) Define the projected conversion probabilities and the amount of rural-to-urban land use change for the NYMR as derived by the UGM and LCDM for the years 2020 and 2050, as defined by the pattern of growth for the years 1960-1990; (2) Down-scale the IPCC SRES A2 and B2 scenarios as a narrative that could be translated into alternative growth projections; and, (3) Create two alternative future growth scenarios: A2 scenario which will be associated with more rapid land conversion than found in initial projections, and a B2 scenario which will be associated with a slower level of land conversion. The results of the modeling experiments successfully illustrate the spectrum of possible land use/land cover change scenarios for the years 2020 and 2050. The application of these results into the broader scale climate and health impact study is discussed, as is the general role of land use/land cover change models in climate change studies and associated environmental management strategies. 相似文献
732.
David Meko Charles W. Stockton W. R. Boggess 《Journal of the American Water Resources Association》1995,31(5):789-801
ABSTRACT: Frequent and persistent droughts exacerbate the problems caused by the inherent scarcity of water in the semiarid to arid parts of the southwestern United States. The occurrence of drought is driven by climatic variability, which for years before about the beginning of the 20th century in the Southwest must be inferred from proxy records. As part of a multidisciplinary study of the potential hydrologic impact of severe sustained drought on the Colorado River, the physical basis and limitations of tree rings as indicators of severe sustained drought are reviewed, and tree-ring data are analyzed to delineate a “worst-case” drought scenario for the Upper Colorado River Basin (UCRB). Runs analysis of a 121-site tree-ring network, 1600–1962, identifies a four-year drought in the 1660s as the longest-duration large-scale drought in the Southwest in the recent tree-ring record. Longer tree-ring records suggest a much longer and more severe drought in 1579–1598. The regression estimate of the mean annual Colorado River flow for this period is 10.95 million acre-feet, or 81 percent of the long-term mean. The estimated flows for the 1500s should be used with caution in impact studies because sample size is small and some reconstructed values are extrapolations. 相似文献
733.
Organochlorine pesticides in soils under different land usage in the
Taihu Lake region, China 总被引:11,自引:0,他引:11
WANG Fang JIANG Xin BIAN Yong-rong YAO Fen-xi GAO Hong-jian YU Gui-fen Jean Charles MUNCH Reiner SCHROLL 《环境科学学报(英文版)》2007,19(5):584-590
A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field > tree land > fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT >1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes. 相似文献
734.
Poonam R. Kulkarni Whitney R. Godwin Justin A. Long Ryan C. Newell Charles J. Newell 《补救:环境净化治理成本、技术与工艺杂志》2020,30(2):15-23
Over the past 10 years, there has been an increased recognition that matrix diffusion processes are a significant factor controlling the success of groundwater remediation. New field techniques and modeling tools have, consequently, been developed to understand how contaminants diffuse into and then out of low‐permeability (“low‐k”) zones and assess the resulting impact on groundwater quality. Matrix diffusion, in turn, is driven by one key factor: geologic heterogeneity. The importance of heterogeneity is being emphasized in the groundwater field by general rules of thumb such as “90% of the mass flux occurs in 10%‐20% of the cross‐sectional area” and conceptual models that show most of the groundwater flow occurs through the aquifer's “mobile porosity” which just a small fraction of commonly used effective porosity values (between 0.02 and 0.10 for mobile porosity vs. 0.25 for effective porosity). For this study, 141 boring logs from 43 groundwater remediation sites were evaluated to develop an empirically based estimate of the groundwater flow versus aquifer cross‐sectional area to confirm or reject the general flow versus area rules of thumb. This study indicated that at these 43 sites, an average of 30% of the cross‐sectional area carried 90% of the groundwater flow. Our flow‐only analysis does provide moderate (but not confirmatory) support for the “mobile porosity” concept with an estimated representative mobile porosity value of about 0.11 at the 43 sites. 相似文献
735.
Environmental Chemistry Letters - Antimicrobial resistance is a major health issue induced by the overuse of antibiotics and disinfection reagents, e.g. chlorine. Resistant bacteria thus occur in... 相似文献
736.
737.
Byung Joon Kim Charles J. Robinson 《International journal of occupational safety and ergonomics》2013,19(3):241-254
Postural control is a common mechanism to compensate for unexpected displacements of the body. In the older population, a slip or fall due to a failure of postural control is a common cause of morbidity and mortality. The ability of postural control decreases with aging or neuropathy. In this study, 2 groups, diabetics and non-diabetics in the older population, were compared to determine how patterns of postural sway during quiet standing were related to the detection of perturbation. The SLIP-FALLS system was applied to the measurement of sway and detection of perturbation. In phase 1 of the development of the predictive model, neural network algorithms were applied to find determinant variables for perturbation detection. In phase 2, a fuzzy logic inference system was developed to investigate the relationship between sway and perturbation detection. Results of this study may be applied to the design of floor mats or shoe insoles for preventing fatigue in workplaces. 相似文献
738.
739.
Elina Tampio Satu Ervasti Teija Paavola Sonia Heaven Charles Banks Jukka Rintala 《Waste management (New York, N.Y.)》2014,34(2):370-377
Anaerobic digestion of autoclaved (160 °C, 6.2 bar) and untreated source segregated food waste (FW) was compared over 473 days in semi-continuously fed mesophilic reactors with trace elements supplementation, at organic loading rates (OLRs) of 2, 3, 4 and 6 kg volatile solids (VS)/m3 d. Methane yields at all OLR were 5–10% higher for untreated FW (maximum 0.483 ± 0.013 m3 CH4/kg VS at 3 kg VS/m3 d) than autoclaved FW (maximum 0.439 ± 0.020 m3 CH4/kg VS at 4 kg VS/m3 d). The residual methane potential of both digestates at all OLRs was less than 0.110 m3 CH4/kg VS, indicating efficient methanation in all cases. Use of acclimated inoculum allowed very rapid increases in OLR. Reactors fed on autoclaved FW showed lower ammonium and hydrogen sulphide concentrations, probably due to reduced protein hydrolysis as a result of formation of Maillard compounds. In the current study this reduced biodegradability appears to outweigh any benefit due to thermal hydrolysis of ligno-cellulosic components. 相似文献
740.
Charles T. Driscoll Ashley Lee Mario Montesdeoca David A. Matthews Steven W. Effler 《Journal of the American Water Resources Association》2014,50(1):143-152
There is detailed literature on the mobilization of aluminum (Al) from soil to surface waters as a result of elevated acidic deposition to base‐poor forest watersheds. There is considerably less information on the mobilization and effects of Al from the application of alum that is used in some water supplies to control turbidity during high‐flow events. We report on the results of field measurements, laboratory sediment release experiments, and chemical equilibrium calculations conducted to evaluate the potential for the mobilization of Al from alum floc deposits in sediments of Kensico Reservoir, New York. Under ambient water quality conditions, mobilization of sediment Al is not a noteworthy concern at Kensico Reservoir. However, under experimental conditions of low pH, low acid neutralizing capacity (ANC), and low temperature, the inorganic fraction of monomeric Al can be mobilized from Kensico sediments to concentrations that would likely impair the health of aquatic organisms (>2 μmol/l). Elevated concentrations of monomeric Al were observed only when ANC decreased below 50 μeq/l, which is outside the range of values observed in Kensico during the 1997‐2007 interval (120‐460 μeq/l). Concentrations of complexing ligands are relatively low in Kensico waters (i.e., fluoride, naturally occurring organic solutes) and do not appear to substantially contribute to potential Al mobilization. For other water supplies with low ANC, the potential for sediment release of Al may exist. 相似文献