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581.
Ronald A. Chadderton 《Journal of the American Water Resources Association》1988,24(1):183-187
ABSTRACT: A hypothetical, although realistic, water pollution problem was studied from a property rights viewpoint. Theoretical and economic justifications were developed. A fully-liable, private owner was found to be financially profitable while improving the water quality and providing recreational potential. The example confirmed that property rights provides an answer to stream pollution problems, but contradicted the view that water pollution control must be justified by recreational benefits. 相似文献
582.
Ronald C. Flemal Monte M. Nienkerk 《Journal of the American Water Resources Association》1976,12(3):501-510
ABSTRACT Using water analyses from 67 gaging stations, discharge-frequency-weighted mean concentrations (QFC) and average annual yield (AAY) per unit area were determined for the total dissolved mineral content of Illinois streams. The resultant data indicates that total dissolved mineral contents are controlled by regional rather than local factors. In most cases plausible explanation for the magnitudes can be found in regional patterns of natural and demographic conditions. Although the data suggest that total dissolved minerals are increasing, the relative contributions of natural versus anthropogenic phenomena are difficult to delimit at this level of investigation. 相似文献
583.
Beth Lemberg James W. Mjelde J. Richard Conner Ronald C. Griffin Wesley D. Rosenthal Jerry W. Stuth 《Journal of the American Water Resources Association》2002,38(2):409-422
ABSTRACT: An analytic methodology utilizing models from three disciplines is developed to assess the viability of brush control for water yield in the Frio River basin, Texas. Ecological, hydrologic, and economic models are used to portray changes in forage production and water supply resulting from brush control, and to value supplemental water produced through brush control. Site‐specific biophysical characteristics are used to simulate water yields from brush control across the watershed. Economic benefits from increased animal production for ranchers undertaking brush control are assessed. Benefits to Corpus Christi residential water consumers from ranchers' brush control activities are evaluated using the change in consumer surplus resulting from supplemental water produced through brush control. Results indicate an increase in water yield with brush control on 35 percent of the land area in the basin. However, the cost of brush control is more than the increase in returns it fosters on most range sites. Consumer surplus change for Corpus Christi residents over 25 years is zero under baseline conditions, implying subsidies for brush control in the Frio basin are not worthwhile at this time. 相似文献
584.
Engagement, broadly defined as involvement, satisfaction, and enthusiasm, is widely used by organizations and consultants for improving retention. However, engagement fails to meet many of the common criteria for positive organizational practice, i.e. theoretical, valid, unique, state‐like, and positive. With attention to these criteria, engagement may useful to management. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
585.
This study focused on irreversible fouling during microfiltration of primary and secondary effluents from municipal wastewater treatment plants. Flow resistances were calculated from the sum of clean membrane resistances, resultant cake layer resistances, and consequent irreversible fouling resistances. Results from a dead-end cell experimental system showed that the accumulated cake resistance was dominating for microfiltration of primary/secondary effluents. Suspended solids in the primary and secondary effluents had a similar compressibility index, n, with a value of approximately 0.5, indicating that they were moderately compressible particles. The value of irreversible resistance is dependent on the intensity of membrane cleaning; however, for a given membrane cleaning strategy, this value steadily increased and reached a maximum after approximately 6 cycles of filtration and cleaning. This study provided an explanation for the significant drop of throughput flux in the early application of membrane processes, and a plateau flux approached correspondingly. 相似文献
586.
587.
Sunayna Best Karen Wou Neeta Vora Ignatia B. Van der Veyver Ronald Wapner Lyn S. Chitty 《黑龙江环境通报》2018,38(1):10-19
Prenatal genetic diagnosis provides information for pregnancy and perinatal decision-making and management. In several small series, prenatal whole exome sequencing (WES) approaches have identified genetic diagnoses when conventional tests (karyotype and microarray) were not diagnostic. Here, we review published prenatal WES studies and recent conference abstracts. Thirty-one studies were identified, with diagnostic rates in series of five or more fetuses varying between 6.2% and 80%. Differences in inclusion criteria and trio versus singleton approaches to sequencing largely account for the wide range of diagnostic rates. The data suggest that diagnostic yields will be greater in fetuses with multiple anomalies or in cases preselected following genetic review. Beyond its ability to improve diagnostic rates, we explore the potential of WES to improve understanding of prenatal presentations of genetic disorders and lethal fetal syndromes. We discuss prenatal phenotyping limitations, counselling challenges regarding variants of uncertain significance, incidental and secondary findings, and technical problems in WES. We review the practical, ethical, social and economic issues that must be considered before prenatal WES could become part of routine testing. Finally, we reflect upon the potential future of prenatal genetic diagnosis, including a move towards whole genome sequencing and non-invasive whole exome and whole genome testing. © 2017 John Wiley & Sons, Ltd. 相似文献
588.
Steven M. Lipson Fatma S. Ozen Laina Karthikeyan Ronald E. Gordon 《Food and environmental virology》2012,4(4):168-178
Cranberry (Vaccinium macrocarpon) and grape (Vitis labrusca) juices, and these species?? secondary plant metabolites [i.e., proanthocyanidins (PACs)] possess antiviral activity. An understanding of the mechanism(s) responsible for these juices and their polyphenolic constituents?? direct effect on enteric virus integrity, however, remains poorly defined. Using the rotavirus (RTV) as a model enteric virus system, the direct effect of manufacturer-supplied and commercially purchased juices [Ocean Spray Pure Cranberry 100?% Unsweetened Juice (CJ), Welch??s 100?% Grape Juice (GJ), 100?% Concord (PG) and 100?% Niagara juices (NG)] and these species?? cranberry (C-PACs) and grape PACs (G-PACs) was investigated. Loss of viral capsid integrity in cell-free suspension by juices and their PACs, and as a factor of pH, was identified by an antigen (RTV) capture enzyme-linked immunosorbent assay. At native and an artificially increased suspension at or near pH 7, loss of viral infectivity occurred after 5?min, in the order CJ?>?NG?=?GJ?>?PG, and PG?>?GJ?=?NG?=?CJ, respectively. Antiviral activity of CJ was inversely related to pH. Grape, but not cranberry PACs, displayed a comparatively greater anti-RTV activity at a suspension pH of 6.7. Anti-RTV activity of C-PACs was regained upon reduction of RTV-cranberry PAC suspensions to pH 4. An alteration or modification of Type A PAC (of V. macrocarpon) structural integrity at or near physiologic pH is suggested to have impacted on this molecule??s antivirus activity. Type B PACs (of V. labrusca) were refractive to alternations of pH. Significantly, findings from pure system RTV?CPAC testing paralleled and in turn, supported those RTV-juice antiviral studies. Electron microscopy showed an enshroudment by PACs of RTV particles, suggesting a blockage of viral antigenic binding determinants. The implications of our work are significant, especially in the interpretation of PAC (and PAC-containing food)?CRTV interactions in the differing [pH] conditions of the gastrointestinal tract. 相似文献
589.
Ronald L. Mersky 《Journal of Material Cycles and Waste Management》2009,11(4):321-327
Vehicle queuing at municipal solid waste (MSW) facilities causes economic and environmental damage. In the United States,
typical MSW receiving facilities (transfer, recycling, energy recovery, and landfill) have three queues: one at the entrance
weighing station, one at the waste tipping location, and one at the exit weighing station. A common method of determining
queue behavior relies on equations that assume exponentially distributed arrival and service times, but there has not been
a comprehensive study to determine whether this assumption is valid for a variety of MSW facilities and conditions. In this
study, data were gathered from two transfer stations, two energy recovery plants, and one transfer/landfill facility. Among
the five facilities there was a variety of queuing styles. The data were plotted as an inverse exponential relationship and
linearized. The linearized plots were regressed and R
2 values were calculated. It was determined that the negative exponential relationship can be used to describe arrival times
at all three queues and service times at weighing queues. The queuing equations are therefore theoretically supported for
use at entering and exiting weighing queues and moderately theoretically supported for use at tipping queues. 相似文献
590.
Ronald G Cummings William D Schulze Arthur F Mehr 《Journal of Environmental Economics and Management》1978,5(3):252-267
The primary concern of this paper is the use of wage-infrastructure trade-offs as a measure for the social benefits of municipal infrastructure in boomtowns. A regression based on pooled cross sectional and time series data for 26 towns in the Rocky Moutain region suggests that individuals will “trade off” a 1% increase in per capita stocks of municipal infrastructure for a 0.035% decline in wages. These results are then used to calculate “optimal” levels of infrastructure investment for an example boomtown. 相似文献