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371.
Reinhold Castensson Ian C. Goulter 《Journal of the American Water Resources Association》1988,24(6):1153-1160
ABSTRACT: Irrigation permits in the Svartå River basin, Sweden, are issued with restricted validities by which irrigation is permitted only in those periods when the release from the primary regulation facility in the basin is greater than 2.0 m3/s. A “risk” measure describing the expected total duration of periods in which irrigation will not be permitted in the basin under a range of conditions has been formulated and applied to the basin. The measure recognizes only the period for which irrigation is not permitted and does not consider water availability as it is not a factor in this case. Comparison of the measure with a previously proposed approach shows that it provides a better measure of system behavior. The new measure is particularly useful for transferring to the nontechnical water user or manager an understanding of how well the overall irrigation system can be expected to perform. 相似文献
372.
373.
A. Ian McLeod Keith W. Hipel Fernando Comancho 《Journal of the American Water Resources Association》1983,19(4):537-547
ABSTRACT A general methodology is described for identifying and statistically modeling trends which may be contained in a water quality time series. A range of useful exploratory data analysis tools are suggested for discovering important patterns and statistical characteristics of the data such as trends caused by external interventions. To estimate the entries in an evenly spaced time series when data are available at irregular time intervals, a new procedure based upon seasonal adjustment is described. Intervention analysis is employed at the confirmatory data analysis stage to rigorously model changes in the mean levels of a series which are identified using exploratory data analysis techniques. Furthermore, intervention analysis can be utilized for estimating missing observations when they are not too numerous. The effects of cutting down a forest upon various water quality variables and also the consequences of acid rain upon the alkalinity in a stream provide illustrative applications which demonstrate the effectiveness of the methodology. 相似文献
374.
An in situ erosion flume was used to measure the stability of sediment deposits in Hamilton Harbour, Ontario, Canada. The flume consists
of a rectangular duct with an opening at the bottom. A submerged pump attached to the downstream end of the flume circulates
the ambient water through the flume, thereby generating turbulent shear flows inside the flume. When the flume rests on a
sediment deposit, the exposed part of the sediment deposit is subjected to the flow shear stress. By applying a continually
increasing flow shear stress on the sediment deposit and by measuring the amount of sediment erosion, it is possible to assess
the erosional stability of the sediment deposits. An under water video camera was mounted on the flume to get visual images
of the sediment erosion process. The flume was used at two sites in the Harbour. The erosional resistances measured by the
flume for the two sites were different. Measurement of dry density of the sediment deposits using an ultrasonic device was
carried out to explain the differences in the stability of sediment deposits from the two sites. 相似文献
375.
Madhumita Mahalanabis Kelly A. Reynolds Ian L. Pepper Charles P. Gerba 《Food and environmental virology》2010,2(4):225-230
The goal of this study was to determine if a cytopathogenic effects (CPE) cell culture assay and an integrated cell culture
PCR (ICC-PCR) assay would yield similar or different results when used to assess virus survival in water. Poliovirus type
1 was added to dechlorinated tapwater and stored at room temperature (22.5–24°C) for a total of 50 days. Samples were assayed
at defined time intervals by the most probable number (MPN) method on Buffalo green monkey kidney cells (BGM) by CPE and additionally
by ICC-PCR. Monolayers that were CPE negative on first passage were passed onto fresh monolayers of cells for a second and
third time if still negative. By CPE assay, second passage was observed to yield a greater titer (2,300 vs. 24,000 MPN/ml)
and third passage also resulted in an increased titer. ICC-PCR proved to be a more rapid and sensitive method than conventional
cell culture for determining virus inactivation rates in water. Poliovirus survived in tapwater for up to 32 days, as assessed
by both third passage ICC-PCR and CPE. There was no statistical difference in the inactivation rates between the two methods.
To determine the total number of infectious viruses, these findings indicate the need for performing three cell culture passages
or, alternatively, ICC-PCR on first passage. 相似文献
376.
377.
Ayesha I. T. Tulloch Micha V. Jackson Elisa Bayraktarov Alexander R. Carey Diego F. Correa-Gomez Michael Driessen Ian C. Gynther Mel Hardie Katherine Moseby Liana Joseph Harriet Preece Andrés Felipe Suarez-Castro Stephanie Stuart John C. Z. Woinarski Hugh P. Possingham 《Conservation biology》2023,37(2):e14032
Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35–5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals. 相似文献
378.
Ryan A. Wymore Tamzen W. Macbeth Joseph S. Rothermel Lance N. Peterson Lee O. Nelson Kent S. Sorenson Naji Akladiss Ian R. Tasker 《补救:环境净化治理成本、技术与工艺杂志》2006,16(4):5-22
An Interstate Technology and Regulatory Council (ITRC) forum was recently held that focused on case studies in which bioremediation of dense nonaqueous‐phase liquids (DNAPLs) was performed. This first case study, the Test Area North (TAN) site of the Idaho National Engineering and Environmental Laboratory, involves a trichloroethene (TCE) residual source area in a deep, fractured basalt aquifer that has been undergoing enhanced bioremediation since January 1999. Complete dechlorination from TCE to ethene was documented within nine months of operation, and sodium lactate injections were shown to enhance TCE mass transfer from the residual source. Since that time, optimization of injection strategies has maintained efficient dechlorination while demonstrating accelerated cleanup at a lower cost by changing to a whey powder amendment that solubilizes DNAPL. © 2006 Wiley Periodicals, Inc. 相似文献
379.
Ian Johnston 《Safety Science》2010,48(9):1175-1181
Forecasts of an “explosion” in the level of road trauma as many of the world’s most populous nations rapidly motorise have contributed to the urgency of documenting best practice thinking and management systems to improve road safety performance. By examining the success stories of nations with either the lowest fatailty rates per head of population or with the largest recent improvements a number of “lessons” have emerged. Data-driven problem identification and the development of evidence-driven countermeasure packages formalised in a strategy for effective implementation, with ambitious, quantitative targets and transparent lines of institutional accountability are the critical success factors. Basing this planning upon the cornerstones of the safe system conceptual model constitutes best practice thinking. This paper argues that critical elements of the safe system model are in discord with behavioural mores in the cultures of many western motorised nations and that this hampers the adoption of the most effective safety programs within key institutions and within political systems. A case is made for a systematic examination of car use and safety cultures in order to add a further dimension to best practice learnings. 相似文献
380.
Ian Shaw Emma Burke Frans Suharyanto Geertruida Sihombing 《Environmental science and pollution research international》2000,7(2):75-77
Milk from Indonesian women (n = 4) was analysed for p,p’-DDT and the fungicide, hexachlorobenzene (HCB). p,p’-DDT was found in all of the samples and at levels that are amongst the highest reported anywhere in the world in 3 of the samples. HCB was found in all 4 samples, 1 sample had an exceptionally high level. The high residue of HCB suggested exposure by eating dressed grain, major environmental contamination or direct exposure when handling the fungicide. These are the first data on pesticide residues in milk from Indonesian women which demonstrate general exposure to p,p’-DDT and HCB. 相似文献