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RAMP I is a screening tool developed to support practitioners in screening for work-related musculoskeletal disorder risk factors related to manual handling. RAMP I, which is part of the RAMP tool, is based on research-based studies combined with expert group judgments. More than 80 practitioners participated in the development of RAMP I. The tool consists of dichotomous assessment items grouped into seven categories. Acceptable reliability was found for a majority of the assessment items for 15 practitioners who were given 1?h of training. The usability evaluation points to RAMP I being usable for screening for musculoskeletal disorder risk factors, i.e., usable for assessing risks, being usable as a decision base, having clear results and that the time needed for an assessment is acceptable. It is concluded that RAMP I is a usable tool for practitioners.  相似文献   
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The paper examines how a public wastewater treatment plant balances objectives of cost minimization and pollution prevention. The parameters of the objective function and state equation in an optimal control model are estimated using maximum entropy and time series observations of water quality and expenditures for wastewater treatment. The estimation method does not require restrictions needed by other techniques used to estimate nonlinear, ill-posed problems. The parameter estimates indicate that the treatment plant emphasizes water quality enhancement over cost minimization. Results from the sensitivity analysis show that the plant favors conventional treatment over pollution prevention.  相似文献   
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Supportive Breeding and Variance Effective Population Size   总被引:2,自引:0,他引:2  
The practice of supporting weak, wild populations through release of individuals bred in captivity is becoming an increasingly important conservation measure. A frequently recommended form of such breeding-release activity refers to supportive breeding: a fraction of the target population is brought into captivity for reproduction, and the resulting progeny are released to mix with the wild segment of the population. We derived an expression for the variance effective size of a population managed through supportive breeding and discuss its relationship to previously published equations that are based on the assumption of random mating. We show that the effect of supportive breeding may be quite different on the inbreeding and the variance effective sizes. Whereas supportive breeding always results in a reduction of the inbreeding effective number, the variance effective number may either decrease, increase, or remain unchanged. We discuss these observations in relation to conservation management and suggest some general guidelines for supportive breeding situations. Our recommendations include making a distinction between inbreeding and variance effective numbers; taking particular care when dealing with organisms with high reproductive potential; assuring that the amount of drift be no larger than it would be without supportive breeding; and focusing primarily on the variance effective size of a population-that is, on the effective number directly related to the rate of loss of gene diversity.  相似文献   
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To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s average) for sulphate (SO4), inorganic nitrogen (NO3-N; NH4-N), calcium (Ca), magnesium (Mg) and potassium (K) were synthesised for 21 forested catchments from 17 regions in Canada, the United States and Europe. Trend analysis was conducted on monthly ion concentrations in deposition and runoff when more than 9 years of data were available (14 regions, 17 sites). Annual average SO4 deposition during the 1990s ranged between 7.3 and 28.4 kg ha−1 per year, and inorganic nitrogen (N) deposition was between 2.8 and 13.8 kg ha−1 per year, of which 41–67% was nitrate (NO3-N). Over the period of record, SO4 concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO4 in runoff decreased at 14/17 catchments. In contrast, NO3-N concentrations in deposition decreased in only 1/14 regions, while NH4-N concentration patterns varied; increasing at 3/14 regions and decreasing at 2/14 regions. Nitrate concentrations in runoff decreased at 4/17 catchments and increased at only 1 site, whereas runoff levels of NH4-N increased at 5/17 catchments. Decreasing trends in deposition were also recorded for Ca, Mg, and K at many of the catchments and on an equivalent basis, accounted for up to 131% (median 22%) of the decrease in acid anion deposition. Base cation concentrations in streams generally declined over time, with significant decreases in Ca, Mg and K occurring at 8, 9 and 7 of 17 sites respectively, which accounted for up to 133% (median 48%) of the decrease in acid anion concentration. Sulphate export exceeded input at 18/21 catchments, likely due to dry deposition and/or internal sources. The majority of N in deposition (31–100%; median 94%) was retained in the catchments, although there was a tendency for greater NO3-N leaching at sites receiving higher (<7 kg ha-1 per year) bulk inorganic N deposition. Mass balance calculations show that export of Ca and Mg in runoff exceeds input at all 21 catchments, but K export only exceeds input at 16/21 sites. Estimates of base cation weathering were available for 18 sites. When included in the mass balance calculation, Ca, Mg and K exports exceeded inputs at 14, 10 and 2 sites respectively. Annual Ca and Mg losses represent appreciable proportions of the current exchangeable soil Ca and Mg pools, although losses at some of the sites likely occur from weathering reactions beneath the rooting zone and there is considerable uncertainty associated with mineral weathering estimates. Critical loads for sulphur (S) and N, using a critical base cation to aluminium ratio of 10 in soil solution, are currently exceeded at 7 of the 18 sites with base cation weathering estimates. Despite reductions in SO4 and H+ deposition, mass balance estimates indicate that acid deposition continues to acidify soils in many regions with losses of Ca and Mg of primary concern. The U.S. Government's right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.  相似文献   
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Exposure to asphalt fumes has a threshold limit value (TLV of 0.5 mg m(-3) (benzene extractable inhalable particulate) as recommended by the American Conference of Governmental Industrial Hygienists (ACGIH). This reflects a recent change (2000) whereby two variables are different from the previous recommendation. First is a 10-fold reduction in quantity from 5 mg m(-3) to 0.5 mg m(-3). Secondly, the new TLV specifies the "inhalable" fraction as compared to what is presumed to be total particulate. To assess the impact of these changes, this study compares the differences between measurements of paving asphalt fume exposure in the field using an "inhalable" instrument versus the historically used 'total' sampler. Particle size is also examined to assist in the understanding of the aerodynamic collection differences as related to asphalt fumes and confounders. Results show that when exposures are limited to asphalt fumes, a 1:1 relationship exists between samplers, showing no statistically significant differences in benzene soluble matter (BSM). This means that for the asphalt fume ACGIH TLV, the 'total' 37-mm sampler is an equivalent method to the "inhalable" method, referred to as IOM (Institute of Occupational Medicine), and should be acceptable for use against the TLV. However, the study found that when confounders (dust or old asphalt millings) are present in the workplace, there can be significant differences between the two samplers' reported exposure. The ratio of IOM/Total was 1.37 for milling asphalt sites, 1.41 for asphalt paving over granular base, and 1.02 for asphalt over asphalt pavements.  相似文献   
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一个农业系统若要是可持续的,好的动物福利是必不可少的.尽管自从我们一开始驯养动物,对它们的健康和繁殖产生依赖,我们就一直在关注动物福利问题,但本文的焦点主要集中在自20世纪60年代以来围绕动物福利的争论的进展上.它将动物福利作为一门由一个社会关注的动物饲养方式问题演化而来的科学来呈现.而这些道德伦理上的关注使得动物福利的价值架构也必须被考虑在内.随着这一领域研究的不断发展,不同的动物福利的定义和研究实例被提出和讨论.比如,近几年来,消费者对动物友好产品(animal-friendly products)的消费方面的研究兴趣大增,一如过去的环境友好产品(environment friendly products);而这也刺激了研究重点从动物福利的实验研究转移至动物福利在实际中的应用和农场的动物福利监控上.传统上讲,这样的测量是基于资源的,比如计算最小饲养空间或者最大饲养密度,但现在的趋势是趋向于基于动物的测量,比如跛足动物的数量、身体状况等.  相似文献   
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The abundance patterns of ant communities were monitored with pitfall traps during 14 weeks in four northern California, dry farmed, apple orchards: an abandoned orchard undisturbed for 25 years, two ‘organically’ managed orchards, one with a cover crop of bell beans (Vicia faba) and grasses and the other kept clean of cover by discing, and a ‘commercial’ clean cultivated orchard sprayed with organophosphate insecticides. Six species of ants coexisted in the abandoned orchard, whereas only two species were found in the managed orchards. In both the organic and sprayed, clean cultivated systems, ants were more abundant in the orchard edges than in the vegetation-free centers. This trend was not apparent in the abandoned or organic cover orchards, where plant diversity in the center was similar to that of the edges. Ant predation on potato tuberworm larvae, Phthorimaea operculella, artificially placed on the orchard floor, declined with the intensity of management and vegetational simplication. A higher incidence of larval removal occurred in the edges than in the centers of the clean cultivated orchards. No noticeable populations of ants were detected on the trees in any of the orchards. Increased vegetational diversity and lack of disturbance appeared to affect ant locomotory activity and foraging efficiency by creating preferred sheltering and feeding sites.  相似文献   
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