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41.
Environment Systems and Decisions - There is great value in understanding the public’s reactions to terror attacks, though such reactions pose stark challenges for sound psychological...  相似文献   
42.
Three endocrine disrupting chemicals (EDCs), triclosan (TCS), 4-n-nonylphenol (4-n-NP), and di-n-butyl phthalate (DBP) were determined using stir bar sorptive extraction (SBSE) along with high-performance liquid chromatography/photodiode array detection (HPLC/DAD). Benzyl butyl phthalate was used as an internal standard. The targeted analytes could be rapidly determined with limits of quantification (LOQ) ranging from 4.1 (DBP), 10 (TCS), to 34 (4-n-NP)?µg?L?1 in real samples such as bottled waters, personal care products, soaps, lotions, and urine. The results show that the developed analytical scheme is solvent-saving, efficient, and capable of fast screening samples for these common EDCs.  相似文献   
43.
A new spatially balanced sampling design for environmental surveys is introduced, called Halton iterative partitioning (HIP). The design draws sample locations that are well spread over the study area. Spatially balanced designs are known to be efficient when surveying natural resources because nearby locations tend to be similar. The HIP design uses structural properties of the Halton sequence to partition a resource into nested boxes. Sample locations are then drawn from specific boxes in the partition to ensure spatial diversity. The method is conceptually simple and computationally efficient, draws spatially balanced samples in two or more dimensions and uses standard design-based estimators. Furthermore, HIP samples have an implicit ordering that can be used to define spatially balanced over-samples. This feature is particularly useful when sampling natural resources because we can dynamically add spatially balanced units from the over-sample to the sample as non-target or inaccessible units are discovered. We use several populations to show that HIP sampling draws spatially balanced samples and gives precise estimates of population totals.  相似文献   
44.
Golf courses are vulnerable to phosphate (PO) and pesticide loss by infiltration of the sandy, porous grass rooting media used and through subsurface tile drainage. In this study, an effort was made to remove PO, chlorothalonil, mefenoxam, and propiconazole in a golf green's drainage water with a filter blend comprised of industrial byproducts, including granulated blast furnace slag, cement kiln dust, silica sand, coconut shell-activated carbon, and zeolite. To test this filter media, two 6-h storm events were simulated by repeat irrigation of the golf green after PO and pesticide application. Drainage flows ranged from 0.0034 to 0.6433 L s throughout the course of the simulations. A significant decrease in the chlorothalonil load for the experimental run (with filter media) was observed compared with the control (without filter media) ( < 0.05). In general, percent reductions in chlorothalonil were very high (>80%) near peak flows. In contrast, filter media was not effective in removing PO, mefenoxam, or propiconazole ( > 0.05). Instead, it appears that the filter blend added PO to the effluent above flow rates of 0.037 L s. Overall, flow rate, the amount of filter media used, and contaminant properties may have influenced the filter media's ability to remove contaminants. More research is needed to determine the optimal blend and configuration for the filter media to remove significant amounts of all contaminants investigated.  相似文献   
45.
As the number of marine protected areas (MPAs) is globally increasing, information is needed on the effectiveness of existing sites. Many protected area agencies however have limited resources and are unable to evaluate MPA effectiveness. An evaluation conducted entirely by the managing agency may also lack credibility. Long-term monitoring and evaluation programs should ideally offer opportunities for participation of diverse groups in the selection of evaluation indicators and their assessment. A participatory approach has the potential to enhance evaluation capacity, to increase credibility and acceptance of results, to strengthen relationships between managers and local stakeholders, and to address more locally relevant information. Using a case study approach, this paper investigates diverse stakeholder groups’ opinions on the design of an evaluation and their interest to participate in an assessment. Respondents were most interested in the assessment of MPA achievements and outcome indicators. Most groups identified a range of government agencies and stakeholders that should participate in an assessment but only half of all respondents were interested to participate in monitoring activities. Most frequently mentioned limitations for more participation were a lack of time and money, but also governance shortcomings such as limited participation possibilities and not paying enough credit to stakeholders’ input. Participation interest was also influenced by occupation, place of residency, and familiarity with the marine environment. Differences exist among stakeholders about suitable evaluators and preferred monitoring partners, which could affect the credibility of evaluation results and affect monitoring activities.  相似文献   
46.
47.
The pink pigeon (Nesoenas mayeri) is an endemic species of Mauritius that has made a remarkable recovery after a severe population bottleneck in the 1970s to early 1990s. Prior to this bottleneck, an ex situ population was established from which captive-bred individuals were released into free-living subpopulations to increase population size and genetic variation. This conservation rescue led to rapid population recovery to 400–480 individuals, and the species was twice downlisted on the International Union for the Conservation of Nature (IUCN) Red List. We analyzed the impacts of the bottleneck and genetic rescue on neutral genetic variation during and after population recovery (1993–2008) with restriction site-associated sequencing, microsatellite analyses, and quantitative genetic analysis of studbook data of 1112 birds from zoos in Europe and the United States. We used computer simulations to study the predicted changes in genetic variation and population viability from the past into the future. Genetic variation declined rapidly, despite the population rebound, and the effective population size was approximately an order of magnitude smaller than census size. The species carried a high genetic load of circa 15 lethal equivalents for longevity. Our computer simulations predicted continued inbreeding will likely result in increased expression of deleterious mutations (i.e., a high realized load) and severe inbreeding depression. Without continued conservation actions, it is likely that the pink pigeon will go extinct in the wild within 100 years. Conservation rescue of the pink pigeon has been instrumental in the recovery of the free-living population. However, further genetic rescue with captive-bred birds from zoos is required to recover lost variation, reduce expression of harmful deleterious variation, and prevent extinction. The use of genomics and modeling data can inform IUCN assessments of the viability and extinction risk of species, and it helps in assessments of the conservation dependency of populations.  相似文献   
48.
An important consideration in conservation and biodiversity planning is an appreciation of the condition or integrity of ecosystems. In this study, we have applied various machine learning methods to the problem of predicting the condition or quality of the remnant indigenous vegetation across an extensive area of south-eastern Australia—the state of Victoria. The field data were obtained using the ‘habitat hectares’ approach. This rapid assessment technique produces multiple scores that describe the condition of various attributes of the vegetation at a given site. Multiple sites were assessed and subsequently circumscribed with GIS and remote-sensed data.  相似文献   
49.
Stream restoration practices are becoming increasingly common, but biological assessments of these improvements are still limited. Rock weirs, a type of constructed riffle, were implemented in the upper Cache River in southern Illinois, USA, in 2001 and 2003–2004 to control channel incision and protect high quality riparian wetlands as part of an extensive watershed-level restoration. Construction of the rock weirs provided an opportunity to examine biological responses to a common in-stream restoration technique. We compared macroinvertebrate assemblages on previously constructed rock weirs and newly constructed weirs to those on snags and scoured clay streambed, the two dominant substrates in the unrestored reaches of the river. We quantitatively sampled macroinvertebrates on these substrates on seven occasions during 2003 and 2004. Ephemeroptera, Plecoptera, and Trichoptera (EPT) biomass and aquatic insect biomass were significantly higher on rock weirs than the streambed for most sample periods. Snags supported intermediate EPT and aquatic insect biomass compared to rock weirs and the streambed. Nonmetric multidimensional scaling (NMDS) ordinations for 2003 and 2004 revealed distinct assemblage groups for rock weirs, snags, and the streambed. Analysis of similarity supported visual interpretation of NMDS plots. All pair-wise substrate comparisons differed significantly, except recently constructed weirs versus older weirs. Results indicate positive responses by macroinvertebrate assemblages to in-stream restoration in the Cache River. Moreover, these responses were not evident with more common measures of total density, biomass, and diversity.  相似文献   
50.
Abstract: Sediment oxygen demand (SOD) is believed to be an important process affecting dissolved oxygen (DO) concentrations in blackwater streams of the southeastern coastal plain. Because very few data on SOD are available, it is common for modelers to take SOD values from the literature for use with DO models. In this study, SOD was measured in seven blackwater streams of the Suwannee River Basin within the Georgia coastal plain for between August 2004 and April 2005. SOD was measured using four in situ chambers and was found to vary on average between 0.1 and 2.3 g O2/m/day across the seven study sites throughout the study period. SOD was found to vary significantly between the watersheds within the Suwannee River Basin. However, land use was not found to be the driving force behind SOD values. Statistical analyses did find significant interaction between land use and watersheds suggesting that an intrinsically different factor in each of the watersheds may be affecting SOD and the low DO concentrations. Further research is needed to identify the factors driving SOD dynamics in the blackwater streams of Georgia’s coastal plain. Results from this study will be used by the Georgia Department of Natural Resources – Environmental Protection Division as model input data for the development and evaluation of DO total maximum daily loads in the Georgia coastal plain.  相似文献   
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