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141.
Armstrong, William H., Mathias J. Collins, and Noah P. Snyder, 2012. Increased Frequency of Low‐Magnitude Floods in New England. Journal of the American Water Resources Association (JAWRA) 48(2): 306‐320. DOI: 10.1111/j.1752‐1688.2011.00613.x Abstract: Recent studies document increasing precipitation and streamflow in the northeastern United States throughout the 20th and early 21st Centuries. Annual peak discharges have increased over this period on many New England rivers with dominantly natural streamflow – especially for smaller, more frequent floods. To better investigate high‐frequency floods (<5‐year recurrence interval), we analyze the partial duration flood series for 23 New England rivers selected for minimal human impact. The study rivers have continuous records through 2006 and an average period of record of 71 years. Twenty‐two of the 23 rivers show increasing trends in peaks over threshold per water year (POT/WY) – a direct measure of flood frequency – using the Mann‐Kendall trend test. Ten of these trends had p < 0.1. Seventeen rivers show positive trends in flood magnitude, six of which had p < 0.1. We also investigate a potential hydroclimatic shift in the region around 1970. Twenty‐two of the 23 rivers show increased POT/WY in the post‐1970 period when comparing pre‐ and post‐1970 records using the Wilcoxon rank‐sum test. More than half of these increases have p < 0.1, indicating a shift in flow regime toward more frequent flooding. Region wide, we found a median increase of one flood per year for the post‐1970 period. Because frequent floods are important channel‐forming flows, these results have implications for channel and floodplain morphology, aquatic habitat, and restoration.  相似文献   
142.
The primary purpose of the study was to address the claim that people are more likely to walk to a transit stop if they live on a “walkable” block. An additional purpose was to evaluate the Irvine Minnesota Inventory (IMI) as an environmental audit tool. The IMI was used to measure walkability features of 19 blocks in a revitalizing neighborhood. We hypothesized that residents who walked to a light rail TRAX stop (n = 22) would live on blocks with higher walkability ratings compared to residents who did not walk to TRAX (nonriders, n = 15), or who walked only after a closer TRAX stop was built (new users, n = 11). A MANCOVA indicated the IMI scales differentiated the blocks; the strongest differences were obtained in subscales that measured the block's diversity, safety from crime and density (marginally significant). Participants' perceptions of their complete walk to the transit stop were consistent with the home block IMI scores, with the continuing riders having more positive views than the other two groups. The results show the ability of the IMI to distinguish among blocks in walkability, and support further use of this audit tool in environmental analyses and active living research. We end with a discussion of conceptual and methodological issues in the use of audit tools and provide recommendations for using these measures for local, immediate interests, as well as for building a broader science of environmental measurement.  相似文献   
143.
Until now, existing remuneration of environmental services has not sufficiently supported the goals of spending money more effectively on the environment and of motivating farmers. Only a small share of the budgets for agriculture in the EU, as well as in US and other countries, is available for buying environmental goods and services beyond the level of good farming practice (GFP). This combined with the insufficient targeting of compensation payments to areas where special measures are needed leads to an unsatisfactorily low impact of agri-environment measures compared to other driving forces that stimulate the intensification of farming. The goal of this paper is to propose a management concept that enhances the ecological and cost efficiency of agri-environment measures. Components of the concept are a comprehensive environmental information base with prioritised goals and targets (available in Germany from landscape planning) and new remuneration models, which complement conventional compensation payments that are based upon predetermined measures and cost. Comprehensive landscape planning locates and prioritises areas which require environmental action. It contains the information that authorities need to prioritise funding for environmental services and direct measures to sites which need environmental services beyond the level of GFP.Also appropriate remuneration models, which can enhance the cost efficiency of public spending and the motivation of the farmers, can be applied on the base of landscape planning.Testing of the planning methodology and of one of the remuneration models (success-oriented remuneration) in a case study area (“Fuhrberger Feld” north of Hanover, Germany) demonstrated the usability of the concept and led to proposals for future development of the methodology and its application in combination with other approaches.  相似文献   
144.
Stomatal conductance and net photosynthesis of common milkweed (Asclepias syriaca L.) plants in two different soil moisture regimes were directly quantified and subsequently modeled over an entire growing season. Direct measurements captured the dynamic response of stomatal conductance to changing environmental conditions throughout the day, as well as declining gas exchange and carbon assimilation throughout the growth period beyond an early summer maximum. This phenomenon was observed in plants grown both with and without supplemental soil moisture, the latter of which should theoretically mitigate against harmful physiological effects caused by exposure to ozone. Seasonally declining rates of stomatal conductance were found to be substantial and incorporated into models, making them less susceptible to the overestimations of effective exposure that are an inherent source of error in ozone exposure indices. The species-specific evidence presented here supports the integration of dynamic physiological processes into flux-based modeling approaches for the prediction of ozone injury in vegetation.  相似文献   
145.
针对中国太阳能利用技术的现状,分析比较了太阳能路灯在国内利用的可行性,详细介绍了浙江某示范村的太阳能路灯工程情况,并对该工程进行了经济可行性的分析。  相似文献   
146.
This paper explains one way in which New Zealand’s free-market reforms have adversely affected its environment. Liberalisation of New Zealand’s economy has radically changed the determinants of agricultural export success, largely due to the elimination of subsidies to domestic producers, and of tariffs on imports. In this exposed agricultural milieu, the dairy industry has thrived; cow numbers have increased by over 50%, with commensurate increases in herd and farm sizes. With this rapid expansion has come increasing pollution of New Zealand’s waterways. New Zealand’s Resource Management Act 1991 is potentially capable of controlling these adverse effects; however, its implementation was slow and piecemeal throughout the 1990s. So, at the same time as production and pollution from dairy farming expanded, the efficacy of environmental policy was limited. The resulting implementation gap has put at risk the ‘clean and green’ image that is an important component of New Zealand’s agricultural export success.Readers should send their comments on this paper to: BhaskarNath@aol.com within 3 months of publication of this issue.  相似文献   
147.
The role of the central government in New Zealand is generally limited to research and policy development, and regional councils are responsible for most monitoring and management of the problem. The role of the federal government in the United States includes research and monitoring, policy development, and regulation. States also have a significant management role. Both countries rely on voluntary approaches for NPS pollution management. Very few national water quality standards exist in New Zealand, whereas standards are widely used in the United States. Loading estimates and modeling are often used in the United States, but not in New Zealand. A wide range of best management practices (BMPs) are used in the United States, including buffer strips and constructed/engineered wetlands. Buffer strips and riparian management have been emphasized and used widely in New Zealand. Many approaches are common to both countries, but management of the problem has only been partly successful. The primary barriers are the inadequacy of the voluntary approach and the lack of scientific tools that are useful to decision-makers. More work needs to be performed on the evaluation of approaches developed in both countries that could be applied in the other countries. In addition, more cooperation and information/technology transfer between the two countries should be encouraged in the future.  相似文献   
148.
Previous soil lead studies in New Orleans focused on the geochemical footprint and its health impacts. This study examines the human geography of race, income, and age in pre-Katrina metropolitan New Orleans within the context of lead accumulation in soils. Sample points of soil lead data (n = 5,467) collected in 1998–2000 were mapped in a geographic information system (GIS), binned into 9 ranges, and queried by (1) 2000 Census racial demographic data, (2) 1999 median household income, and (3) 2000 age data. The absolute population generally declines as lead levels increase except at lead levels from 200–400 to 400–1,000 mg/kg when population increases; the African–American population comprises a disproportionate share of this cohort. The high-lead areas occur in the inner city, home to the largest populations of African-Americans in New Orleans. The mean household income curve indicates that lower economic groups are at risk to higher levels of lead. A total of 44,701 children under the age of 5 years, plus 123,579 children aged 5–17, lived in census block groups containing at least one sample point with over 100 mg/kg lead, and these include 23,124 and 64,064 young people, respectively, who live near at least one point over 400 mg/kg. Lead exposure affects a panoply of outcomes that influence the health and welfare of the community. Unless corrected, children are likely to return to the same or, because of lack of lead-safe practices during renovation, even higher exposure risks than before the flooding of New Orleans.  相似文献   
149.
Abstract:  Scarce resources and competing land-use goals necessitate efficient biodiversity conservation. Combining multicriteria analysis with conservation decision-support tools improves efficiency of conservation planning by maximizing outcomes for biodiversity while minimizing opportunity costs to society. An opportunity cost is the benefit that could have been received by taking an alternative course of action (i.e., costs to society of protecting an area for biodiversity rather than developing it for some other use). Although different ways of integrating multiple opportunity costs into conservation planning have been suggested, there have been no tests as to which method is most efficient. We compared the relative efficiency of 3 such procedures ( Faith & Walker [1996] , Sarkar et al. [2004] , and a procedure of our own design) in a systematic conservation-planning framework for the Milne Bay Province of Papua New Guinea. We devised 14 opportunity costs and assigned these to 3 scenarios representing different conservation planning concerns: food security, macro-economic development, and biodiversity persistence. For each scenario, we compared the efficiency of the 3 methods in terms of amount of biodiversity protected relative to total expenditure for each opportunity cost. All 3 methods captured similar amounts of biodiversity, but differed in total cost. Our method had the least overall cost and was therefore most efficient. Nevertheless, there was a high correlation and geographical concordance among all 3 methods, indicating a high degree of spatial overlap. This suggests that choosing an appropriate approach may often depend on contextual factors related to the design of the planning question, rather than efficiency alone.  相似文献   
150.
沈北新区土壤中多环芳烃污染特征及源解析   总被引:10,自引:6,他引:4  
采用均匀网格布点法采集沈阳市沈北新区不同土地利用类型101个表层(0~20 cm)土壤样品,开展土壤中美国环保署优先控制的16种多环芳烃(PAHs)的含量空间分布特征、成分谱分析和污染物来源解析研究.结果表明,沈北新区土壤中16种PAHs(ΣPAHs)总含量为123.7~932.5μg·kg~(-1);PAHs组分以3~4环的中、低环组分为主,其中3环PAHs比例最高;ΣPAHs的空间分布特征明显,呈现出由南向北、自东向西逐渐递减的趋势.在研究区域所涉及的5种土地利用类型土壤中,土壤ΣPAHs含量的高值主要集中在城区绿地和人工绿化林地,其次为设施菜地,水稻田和玉米田中ΣPAHs含量相对较低且无明显空间分布差异.利用特征比值分析和因子分析/多元线性回归分析进行土壤中PAHs的污染源解析,初步确定沈北新区表土中PAHs的主要污染源为燃烧源和石油源的混合源,其中,工业燃煤和机动车尾气是PAHs的主要污染源,其贡献率达79.6%,石油泄漏和焦炉排放贡献率约为16.2%,生物质燃料的燃烧贡献率占4.2%.  相似文献   
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