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681.
基于TM遥感影像、城市规划图等数据,利用logistic—CA模型,模拟了2005~2010年天津市滨海新区城市形态演化,经过模拟面积和Lee-Sallle指数两个指标的精度评价后,定量分析了新版总规实施后城市形态演化的驱动力。实证研究表明:滨海新区城市形态扩展迅速,驱动力大小依次是自然环境、经济发展、交通带动、城市规划引导;其中交通驱动力中,影响最强烈的依次是火车站、城市的道路、高速出入口、县乡道、航道、省道。因此提出:城市规划必须顺应城市形态发展的规律,把握好可控的关键驱动力,科学预测城市形态发展和提出城市规划方案,做到积极有效的引导城市形态发展。  相似文献   
682.
Fate of radium (Ra) in liquid regeneration brine wastes from water softeners disposed to septic tanks in the New Jersey Coastal Plain was studied. Before treatment, combined Ra (226Ra plus 228Ra) concentrations (maximum, 1.54 Bq L−1) exceeded the 0.185 Bq L−1 Maximum Contaminant Level in 4 of 10 studied domestic-well waters (median pH, 4.90). At the water table downgradient from leachfields, combined Ra concentrations were low (commonly ≤0.019 Bq L−1) when pH was >5.3, indicating sequestration; when pH was ≤5.3 (acidic), concentrations were elevated (maximum, 0.985 Bq L−1 - greater than concentrations in corresponding discharged septic-tank effluents (maximum, 0.243 Bq L−1)), indicating Ra mobilization from leachfield sediments. Confidence in quantification of Ra mass balance was reduced by study design limitations, including synoptic sampling of effluents and ground waters, and large uncertainties associated with analytical methods. The trend of Ra mobilization in acidic environments does match observations from regional water-quality assessments.  相似文献   
683.
Ra isotopes are a powerful tool for quantifying the flux of submarine groundwater discharge (SGD) into the sea. Previous studies of 223Ra and 224Ra mass balances in coastal embayments have shown that the Ra balance is dominated by supply via SGD, exchange with the open ocean and radioactive decay. The current study shows that a single time series over a tidal cycle at the principal inlet to Great South Bay (NY, US) is sufficient to determine the net flux of Ra across the inlet, and also can be used to estimate the decay of short-lived Ra in the bay. Estimates of the net Ra flux obtained from a single tidal time-series by using three different approaches agree with those determined from a more time-consuming survey of Ra within the bay, and may represent a first step of estimating SGD in bays and coastal lagoons.  相似文献   
684.
乐安河水环境现状及其治理措施   总被引:3,自引:0,他引:3  
根据水文、水质和污染源调查结果,分析了乐安河流域水质的污染现状和综合环境质量,认为CODCr和氨氮是乐安河流域的主要水污染物,畜牧养殖业和城镇居民生活污水是最主要的污染源。根据这些分析,从乐安河流域的水质控制目标出发,提出了以污染源达标排放、筹建生活污水处理厂、控制面源污染、实施生态恢复、加强监控与管理等措施作为乐安河水环境综合治理的对策。  相似文献   
685.
1 INTORDUCTIONRivers are the artery of the earth surface system; and it isone of the major components of natural environment incities, whose quantity and quality result from the long-time interaction between environment and human activities(Chen Dechao, et al. 2002; Wang Ying, Sheng Jingfen.2002). As a symbol of reform and opening in China,Pudong New Area plays an important role in the economicdevelopment around Yangtze Delta and even all over thecountry. The 14th congress of the Com…  相似文献   
686.
南京近城市河流沉积物营养水平与磷形态的空间分布   总被引:1,自引:0,他引:1  
近城市河流位于城市与农村的过渡带,其环境现状反映城市化过程对河流的影响。通过不同断面的样品研究了南京近城市河流--秦淮新河沉积物中主要营养元素与磷形态的空间分布,分析其变化特征和污染成因。研究表明,不同河段由于受人为活动和沉积环境的影响营养程度差异较大。河流表层沉积物的TOC、TN和TP范围分别为307~3497 g/kg、830~2 370 mg/kg和447~3 517 mg/kg,磷的形态显示Fe P或Ca P>Org P>>Al P>DP,其中Fe P和Ca P二者之和占TP的70%以上,两者均可指示营养化程度的轻重。通过西善桥段和入江口段柱状沉积物分析表明,营养元素和磷形态垂向上均呈现明显的“沉降 降解 堆积”三段式变化,西善桥段以Fe P为优势形态,占TP的431%~505%,入江口段以Ca P为优势形态,占TP的463%~603%。通过不同河流磷含量的对比,表明秦淮新河作为近城市河流,营养水平介于一般的乡村河流与城市河流之间,并且优势形态磷空间分布带有区域性,表明长三角的城市化对近郊河流的影响是局部的  相似文献   
687.
Abstract

The main purpose of this study is to put forward a reasonable idea of the general protection for Singing Sand Mountain and Crescent Moon Spring, a rare and unique desert wonder, and of sustainable tourism development based on the research on the ecological environment around. Methods of documentation, case study and comparison were employed. Finally, aiming at solving the problems of natural environment and those existing after the exploitation of Singing Sand Mountain and Crescent Moon Spring the author puts forward three measures: the comprehensive treatment for Crescent Moon Spring (broadening resources of water and reducing expenditures, checking the decreasing depth of Crescent Moon Spring, and improving the geographical environment), the general protection envisions for Singing Sand Mountain and Crescent Moon Spring and establishing a dynamic monitoring and early-warning system of regional ecosystem.  相似文献   
688.
ABSTRACT

The evolution of Chinese environmental policy and politics can be better understood in the broader context of institutional changes that have taken place since the late 1970s. In this study, an analytical framework was established to analyze how overall institutional changes were reflected in the roles of relationships between governmental and non-governmental actors engaged in environmental governance. Institutional changes were observed at three levels: informal institutions (cultural traditions, and political ideology); formal institutions (the polity, political system, property rights, and judiciary); and governing mechanisms (structures, regulatory approaches, and incentives). This analysis of interactions between institutional changes and the changing environmental process explained not only the drives and constraints behind China’s environmental policy evolution so far but also shed light on future challenges and opportunities.  相似文献   
689.
Canoes forging through cold waters, mountains rising from the sea, a heart beating under a mountain lake, an albatross sailing toward the Antarctic: these were the story-images of Coastal Mappings, a large-scale community project set in and around Dunedin, New Zealand. In the Coastal Mappings performance project, people in the last months of their lives joined cancer survivors, family members and other interested people in explorations of Pakeha myths (by European-settler descendents) and Maori myths (by descendents of the crews of the first canoes, first inhabitants of New Zealand). Together, we created personal landscapes through movement, storytelling, photography and video. In this essay, I discuss some of the opportunities, challenges and experiences of leading a community dance project in an intercultural social environment, and with people whose relationship to their environment is different from mine.  相似文献   
690.
Abstract:  For many regions worldwide, multiple and often contrasting biogeographic classifications exist that are derived from a variety of taxa and techniques. This presents a challenge for managers who must choose appropriate large-scale spatial frameworks for systematic conservation planning. We demonstrate how systematically collected community data can be used to evaluate existing biogeographic classifications, identify the most appropriate metric for biogeographic patterns seen in other taxonomic groups, and develop an independent biogeographic classification scheme for systematic conservation planning. We evaluated 6 existing biogeographic classifications for New Zealand's nearshore marine environment with community-similarity metrics derived from abundance and presence–absence data for macroalgae (107 species) and mobile macroinvertebrates (44 species). The concordance between community metrics and the previous classifications was high, as indicated by a high multivariate classification success (CS) (74.3–98.3%). Subsequently, we carried out an independent classification analysis on each community metric to identify biogeographic units within a hierarchical spatial framework. The classification derived from macroalgal presence–absence data achieved the highest CS and could be used as a mesoscale classification scheme in which 11 regional groupings (i.e., bioregions) (CS = 73.8–84.8%) are nested within northern and southern biogeographic provinces (CS = 90.3–98.7%). These techniques can be used in systematic conservation planning to inform the design of representative and comprehensive networks of marine protected areas through evaluation of the current coverage of marine reserves in each bioregion. Currently, 0.22% of the territorial sea around mainland New Zealand is protected in no-take marine protected areas in which 0–1.5% of each bioregion represented.  相似文献   
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