全文获取类型
收费全文 | 557篇 |
免费 | 57篇 |
国内免费 | 165篇 |
专业分类
安全科学 | 24篇 |
废物处理 | 30篇 |
环保管理 | 77篇 |
综合类 | 406篇 |
基础理论 | 94篇 |
污染及防治 | 73篇 |
评价与监测 | 16篇 |
社会与环境 | 48篇 |
灾害及防治 | 11篇 |
出版年
2024年 | 2篇 |
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 19篇 |
2020年 | 11篇 |
2019年 | 15篇 |
2018年 | 13篇 |
2017年 | 20篇 |
2016年 | 22篇 |
2015年 | 19篇 |
2014年 | 28篇 |
2013年 | 68篇 |
2012年 | 52篇 |
2011年 | 47篇 |
2010年 | 20篇 |
2009年 | 27篇 |
2008年 | 15篇 |
2007年 | 43篇 |
2006年 | 45篇 |
2005年 | 38篇 |
2004年 | 27篇 |
2003年 | 26篇 |
2002年 | 27篇 |
2001年 | 17篇 |
2000年 | 27篇 |
1999年 | 22篇 |
1998年 | 16篇 |
1997年 | 18篇 |
1996年 | 10篇 |
1995年 | 17篇 |
1994年 | 7篇 |
1993年 | 17篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有779条查询结果,搜索用时 78 毫秒
491.
Philip N. Owens William H. Blake Ellen L. Petticrew 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):637-645
This paper describes a study examining the potential of mineral magnetic, geochemical and organic properties to determine
if a 2003 wildfire in a catchment in British Columbia, Canada, caused a change in the sources of the suspended sediment transported
in the channel relative to a nearby unburnt (reference) catchment. The results show that some of the properties offer the
potential to determine sediment sources in the unburnt catchment. However, the 2003 wildfire modified the concentrations of
some properties and this can either compromise or enhance their ability as tracers in the burnt catchment. At present, the
source tracing results are inconclusive. This has implications for the use of certain properties as fingerprints and raises
important issues about approaches to sediment source identification. 相似文献
492.
矿产资源开发利用对环境危害的货币化研究 总被引:2,自引:0,他引:2
本文通过辨识矿产资源开发利用过程中的环境危害因子,建立了环境危害所造成的损失货币化模型,定量地确定矿产开发利用中的负效益,并通过与矿产开采所得到的社会效益和经济效益比较.计算矿产开发利用的适宜度。为矿产资源可持续发展和生态环境保护提供决策依据。 相似文献
493.
Trochkine D. Iwasaka Y. Matsuki A. Yamada M. Kim Y.-S. Zhang D. Shi G.-Y. Shen Z. Li G. 《Water, Air, & Soil Pollution: Focus》2003,3(2):161-172
The Asian continent is recognized as one of the most important sources of mineral (or soil) particles. These particles have a large potential to effect global changes through the biogeochemical cycle of particulates and through radiative balance (IPCC Third Assessment Report, 2001). Therefore, comparison of particle compositions near the source region and those after long-range transport is important in understanding the long-range particle transport phenomenon. Individual aerosolparticles were collected in Dunhuang (40°09N; 94°41E), China. Particles were collected at the campus of the Meteorological Bureau of Dunhuang City (17 August 2001) and near the Mogao Grots, located approximately 30 km from Dunhuang (18 August 2001, 18 October 2001 and 13 January 2002) using a two-stage low-volume impactor. The morphology of individual aerosol particles and their elemental compositions were examined via a scanning electron microscope (Hitachi, S-3000N) equipped with an energy dispersive X-ray (EDX) analyzer (Horiba, EMAX-500). The particles collected at these locations were comprised primarily of minerals, with the exception of sulphateparticles in the submicron range that were contained in thesample collected on 18 October 2001 (likely, ammonium sulphate). The most abundant elements were found to be Si and Al. Approximately 46–77% of the collected particles were Si-richparticles (composed primarily of quartz and aluminosilicate),and 13–41% of the collected particles were Ca-rich particles,such as calcite (CaCO3), dolomite (CaMg(CO3)2),and gypsum (CaSO42H2O). The fractions of Fe-rich, Mg-rich, Ti-rich, K-rich, and Cl-rich were 3–10, 0–7, 0–3, 0–1, and 0–1%, respectively. Similar types of mineral particles were found in the free troposphere over Japan(Trochkine et al., 2002). A number of differences were found to exist between the particles collected in China and thosecollected in Japan, and these differences can be explained bychemical modification of the particles during transport fromChina to Japan. 相似文献
494.
495.
长江中游矿产资源跨世纪开发布局 总被引:1,自引:1,他引:0
长江中游地区矿产资源丰富,分相布对集中,配套程度较好。主要矿产资源绝大部分可保证跨世纪供需,作者提出利用三峡枢纽工程跨世纪建设,发挥中心枢纽地位和区内外资源及水运优势,依托现有磷矿开发及磷化工和钢铁,盐,磷化工和石油化工基地及建材工业基地,并指出了矿产资源开发的一具体对策。 相似文献
496.
In the crustacean Eudiaptomus gracilisSars, relationships between mortality (D) and the ratio of main cations (R, the ratio of the sum of potassium and sodium equivalent concentrations to the sum of calcium and magnesium equivalent concentrations) were studied. The calculated regression equation D= 315 – 355/Rwas used for predicting the state of E. gracilispopulation in Lake Poppalijarvi (Karelia) polluted with mining waste. At R< 0.47, the population will survive; at R> 1.53, its extinction should be expected. The results of hydrobiological observations on Lake Poppalijarvi confirmed the prognosis based on the equation. 相似文献
497.
Samples have been collected from major horizons of 34 podzol profiles distributed throughout Scotland, all developed from granite or granitic tills and under Calluna moorland. the pH in water and calcium chloride pastes, exchangeable cations and cation exchange capacity, and extractable aluminium of the soils collected have been measured, and the results studied in relation to reported atmospheric deposition of H+, non-marine sulphur and nitrate. for all horizons, significant positive correlations were found between soil pH and rainfall mean pH, as might be expected when the critical load of H+ deposition is exceeded. Acidifying pollutant deposition also apparently increased soil extractable aluminium concentrations in the B and C horizons. However, exchangeable base cation concentrations tended to increase, rather than decrease, with increasing precipitation acidity. This effect was attributed to increases in biogeochemical cycling of base cations, increases in leaching inputs of base cations from overlying A/E horizon soils, and increases in the inputs of base cations leached from upslope. the results suggest that the simple steady state mass approach to the quantification of critical loads, as often applied, may be an oversimplification. 相似文献
498.
根据井矿盐生产工艺特点及云应地区实际,分析了冲渣除尘水、冷却水和工艺废水循环使用的可能性,论证了云应地区制盐行业实现废水零排放的可行性,并提出了实现零排放的具体建议。 相似文献
499.
Explaining the resource curse, with special reference to mineral-exporting countries 总被引:2,自引:0,他引:2
Raymond F Mikesell 《Resources Policy》1997,23(4):191-199
Recent studies have found an inverse correlation between economic growth and natural resource abundance among developing countries. There appears to be no obvious explanation for this finding, such as an important growth variable that is common in resource-poor countries and deficient in resource-abundant countries. The resource curse hypothesis is closely related to the problem of sustainability for resource-exporting countries since periods of high growth are frequently followed by long periods of stagnation. Models are examined showing how increases in export income can affect relative prices in the trade and nontrade sectors and how the changes in relative prices affect investment and growth. It is the thesis of this article that there is nothing inherent in resource-abundance that condemns countries to either low growth or nonsustainability. 相似文献
500.
铀尾矿库中核素U(Ⅵ)的扩散迁移试验 总被引:1,自引:0,他引:1
利用自制的设备,采用水平土柱吸渗法,测定了不同参数土壤中铀溶液的质量浓度,通过Fick扩散第二定律推导的公式计算其扩散系数。并对比氯离子迁移试验,探讨了时间、距离、土质、孔隙度等对铀扩散的影响,进而研究尾矿库中核素U(Ⅵ)的运移扩散规律。结果表明:铀和氯离子在砂质土壤中的扩散均比在黏质土壤中快,氯离子在黏土中的扩散系数D=0.354×10~(-3)m~3/d,在砂土中的扩散系数D=1.830×10~(-3)m~3/d,铀在黏土的扩散系数D=0.950×10~(-3)m~3/d,在砂土中的扩散系数D=1.623×10~(-3)m~3/d;铀在土壤中的质量浓度随扩散时间延长逐渐增大,且与扩散距离呈比例关系;铀在土壤中的扩散系数随土壤孔隙度增大而变大。 相似文献