全文获取类型
收费全文 | 17204篇 |
免费 | 188篇 |
国内免费 | 140篇 |
专业分类
安全科学 | 389篇 |
废物处理 | 699篇 |
环保管理 | 2166篇 |
综合类 | 3743篇 |
基础理论 | 4036篇 |
环境理论 | 9篇 |
污染及防治 | 4227篇 |
评价与监测 | 1108篇 |
社会与环境 | 1089篇 |
灾害及防治 | 66篇 |
出版年
2022年 | 132篇 |
2021年 | 152篇 |
2019年 | 129篇 |
2018年 | 234篇 |
2017年 | 236篇 |
2016年 | 362篇 |
2015年 | 283篇 |
2014年 | 408篇 |
2013年 | 1197篇 |
2012年 | 461篇 |
2011年 | 716篇 |
2010年 | 533篇 |
2009年 | 629篇 |
2008年 | 729篇 |
2007年 | 761篇 |
2006年 | 671篇 |
2005年 | 555篇 |
2004年 | 575篇 |
2003年 | 558篇 |
2002年 | 514篇 |
2001年 | 631篇 |
2000年 | 403篇 |
1999年 | 310篇 |
1998年 | 196篇 |
1997年 | 217篇 |
1996年 | 238篇 |
1995年 | 240篇 |
1994年 | 248篇 |
1993年 | 227篇 |
1992年 | 209篇 |
1991年 | 211篇 |
1990年 | 200篇 |
1989年 | 177篇 |
1988年 | 173篇 |
1987年 | 157篇 |
1986年 | 158篇 |
1985年 | 150篇 |
1984年 | 172篇 |
1983年 | 173篇 |
1982年 | 177篇 |
1981年 | 150篇 |
1980年 | 139篇 |
1979年 | 124篇 |
1978年 | 138篇 |
1977年 | 116篇 |
1976年 | 105篇 |
1975年 | 109篇 |
1974年 | 118篇 |
1971年 | 98篇 |
1967年 | 101篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
851.
The radon isotope 222Rn and salinity in coastal surface water were mapped on regional scales, to improve the understanding of coastal processes and their spatial variability. Radon was measured with a surface-towed, continuously recording multi-detector setup on a moving vessel. Numerous processes and locations of land-ocean interaction along the Central Great Barrier Reef coastline were identified and interpreted based on the data collected. These included riverine fluxes, terrestrially-derived fresh submarine groundwater discharge (SGD) and the tidal pumping of seawater through mangrove forests. Based on variations in the relationship of the tracers radon and salinity, some aspects of regional freshwater inputs to the coastal zone and to estuaries could be assessed. Concurrent mapping of radon and salinity allowed an efficient qualitative assessment of land-ocean interaction on various spatial and temporal scales, indicating that such surveys on coastal scales can be a useful tool to obtain an overview of SGD locations and processes. 相似文献
852.
L.Q. Xu L.G. Sun H. Yan Y.H. Luo Y.H. Wang 《Journal of environmental radioactivity》2010,101(5):362-368
Several natural and anthropogenic radionuclides (210Pb, 226Ra and 137Cs) in guano-phosphatic coral sediments and pure guano particles collected from Ganquan, Guangjin, Jinqing and Jinyin Islands of the Xisha archipelago, South China Sea, were analyzed. The Constant Initial Concentration (CIC) model and the Constant Rate of Supply (CRS) model were applied for age calculation. The average supply rate of 210Pb was 126 Bq m−2 a−1, very close to the flux of northern hemisphere average (125 Bq m−2 a−1). The activities of anthropogenic radionuclides in the sediments were very low, indicating that human nuclear tests did not notably impact this region. The main source of radionuclides in the sediments was from atmospheric precipitation, and the organic matter derived from plant and produced by nutrient-rich guano could further enhance them. 相似文献
853.
A Carbon Cycle Science Update Since IPCC AR-4 总被引:1,自引:0,他引:1
Dolman AJ van der Werf GR van der Molen MK Ganssen G Erisman JW Strengers B 《Ambio》2010,39(5-6):402-412
854.
G. Shi Z. Chen C. Bi J. Teng S. Xu 《Environmental pollution (Barking, Essex : 1987)》2010,158(3):694-703
A set of toxic metals, i.e. As, Hg, Pb, Cd, Cu, Zn, Ni and Cr, in urban and suburban SDSs were investigated comparatively in the biggest metropolitan area of China, Shanghai. Results showed that all of the metals except As were accumulated greatly, much higher than background values. Geo-accumulation index indicated that metal contamination in urban SDSs was generally heavier than that in suburban SDSs. Potential ecological risk index demonstrated that overall risks caused by metals were considerable. Cd contributed 52% to the overall risk. Multivariate statistical analysis revealed that in urban SDSs, Zn, Ni, Cd, Pb, Cu and Cr were related to traffic and industry; coal combustion led to elevated levels of Hg; soil parent materials controlled As contents. In suburban SDSs, Pb, Cu, As and Cd largely originated from traffic pollution; Zn, Ni and Cr were associated with industrial contaminants; Hg was mainly from domestic solid waste. 相似文献
855.
C. Munschy K. Héas-Moisan G. Pacepavicius 《Environmental pollution (Barking, Essex : 1987)》2010,158(12):3527-3533
The uptake, elimination and transformation of six PBDE congeners (BDE-28, -47, -99, -100, -153, -209) were studied in juvenile common sole (Solea solea L.) exposed to spiked contaminated food over a three-month period, and then depurated over a five-month period. Methoxylated (MeO-) and hydroxylated (OH-) PBDEs were determined in fish plasma exposed to PBDEs and compared to those obtained in control fish. While all MeO- and some OH- congeners identified in fish plasma were found to originate from non-metabolic sources, several OH- congeners, i.e., OH-tetraBDEs and OH-pentaBDEs, were found to originate from fish metabolism. Among these, 4′-OH-BDE-49 was identified as a BDE-47 metabolite. Congener 4′-OH-BDE-101, identified here for the first time, may be the result of BDE-99 metabolic transformation. Our results unequivocally showed that PBDEs are metabolised in juvenile sole via the formation of OH- metabolites. However, this was not a major biotransformation route compared to biotransformation through debromination. 相似文献
856.
The critical load (CL) of acidic atmospheric deposition represents the load of acidity deposited from the atmosphere to the earth’s surface at which harmful acidification effects on sensitive biological receptors are thought to occur. In this study, the CL for forest soils was estimated for 27 watersheds throughout the United States using a steady-state mass balance approach based on both national and site-specific data and using different approaches for estimating base cation weathering. Results suggested that the scale and source of input data can have large effects on the calculated CL and that the most important parameter in the steady-state model used to estimate CL is base cation weathering. These results suggest that the data and approach used to estimate weathering must be robust if the calculated CL is to be useful for its intended purpose. 相似文献
857.
Ben K. Greenfield Andrew Jahn 《Environmental pollution (Barking, Essex : 1987)》2010,158(8):2716-2724
In the San Francisco Estuary, management actions including tidal marsh restoration could change fish mercury (Hg) concentrations. From 2005 to 2007, small forage fish were collected and analyzed to identify spatial and interannual variation in biotic methylmercury (MeHg) exposure. The average whole body total Hg concentration was 0.052 μg g−1 (wet-weight) for 457 composite samples representing 13 fish species. MeHg constituted 94% of total Hg. At a given length, Hg concentrations were higher in nearshore mudflat and wetland species (Clevelandia ios, Menidia audens, and Ilypnus gilberti), compared to species that move offshore (e.g., Atherinops affinis and Lepidogobius lepidus). Gut content analysis indicated similar diets between Atherinops affinis and Menidia audens, when sampled at the same locations. Hg concentrations were higher in sites closest to the Guadalupe River, which drains a watershed impacted by historic Hg mining. Results demonstrate that despite differences among years and fish species, nearshore forage fish exhibit consistent Hg spatial gradients. 相似文献
858.
The Efficacy of a Programme of Landslide Risk Reduction in Areas of Unplanned Housing in the Eastern Caribbean 总被引:1,自引:0,他引:1
Malcolm G. Anderson Elizabeth Holcombe Maricarmen Esquivel Joaquin Toro Francis Ghesquiere 《Environmental management》2010,45(4):807-821
Poor countries are disproportionately affected by the cost of disasters. Yet there is evidence of the benefits of seeking
to mitigate the impact of a disaster, compared with the costs incurred in ‘making good’ after a major event has occurred.
This article reviews a programme of landslide risk reduction in unplanned communities in the Eastern Caribbean. The construction
of appropriate surface water management measures, based on the application of scientific and engineering principles, has been
demonstrated to reduce the hazard from rainfall-triggered landslides. Adopting a community-based approach additionally delivers
social and environmental benefits relating to employment generation, improvements in the environmental conditions within the
community, and improvements slope management practices. The sustained implementation of the community-based projects has provided
the necessary evidence-base for these practices to influence Government policy and practice, and gain recognition from regional
development agencies. The strategic and incremental uptake of the community-based methodology is demonstrated to be an effective
means for delivering physical landslide risk reduction measures in the most ‘at risk’ areas of unplanned housing. 相似文献
859.
In this second part of the work, two other long-term technologies for power generation from coal are investigated. The Zecomag plant has the same syngas production system of the Zecomix plant, described in the first part of this paper, but hydrogen-rich syngas is here burned with air in an open-cycle gas turbine. The aim is a simplification of the power island, more similar to a combined cycle; however, CO2 capture falls from 100% to about 90% and NOx emissions are present.An advanced oxy-fuel IGCC is the second plant investigated in this paper, presenting the same zero-emission potential of Zecomix. Syngas is produced in a high pressure, dry feed, oxygen blown gasifier and cleaned in a hot-gas-clean-up system. Clean syngas is then burned with oxygen and expanded in a turbine, using compressed recirculated CO2 to moderate firing temperature and to cool turbine blades.The loss of net efficiency, with respect to Zecomix, is very limited (1–2 points) with both configurations. In order to better evaluate the performances obtained, a comparison with reference state-of-the art IGCCs and a long-term IGCC without CO2 capture is also presented. 相似文献
860.