全文获取类型
收费全文 | 3113篇 |
免费 | 4篇 |
国内免费 | 34篇 |
专业分类
安全科学 | 72篇 |
废物处理 | 151篇 |
环保管理 | 321篇 |
综合类 | 425篇 |
基础理论 | 1151篇 |
污染及防治 | 652篇 |
评价与监测 | 196篇 |
社会与环境 | 180篇 |
灾害及防治 | 3篇 |
出版年
2022年 | 6篇 |
2021年 | 10篇 |
2020年 | 11篇 |
2019年 | 6篇 |
2018年 | 113篇 |
2017年 | 123篇 |
2016年 | 192篇 |
2015年 | 59篇 |
2014年 | 26篇 |
2013年 | 35篇 |
2012年 | 432篇 |
2011年 | 238篇 |
2010年 | 42篇 |
2009年 | 43篇 |
2008年 | 58篇 |
2007年 | 84篇 |
2006年 | 85篇 |
2005年 | 411篇 |
2004年 | 543篇 |
2003年 | 406篇 |
2002年 | 48篇 |
2001年 | 43篇 |
2000年 | 18篇 |
1999年 | 34篇 |
1998年 | 6篇 |
1997年 | 11篇 |
1996年 | 3篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1990年 | 5篇 |
1989年 | 5篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1966年 | 2篇 |
1961年 | 1篇 |
1960年 | 1篇 |
1957年 | 1篇 |
排序方式: 共有3151条查询结果,搜索用时 406 毫秒
601.
602.
J T Smith O V Voitsekhovitch L H?kanson J Hilton 《Journal of environmental radioactivity》2001,56(1-2):11-32
Following a radioactive fallout event, there are a number of possible intervention measures to reduce radioactive doses to the public via the surface water pathway. We have critically reviewed the options available to decision-makers in the event of radioactive contamination of surface waters. We believe that the most effective and viable measures to reduce radioactivity in drinking water are those which operate at the water treatment and distribution stage. Intervention measures to reduce concentrations of radioactivity in rivers and reservoirs are expected to be much less viable and efficient at reducing doses via the drinking water pathway. Bans on consumption of freshwater fish can be effective, but there are few viable measures to reduce radioactivity in fish prior to the preparation stage. Lake liming and biomanipulation have been found to be ineffective for radiocaesium, although the addition of potassium to lakewaters appears promising in some situations. Lake liming may be effective in reducing radiostrontium in fish, though this has not, to our knowledge, been tested. De-boning fish contaminated by strontium is probably the most effective food preparation measure, but salting and freezing can also reduce radiocaesium concentrations in fish. The provision of accurate information to the public is highlighted as a key element of countermeasure implementation. 相似文献
603.
H Vandenhove Y Thiry A Gommers F Goor J M Jossart E Holm T G?fvert J Roed A Grebenkov S Timofeyev T G?ufert 《Journal of environmental radioactivity》2001,56(1-2):157-184
When dealing with large-scale environmental contamination, as following the Chernobyl accident, changed land use such that the products of the land are radiologically acceptable and sustain an economic return from the land is a potentially sustainable remediation option. In this paper, willow short rotation coppice (SRC) is evaluated on radiological, technical and economic grounds for W. European and Belarus site conditions. Radiocaesium uptake was studied in a newly established and existing SRC. Only for light-texture soils with low soil potassium should cultivation be restricted to soils with contamination levels below 100-370 kBq m-2 given the TFs on these soils (5 x 10(-4) and 2 x 10(-3) m2 kg-1) and considering the Belarus exemption limit for firewood (740 Bq kg-1). In the case of high wood contamination levels (> 1000 Bq kg-1), power plant personnel working in the vicinity of ash conveyers should be subjected to radiation protection measures. For appropriate soil conditions, potential SRC yields are high. In Belarus, most soils are sandy with a low water retention, for which yield estimates are too low to make production profitable without irrigation. The economic viability should be thoroughly calculated for the prevailing conditions. In W. Europe, SRC production or conversion is not profitable without price incentives. For Belarus, the profitability of SRC on the production side largely depends on crop yield and price of the delivered bio-fuel. Large-scale heat conversion systems seem the most profitable and revenue may be considerable. Electricity routes are usually unprofitable. It could be concluded that energy production from SRC is potentially a radiologically and economically sustainable land use option for contaminated agricultural land. 相似文献
604.
Female and male reproductive interests often differ. In species in which matings are accompanied by a transfer of resources
valuable for both participants, such as nuptial prey gifts, conflicts may readily occur. Scorpionflies may use alternative
mating tactics. One is to offer a prey item (dead arthropod) to females in exchange for mating. This prey gift tactic includes
a conflict because a male must decide on whether to offer the gift rather than to fight the female and consume the gift. The
outcome may depend on the nutritional status of both males and females. Males may be more willing to give if they themselves
are satiated and the condition of the females may influence the payoff from the males’ investment. Similarly, females may
be more willing to accept food gifts if they are in poor nutritional condition. In this study of the scorpionfly Panorpa cognata, I experimentally manipulated the feeding history of both males and females. I observed the outcome of the direct interactions
that followed when males that were holding prey were approached by females. I found that well-fed males offered the food gift
sooner than males in poor nutritional condition that fed extensively on the food item before offering. Female condition had
no significant influence on whether prey items were offered by males or accepted by females. I also found that well-fed males
rarely searched for prey to pursue the prey gift tactic in courtship. Thus, the prey tactic does not seem to be the males’
first option. 相似文献
605.
Securing sustainable livelihood conditions and reducing the risk of outmigration in savanna ecosystems hosted in the tropical semiarid regions is of fundamental importance for the future of humanity in general. Although precipitation in tropical drylands, or savannas, is generally more significant than one might expect, these regions are subject to considerable rainfall variability which causes frequent periods of water deficiency. This paper addresses the twin problems of “drought and desertification” from a water perspective, focusing on the soil moisture (green water) and plant water uptake deficiencies. It makes a clear distinction between long‐term climate change, meteorological drought, and agricultural droughts and dry spells caused by rainfall variability and land degradation. It then formulates recommendations to better cope with and to build resilience to droughts and dry spells. Coping with desertification requires a new conceptual framework based on green‐blue water resources to identify hydrological opportunities in a sea of constraints. This paper proposes an integrated land/water approach to desertification where ecosystem management supports agricultural development to build social‐ecological resilience to droughts and dry spells. This approach is based on the premise that to combat desertification, focus should shift from reducing trends of land degradation in agricultural systems to water resource management in savannas and to landscape‐wide ecosystem management. 相似文献
606.
Soil sensitivity to acidification in Asia: status and prospects 总被引:5,自引:0,他引:5
Exceedance of steady-state critical loads for soil acidification is consistently found in southern China and parts of SE Asia, but there is no evidence of impacts outside of China. This study describes a methodology for calculating the time to effects for soils sensitive to acidic deposition in Asia under potential future sulfur (S), nitrogen (N), and calcium (Ca) emission scenarios. The calculations are matched to data availability in Asia to produce regional-scale maps that provide estimates of the time (y) it will take for soil base saturation to reach a critical limit of 20% in response to acidic inputs. The results show that sensitive soil types in areas of South, Southeast, and East Asia, including parts of southern China, Burma, Hainan, Laos, Thailand, Vietnam, and the Western Ghats of India, may acidify to a significant degree on a 0-50 y timescale, depending on individual site management and abiotic and biotic characteristics. To make a clearer assessment of risk, site-specific data are required for soil chemistry and deposition (especially base cation deposition); S and N retention in soils and ecosystems; and biomass harvesting and weathering rates from sites across Asia representative of different soil and vegetation types and management regimes. National and regional assessments of soils using the simple methods described in this paper can provide an appreciation of the time dimension of soil acidification-related impacts and should be useful in planning further studies and, possibly, implementing measures to reduce risks of acidification. 相似文献
607.
Th. Knacker und J. R?mbke 《Umweltwissenschaften und Schadstoff-Forschung》2008,20(4):301-302
Ohne Zusammenfassung 相似文献
608.
Ohne Zusammenfassung
Original erschienen in UWSF – Z Umweltchem ?kotox 20(2):133–144 (2008) DOI:
Herausgeber: Martin Pehnt und Eckard Helmers 相似文献
609.
Singh S Sharma DK Dhar S Kumar A Kumar A 《Environmental monitoring and assessment》2007,130(1-3):301-309
Two measurement campaigns were conducted in two sampling sites, An Thinh and Duy Minh, in northern Vietnam during the months
of November–December 2000 and November 2001–February 2002 in order to investigate the extend of the particulate air pollution
from the Pha Lai coal fired power plant. Fine particle samples were analyzed by Energy Dispersive X-Ray Fluorescence spectrometry
and soot samples were analyzed by reflectometer. The result showed that high concentration of soot and elements mostly coincided
with the air masses originating from the power plant. Sea spray aerosol was found to be the major source of chlorine at both
sites. Ratios of specific elements and principal component analysis (PCA) revealed that coal combustion was the main contributor
to the air pollution at both sites. PCA also indicated that there were other sources responsible for the elements emission,
probably the influence of long distance transport and Asian Brown Cloud. 相似文献
610.
This work examines the performance of a hydrous ferric oxide (HFO) reactive filtration (RF) process with coupled chemically enhanced secondary treatment (RECYCLE) for phosphorus removal from municipal wastewater (HFO-RF-RECYCLE). A 3-month, 0.95-ML/d (0.25-mgd) demonstration of HFO-RF-RECYCLE was performed at a municipal wastewater treatment plant equipped with oxidation ditches and secondary clarifiers. Influent to the plant averaged 6.0 mg/L phosphorus, with a tertiary effluent average of 0.011 mg/L phosphorus. Iron doses to the plant were low, at 5 mg/L. Inline recycling of HFO solution rejects to the plant influent resulted in a maximum 90.3%, dose-dependent reduction of phosphorus in the secondary effluent at 4.5 ML/d (1.2 mgd). Other results included reduction of total suspended solids and turbidity. A mass balance analysis was performed. We conclude that HFO-RF-RECYCLE may allow very low levels of phosphorus discharge from municipal wastewater treatment plants with a ferric-iron-based tertiary filtration process and residual recycling. 相似文献