全文获取类型
收费全文 | 1132篇 |
免费 | 118篇 |
国内免费 | 502篇 |
专业分类
安全科学 | 57篇 |
废物处理 | 6篇 |
环保管理 | 83篇 |
综合类 | 973篇 |
基础理论 | 255篇 |
污染及防治 | 86篇 |
评价与监测 | 115篇 |
社会与环境 | 131篇 |
灾害及防治 | 46篇 |
出版年
2024年 | 14篇 |
2023年 | 33篇 |
2022年 | 72篇 |
2021年 | 72篇 |
2020年 | 70篇 |
2019年 | 67篇 |
2018年 | 64篇 |
2017年 | 82篇 |
2016年 | 96篇 |
2015年 | 81篇 |
2014年 | 87篇 |
2013年 | 109篇 |
2012年 | 118篇 |
2011年 | 100篇 |
2010年 | 74篇 |
2009年 | 63篇 |
2008年 | 63篇 |
2007年 | 69篇 |
2006年 | 75篇 |
2005年 | 67篇 |
2004年 | 60篇 |
2003年 | 22篇 |
2002年 | 31篇 |
2001年 | 26篇 |
2000年 | 37篇 |
1999年 | 17篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 10篇 |
1995年 | 6篇 |
1994年 | 14篇 |
1993年 | 11篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有1752条查询结果,搜索用时 593 毫秒
471.
Environmental change challenges local and global survival of populations and species. In a species-poor environment like the
Baltic Sea this is particularly critical as major ecosystem functions may be upheld by single species. A complex interplay
between demographic and genetic characteristics of species and populations determines risks of local extinction, chances of
re-establishment of lost populations, and tolerance to environmental changes by evolution of new adaptations. Recent studies
show that Baltic populations of dominant marine species are locally adapted, have lost genetic variation and are relatively
isolated. In addition, some have evolved unusually high degrees of clonality and others are representatives of endemic (unique)
evolutionary lineages. We here suggest that a consequence of local adaptation, isolation and genetic endemism is an increased
risk of failure in restoring extinct Baltic populations. Additionally, restricted availability of genetic variation owing
to lost variation and isolation may negatively impact the potential for evolutionary rescue following environmental change. 相似文献
472.
Rhind SM Kyle CE Mackie C Yates K Duff EI 《Environmental pollution (Barking, Essex : 1987)》2011,159(2):416-422
Muscle tissue was collected from ewes and lambs derived from farms throughout Scotland and sample concentrations of five endocrine disrupting compound groups were determined. Farms of origin were categorised according to geographic region. There were few statistically-significant differences with region or distance from cities. However, the magnitude of the difference between the highest and lowest mean values in ewe muscle from different regions exceeded 30% for 13 of the 15 compounds that were consistently detected in muscle, with animals derived from the industrialised region having the highest mean values for 11 of the 13 compounds. A less marked trend was apparent in the lamb muscle (8 of 13 highest were in the industrialised region). The physiological effects of such small differences in exposure to mixtures of pollutants remain to be determined. 相似文献
473.
Nikula S Manninen S Vapaavuori E Pulkkinen P 《Environmental pollution (Barking, Essex : 1987)》2011,159(7):1823-1830
Road traffic contributes considerably to ground-level air pollution and is therefore likely to affect roadside ecosystems. Differences in growth and leaf traits among 13 hybrid aspen (Populus tremula × P. tremuloides) clones were studied in relation to distance from a motorway. The trees sampled were growing 15 and 30 m from a motorway and at a background rural site in southern Finland. Litter decomposition was also measured at both the roadside and rural sites. Height and diameter growth rate and specific leaf area were lowest, and epicuticular wax amount highest in trees growing 15 m from the motorway. Although no significant distance × clone interactions were detected, clone-based analyses indicated differences in genotypic responses to motorway proximity. Leaf N concentration did not differ with distance from the motorway for any of the clones. Leaf litter decomposition was only temporarily retarded in the roadside environment, suggesting minor effects on nutrient cycling. 相似文献
474.
Raysoni AU Sarnat JA Sarnat SE Garcia JH Holguin F Luèvano SF Li WW 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2476-2486
Paired indoor and outdoor concentrations of fine and coarse particulate matter (PM), PM2.5 reflectance [black carbon(BC)], and nitrogen dioxide (NO2) were determined for sixteen weeks in 2008 at four elementary schools (two in high and two in low traffic density zones) in a U.S.-Mexico border community to aid a binational health effects study. Strong spatial heterogeneity was observed for all outdoor pollutant concentrations. Concentrations of all pollutants, except coarse PM, were higher in high traffic zones than in the respective low traffic zones. Black carbon and NO2 appear to be better traffic indicators than fine PM. Indoor air pollution was found to be well associated with outdoor air pollution, although differences existed due to uncontrollable factors involving student activities and building/ventilation configurations. Results of this study indicate substantial spatial variability of pollutants in the region, suggesting that children’s exposures to these pollutants vary based on the location of their school. 相似文献
475.
太湖蓝藻水华分级及其时空变化 总被引:5,自引:0,他引:5
根据MODIS影像和实地监测叶绿素a浓度数据,采用太湖蓝藻水华分级评估方法,对2004~2008年太湖不同类型蓝藻水华类型进行评估并统计分析,探求太湖蓝藻水华特征及其时空变化规律,以期为太湖蓝藻水华预防和预警提供支持。结果表明:(1)2004~2008年,全湖共发生蓝藻水华414次,以小型蓝藻水华为主,发生333次,占总次数的80.43%;随着蓝藻水华级别的增加,发生次数逐渐减少;(2)空间上,蓝藻水华主要发生在太湖的北部和西部区域,并且蓝藻水华发生级别由高到低基本上沿西北-东南方向分布;(3)年际变化上,蓝藻水华发生次数呈逐渐增加趋势,蓝藻水华级别较高、次数较多的年份主要集中于2006年和2007年;(4)年内变化上,4~8月份,蓝藻水华发生次数呈增加趋势,8~11月,蓝藻水华发生次数逐渐减少。并且,蓝藻水华主要集中于5月和7~10月份,尤其是8~10月。 相似文献
476.
Unusual Salinity Conditions in the Yangtze Estuary in 2006: Impacts of an Extreme Drought or of the Three Gorges Dam? 总被引:1,自引:0,他引:1
During the extreme dry year of 2006, abnormal salinity conditions in the Changjiang Estuary of the Yangtze River occurred
in partial coincidence with the second impoundment phase of the TGD (Three Gorges Dam). Analysis of discharge observations
in the upper reaches of the estuary and of salinity observations in the estuary as a whole reveals that in 2006 salinity was
over 100 mg/l during 275 days, over 250 mg/l during 75 days and over 400 mg/l during 48 days. It is well known that this is
due to extreme low discharges from the upper catchment area into the estuary. Moreover, large amounts of water consumed along
the lower reaches of the Yangtze River can also aggravate the low discharges that lead to stronger saltwater intrusion in
the estuary. Of the 75 days that salinity was over 250 mg/l, the low discharge was decreased further by 10 to 20% due to water
consumption. The additional impact of the impoundment phase of the TGD (lasting 37 days in autumn) was noticeable only during
7 days in 2006. During that period, the relative contributions of the TGD and the water consumption in the lower reaches of
the Yangtze River amounted to 70 and 30%, respectively. It may be concluded that the impact of the second impoundment phase
of the TGD on salinity intrusion in the estuary was modest, while the extreme drought of 2006 was the dominant cause. 相似文献
477.
478.
Chile and Peru produce almost 45% of world’s mine copper output. This situation reflects their natural endowment and mining tradition, but is also the result of development processes undertaken over the last decades. As a result, both countries multiplied its mine copper production in more than 3 times in the last 20 years. Mining labor productivity played a central role achieving these amazing growth rates. Although there is a consensus about the relevance of this variable for the mining industry, the specific factors behind labor productivity changes are not completely understood. 相似文献
479.
480.
The wetlands play an important role in carbon storage, especially at high latitudes, at which they store nearly one-third of global soil carbons. However, few studies have investigated the emissions of CO(2), CH(4) and N(2)O in the long-term, especially effects of freeze-thaw cycles on these gases emissions in freshwater marsh ecosystems. In this paper, we collected greenhouse gas emission data from a freshwater marsh area in China for 4 years, evaluated their release variables and speculated on their potential atmospheric impact. For this paper, we report on the CO(2), CH(4) and N(2)O emission rates recorded from June 2002 to November 2005 in the Sanjiang Plain of northeast China. We measured their interannual variations and fluctuations, as well as factors affecting their emissions, and estimated their regulation and freeze-thaw cycle impacts. Our results revealed obvious CO(2) and CH(4) emission fluctuations during the winter months, and during the freeze-thaw cycle, and a strong interannual variation during the growing season. Overall, we documented a close relationship between the CO(2) and CH(4) emissions, implicating some regulatory commonality. We determined that the marsh was a N(2)O sink during the winter, but a significant source of N(2)O during the freeze-thaw cycle as the temperature increased, especially in early summer. During the thaw-freeze period, the N(2)O levels were positively correlated with the water depth. Additionally, water depth greatly governed the interannual variation of the N(2)O emissions from the marshes during the thaw-freeze period. 相似文献