全文获取类型
收费全文 | 1067篇 |
免费 | 62篇 |
国内免费 | 73篇 |
专业分类
安全科学 | 75篇 |
废物处理 | 23篇 |
环保管理 | 347篇 |
综合类 | 333篇 |
基础理论 | 75篇 |
污染及防治 | 152篇 |
评价与监测 | 88篇 |
社会与环境 | 47篇 |
灾害及防治 | 62篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 18篇 |
2021年 | 32篇 |
2020年 | 39篇 |
2019年 | 28篇 |
2018年 | 42篇 |
2017年 | 40篇 |
2016年 | 50篇 |
2015年 | 36篇 |
2014年 | 43篇 |
2013年 | 44篇 |
2012年 | 53篇 |
2011年 | 98篇 |
2010年 | 43篇 |
2009年 | 71篇 |
2008年 | 80篇 |
2007年 | 53篇 |
2006年 | 58篇 |
2005年 | 25篇 |
2004年 | 33篇 |
2003年 | 37篇 |
2002年 | 27篇 |
2001年 | 29篇 |
2000年 | 25篇 |
1999年 | 26篇 |
1998年 | 15篇 |
1997年 | 19篇 |
1996年 | 14篇 |
1995年 | 14篇 |
1994年 | 16篇 |
1993年 | 3篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1980年 | 3篇 |
1979年 | 2篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有1202条查询结果,搜索用时 661 毫秒
611.
612.
613.
AHP法是规划决策管理的有效工具,本文通过在城市生态系统质量评价中AHP法的应用着重阐述了城市生态系统的层次结构分析和在多级递阶结构的基础上,经过判断矩阵的建立和运算,为城市生态系统质量评价中权重确定的科学化提供了定量的依据。 相似文献
614.
615.
This paper presents the main results of two studies of contrasting natural and man-induced conditions along the Pacific coast
of Baja California (Mexico), based on the assumption that ecological insight can be obtained from man-induced modifications
insofar as relevant activities are explicitly addressed as parts of the systems under study. The study is concerned with a
fragmented coastal succulent-sage scrub and showed that several patches of different size and age may harbor as many species
as non-fragmented areas, and that 83% of the original species assemblage persisted in the fragments, in which the invasion
by opportunistic exotic species may not progress beyond certain limits. The study of dune-backed and urban-backed beaches
showed a significantly greater abundance of the Snowy Plover (Charadrius alexandrinus) at the dune-backed beach, where a much more active back-shore feeding of adult birds and the only evidences of breeding
occurred. Both studies refer to landscape features of regional concern and its results may be used in conservation management.
The results on fragmented coastal succulentsage scrub may encourage alternative urban designs that keep patches of the original
landscape, thus meeting existing requirements of low density urban development for most of the coastal succulent-sage scrub
area. The evidence presented on the negative effects of dune destruction on the abundance, feeding and reproductive performance
of a threatened bird species has a bearing on the topic of biodiversity management. It may also contribute to the conservation
of the coastal dunes system. 相似文献
616.
以磁铁矿滤料与石英砂滤料为填设滤料层的级配模式一直广泛应用于油田含聚污水处理过程中,但这种滤料级配与污水过滤性能之间的影响关系及规律认识却较为缺乏,本文以悬浮粒子吸附与截留形成的聚集特征为切入,定量分析出水水质特性,对含聚污水过滤过程中滤料级配的影响效果展开数值模拟研究。研究认为:磁铁矿滤料层厚度较大的级配模式过滤具有更好的悬浮粒子吸附与截留效果,对更小粒径悬浮粒子过滤能力更优,但滤料填充高度比与过滤效果存在一定适配性;以1.28以上磁铁矿滤料厚度较大的级配模式过滤较低含聚浓度污水、以1.67以上磁铁矿滤料厚度较小的级配模式过滤较高含聚浓度污水,均可以使出水悬浮固体颗粒与油滴含量均低于5mg/L,满足过滤出水水质指标要求。 相似文献
617.
Brown RW Gonzales C Hooper MJ Bayat AC Fornerette AM McBride TJ Longoria T Mielke HW 《Environmental geochemistry and health》2008,30(6):541-547
Residential lead (Pb) contamination, resulting from decades-long use of leaded gasoline and lead-based paint, is likely to
be present in soils in most urban areas. A screening level sampling effort demonstrated that Lubbock, Texas, USA, like other
cities of its age and size, has areas of elevated soil Pb. This effort was based on soil sampling performed on residential,
commercial and thoroughfare properties. The focus of this study was to investigate that component of soil contamination due
to combustion of leaded gasoline. Soils were collected from the 1–2 cm surface layer from street-side property borders, well
away from buildings that might lead to soil contamination from leaded paint chips. All samples were analyzed for Pb after
a 1 M HNO3 mild extraction to determine the amount of bioavailable Pb. Two of three transects through the city demonstrated significant
trends of decreasing Pb concentrations with distance from the city center, paralleling a decrease in developed property age.
Peak soil Pb concentrations outside city development was 4.9 ± 0.6 mg/kg while the median concentration for the city was 35.4 mg/kg.
Peak soil Pb concentrations in the city center ranged from 90.0 to 174.0 mg/kg and decreased exponentially to 6.0–9.0 mg/kg
at the furthest terminus of the residential transects. 相似文献
618.
Kenneth W. Potter T. Matthew Boyington 《Journal of the American Water Resources Association》2020,56(2):323-332
River floodplains provide critical habitat for a wide range of animal and plant species and reduce phosphorus and nitrogen loads in streams. It has been observed that baseflow‐dominated streams flowing through wetlands are commonly at or near bankfull and overflow their banks much more frequently than other streams. However, there is very little published quantitative support for this observation. The study focuses on a 1‐km reach of Black Earth Creek, a stream in the Midwestern United States (U.S.). We used one‐dimensional hydraulic modeling to estimate bankfull discharge at evenly spaced stream cross sections, and two‐dimensional modeling to quantitate the extent of wetland inundation as a function of discharge. We then used historical streamflow data from two U.S. Geological Survey gaging stations to quantitate the frequency of wetland inundation. For the with‐sediment case, the frequency of overbank conditions at the 38 cross sections in the wetland ranged from 3 to 85 days per year and averaged 43 days per year. Ten percent of the wetland was inundated for an average of 35 days per year. For the without‐sediment case, the frequency of overbank conditions ranged from 2.6 to 48 days per year and averaged 14 days per year. Also, 10% of the wetland was inundated for an average of 25 days per year. These unusually high rates of floodplain inundation are likely due in part to the very low stream gradient and shallow depths of overbank flow. 相似文献
619.
近年来,城市化进程不断加剧,而生态环境也遭到了严重的破坏,特别是城市河道水环境的破坏,这也是当前急需解决的一项难题。在人们的日常生活和工作当中,水起着十分重要的作用,一旦城市河道出现问题,将会严重影响人们的正常生活,水资源的破坏是政府部门面临的主要困扰之一,也是阻碍城市经济发展的重要问题,为此,水利以及环保部门一定要采取措施进行解决,进而保证生态环境的发展。本文就城市河道水环境生态治理措施进行了深入分析和研究,以期为相关工作提供借鉴。 相似文献
620.
人类文明的发展,不断地在改变地球的生态环境,我们赖以生存的环境正在逐渐恶化,在城市中生活的人们远离了自然,生活环境已经不再健康,雾霾、水污染以及绿化的减少,都严重影响着人类自身的发展。在意识到环境对人类社会发展的重要性之后,人们开始重视城市环境的改造,引入原生态环境景观,希望获得人类与自然的和谐与平衡,在这样的背景下城市公园的概念受到了广泛的关注,城市公园的景观设计开始追求原生态,综合考虑了对原生态环境的保护和利用,不断完善城市公园的设计,发挥原有自然环境的作用,让人工设计与自然天成融为一体,打造城市中心的绿肺,改善城市生态环境,维护人类社会生产生活与自然环境的平衡,为人类建设更为宜居的生活环境。 相似文献