全文获取类型
收费全文 | 633篇 |
免费 | 8篇 |
国内免费 | 25篇 |
专业分类
安全科学 | 22篇 |
废物处理 | 20篇 |
环保管理 | 69篇 |
综合类 | 342篇 |
基础理论 | 64篇 |
污染及防治 | 99篇 |
评价与监测 | 26篇 |
社会与环境 | 10篇 |
灾害及防治 | 14篇 |
出版年
2023年 | 9篇 |
2022年 | 6篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2018年 | 7篇 |
2017年 | 10篇 |
2016年 | 11篇 |
2015年 | 20篇 |
2014年 | 14篇 |
2013年 | 22篇 |
2012年 | 15篇 |
2011年 | 18篇 |
2010年 | 26篇 |
2009年 | 27篇 |
2008年 | 17篇 |
2007年 | 23篇 |
2006年 | 21篇 |
2005年 | 22篇 |
2004年 | 12篇 |
2003年 | 16篇 |
2002年 | 12篇 |
2001年 | 9篇 |
2000年 | 8篇 |
1999年 | 14篇 |
1998年 | 9篇 |
1995年 | 10篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1984年 | 5篇 |
1967年 | 7篇 |
1966年 | 6篇 |
1965年 | 5篇 |
1963年 | 9篇 |
1961年 | 7篇 |
1959年 | 6篇 |
1958年 | 8篇 |
1957年 | 5篇 |
1956年 | 10篇 |
1955年 | 12篇 |
1954年 | 10篇 |
1939年 | 10篇 |
1938年 | 8篇 |
1937年 | 5篇 |
1933年 | 6篇 |
1932年 | 6篇 |
1929年 | 5篇 |
1926年 | 5篇 |
1925年 | 4篇 |
1914年 | 5篇 |
1913年 | 4篇 |
排序方式: 共有666条查询结果,搜索用时 46 毫秒
41.
Spivak-Birndorf LJ Stewart BW Capo RC Chapman EC Schroeder KT Brubaker TM 《Journal of environmental quality》2012,41(1):144-154
Sequential leaching experiments on coal utilization by-products (CUB) were coupled with chemical and strontium (Sr) isotopic analyses to better understand the influence of coal type and combustion processes on CUB properties and the release of elements during interaction with environmental waters during disposal. Class C fly ash tended to release the highest quantity of minor and trace elements-including alkaline earth elements, sodium, chromium, copper, manganese, lead, titanium, and zinc-during sequential extraction, with bottom ash yielding the lowest. Strontium isotope ratios ((87)Sr/(86)Sr) in bulk-CUB samples (total dissolution of CUB) are generally higher in class F ash than in class C ash. Bulk-CUB ratios appear to be controlled by the geologic source of the mineral matter in the feed coal, and by Sr added during desulfurization treatments. Leachates of the CUB generally have Sr isotope ratios that are different than the bulk value, demonstrating that Sr was not isotopically homogenized during combustion. Variations in the Sr isotopic composition of CUB leachates were correlated with mobility of several major and trace elements; the data suggest that arsenic and lead are held in phases that contain the more radiogenic (high-(87)Sr/(86)Sr) component. A changing Sr isotope ratio of CUB-interacting waters in a disposal environment could forecast the release of certain strongly bound elements of environmental concern. This study lays the groundwork for the application of Sr isotopes as an environmental tracer for CUB-water interaction. 相似文献
42.
The communication of science to science users is evolving to an approach that translates knowledge to targeted audiences.
Under this evolution, knowledge brokers play an increasingly important role and users help ‘pull’ the required science to
meet a policy or management imperative. To do this effectively, more insight is required into the knowledge seeking behaviour
of science users and practitioners. The findings from a series of interviews that identify the science needs of Ontario’s
Conservation Authorities (CAs) are presented. Results indicate that emerging functions, such as source water protection and
integrated water resource planning, require more science input than mature functions. Senior CA officials view personal communication
with their knowledgeable staff as the most used, accessible, trustworthy, relevant, shared, and preferable source of science
information. While the internet and media were considered highly accessible, they were not viewed as trustworthy. We found
no relationship between CA size and science use. Further research is needed to identify where junior and intermediate CA staff
obtain their science knowledge from and whether this varies as a function of CA size. Our findings will be of interest to
both policy/program communities and science providers. 相似文献
43.
Karl Ceulemans Steven Compernolle Jozef Peeters Jean-François Müller 《Atmospheric environment (Oxford, England : 1994)》2010,44(40):5434-5442
BOREAM, a detailed model for the gas-phase oxidation of α-pinene and its subsequent formation of Secondary Organic Aerosol (SOA), is tested against a large set of SOA yield measurements obtained in dark ozonolysis experiments. For the majority of experiments, modelled SOA yields are found to agree with measured yields to within a factor 2. However, the comparisons point to a general underestimation of modelled SOA yields at high temperatures (above 30 °C), reaching an order of magnitude or more in the worst cases, whereas modelled SOA yields are often overestimated at lower temperature (by a factor of about 2). Comparisons of results obtained using four different vapour pressure prediction methods indicate a strong sensitivity to the choice of the method, although the overestimated temperature dependence of the yields is found in all cases. Accounting for non-ideality of the aerosol mixture (based on an adapted UNIFAC method) has significant effects, especially at low yields. Our simulations show that the formation of oligomers through the gas-phase reactions of Stabilised Criegee Intermediates (SCI) with other molecular organic products could increase the SOA yield significantly only at very low relative humidity (below 1%). Further tests show that the agreement between model and measurements is improved when the ozonolysis mechanism includes additional production of non-volatile compounds. 相似文献
44.
非均相Fenton-流化床体系主要使用石英砂作为催化剂载体,该技术的实际应用由于催化剂活性寿命低、制备困难等原因而受到限制.提出了一种新型的Fenton-流化床催化剂——负载氧化铁陶粒.使用循环浸泡法制备的负载陶粒对苯甲酸模拟废水的处理效果良好.表征结果分析表明,载体表面铁含量大幅度上升,负载的氧化铁紧紧包裹在陶粒表面,且表面有大量缝隙,利于增加反应比表面积,而密度变化不大.该催化剂的催化活性重复性良好,重复使用4次后对苯甲酸模拟废水依然有较好的处理效果.使用该催化剂进行垃圾渗滤液的降解实验能在一定程度上减少亚铁的投加量,具有较好的实际应用前景. 相似文献
45.
46.
47.
48.
试论沙漠化灾害危险度评价因子体系 总被引:3,自引:0,他引:3
本文通过对国内外沙漠化灾害危险度评价因子体系研究现状的分析,从我国实际出发,根据沙漠化灾害危险度的基本内容,首次提出了沙漠化灾害危险度评价因子体系,并给出了相应因子的分级标准。 相似文献
49.
Amid growing concern about the conservation of renewable natural resources, the process, extent and symptoms of their degradation are examined with specific reference to the Upper Pokhara Valley. Based on a household survey, field observations, informal deliberations and land use analysis, the results of this study reveal that forests and grazing land have been subject to increasing degradation caused by demographic, socioeconomic and institutional factors. The intensity of degradation varies by watershed. In particular, rainfed pakho land on steep slopes is under the severe threat of accelerating soil erosion, despite the construction of terraces. This calls for the formulation of a comprehensive natural resource conservation strategy which should be based on a framework comprising an integrated population control programme, planned land use changes and institutional reforms . 相似文献
50.
中国沙漠化灾害现状及其趋势分析 总被引:4,自引:1,他引:4
沙漠化灾害是危及我国广大干旱半干旱及部分半湿润地区持续发展的重大灾种之一。我国现有沙漠化土地20.1万km^3,造成的年直接经济损失17.4-20.4亿元。年总损失达783-918亿元,受危害的212个县(旗、市)的沙漠化灾害程度分别是134个轻度、54个中度和24个重度,随着沙漠化灾害的不断发展,预计到2000年时我国沙漠化土地的面积将达到23.3万km^2,107个县(旗、市)的沙漠化灾害程度 相似文献