全文获取类型
收费全文 | 806篇 |
免费 | 27篇 |
国内免费 | 24篇 |
专业分类
安全科学 | 192篇 |
废物处理 | 22篇 |
环保管理 | 95篇 |
综合类 | 415篇 |
基础理论 | 33篇 |
污染及防治 | 24篇 |
评价与监测 | 21篇 |
社会与环境 | 15篇 |
灾害及防治 | 40篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 11篇 |
2018年 | 7篇 |
2017年 | 10篇 |
2016年 | 14篇 |
2015年 | 6篇 |
2014年 | 27篇 |
2013年 | 23篇 |
2012年 | 56篇 |
2011年 | 61篇 |
2010年 | 47篇 |
2009年 | 57篇 |
2008年 | 24篇 |
2007年 | 74篇 |
2006年 | 68篇 |
2005年 | 54篇 |
2004年 | 44篇 |
2003年 | 48篇 |
2002年 | 49篇 |
2001年 | 25篇 |
2000年 | 30篇 |
1999年 | 20篇 |
1998年 | 14篇 |
1997年 | 10篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 4篇 |
1993年 | 8篇 |
1992年 | 9篇 |
1991年 | 3篇 |
1990年 | 3篇 |
排序方式: 共有857条查询结果,搜索用时 17 毫秒
21.
江西省是我国南方山地森林资源丰富的省份之一。本文详细分析了江西山地森林资源的现状和存在的问题,并就山地森林的保护和合理开发利用提出了6项综合治理措施。 相似文献
22.
西部管道工程需要通过安西极旱荒漠国家级自然保护区的试验区,该保护区有中亚荒漠最具代表性的植被类型,为保护试验区的植被,建设单位从源头保护开始做起,在施工组织设计、施工期环境管理和生态恢复上采取了一系列措施,确保了管道施工对区域环境的影响控制在预测的范围内,实现了生产和环境保护双赢。 相似文献
23.
运用预防医学手段减少疾病,维护灾民身体健康,是抗洪救灾的重要内容。本文结合沟后水库垮坝后采取的对策来概述洪涝灾害的卫生防疫措施,供有关部门参考。 相似文献
24.
25.
随着计算机的普及 ,局域网络越来越广为利用 ,但也出现了相应的失密问题。本文从信息及实体两个方面 ,论述了局域网络的保密措施。 相似文献
26.
27.
Singapore has pledged to attain 7–11% Business-As-Usual carbon emissions reduction by 2020. About 19% of CO2 contribution stemmed from road transport in 2005. Commercial vehicles, which uses mainly diesel, consumed 695 million litres diesel in 2012. An estimated 115,585 tonnes or 127 million litres cooking oils (derived from seeds/fruits) were consumed in 2010, in which the bulk of used cooking oil is re-incorporated into the food preparation process while only a small amount is being recycled into biodiesel or disposed into the sewerage. Nevertheless, the present research reveals that biodiesel derived from spent cooking oil has potential to be a viable fuel supplement. Surveys were carried out involving three market segments – suppliers, processors and end-users – to identify the barriers and obstacles in mass production of biodiesel. A key enabler of biodiesel as a fuel supplement towards a greener environment lies in government mandate/policies in promoting greater biodiesel usage. 相似文献
28.
摘要:对2006~2011年宜良县城NO2、SO2、PM10监测数据进行统计分析,认为SO2是县城的主要污染物。3种污染物年际浓度变化为:NO2、SO2下降趋势显著,PM10下降趋势不显著;季节浓度变化为:S02冬〉秋〉春〉夏,N02、PM10冬〉春〉秋〉夏,并提出防治建议。 相似文献
29.
介绍了地铁运行振动对环境的影响,概述了目前国内常用的轨道减振措施。结合天津地铁1号线实际工程情况分析了减振措施及效果。 相似文献
30.
Diatom Thalassiosira weissflogii in oligotrophic versus eutrophic culture: models and ultrastructure
Populations of marine diatom Thalassiosira weissflogii were grown in continuous cultures enriched with f/2 medium. One of the two contrasting cultures (‘eutrophic’) received 5.6 times more nutrients than the other (‘oligotrophic’). Two mathematical models are analyzed to estimate eutrophication differences. The second model based on the Michaelis–Menten uptake and Droop growth shows that cells in the eutrophic culture should have about 56% higher content of silica which is the limiting nutrient. Diatom samples were prepared for the transmission electron microscopy after cells have been kept in chemostats for 37 days. The structure of diatom cells was investigated and a comparison is made between cells grown in oligotrophic and eutrophic conditions. In eutrophic culture, dividing cells were encountered more frequently while cell concentration was approximately equal in both chemostats. The central vacuole of cells in eutrophic culture accumulated dispersed and compact material from amorphous to spherical shape. In some cells the large central vacuole had fibrilar and peppered dense materials in addition to translucent granules, vesicules and multivesicular bodies. In the cytoplasm we found increased number of multivesicular bodies, dense and lucent granules some of which enclose membrane particles and lucent vesicules. Dense material depositions observed in the vacuole are also seen in the cytoplasm associated with organelles, mitochondria and plasmalemma. Cells have well-developed, active and slightly increased number of dictyosomes (5–6). Some dictyosomes with dense secretory material in the cistern are apparently engaged in a granule formation process. Functional significance of dense material in the central vacuole, which has not been observed in cells grown in oligotrophic condition, is discussed. 相似文献