首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2717篇
  免费   76篇
  国内免费   24篇
安全科学   124篇
废物处理   114篇
环保管理   813篇
综合类   267篇
基础理论   635篇
环境理论   1篇
污染及防治   581篇
评价与监测   162篇
社会与环境   85篇
灾害及防治   35篇
  2023年   17篇
  2022年   26篇
  2021年   36篇
  2020年   22篇
  2019年   34篇
  2018年   54篇
  2017年   51篇
  2016年   64篇
  2015年   54篇
  2014年   53篇
  2013年   293篇
  2012年   107篇
  2011年   140篇
  2010年   111篇
  2009年   119篇
  2008年   156篇
  2007年   144篇
  2006年   127篇
  2005年   95篇
  2004年   77篇
  2003年   98篇
  2002年   87篇
  2001年   56篇
  2000年   45篇
  1999年   24篇
  1998年   43篇
  1997年   28篇
  1996年   38篇
  1995年   46篇
  1994年   31篇
  1993年   44篇
  1992年   36篇
  1991年   15篇
  1990年   23篇
  1989年   17篇
  1988年   24篇
  1987年   15篇
  1986年   19篇
  1985年   28篇
  1984年   23篇
  1983年   24篇
  1982年   34篇
  1981年   34篇
  1980年   32篇
  1979年   21篇
  1978年   23篇
  1977年   11篇
  1976年   8篇
  1974年   7篇
  1972年   9篇
排序方式: 共有2817条查询结果,搜索用时 15 毫秒
111.
In agricultural areas, the contamination of feedstuffs with molds and mycotoxins presents major environmental and health concerns. During cattle feeding, fungi and mycotoxins were monitored in corn silage, oilseed cakes and bioaerosols collected in Normandy. Most of the corn silages were found to be contaminated by deoxynivalenol (mean concentration: 1883 μg kg?1) while a few of oilseed cakes were contaminated by alternariol, fumonisin B1 or gliotoxin. In ambient bioaerosols, the values for fungi per cubic meter of air varied from 4.3 × 102 to 6.2 × 105 cfu m?3. Seasonal variations were observed with some species like Aspergillus fumigatus which significantly decreased between the 2 seasons (P = 0.0186) while the Penicillium roqueforti group significantly increased during the second season (P = 0.0156). In the personal bioaerosols, the values for fungi per cubic meter of air varied from 3.3 103 to 1.7 106 cfu m?3 and the number of A. fumigatus spores significantly decreased between the 2 seasons (P = 0.0488). Gliotoxin, an immunosuppressive mycotoxin, was quantified in 3 personal filters at 3.73 μg m?3, 1.09 μg m?3 and 2.97 μg m?3.  相似文献   
112.
Chinese forest resources have become very scarce in the face of rapid economic growth demand, while the reform of collective forest right system is in full swing across the country. It will directly affect the regeneration level of forest resources and the diverse ecological value functions. In this article, the mainstream model paradigm of forest economics, that is, the basic framework of the Faustmann model and its evolution process are made in a more detailed explanation, especially the extended model in...  相似文献   
113.
114.
115.
The impact of residual PAHs (2250 ± 71 μg total PAHs g−1) following enhanced natural attenuation (ENA) of creosote-contaminated soil (7767 ± 1286 μg total PAHs g−1) was assessed using a variety of ecological assays. Microtox™ results for aqueous soil extracts indicated that there was no significant difference in EC50 values for uncontaminated, pre- and post-remediated soil. However, in studies conducted with Eisenia fetida, PAH bioaccumulation was reduced by up to 6.5-fold as a result of ENA. Similarly, Beta vulgaris L. biomass yields were increased 2.1-fold following ENA of creosote-contaminated soil. While earthworm and plant assays indicated that PAH bioavailability was reduced following ENA, the residual PAH fraction still exerted toxicological impacts on both receptors. Results from this study highlight that residual PAHs following ENA (presumably non-bioavailable to bioremediation) may still be bioavailable to important receptor organisms such as earthworms and plants.  相似文献   
116.
117.
Freshwater ecosystems are important for global biodiversity and provide essential ecosystem services. There is consensus in the scientific literature that freshwater ecosystems are vulnerable to the impacts of environmental change, which may trigger irreversible regime shifts upon which biodiversity and ecosystem services may be lost. There are profound uncertainties regarding the management and assessment of the vulnerability of freshwater ecosystems to environmental change. Quantitative approaches are needed to reduce this uncertainty. We describe available statistical and modeling approaches along with case studies that demonstrate how resilience theory can be applied to aid decision-making in natural resources management. We highlight especially how long-term monitoring efforts combined with ecological theory can provide a novel nexus between ecological impact assessment and management, and the quantification of systemic vulnerability and thus the resilience of ecosystems to environmental change.  相似文献   
118.
119.
Human population growth challenges efforts toward sustainability. People who are concerned about the environment, development, and sustainability are in a position to stress the importance of human population and to encourage people to choose small family size (Grossman, in Conserv Biol, 24(6), pp 1435–1436, 2010). Nevertheless, this vital subject has been treated infrequently in this journal. Of more than 500 articles published since its inception, only 15 have touched on human population, few have had population as a primary subject and only three have suggested that readers of this journal can and should have influence over population growth. This article concludes by suggesting ways that we who are concerned about sustainability should promote education about family planning and the advantages of small family size.  相似文献   
120.
To restore food security to a traditional African cropping system following a sudden loss of seed, genetic diversity must be re-established. This study examines the extent to which Cowpea diversity was reinstated two years after a flood disaster in Gaza Province, Mozambique. The contribution that seed from various sources made to the recovery was assessed using semi-structured interviews and morphological and molecular data. Data suggest that diversity had recovered to some extent yet there was evidence of a narrowing of the genetic base, with fewer rare alleles and differences in the distribution of allele frequencies. Although the main channels for accessing seed after the flood were seed relief and markets, these sources contributed to minimal and different diversity. It appears that diversity was regained primarily through social networking in the form of loans or gifts of seed from friends and relatives. The results of the study are discussed in relation to seed relief approaches.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号