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   44449篇
  免费   501篇
  国内免费   345篇
安全科学   1391篇
废物处理   2067篇
环保管理   5971篇
综合类   7031篇
基础理论   11982篇
环境理论   18篇
污染及防治   10989篇
评价与监测   2974篇
社会与环境   2584篇
灾害及防治   288篇
  2022年   347篇
  2021年   416篇
  2020年   277篇
  2019年   330篇
  2018年   597篇
  2017年   655篇
  2016年   1003篇
  2015年   731篇
  2014年   1150篇
  2013年   3601篇
  2012年   1395篇
  2011年   1892篇
  2010年   1554篇
  2009年   1606篇
  2008年   1945篇
  2007年   1927篇
  2006年   1720篇
  2005年   1529篇
  2004年   1468篇
  2003年   1418篇
  2002年   1340篇
  2001年   1616篇
  2000年   1160篇
  1999年   690篇
  1998年   548篇
  1997年   587篇
  1996年   603篇
  1995年   708篇
  1994年   617篇
  1993年   555篇
  1992年   565篇
  1991年   554篇
  1990年   545篇
  1989年   524篇
  1988年   483篇
  1987年   428篇
  1986年   398篇
  1985年   401篇
  1984年   462篇
  1983年   416篇
  1982年   474篇
  1981年   395篇
  1980年   311篇
  1979年   348篇
  1978年   309篇
  1977年   269篇
  1975年   251篇
  1974年   251篇
  1973年   288篇
  1972年   261篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Russian Journal of Ecology - The dynamics of the species richness, breeding density, and structure of the community of birds occupying nest-boxes upon a 50-fold reduction of atmospheric emissions...  相似文献   
2.
Russian Journal of Ecology - In this paper, Ellenberg’s indicator values were estimated in order to soil nitrogen (N), pH (R) and soil moisture (M) in different subalpine grassland...  相似文献   
3.
Russian Journal of Ecology - A new method for assessing the response of biota to climatic changes in the ecosystem has been tested. In the Central Forest Natural Biosphere Reserve, the average...  相似文献   
4.
Environmental Chemistry Letters - Swine production generates large volumes of wastewater, rich in organic matter, nutrients and pathogens. Electrodisinfection is used to remove organic matter and...  相似文献   
5.
Brazil hosts the largest expanse of tropical ecosystems within protected areas (PAs), which shelter biodiversity and support traditional human populations. We assessed the vulnerability to climate change of 993 terrestrial and coastal-marine Brazilian PAs by combining indicators of climatic-change hazard with indicators of PA resilience (size, native vegetation cover, and probability of climate-driven vegetation transition). This combination of indicators allows the identification of broad climate-change adaptation pathways. Seventeen PAs (20,611 km2) were highly vulnerable and located mainly in the Atlantic Forest (7 PAs), Cerrado (6), and the Amazon (4). Two hundred fifty-eight PAs (756,569 km2), located primarily in Amazonia, had a medium vulnerability. In the Amazon and western Cerrado, the projected severe climatic change and probability of climate-driven vegetation transition drove vulnerability up, despite the generally good conservation status of PAs. Over 80% of PAs of high or moderate vulnerability are managed by indigenous populations. Hence, besides the potential risks to biodiversity, the traditional knowledge and livelihoods of the people inhabiting these PAs may be threatened. In at least 870 PAs, primarily in the Atlantic Forest and Amazon, adaptation could happen with little or no intervention due to low climate-change hazard, high resilience status, or both. At least 20 PAs in the Atlantic Forest, Cerrado, and Amazonia should be targeted for stronger interventions (e.g., improvement of ecological connectivity), given their low resilience status. Despite being a first attempt to link vulnerability and adaptation in Brazilian PAs, we suggest that some of the PAs identified as highly or moderately vulnerable should be prioritized for testing potential adaptation strategies in the near future.  相似文献   
6.
7.
Unsustainable wildlife trade affects biodiversity and the livelihoods of communities dependent upon those resources. Wildlife farming has been proposed to promote sustainable trade, but characterizing markets and understanding consumer behavior remain neglected but essential steps in the design and evaluation of such operations. We used sea turtle trade in the Cayman Islands, where turtles have been farm raised for human consumption for almost 50 years, as a case study to explore consumer preferences toward wild‐sourced (illegal) and farmed (legal) products and potential conservation implications. Combining methods innovatively (including indirect questioning and choice experiments), we conducted a nationwide trade assessment through in‐person interviews from September to December 2014. Households were randomly selected using disproportionate stratified sampling, and responses were weighted based on district population size. We approached 597 individuals, of which 37 (6.2%) refused to participate. Although 30% of households had consumed turtle in the previous 12 months, the purchase and consumption of wild products was rare (e.g., 64–742 resident households consumed wild turtle meat [i.e., 0.3–3.5% of households] but represented a large threat to wild turtles in the area due to their reduced populations). Differences among groups of consumers were marked, as identified through choice experiments, and price and source of product played important roles in their decisions. Despite the long‐term practice of farming turtles, 13.5% of consumers showed a strong preference for wild products, which demonstrates the limitations of wildlife farming as a single tool for sustainable wildlife trade. By using a combination of indirect questioning, choice experiments, and sales data to investigate demand for wildlife products, we obtained insights about consumer behavior that can be used to develop conservation‐demand‐focused initiatives. Lack of data from long‐term social–ecological assessments hinders the evaluation of and learning from wildlife farming. This information is key to understanding under which conditions different interventions (e.g., bans, wildlife farming, social marketing) are likely to succeed.  相似文献   
8.
Environmental Science and Pollution Research - Seasonal distribution of phytoplankton community and size structure was assessed in three different tropical ecosystems of the western Bay of Bengal...  相似文献   
9.
10.
Journal of Material Cycles and Waste Management - The present research work focused on fabricating Biodegradable Plate (BD plate) composed of rice husk ash, bagasse and corn starch which is...  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