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   9479篇
  免费   439篇
  国内免费   3371篇
安全科学   655篇
废物处理   579篇
环保管理   708篇
综合类   4927篇
基础理论   1578篇
污染及防治   3674篇
评价与监测   397篇
社会与环境   400篇
灾害及防治   371篇
  2024年   17篇
  2023年   180篇
  2022年   497篇
  2021年   415篇
  2020年   318篇
  2019年   320篇
  2018年   339篇
  2017年   425篇
  2016年   515篇
  2015年   560篇
  2014年   680篇
  2013年   937篇
  2012年   788篇
  2011年   808篇
  2010年   622篇
  2009年   560篇
  2008年   674篇
  2007年   534篇
  2006年   514篇
  2005年   366篇
  2004年   291篇
  2003年   337篇
  2002年   325篇
  2001年   252篇
  2000年   278篇
  1999年   294篇
  1998年   240篇
  1997年   231篇
  1996年   198篇
  1995年   159篇
  1994年   119篇
  1993年   119篇
  1992年   108篇
  1991年   84篇
  1990年   34篇
  1989年   36篇
  1988年   30篇
  1987年   18篇
  1986年   14篇
  1985年   10篇
  1984年   7篇
  1983年   4篇
  1982年   11篇
  1981年   6篇
  1979年   2篇
  1976年   1篇
  1974年   2篇
  1973年   4篇
  1972年   3篇
  1970年   1篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
141.
Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter, remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon (DOC) and soil temperature, but negatively correlated with soil pH. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment (ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils, but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while pH and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota (69.65% in relative abundance) and Basidiomycota (30.35%). Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.  相似文献   
142.
Conflicts between local people's livelihoods and conservation have led to many unsuccessful conservation efforts and have stimulated debates on policies that might simultaneously promote sustainable management of protected areas and improve the living conditions of local people. Many government‐sponsored payments‐for‐ecosystem‐services (PES) schemes have been implemented around the world. However, few empirical assessments of their effectiveness have been conducted, and even fewer assessments have directly measured their effects on ecosystem services. We conducted an empirical and spatially explicit assessment of the conservation effectiveness of one of the world's largest PES programs through the use of a long‐term empirical data set, a satellite‐based habitat model, and spatial autoregressive analyses on direct measures of change in an ecosystem service (i.e., the provision of wildlife species habitat). Giant panda (Ailuropoda melanoleuca) habitat improved in Wolong Nature Reserve of China after the implementation of the Natural Forest Conservation Program. The improvement was more pronounced in areas monitored by local residents than those monitored by the local government, but only when a higher payment was provided. Our results suggest that the effectiveness of a PES program depends on who receives the payment and on whether the payment provides sufficient incentives. As engagement of local residents has not been incorporated in many conservation strategies elsewhere in China or around the world, our results also suggest that using an incentive‐based strategy as a complement to command‐and‐control, community‐ and norm‐based strategies may help achieve greater conservation effectiveness and provide a potential solution for the park versus people conflict.  相似文献   
143.
Environmental Science and Pollution Research - The massive use of silver nanoparticles (AgNPs) is potentially harmful to exposed humans. Although previous studies have found that AgNPs can induce...  相似文献   
144.
Environmental Science and Pollution Research - The concentrations of major and trace elements in the sediments from the Four River inlets of Dongting Lake were analysed. The results show that the...  相似文献   
145.
Environmental Science and Pollution Research - In recent years, the development and utilization of water resources have imposed great impacts on hydrological characteristics and ecological...  相似文献   
146.
Environmental Science and Pollution Research - It is of great significance for the coordinated development of the environment and the economy to study the impact of the human driving factors of...  相似文献   
147.
Environmental Science and Pollution Research - Mechanical vapor compression and multi-effect evaporation have been widely used in achieving zero discharge of desulfurization wastewater as they are...  相似文献   
148.
Environmental Science and Pollution Research - Plastics are synthetic polymers known for their outstanding durability and versatility, and have replaced traditional materials in many applications....  相似文献   
149.
Environmental Science and Pollution Research - Low-carbon transition has gradually become the focus of research on environmental issues. This paper takes China’s eight major economic regions...  相似文献   
150.
Environmental Science and Pollution Research - In this study, a composite aerogel (WP-MMT) composed of wastepaper (WP) and montmorillonite (MMT) was prepared by ambient pressure drying technology...  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