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   1006篇
  免费   32篇
  国内免费   8篇
安全科学   52篇
废物处理   44篇
环保管理   272篇
综合类   85篇
基础理论   261篇
环境理论   2篇
污染及防治   217篇
评价与监测   67篇
社会与环境   38篇
灾害及防治   8篇
  2023年   9篇
  2022年   17篇
  2021年   12篇
  2020年   7篇
  2019年   14篇
  2018年   21篇
  2017年   21篇
  2016年   29篇
  2015年   31篇
  2014年   26篇
  2013年   71篇
  2012年   60篇
  2011年   60篇
  2010年   40篇
  2009年   60篇
  2008年   72篇
  2007年   60篇
  2006年   58篇
  2005年   33篇
  2004年   42篇
  2003年   40篇
  2002年   37篇
  2001年   12篇
  2000年   19篇
  1999年   14篇
  1998年   15篇
  1997年   11篇
  1996年   14篇
  1995年   15篇
  1994年   18篇
  1993年   11篇
  1992年   9篇
  1991年   7篇
  1990年   5篇
  1989年   9篇
  1988年   5篇
  1987年   4篇
  1986年   4篇
  1985年   8篇
  1984年   5篇
  1983年   10篇
  1982年   8篇
  1981年   3篇
  1980年   4篇
  1979年   3篇
  1978年   2篇
  1977年   4篇
  1976年   2篇
  1971年   2篇
  1957年   2篇
排序方式: 共有1046条查询结果,搜索用时 218 毫秒
101.
An account is given of HAZOP study training from the simple methods used initially to modern methods such as e-learning courses. An especial mention is given to the role of Trevor Kletz in initiating public courses.  相似文献   
102.
103.
104.
Remotely operated vehicle dive video recordings of deep-sea squid ink release were examined to determine species, ink release type, release depth, and accompanying behavior/s. Ink release was commonly observed between the surface and 1,842.1 m in Monterey Bay, CA, and surrounding waters. Six ink release types were observed: pseudomorphs, pseudomorph series, ink ropes, clouds/smokescreens, diffuse puffs and mantle fills. Each species released ink throughout all or most of its depth range; inking was not limited to shallow, sunlit waters. Individuals of each species produced one ink release type more commonly than other types, however, multiple ink types could be released by individuals of all species. Common behaviors preceded and/or followed each release type; pseudomorphs and pseudomorph series were generally associated with escape behaviors, while ink ropes, clouds, and puffs normally involved the animal remaining adjacent to or amid the ink. Deep-sea squids may use ink for defensive purposes similar to those of shallow-dwelling species when they release pseudomorphs, pseudomorph series, or large clouds, and may use ink puffs in intra-specific communication. The function of ink ropes and mantle fills is unknown.  相似文献   
105.
106.
107.
The catalytic effects of copper and iron compounds were examined for their behavior in promoting formation of chlorine (Cl2), the major chlorinating agent of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), in an environment simulating that of municipal waste fly ash. Formation of Cl2 occurred as a result of a metal-catalyzed reaction of HCl with O2. Catalytic activity was greatest at a temperature of approximately 400 °C, supporting a theory of de novo synthesis of PCDDs and PCDFs on fly ash particles downstream of waste combustion.  相似文献   
108.
109.
Estuarine ecosystems are largely influenced by watersheds directly connected to them. In the Mobile Bay, Alabama watersheds we examined the effect of land cover and land use (LCLU) changes on discharge rate, water properties, and submerged aquatic vegetation, including freshwater macrophytes and seagrasses, throughout the estuary. LCLU scenarios from 1948, 1992, 2001, and 2030 were used to influence watershed and hydrodynamic models and evaluate the impact of LCLU change on shallow aquatic ecosystems. Overall, our modeling results found that LCLU changes increased freshwater flows into Mobile Bay altering temperature, salinity, and total suspended sediments (TSS). Increased urban land uses coupled with decreased agricultural/pasture lands reduced TSS in the water column. However, increased urbanization or agricultural/pasture land coupled with decreased forest land resulted in higher TSS concentrations. Higher sediment loads were usually strongly correlated with higher TSS levels, except in areas where a large extent of wetlands retained sediment discharged during rainfall events. The modeling results indicated improved water clarity in the shallow aquatic regions of Mississippi Sound and degraded water clarity in the Wolf Bay estuary. This integrated modeling approach will provide new knowledge and tools for coastal resource managers to manage shallow aquatic habitats that provide critical ecosystem services.  相似文献   
110.
A comprehensive review of online, official, and scientific literature was carried out in 2012–13 to develop a framework of disaster social media. This framework can be used to facilitate the creation of disaster social media tools, the formulation of disaster social media implementation processes, and the scientific study of disaster social media effects. Disaster social media users in the framework include communities, government, individuals, organisations, and media outlets. Fifteen distinct disaster social media uses were identified, ranging from preparing and receiving disaster preparedness information and warnings and signalling and detecting disasters prior to an event to (re)connecting community members following a disaster. The framework illustrates that a variety of entities may utilise and produce disaster social media content. Consequently, disaster social media use can be conceptualised as occurring at a number of levels, even within the same disaster. Suggestions are provided on how the proposed framework can inform future disaster social media development and research.  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