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   28003篇
  免费   196篇
  国内免费   248篇
安全科学   597篇
废物处理   1281篇
环保管理   3407篇
综合类   3987篇
基础理论   7669篇
环境理论   7篇
污染及防治   6793篇
评价与监测   2210篇
社会与环境   2365篇
灾害及防治   131篇
  2023年   103篇
  2022年   238篇
  2021年   260篇
  2020年   161篇
  2019年   198篇
  2018年   830篇
  2017年   788篇
  2016年   953篇
  2015年   446篇
  2014年   671篇
  2013年   1997篇
  2012年   944篇
  2011年   1617篇
  2010年   1225篇
  2009年   1300篇
  2008年   1526篇
  2007年   1824篇
  2006年   982篇
  2005年   882篇
  2004年   844篇
  2003年   890篇
  2002年   877篇
  2001年   1013篇
  2000年   714篇
  1999年   448篇
  1998年   314篇
  1997年   280篇
  1996年   311篇
  1995年   317篇
  1994年   278篇
  1993年   264篇
  1992年   268篇
  1991年   238篇
  1990年   255篇
  1989年   257篇
  1988年   222篇
  1987年   180篇
  1986年   146篇
  1985年   168篇
  1984年   201篇
  1983年   190篇
  1982年   216篇
  1981年   170篇
  1980年   148篇
  1979年   179篇
  1978年   139篇
  1977年   128篇
  1976年   121篇
  1975年   103篇
  1974年   101篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
111.
Simmonds S  Cuttst F  Dick B 《Disasters》1985,9(1):61-69
Many problems have been encountered in the planning and implementation of health care in refugee camps, and more specifically in the training of refugees as primary health care workers. A review of the published literature and a "survey" of the opinions and experiences of refugee, national and international health personnel regarding training has therefore been undertaken to provide an overview of what has been done and to make recommendations for future work.
The review highlights the need to reallocate resources away from high visibility emergency aid to development activities, such as training, that will create an infrastructure for primary health care and promote self-reliance.  相似文献   
112.
Environment, Development and Sustainability - Land use and land cover change (LULCC) is one of the problems that the world has been facing for the last few decades despite political attention....  相似文献   
113.
114.
115.
116.
The distribution and sources of organochlorine pesticides (OCPs) in air and surface waters were monitored in Nairobi City using triolein-filled semipermeable membrane devices (SPMDs). The SPMDs were extracted by dialysis using n-hexane, followed by cleanup by adsorption chromatography on silica gel cartridges. Sample analysis was done by GC-ECD and confirmed by GC–MS. Separation of means was achieved by analysis of variance, followed by pair-wise comparison using the t-test (p≤ 0.05). The total OCPs ranged between 0.018 – 1.277 ng/m3 in the air and <LOD – 1391.000 ng/m3 in surface waters. Based on the results, the means of Industrial Area, Dandora and Kibera were not significantly different (p≤ 0.05), but were higher (p≤ 0.05) than those of City square and Ngong’ Forest. The results revealed non-significant (p≤ 0.05) contribution of long-range transport to OCP pollution in Nairobi City. This indicated possible presence of point sources of environmental OCPs in the city. The water-air fugacity ratios indicated that volatilization and deposition played an important role in the spatial distribution of OCPs in Nairobi City. This indicated that contaminated surface waters could be major sources of human exposure to OCPs, through volatilization. The incremental lifetime cancer risks (ILCR) determined from inhalation of atmospheric OCPs were 2.3745  ×  10?13 – 1.6845  ×  10?11 (adult) and 5.5404  ×  10?13 – 3.9306  ×  10?11 (child) in the order: Dandora > Kibera > Industrial Area > City Square > Ngong’ Forest. However, these were lower than the USEPA acceptable risks, 10?6 – 10?4. This study concluded that atmospheric OCPs did not pose significant cancer risks to the residents.  相似文献   
117.

The combination of concentrated solar power–chemical looping air separation (CSP-CLAS) with an oxy-fuel combustion process for carbon dioxide (CO2) capture is a novel system to generate electricity from solar power and biomass while being able to store solar power efficiently. In this study, the computer program Advanced System for Process Engineering Plus (ASPEN Plus) was used to develop models to assess the process performance of such a process with manganese (Mn)-based oxygen carriers on alumina (Al2O3) support for a location in the region of Seville in Spain, using real solar beam irradiance and electricity demand data. It was shown that the utilisation of olive tree prunings (Olea europaea) as the fuel—an agricultural residue produced locally—results in negative CO2 emissions (a net removal of CO2 from the atmosphere). Furthermore, it was found that the process with an annual average electricity output of 18 MW would utilise 2.43% of Andalusia’s olive tree prunings, thereby capturing 260.5 k-tonnes of CO2, annually. Drawbacks of the system are its relatively high complexity, a significant energy penalty in the CLAS process associated with the steam requirements for the loop-seal fluidisation, and the gas storage requirements. Nevertheless, the utilisation of agricultural residues is highly promising, and given the large quantities produced globally (~?4 billion tonnes/year), it is suggested that other novel processes tailored to these fuels should be investigated, under consideration of a future price on CO2 emissions, integration potential with a likely electricity grid system, and based on the local conditions and real data.

  相似文献   
118.
119.
120.
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