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   732篇
  免费   3篇
  国内免费   8篇
安全科学   19篇
废物处理   37篇
环保管理   78篇
综合类   139篇
基础理论   106篇
污染及防治   258篇
评价与监测   64篇
社会与环境   39篇
灾害及防治   3篇
  2023年   9篇
  2022年   25篇
  2021年   17篇
  2020年   14篇
  2019年   7篇
  2018年   19篇
  2017年   25篇
  2016年   32篇
  2015年   24篇
  2014年   44篇
  2013年   78篇
  2012年   52篇
  2011年   55篇
  2010年   32篇
  2009年   33篇
  2008年   54篇
  2007年   37篇
  2006年   36篇
  2005年   38篇
  2004年   20篇
  2003年   24篇
  2002年   14篇
  2001年   7篇
  2000年   4篇
  1999年   2篇
  1998年   4篇
  1997年   3篇
  1996年   6篇
  1995年   2篇
  1994年   7篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   4篇
  1986年   2篇
  1982年   1篇
  1978年   1篇
  1973年   1篇
  1954年   1篇
排序方式: 共有743条查询结果,搜索用时 312 毫秒
661.
662.
663.
664.
The aim of this work consists on determining biomass fuels properties and studying their relation with fixed and variable costs of stores and handling systems. To do that, dimensions (length and diameter), bulk density, particle density and durability of several brands and batches of wood pellets and briquettes were tested, according to international standards. Obtained results were compared with those in literature. Bulk density tests were applied for several other biomass fuels too, and later used to determinate which ones of all the biomass-fuels tested are economically more profitable for a typical transport/store system made of a screw conveyor and a concrete bunker silo.  相似文献   
665.
Placental development is a major cause of a successful pregnancy, and in the presence of placental dysfunction, there is a higher risk of pregnancy complications. Doppler technology can be used for screening and detecting the more common pregnancy-associated diseases like preeclampsia, intrauterine growth retardation, and perinatal loss. In this review, the biophysical markers are discussed in the light of the latest information that appeared in the medical literature. © 2014 John Wiley & Sons, Ltd.  相似文献   
666.
667.
668.
669.
670.
The conventional (hot pressing or HP) and the novel (spark plasma sintering or SPS) consolidation techniques were compared when processing Ti–Al2O3–TiC powders obtained by self-propagating high-temperature synthesis (SHS). It was found that the two different methods are able to produce similar materials, in some cases (Vickers hardness and wear rate) slightly better for SPSed samples. However, SPS does not need sintering temperatures as high as HP to obtain fully dense products. Most significantly, processing times were strongly reduced when adopting the SPS technique instead of HP, i.e. 4–7 min and about 5 h, respectively. Finally, when the total energies required during each SPS or HP experiment were compared, it was found that the use of the SPS technology allowed for an energy saving in the order of 90–95%. This fact makes SPS significantly advantageous from environmental and economical points of view compared to HP.  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