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   63篇
  免费   0篇
  国内免费   3篇
废物处理   3篇
环保管理   4篇
综合类   38篇
基础理论   9篇
污染及防治   6篇
评价与监测   3篇
社会与环境   3篇
  2023年   1篇
  2022年   2篇
  2021年   1篇
  2019年   5篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   3篇
  2014年   3篇
  2013年   7篇
  2012年   3篇
  2011年   7篇
  2010年   5篇
  2009年   2篇
  2008年   5篇
  2007年   1篇
  2006年   3篇
  2005年   4篇
  2004年   1篇
  2003年   1篇
  2002年   2篇
  1997年   1篇
  1995年   1篇
  1992年   1篇
  1990年   1篇
  1981年   2篇
排序方式: 共有66条查询结果,搜索用时 15 毫秒
61.
Prenatal morphology of Meckel's syndrome was studied in five fetuses of different gestational age, that had been aborted because ultrasonography and elevated amniotic AFP-levels indicated neural tube defect. Histologically, the enlarged polycystic kidneys were completely alike with respect to the type of involvement and differed only in the severity of changes. They could be identified as type III cystic kidneys according to the classification of Potter. Proliferation of hepatic bile ducts and slight cystic dilatation of pancreatic ducts is already evident in the youngest fetus. Additional cyst formation in the epididymis was found in one of the cases. Occipital encephalocele, located within an apical occipital bone defect was always associated with a second mostly occult encephalocele protruding through a separate defect of the basal occipital squame and of the first and second vertebral arch. It is assumed that double encephalocele represents a constant finding in Meckel's syndrome, indicating a specific pattern within the disturbance of neural tube closure.  相似文献   
62.
This paper explores the implications of a form of nonconvexity in individual preferences over the public good “cleanliness.” The implications of this nonconvexity on equilibrium outcomes, welfare analysis, the process of development, and optimal government policy are examined. The nonconvexity can imply a role for government in providing a commitment to a clean environment even if the government has a cost disadvantage in cleaning compared with individuals. By providing a credible commitment to a clean environment the government can induce private individuals to undertake optimal levels of cleaning on their own.  相似文献   
63.
64.
65.
66.
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