首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
3.
4.
5.

New political, economical, and technical developments have changed the character of world fisheries. The exploitation of relatively small marine organisms, mainly pelagic fish, as a source of protein and the large distant-water fishing fleets of some countries operating worldwide make it possible to change marine ecosystems and particularly the upper parts of the food chain rapidly and drastically. The paper discusses recent changes in North Sea fish stocks and the ecological effects of antarctic whaling.

  相似文献   

6.
7.
8.
9.
A "European Biosafety Workshop on the Uncontained Use of Modified Organisms in the Environment" was held in Berlin on 27-30 November 1988. The author's concluding remarks are given here in a free German translation. The article briefly summarizes the overall conditions for a general evaluation of potential benefits and risks that may be associated with the use of genetically modified organisms.  相似文献   

10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
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