全文获取类型
收费全文 | 329篇 |
免费 | 4篇 |
专业分类
安全科学 | 9篇 |
废物处理 | 11篇 |
环保管理 | 39篇 |
综合类 | 161篇 |
基础理论 | 51篇 |
污染及防治 | 40篇 |
评价与监测 | 13篇 |
社会与环境 | 7篇 |
灾害及防治 | 2篇 |
出版年
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 9篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 11篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 8篇 |
2007年 | 7篇 |
2006年 | 7篇 |
2005年 | 4篇 |
2003年 | 6篇 |
2002年 | 6篇 |
1998年 | 5篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1994年 | 11篇 |
1993年 | 9篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1985年 | 5篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1972年 | 5篇 |
1971年 | 3篇 |
1970年 | 7篇 |
1969年 | 3篇 |
1965年 | 4篇 |
1964年 | 5篇 |
1963年 | 3篇 |
1962年 | 4篇 |
1961年 | 4篇 |
1960年 | 5篇 |
1959年 | 5篇 |
1957年 | 7篇 |
1956年 | 4篇 |
1955年 | 9篇 |
1954年 | 3篇 |
1952年 | 3篇 |
1934年 | 4篇 |
排序方式: 共有333条查询结果,搜索用时 15 毫秒
91.
92.
/ Protected area management is increasingly important throughout the world, particularly in less developed countries and arid regions. The Middle East, includingJordan, has important and unique resources due to its varied topography and climate. In Jordan, the protected areas are privately, rather than publicly, managed, and this provides for a unique and somewhat challenging management effort. The purpose of this paper is to review the establishment and administration of Jordan's protected areas with particular emphasis on the challenges of multiple administrative and legislative layers, departmental working relationships, and a paucity of funding. Interviews with government and nongovernmental experts in Jordan, coupled with a review of pertinent academic and planning literature, served as the information base for this study. Despite new legislative and administrative initiatives, results reveal important and continuing challenges for Jordan. Recommendations include completion of protected area inventories, government wide institutional strengthening, partnering with organizations and the public, as well as legislative reexamination. 相似文献
93.
A project to characterize the radionuclide and chemical components in natural spring waters in the vicinity of Saratoga Springs, New York (USA) has been completed. As a result of the measured radionuclide and chemical content, eight springs were labeled as mineral waters, whereas three springs contained very low concentrations of these components. The mineral waters were highly enriched in alkaline and alkaline-earth elements, as well as chloride ions. Three isotopes of radium ((224)Ra, (226)Ra, (228)Ra) were detected in the mineral waters and reached concentrations of 1, 20, and 2 Bq/L, respectively. Overall, the (226)Ra isotope constituted about 80% of the total radioactivity measured in the water samples. Dissolved uranium concentrations in the mineral waters were very low (mean approximately 50 mBq/L). 相似文献
94.
95.
96.
97.
98.
99.
100.