全文获取类型
收费全文 | 82篇 |
免费 | 0篇 |
国内免费 | 1篇 |
专业分类
安全科学 | 2篇 |
废物处理 | 6篇 |
环保管理 | 23篇 |
综合类 | 5篇 |
基础理论 | 18篇 |
污染及防治 | 23篇 |
评价与监测 | 3篇 |
社会与环境 | 3篇 |
出版年
2019年 | 1篇 |
2018年 | 1篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 1篇 |
2013年 | 14篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 4篇 |
2008年 | 2篇 |
2007年 | 1篇 |
2006年 | 1篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 4篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1996年 | 3篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有83条查询结果,搜索用时 0 毫秒
81.
Estimating recreational trout fishing damages in Montana's Clark Fork River basin: summary of a natural resource damage assessment 总被引:1,自引:0,他引:1
This paper summarizes a natural resource damage assessment for the State of Montana. Mining wastes have caused significant reductions in trout stocks in a 145-mile stretch of Montana's Silver Bow Creek and Clark Fork River. To estimate economic damages from decreases in catch rates, we develop and estimate an individual-based utility-theoretic model of where and how often an angler will fish as a function of travel costs, catch rates, and other influential characteristics of the site and individuals. The model includes resident and nonresident anglers who currently fish in Montana, and allows them to have different preferences. Demand parameters and expected catch rates are simultaneously estimated. The value of time is endogenously estimated as a proportion of the wage rate. Catch rates are linked to trout stocks through a stock-catch function. Collection of the angler data involved a three-step process: anglers were intercepted at 26 study sites, a subsample of anglers was selected to reflect the population trip-taking proportions to the study sites, and these anglers received follow-up surveys through the fishing season. Avidity weights are used to correct for the higher level of avidity inherent in intercept samples. 相似文献
82.
83.
In darkness, hamsters commute between their nest and a feeding site through path integration only, and therefore show cumulative
errors in the return direction to the nest. We examined whether a brief presentation of familiar room cues could reset the
path integrator. The hamsters could see the room cues either during, or at the end of, the outward journey to the food place,
in a conflict situation where motion cues and visual information were set at variance. In both conditions, the animals used
mainly visual information to return home. Thus, hamsters can determine their azimuth, and possibly their location, through
a visual fix, and can reset their path integrator through the fix. This allows them to update their position during further
locomotion in the dark and thus to compute a correct homing vector with respect to a visually induced reference frame. Taking
episodic positional fixes may greatly enhance the functional value of path integration.
Received: 17 May 2000 / Accepted in revised form: 11 September 2000 相似文献