全文获取类型
收费全文 | 780篇 |
免费 | 9篇 |
国内免费 | 14篇 |
专业分类
安全科学 | 37篇 |
废物处理 | 41篇 |
环保管理 | 214篇 |
综合类 | 80篇 |
基础理论 | 160篇 |
污染及防治 | 188篇 |
评价与监测 | 54篇 |
社会与环境 | 28篇 |
灾害及防治 | 1篇 |
出版年
2022年 | 4篇 |
2021年 | 3篇 |
2020年 | 10篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 15篇 |
2014年 | 20篇 |
2013年 | 94篇 |
2012年 | 20篇 |
2011年 | 45篇 |
2010年 | 24篇 |
2009年 | 35篇 |
2008年 | 44篇 |
2007年 | 46篇 |
2006年 | 49篇 |
2005年 | 17篇 |
2004年 | 20篇 |
2003年 | 36篇 |
2002年 | 29篇 |
2001年 | 17篇 |
2000年 | 11篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 7篇 |
1994年 | 9篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 8篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 13篇 |
1981年 | 18篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1974年 | 7篇 |
1973年 | 3篇 |
1970年 | 3篇 |
排序方式: 共有803条查询结果,搜索用时 93 毫秒
801.
Mating behaviors of ants fall into two categories: female calling, in which a female alate releases pheromones that attract
males, and male swarming, in which large male aggregations attract females. Female calling is common in species with queens
that return to their natal nest to found colonies dependently after mating, while male swarming is common in species with
queens that disperse to found independently. In some species that display both founding strategies, a queen-size polymorphism
has evolved in which dependent-founding queens are smaller than independent-founding queens. Dependent founding is likely
difficult if gynes (virgin queens) are mating in distant swarms. Therefore, a queen may adopt one or the other mating strategy
based on its size and founding behavior. We investigated mating behaviors in the queen-polymorphic ant, Temnothorax longispinosus. Observations in laboratory mating arenas indicated that small gynes exhibited significantly lower flight activity than large
gynes. Both forms mated in male swarms, and neither form exhibited female calling. The reduced flight activity of the small
morph may facilitate returning to the natal nest after mating, provided the mating swarm is located nearby. Therefore, alternative
colony-founding behaviors may be possible without the evolution of female-calling behavior; however, the reduced flight activity
of small morphs may require that mating swarms are not distant from the natal nest. 相似文献
802.
Trust in Sources of Soil and Water Quality Information: Implications for Environmental Outreach and Education 下载免费PDF全文
Amber Saylor Mase Nicholas L. Babin Linda Stalker Prokopy Kenneth D. Genskow 《Journal of the American Water Resources Association》2015,51(6):1656-1666
Public trust in organizations focused on improving environmental quality is important for increasing awareness and changing behaviors that have water quality implications. Few studies have addressed trust in soil and water quality information sources, particularly for both agricultural and nonagricultural respondents of the same watersheds. Surveys in 19 watersheds across five states in the Midwest assessed trust in, and familiarity with, soil and water quality information sources. Overall, respondents most trusted University Extension, Soil and Water Conservation Districts, and the Natural Resource Conservation Service, while lawn care companies, environmental groups, and land trusts were less trusted. Significant differences in trusted sources were found between watersheds, and between agricultural and nonagricultural respondents across and within watersheds. Among agricultural respondents, a clear relationship exists between familiarity and trust; as familiarity with an organization increases, so too does level of trust. This relationship is less clear‐cut for nonagricultural respondents in this region. We highlight implications of these findings for soil and water quality outreach efforts. 相似文献
803.
Xiaoge Huang Lihao Chen Ziqi Ma Kenneth C. Carroll Xiao Zhao Zailin Huo 《Frontiers of Environmental Science & Engineering》2022,16(12):151