全文获取类型
收费全文 | 1505篇 |
免费 | 25篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 64篇 |
废物处理 | 45篇 |
环保管理 | 323篇 |
综合类 | 164篇 |
基础理论 | 339篇 |
环境理论 | 2篇 |
污染及防治 | 471篇 |
评价与监测 | 92篇 |
社会与环境 | 50篇 |
灾害及防治 | 9篇 |
出版年
2023年 | 10篇 |
2022年 | 20篇 |
2021年 | 23篇 |
2020年 | 8篇 |
2019年 | 25篇 |
2018年 | 24篇 |
2017年 | 36篇 |
2016年 | 39篇 |
2015年 | 41篇 |
2014年 | 45篇 |
2013年 | 211篇 |
2012年 | 61篇 |
2011年 | 66篇 |
2010年 | 68篇 |
2009年 | 75篇 |
2008年 | 71篇 |
2007年 | 88篇 |
2006年 | 84篇 |
2005年 | 49篇 |
2004年 | 48篇 |
2003年 | 50篇 |
2002年 | 40篇 |
2001年 | 21篇 |
2000年 | 28篇 |
1999年 | 17篇 |
1998年 | 12篇 |
1997年 | 23篇 |
1996年 | 10篇 |
1995年 | 19篇 |
1994年 | 19篇 |
1993年 | 22篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 14篇 |
1989年 | 10篇 |
1988年 | 7篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1984年 | 8篇 |
1983年 | 14篇 |
1982年 | 15篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1974年 | 5篇 |
1972年 | 8篇 |
1971年 | 6篇 |
1970年 | 5篇 |
排序方式: 共有1559条查询结果,搜索用时 0 毫秒
541.
542.
Summary Laboratory-overwintered paper wasp (Polistes metricus) females preferentially associate on new nests with former nestmates (presumably their sisters) rather than with non-nestmates in the absence of cues associated with their natal nests or nest sites. Females isolated from conspecifics and nests for 74–99 days retain the ability to discriminate nestmates from nonnestmates. 相似文献
543.
544.
International trade in water has been pioneered by coastal or island city-states, by areas subject to boundary revision after a water supply system had been established, by informal accommodations among good neighbors, and by co-riparians agreeing to negotiate on compensation as an element in water allocation. Specific examples are described. Formulations of criteria for an equitable agreement for possible transfers of Canadian water to the United States have been published by Laycock and by Kuiper. Many other Canadians have expressed serious concern over the long-range implications of water export and have frequently proposed restrictions which they believe that Canada should insist upon in any negotiations. Explicitly or implicitly in nearly all Canadian discussion of water export is the conviction that international transfer, should it be permitted at all, should occur at some mutually satisfactory point or points on the border with all questions or sources and routes within Canada being left to the agencies within Canada selected by the Canadians for the task. 相似文献
545.
546.
547.
548.
549.
550.
Human Population Numbers as a Function of Food Supply 总被引:1,自引:1,他引:0
Human population growth has typically been seen as the primary causative factor of other ecologically destructive phenomena. Current human disease epidemics are explored as a function of population size. That human population growth is itself a phenomenon with clearly identifiable ecological/biological causes has been overlooked. Here, human population growth is discussed as being subject to the same dynamic processes as the population growth of other species. Contrary to the widely held belief that food production must be increased to feed the growing population, experimental and correlational data indicate that human population growth varies as a function of food availability. By increasing food production for humans, at the expense of other species, the biologically determined effect has been, and continues to be, an increase in the human population. Understanding the relationship between food increases and population increases is proposed as a necessary first step in addressing this global problem. Resistance to this perspective is briefly discussed in terms of cultural bias in science. 相似文献