全文获取类型
收费全文 | 6403篇 |
免费 | 510篇 |
国内免费 | 499篇 |
专业分类
安全科学 | 444篇 |
废物处理 | 49篇 |
环保管理 | 1251篇 |
综合类 | 3559篇 |
基础理论 | 639篇 |
环境理论 | 8篇 |
污染及防治 | 269篇 |
评价与监测 | 486篇 |
社会与环境 | 605篇 |
灾害及防治 | 102篇 |
出版年
2024年 | 37篇 |
2023年 | 93篇 |
2022年 | 137篇 |
2021年 | 169篇 |
2020年 | 203篇 |
2019年 | 120篇 |
2018年 | 106篇 |
2017年 | 214篇 |
2016年 | 218篇 |
2015年 | 214篇 |
2014年 | 264篇 |
2013年 | 371篇 |
2012年 | 356篇 |
2011年 | 452篇 |
2010年 | 313篇 |
2009年 | 350篇 |
2008年 | 285篇 |
2007年 | 426篇 |
2006年 | 443篇 |
2005年 | 345篇 |
2004年 | 318篇 |
2003年 | 299篇 |
2002年 | 299篇 |
2001年 | 218篇 |
2000年 | 248篇 |
1999年 | 202篇 |
1998年 | 117篇 |
1997年 | 133篇 |
1996年 | 83篇 |
1995年 | 100篇 |
1994年 | 54篇 |
1993年 | 72篇 |
1992年 | 43篇 |
1991年 | 35篇 |
1990年 | 26篇 |
1989年 | 12篇 |
1988年 | 10篇 |
1987年 | 2篇 |
1986年 | 4篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 4篇 |
1982年 | 1篇 |
1981年 | 5篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 1篇 |
1971年 | 3篇 |
排序方式: 共有7412条查询结果,搜索用时 15 毫秒
1.
María L. Pignata Martha S. Cañas Hebe A. Carreras Liliana Orellana 《Environmental management》1997,21(5):793-801
Ligustrum lucidum Ait. f. tricolor (Rehd.) Rehd. in relation to atmospheric pollutants in Córdoba city, Argentina. The study area receives
regional pollutants and was categorized taking into account traffic level, industrial density, type of industry, location
of the sample point in relation to the street corner, treeless condition, and topographic level. Dried weight/fresh weight
ratio (DW/FW) and specific leaf area (SLA) were calculated, and concentrations of chlorophylls, carotenoids, total sulfur,
soluble proteins, malondialdehyde (MDA), and hydroperoxy conjugated dienes (HPCD) were determined in leaf samples. Sulfur
content correlates positively with traffic density and SLA correlates negatively with some combinations of the categorical
variables; MDA correlates positively with topographic level and total protein concentration correlates negatively with treeless
condition. On the basis of our results, traffic, location of trees, type of industry, situation of a tree with respect to
others, and topographic level are the environmental variables to bear in mind when selecting analogous sampling points in
a passive monitoring program. An approximation to predict tree injury may be obtained by measuring DW/FW ratio, proteins,
pigments, HPCD, and MDA as they are responsible for the major variability of data. 相似文献
2.
3.
根据自然地理、海洋动力、生物等特征!本文研究受大河作用的大丰潮滩地貌、沉积过程,讨论老黄河和长江对该潮滩发育的影响和潮滩生物群落空间分布及演变规律。本文评价了大丰潮滩开发利用现状,分析了它们的经济效益和环境效益,提出把目前受到强烈改造、过度利用的模式改变为顺应潮滩自然演变、有步骤合理开发利用潮滩的模式。 相似文献
4.
小城镇的生态环境保护 总被引:1,自引:0,他引:1
在城镇化不断发展的进程中,小城镇的生态环境日益恶化。分析了小城镇生态环境存在的问题,提出了应采取的生态环境保护规划与对策。 相似文献
5.
对以发展康平县生态农业建设为主要措施,控制生态环境破坏,促进农村经济持续发展进行了系统的分析和阐述.并提出具体防治措施 相似文献
6.
7.
Robert T. LackeyAuthor vitae 《Environmental Science & Policy》1998,1(4):329-335
Fisheries management is the practice of analyzing and selecting options to maintain or alter the structure, dynamics, and interaction of habitat, aquatic biota, and man to achieve human goals and objectives. The theory of fisheries management is: managers or decision makers attempt to maximize renewable `output' from an aquatic resource by choosing from among a set of decision options and applying a set of actions that generate an array of outputs. Outputs may be defined as a tangible catch, a fishing experience, an existence value, or anything else produced or supported by renewable aquatic resources. Overall output is always a mix of tangible and intangible elements. However defined, management goals and objectives are essential components of fisheries management or any other field of renewable natural resource management. Reaching consensus on management goals and objectives has never been a simple task. Beyond the broad and often conflicting goals of an agency, managers must decide who should set specific management objectives — agency personnel, the public, or a combination of the two. Historically, rhetoric aside, fisheries managers in North America nearly always have consulted with professionals in governmental roles to set management objectives. In a strongly pluralistic society, this often resulted in protracted political and legal conflict. Increasingly, there are calls for use of risk assessment to help solve such ecological policy and management problems commonly encountered in fisheries management. The basic concepts of ecological risk assessment may be simple, but the jargon and details are not. Risk assessment (and similar analytical tools) is a concept that has evoked strong reactions whenever it has been used. In spite of the difficulties of defining problems and setting management objectives for complex ecological policy questions, use of risk assessment to help solve ecological problems is widely supported. Ecological risk assessment will be most useful (and objective) in political deliberations when the policy debate revolves around largely technical concerns. To the extent that risk assessment forces policy debate and disagreement toward fundamental differences rather than superficial ones, it will be useful in decision making. 相似文献
8.
9.
10.
耕地资源的可持续发展探讨 总被引:1,自引:0,他引:1
耕地是重要的发展源,也最易受到毁坏,在系统分析我国耕地不断减少和污染,退化的原因的基础上,提出了全面加强耕地资源保护及其可持续发展的途径和对策。 相似文献