全文获取类型
收费全文 | 20246篇 |
免费 | 1859篇 |
国内免费 | 1894篇 |
专业分类
安全科学 | 8153篇 |
废物处理 | 313篇 |
环保管理 | 2903篇 |
综合类 | 7648篇 |
基础理论 | 1583篇 |
环境理论 | 18篇 |
污染及防治 | 669篇 |
评价与监测 | 906篇 |
社会与环境 | 868篇 |
灾害及防治 | 938篇 |
出版年
2024年 | 65篇 |
2023年 | 306篇 |
2022年 | 592篇 |
2021年 | 801篇 |
2020年 | 840篇 |
2019年 | 752篇 |
2018年 | 512篇 |
2017年 | 851篇 |
2016年 | 827篇 |
2015年 | 1012篇 |
2014年 | 921篇 |
2013年 | 1162篇 |
2012年 | 1505篇 |
2011年 | 1680篇 |
2010年 | 1177篇 |
2009年 | 1220篇 |
2008年 | 888篇 |
2007年 | 1339篇 |
2006年 | 1332篇 |
2005年 | 1013篇 |
2004年 | 799篇 |
2003年 | 765篇 |
2002年 | 633篇 |
2001年 | 529篇 |
2000年 | 431篇 |
1999年 | 342篇 |
1998年 | 257篇 |
1997年 | 235篇 |
1996年 | 206篇 |
1995年 | 164篇 |
1994年 | 141篇 |
1993年 | 134篇 |
1992年 | 85篇 |
1991年 | 62篇 |
1990年 | 50篇 |
1989年 | 40篇 |
1988年 | 45篇 |
1987年 | 26篇 |
1986年 | 21篇 |
1985年 | 23篇 |
1984年 | 14篇 |
1983年 | 14篇 |
1982年 | 26篇 |
1981年 | 23篇 |
1980年 | 19篇 |
1979年 | 20篇 |
1978年 | 17篇 |
1977年 | 14篇 |
1972年 | 18篇 |
1971年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
91.
Diazinon contamination of California's rivers has resulted in placing several rivers on the federal Clean Water Act § 303d list of impaired waterways. Impaired water body listing requiresthe development of Total Maximum Daily Loads (TMDL). Previous studies identified stormwater related diazinon pulses in California rivers. This study was conducted to monitor diazinonconcentrations in the Sacramento River watershed after rainfallevents, to ascertain whether pulses could be identified and, ifconcentrations of concern were observed, to estimate loadings anddetermine geographic origins of the insecticide. TMDL developmentrequires knowledge of contaminant sources, loadings, and geographic origins. Flow and diazinon concentrations peaked in the Sacramento River at Sacramento after the three largest stormsduring January and February 1994. Diazinon concentrations peakedconsequent to each of three storms. Diazinon concentrationsmeasured in the Sacramento River at Sacramento exceeded theCalifornia Department of Fish and Game acute and chroniccriteria for protection of aquatic life during January andFebruary for nine and nineteen days, respectively. Multipleexceedances were observed throughout the watershed. Diazinon loading and geographic origin differed with each of the three storms. The design of this study provides a useful template for others attempting to identify loadings and sources of contaminants in surface waters and to rectify aquatic ecosystemcontamination from various land use practices. 相似文献
92.
Spatial structure analysis and kriging analysis have been identified to be useful tools in illustrating the spatial patterns of variables. Taihu Lake is one of the largest fresh water lakes in China, and has suffered serious eutrophication in recent years due to the rapid economic development and growing environmental pollution in the Taihu Catchment. In this paper, spatial structural analysis, kriging interpolation and eutrophication assessment were carried out for chlorophyll a in the lake. Studies show that spherical model could be applied to fit all experimental variograms. Positive nuggets were observed for three directions except NE–SW direction. The variograms show some anisotropy with anisotropic ratio falling within 1.76. The spatial structural patterns of chlorophyll a in the lake were affected by factors such as distribution of pollution sources, water flow and wind. Two-dimensional ordinary block kriging was applied for interpolation process. An eutrophication assessment map was also made based on a water-quality evaluation standard. Results show that the content of chlorophyll a in Taihu Lake was quite high. The whole lake has suffered serious eutrophication. However, the eutrophic situation varied in space. Higher contents of chlorophyll a appeared mainly in the northern part of the lake. 相似文献
93.
A. Haurie J.J.E. Kübler A. Clappier H. van den Bergh 《Environmental Modeling and Assessment》2004,9(1):1-12
A method is proposed to build integrated models (also called Metamodels) aimed at quantifying the economic efficiency of air quality policies. This Metamodeling approach is based on the coupling of two complementary models, that operate at different scales in space and time, and which represent the economic and the physical and chemical processes, respectively. The joint consideration of the physico-chemical and techno-economic structure of the pollution control problems permits a comprehensive evaluation of air pollution abatement strategies. The motivating pollution control problems include urban-regional air quality management through efficient energy and traffic control policies. A pilot study, exploiting data collected in the Geneva canton (Switzerland), is used to demonstrate the potential of the approach. 相似文献
94.
滨州沿海湿地生物多样性保护探讨 总被引:1,自引:0,他引:1
重点研究了该区域海洋生物多样性、淡水生物多样性、陆生和海岛等高等植物多样性、陆栖动物多样性与特点。分析了其破坏现状及原因,提出了生物多样性保护对策和可持续利用途径。 相似文献
95.
介绍了灰色关联度因子分析方法,以及此法在水污染因子分析中的应用.对于一般监测资料系列短而监测项目却较齐全的情况,应用本法是较适宜的. 相似文献
96.
97.
地震安全性评价工作在城市建设中起着非常重要的作用,为工程抗震提供精确的设计依据,提供科学合理的地震动参数,提出科学合理的设防要求,能够在一定程度上避免破坏性地震造成的损失,从而达到有效减灾的目的。 相似文献
98.
99.
环境保护的两种重要手段-政府决策与公众参与 总被引:1,自引:0,他引:1
综述了目前我国环境保护的两种重要手段-政府决策和公众参与的现状及必要性,将政府决策与公众参与结合起来,以推动我国环保事业的进一步发展. 相似文献
100.
西藏公路建设过程中的生态保护 总被引:1,自引:1,他引:1
针对西藏独特的高原生态环境特征,分析了公路建设的生态影响,提出了不同生态系统类型的生态恢复和保护措施。 相似文献