全文获取类型
收费全文 | 40356篇 |
免费 | 404篇 |
国内免费 | 370篇 |
专业分类
安全科学 | 1281篇 |
废物处理 | 1877篇 |
环保管理 | 5113篇 |
综合类 | 7000篇 |
基础理论 | 10248篇 |
环境理论 | 13篇 |
污染及防治 | 9918篇 |
评价与监测 | 2890篇 |
社会与环境 | 2547篇 |
灾害及防治 | 243篇 |
出版年
2022年 | 364篇 |
2021年 | 391篇 |
2020年 | 248篇 |
2019年 | 318篇 |
2018年 | 568篇 |
2017年 | 609篇 |
2016年 | 936篇 |
2015年 | 699篇 |
2014年 | 1121篇 |
2013年 | 3221篇 |
2012年 | 1355篇 |
2011年 | 1769篇 |
2010年 | 1435篇 |
2009年 | 1521篇 |
2008年 | 1794篇 |
2007年 | 1736篇 |
2006年 | 1571篇 |
2005年 | 1412篇 |
2004年 | 1351篇 |
2003年 | 1320篇 |
2002年 | 1236篇 |
2001年 | 1513篇 |
2000年 | 1026篇 |
1999年 | 671篇 |
1998年 | 467篇 |
1997年 | 509篇 |
1996年 | 530篇 |
1995年 | 595篇 |
1994年 | 533篇 |
1993年 | 444篇 |
1992年 | 493篇 |
1991年 | 479篇 |
1990年 | 456篇 |
1989年 | 430篇 |
1988年 | 413篇 |
1987年 | 319篇 |
1986年 | 335篇 |
1985年 | 353篇 |
1984年 | 360篇 |
1983年 | 344篇 |
1982年 | 362篇 |
1981年 | 320篇 |
1980年 | 238篇 |
1979年 | 269篇 |
1978年 | 248篇 |
1977年 | 203篇 |
1975年 | 204篇 |
1974年 | 218篇 |
1973年 | 237篇 |
1972年 | 214篇 |
排序方式: 共有10000条查询结果,搜索用时 843 毫秒
151.
Byron A. Bodo 《Environmental monitoring and assessment》1992,23(1-3):165-187
Historical records from Ontario's Provincial Water Quality Monitoring Network (PWQMN) for rivers and streams were analyzed to assess the feasibility of mapping regional water quality patterns in southeastern Ontario which spans two major geologic zones, the Precambrian Shield and the St. Lawrence Lowlands, thus serving as a paradigm for much of Ontario. Despite biases toward the populated Lowlands and associated pollution problems, general spatial trends are evident via the analysis of intervariable relations, individual parameter maps and multivariate analysis. Using a robust algorithm designed to identify outliers and abstract underlying bivariate relations, a linear regional hardness-alkalinity relation was derived, where most anomalies proved to be mine drainage impacted sites. Regionally, multivariate ordination reveals that central tendencies of common indicators of ionic strength and nutrient richness correlate positively and that site clusters broadly reflect the transition from oligotrophic Shield waters to eutrophic conditions of heavily agricultural Lowland streams. Results suggest that on the Shield more precisely delineated aquatic regions may be realized by applying GIS to integrate river and synoptic lake survey data. Further synthesis with bedrock and surficial geology, physiography, pedology and other temporally invariant spatial attributes should yield regional patterns of background quality from which locally attainable water objectives might be defined. Additional synoptic surveys of sedimentary Lowland streams may be required as most available sites relflect anthropogenic pollution. 相似文献
152.
Jensen AL 《Environmental pollution (Barking, Essex : 1987)》1992,76(2):177-181
The relation between mortality of young fish and recruitment is important for assessment of the environmental effects of facilities that kill large numbers of young fish, such as electric power stations and hydropower plants. A simulation model with a bioenergetic growth component was applied to examine the relation between mortality of young and recruitment for walleye (Stizostedion vitreum) with different forms of population regulation, including: food limited growth, food limited growth with size-dependent mortality, and food limited growth with age at maturity dependent on size. With food limited growth small increases in mortality of young reduced recruitment considerably, but the population slowly approached a new equilibrium. If mortality of young increased when growth was food limited, the population approached a new equilibrium of natality and mortality because with fewer individuals there was more food per individual, and individuals were larger in size and produced more eggs; this feedback adjusted natality to equal mortality. With either mortality or age at maturity dependent on size, large increases in mortality of young resulted in only small decreases in recruitment. 相似文献
153.
Taylor AJ 《Disasters》1986,10(1):70-73
This paper was prepared in 1978 on the basis of a review of sociological and anthropological fieldwork conducted up to that time. Although theoretical in presentation its conclusions are formulated in accordance with the author's own extensive observations of organizational response to natural disasters in developing countries, especially those having sudden onset. Practical implications for co-ordination agencies and pre-disaster training are drawn. 相似文献
154.
Horry Rosemary Booth Colin A. Mahamadu Abdul–Majeed Manu Patrick Georgakis Panos 《Environment, Development and Sustainability》2022,24(9):10585-10615
Environment, Development and Sustainability - Realisation of the sustainable development goals (SDGs) will provide improvements to people's lives and longevity of the planet. The architectural,... 相似文献
155.
Russian Journal of Ecology - Populations at the border of ranges are considered more vulnerable than those in the center. However, some recent reviews contradict this hypothesis. We have studied... 相似文献
156.
Russian Journal of Ecology - Abstract—We tested a hypothesis about the different abilities of alien and native plants to form arbuscular mycorrhizae. The studies were carried out in the... 相似文献
157.
Andharia Jigar K. Haldar Sanjay Samaddar Shilpa Maiti Subarna 《Environment, Development and Sustainability》2022,24(9):11449-11469
Environment, Development and Sustainability - Drying of fish at the Sagar Island (21.7269° N, 88.1096° E) is generally carried out in open sun on the seashore on plastic sheets or mat of... 相似文献
158.
159.
160.