全文获取类型
收费全文 | 89620篇 |
免费 | 1225篇 |
国内免费 | 1110篇 |
专业分类
安全科学 | 3732篇 |
废物处理 | 3202篇 |
环保管理 | 13909篇 |
综合类 | 21069篇 |
基础理论 | 26130篇 |
环境理论 | 72篇 |
污染及防治 | 14375篇 |
评价与监测 | 5354篇 |
社会与环境 | 3576篇 |
灾害及防治 | 536篇 |
出版年
2022年 | 799篇 |
2021年 | 805篇 |
2020年 | 648篇 |
2019年 | 872篇 |
2018年 | 1121篇 |
2017年 | 1148篇 |
2016年 | 2153篇 |
2015年 | 1820篇 |
2014年 | 2577篇 |
2013年 | 9241篇 |
2012年 | 2127篇 |
2011年 | 2347篇 |
2010年 | 3238篇 |
2009年 | 3355篇 |
2008年 | 1918篇 |
2007年 | 1766篇 |
2006年 | 2213篇 |
2005年 | 2170篇 |
2004年 | 2550篇 |
2003年 | 2337篇 |
2002年 | 1889篇 |
2001年 | 2241篇 |
2000年 | 1973篇 |
1999年 | 1474篇 |
1998年 | 1364篇 |
1997年 | 1352篇 |
1996年 | 1470篇 |
1995年 | 1577篇 |
1994年 | 1475篇 |
1993年 | 1327篇 |
1992年 | 1328篇 |
1991年 | 1290篇 |
1990年 | 1242篇 |
1989年 | 1191篇 |
1988年 | 1046篇 |
1987年 | 980篇 |
1986年 | 990篇 |
1985年 | 1063篇 |
1984年 | 1156篇 |
1983年 | 1169篇 |
1982年 | 1176篇 |
1981年 | 1096篇 |
1980年 | 941篇 |
1979年 | 922篇 |
1978年 | 825篇 |
1977年 | 717篇 |
1976年 | 639篇 |
1975年 | 611篇 |
1973年 | 641篇 |
1972年 | 646篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
Richard A. Sims Kenneth A. Baldwin H. Maureen Kershaw Yonghe Wang 《Environmental monitoring and assessment》1996,39(1-3):471-484
Selected data on site, vegetation cover, and soil, including soil moisture regime (SMR), were collected from 2 167 field plots in northwestern Ontario, Canada. SMR provides an estimate of an averaged, annualized soil moisture supply throughout a complete vegetation cycle. SMR is based upon a relative scale that subjectively ranks sites from , 0, and 1 through 9 along a soil moisture continuum which relates to a dry to wet gradient. SMR may be generally correlated to tree growth, stand composition, degree of competition, nutrient availability and overall site quality.This paper reports on relationships between SMR and major tree species. Results highlight relationships between SMR class and the broad ecological ranges of several tree species. In northwestern Ontario, the determination of SMR can help resource managers to better understand the ecology of boreal sites. 相似文献
162.
Industrial and weathering inputs of Cd and Zn to the Sepetiba Bay and basin were assessed, based on production parameters obtained from local environment and industry authorities, and literature data. The results are compared with similar evaluations from other coastal regions and field data obtained in measuring Zn and Cd transport by rivers, direct run-off and atmospheric deposition in the region. Cadmium and zinc inputs to the bay increased by three orders of magnitude relative to pre-industrial fluxes and presently reach up to 1.6 and 180 tonnes per year for Cd and Zn, respectively, which represents a large input-to-area ratio, and explains the high concentration of these metals previously reported in the estuarine biota and sediments of Sepetiba Bay. Industrial activities, mainly metallurgical and chemical, comprise 94% and 84% of the total Cd and Zn inputs to the Bay. This figure identifies the point sources as being responsible for the environmental contamination and for regional poisoning risks. 相似文献
163.
Kristina?D.?RothleyEmail author Charlene?Rae 《Environmental Modeling and Assessment》2005,10(2):107-113
In this paper we apply graph theory in a reserve selection exercise to explore the tradeoffs between maintaining connectivity and minimizing the total area of a protected area network. Rather than focus on a single organism, we used a multi-species approach and looked at the tradeoff curves for organisms with varying dispersal abilities. We first generated the tradeoff curves using a graph-based metric to determine the importance of individual patches for maintaining connectivity. We then performed an analogous set of analyses using patch size as a surrogate measure of importance. 相似文献
164.
K. Stamatelatou G. Lyberatos C. Tsiligiannis S. Pavlou P. Pullammanappallil S.A. Svoronos 《Environmental Modeling and Assessment》1997,2(4):355-363
Anaerobic digester failure due to entry of inhibitors or sudden changes in the feed substrate concentration may be encompassed beneficially by applying optimal control theory. An almost proportional relationship between the dilution rate and the methane production rate leads to a simple suboptimal control law with only minor loss in performance, after the occurrence of the above mentioned events. 相似文献
165.
W. Henry McNab 《Environmental monitoring and assessment》1996,39(1-3):215-229
Five local ecological types based on vegetative communities and two landscape types based on groups of communities, were identified by integrating landform, soil, and vegetation components using multivariate techniques. Elevation and several topographic and soil variables were highly correlated with types of both scales. Landscape ecological types based only on landform and soil variables without vegetation did not correspond with types developed using vegetation. Models developed from these relationships could allow classification and mapping of extensive areas using geographic information systems. 相似文献
166.
Stephen C. Sheppard 《Environmental monitoring and assessment》1995,34(1):27-44
Soil ingestion is an important exposure pathway for contaminants that are not otherwise very mobile in the environment. Health of both humans and animals can be affected. This paper summarizes the literature and recommends models and probabilistic parameter values for risk assessment applications. Models of the pathway require estimates of the amounts of soil ingested, the concentration of contaminants relative to the original soil, and the bioavailability in the gut of the contaminants ingested with soil. Using a lead-contaminated sandbox as an example, the modelling recommendations suggest that a child typically may consume 50 mg d–1 of the sandbox soil, the soil ingested will have a tenfold higher lead concentration than the original soil, and the lead will be as bioavailable as if ingested as inorganic lead in water.The Canadian Government right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. 相似文献
167.
Methods derived from time-series analysis are proposed for processing monitoring data. The necessity for the use of these methods is demonstrated. In a case study time-series analysis was applied to assess the impact of the closure of the Grevelingen estuary (S. W. Netherlands) in 1971 on a local wintering population of Oystercatchers (Haematopus ostralegus) in the adjacent Oosterschelde estuary.Communication No. 328 of the Delta Institute for Hydrobiological Research. 相似文献
168.
169.
170.