全文获取类型
收费全文 | 17299篇 |
免费 | 205篇 |
国内免费 | 159篇 |
专业分类
安全科学 | 500篇 |
废物处理 | 687篇 |
环保管理 | 2535篇 |
综合类 | 2660篇 |
基础理论 | 4700篇 |
环境理论 | 7篇 |
污染及防治 | 4488篇 |
评价与监测 | 1078篇 |
社会与环境 | 896篇 |
灾害及防治 | 112篇 |
出版年
2022年 | 124篇 |
2021年 | 143篇 |
2020年 | 123篇 |
2019年 | 160篇 |
2018年 | 259篇 |
2017年 | 261篇 |
2016年 | 409篇 |
2015年 | 281篇 |
2014年 | 391篇 |
2013年 | 1340篇 |
2012年 | 490篇 |
2011年 | 709篇 |
2010年 | 582篇 |
2009年 | 570篇 |
2008年 | 735篇 |
2007年 | 748篇 |
2006年 | 701篇 |
2005年 | 536篇 |
2004年 | 624篇 |
2003年 | 553篇 |
2002年 | 507篇 |
2001年 | 714篇 |
2000年 | 487篇 |
1999年 | 296篇 |
1998年 | 258篇 |
1997年 | 235篇 |
1996年 | 240篇 |
1995年 | 255篇 |
1994年 | 273篇 |
1993年 | 231篇 |
1992年 | 255篇 |
1991年 | 230篇 |
1990年 | 258篇 |
1989年 | 242篇 |
1988年 | 197篇 |
1987年 | 181篇 |
1986年 | 162篇 |
1985年 | 170篇 |
1984年 | 194篇 |
1983年 | 183篇 |
1982年 | 187篇 |
1981年 | 182篇 |
1980年 | 142篇 |
1979年 | 154篇 |
1978年 | 133篇 |
1977年 | 117篇 |
1975年 | 118篇 |
1974年 | 115篇 |
1973年 | 110篇 |
1972年 | 133篇 |
排序方式: 共有10000条查询结果,搜索用时 781 毫秒
881.
882.
883.
884.
885.
Steven?J.?CookeEmail authorView authors OrcID profile Eduardo?G.?Martins Daniel?P.?Struthers Lee?F.?G.?Gutowsky Michael?Power Susan?E.?Doka John?M.?Dettmers David?A.?Crook Martyn?C.?Lucas Christopher?M.?Holbrook Charles?C.?Krueger 《Environmental monitoring and assessment》2016,188(4):239
Freshwater fish move vertically and horizontally through the aquatic landscape for a variety of reasons, such as to find and exploit patchy resources or to locate essential habitats (e.g., for spawning). Inherent challenges exist with the assessment of fish populations because they are moving targets. We submit that quantifying and describing the spatial ecology of fish and their habitat is an important component of freshwater fishery assessment and management. With a growing number of tools available for studying the spatial ecology of fishes (e.g., telemetry, population genetics, hydroacoustics, otolith microchemistry, stable isotope analysis), new knowledge can now be generated and incorporated into biological assessment and fishery management. For example, knowing when, where, and how to deploy assessment gears is essential to inform, refine, or calibrate assessment protocols. Such information is also useful for quantifying or avoiding bycatch of imperiled species. Knowledge of habitat connectivity and usage can identify critically important migration corridors and habitats and can be used to improve our understanding of variables that influence spatial structuring of fish populations. Similarly, demographic processes are partly driven by the behavior of fish and mediated by environmental drivers. Information on these processes is critical to the development and application of realistic population dynamics models. Collectively, biological assessment, when informed by knowledge of spatial ecology, can provide managers with the ability to understand how and when fish and their habitats may be exposed to different threats. Naturally, this knowledge helps to better evaluate or develop strategies to protect the long-term viability of fishery production. Failure to understand the spatial ecology of fishes and to incorporate spatiotemporal data can bias population assessments and forecasts and potentially lead to ineffective or counterproductive management actions. 相似文献
886.
887.
888.
889.
An Approach to Reaeration Coefficient Modeling in Local Surface Water Quality Monitoring 总被引:1,自引:0,他引:1
Reaeration coefficient (k 2) for River Atuwara, Ogun State, Nigeria was calculated from dissolved oxygen and biochemical oxygen demand data collected over period of 3 months covering the two prevailing climatic seasons in the country. Both the Akaike and Bayesian information criteria were used in the selection and analysis of ten models to identify the most suitable reaeration coefficient (k 2) model for Atuwara River. Models that passed the confidence limit were subjected to model evaluation using measures of agreement between observed and predicted data such as percent bias, Nash–Sutcliffe efficiency, and root mean square observation standard deviation ratio. The used approach yield better results than empirical models developed for local conditions while it is also useful in conserving scarce resources. 相似文献
890.
Metal release from serpentine soils in Sri Lanka 总被引:2,自引:0,他引:2
Meththika Vithanage Anushka Upamali Rajapaksha Christopher Oze Nishanta Rajakaruna C. B. Dissanayake 《Environmental monitoring and assessment》2014,186(6):3415-3429
Ultramafic rocks and their related soils (i.e., serpentine soils) are non-anthropogenic sources of metal contamination. Elevated concentrations of metals released from these soils into the surrounding areas and groundwater have ecological-, agricultural-, and human health-related consequences. Here we report the geochemistry of four different serpentine soil localities in Sri Lanka by coupling interpretations garnered from physicochemical properties and chemical extractions. Both Ni and Mn demonstrate appreciable release in water from the Ussangoda soils compared to the other three localities, with Ni and Mn metal release increasing with increasing ionic strengths at all sites. Sequential extraction experiments, utilized to identify “elemental pools,” indicate that Mn is mainly associated with oxides/(oxy)hydroxides, whereas Ni and Cr are bound in silicates and spinels. Nickel was the most bioavailable metal compared to Mn and Cr in all four soils, with the highest value observed in the Ussangoda soil at 168?±?6.40 mg kg?1 via the 0.01-M CaCl2 extraction. Although Mn is dominantly bound in oxides/(oxy)hydroxides, Mn is widely dispersed with concentrations reaching as high as 391 mg kg?1 (Yudhaganawa) in the organic fraction and 49 mg kg?1 (Ussangoda) in the exchangeable fraction. Despite Cr being primarily retained in the residual fraction, the second largest pool of Cr was in the organic matter fraction (693 mg kg?1 in the Yudhaganawa soil). Overall, our results support that serpentine soils in Sri Lanka offer a highly labile source of metals to the critical zone. 相似文献