全文获取类型
收费全文 | 1836篇 |
免费 | 31篇 |
国内免费 | 10篇 |
专业分类
安全科学 | 70篇 |
废物处理 | 76篇 |
环保管理 | 406篇 |
综合类 | 171篇 |
基础理论 | 506篇 |
环境理论 | 2篇 |
污染及防治 | 421篇 |
评价与监测 | 125篇 |
社会与环境 | 83篇 |
灾害及防治 | 17篇 |
出版年
2022年 | 10篇 |
2021年 | 15篇 |
2020年 | 19篇 |
2019年 | 17篇 |
2018年 | 34篇 |
2017年 | 20篇 |
2016年 | 57篇 |
2015年 | 41篇 |
2014年 | 45篇 |
2013年 | 172篇 |
2012年 | 51篇 |
2011年 | 93篇 |
2010年 | 65篇 |
2009年 | 78篇 |
2008年 | 82篇 |
2007年 | 99篇 |
2006年 | 71篇 |
2005年 | 66篇 |
2004年 | 49篇 |
2003年 | 67篇 |
2002年 | 60篇 |
2001年 | 45篇 |
2000年 | 29篇 |
1999年 | 31篇 |
1998年 | 33篇 |
1997年 | 30篇 |
1996年 | 27篇 |
1995年 | 40篇 |
1994年 | 21篇 |
1993年 | 24篇 |
1992年 | 18篇 |
1991年 | 32篇 |
1990年 | 24篇 |
1989年 | 21篇 |
1988年 | 16篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 15篇 |
1984年 | 33篇 |
1983年 | 18篇 |
1982年 | 20篇 |
1981年 | 15篇 |
1980年 | 15篇 |
1979年 | 13篇 |
1978年 | 10篇 |
1977年 | 17篇 |
1975年 | 12篇 |
1974年 | 12篇 |
1973年 | 13篇 |
1971年 | 8篇 |
排序方式: 共有1877条查询结果,搜索用时 421 毫秒
211.
Concentrations of sixteen volatile hydrocarbons present in internal combustion engine exhaust gases and two halogenated hydrocarbons have been measured in ambient air samples at six sites around Gatwick Airport. Correlations between their concentrations have been drawn in an attempt to establish the exact nature of the sources of these emissions, together with consideration of the overall hydrocarbon profiles. 相似文献
212.
Roger H. Willsie Harry L. Ratt 《Journal of the American Water Resources Association》1974,10(2):360-371
ABSTRACT: The paper outlines both the methods used and the results obtained in a study of the demand for municipal and industrial water for the Seattle region. The study was made as part of a regional water management study program, one objective of which is to “… identify, quantify, and set priorities for all current and future water uses …”. A basic concept in the study of municipal and industrial water use is that the demand for water is derived from the demand for output and the direct services that water provides. Principal characteristics of the study are: (1) Water use is studied by type - residential, commercial, industrial and public -with identification of factors affecting each; (2) Water demands are studied by season as well as on an annual basis; (3) Projections of future water use are tied directly to projections of economic change in the service area; and (4) The effects of alternative policies on water use are estimated. Water use levels are projected under alternative regional growth assumptions provided by the Puget Sound Governmental Conference, a regional planning agency. Thus, the water use planning is consistent with other regional planning programs in this respect. The results can be varied according to changes in specific factors affecting water use. The factors considered in the present study include: single-family residential lot size, distribution of population between single- and multi-family units, per capita water use by multi-family unit residents, and industrial and commercial water use per employee. An income elasticity of demand was estimated for single-family residential water use. 相似文献
213.
214.
The date when a landbird migrant arrives on its breeding grounds may have reproductive consequences. Generally, early arriving individuals begin breeding earlier and consequently experience greater seasonal reproductive performance. Here, we describe relationships between arrival timing and seasonal reproductive performance in the American redstart (Setophaga ruticilla), a long-distance passerine migrant, arriving at northerly breeding grounds in Michigans eastern Upper Peninsula. Evidence suggests that both males and females benefited from early arrival at the breeding grounds. Early males appeared to settle on higher quality territories and hatched nestlings sooner than later arrivals. Early females began their clutches early, produced heavier nestlings and possibly laid more eggs than later arrivals. Larger clutches and heavier offspring increase the likelihood of offspring recruiting into the breeding population. The findings of this study point to fitness consequences arising from when a bird arrives at its breeding grounds. These results also have implications for understanding how events occurring during spring migration influence reproductive performance as migratory delays likely influence arrival timing.Communicated by: W. Wiltschko 相似文献
215.
Monte L Boyer P Brittain JE Håkanson L Lepicard S Smith JT 《Journal of environmental radioactivity》2005,79(3):273-296
The present paper summarises the results of the review and assessment of state-of-the-art models developed for predicting the migration of radionuclides through rivers. The different approaches of the models to predict the behaviour of radionuclides in lotic ecosystems are presented and compared. The models were classified and evaluated according to their main methodological approaches. The results of an exercise of model application to specific contamination scenarios aimed at assessing and comparing the model performances were described. A critical evaluation and analysis of the uncertainty of the models was carried out. The main factors influencing the inherent uncertainty of the models, such as the incompleteness of the actual knowledge and the intrinsic environmental and biological variability of the processes controlling the behaviour of radionuclides in rivers, are analysed. 相似文献
216.
Santucci P Kontic B Coughtrey P McKenney C Smith G 《Journal of environmental radioactivity》2005,84(2):151-170
The BIOMASS programme's Theme 1 evaluated a number of scenarios, which assisted in the development of practical guidance. A total of four Example Reference Biospheres were fully developed, with the assumptions, data, and models thoroughly documented. These Examples display both the practicality and the transparency available through the use of the Reference Biosphere Methodology. While the methodology is designed to promote transparency and traceability, proper documentation and justification is still the responsibility of the user. The Examples can also be used as generic analyses in some situations. Although it is anticipated that each of the Reference Biospheres explored within BIOMASS Theme 1 should be a useful practical example, the quantitative results of the model calculations are not intended to be understood as prescribed biosphere 'conversion factors'. In choosing to implement an Example, careful consideration would need to be given to their relevance (including associated data) to the particular assessment context at hand. In general, the more complex the model is, the more limited applicability it has for generic purposes. For example, ERB1A (direct use of well water for drinking) can be used straightforwardly, with minor or no adjustments, at a number of generic sites. Example 2A, however, for which climatic conditions and agricultural practices need to be specified, would need to be implemented for each specific situation. 相似文献
217.
218.
Kristie L. Ebi Joel Smith Ian Burton Joel Scheraga 《Mitigation and Adaptation Strategies for Global Change》2006,11(3):607-620
Lessons learned from more than 150 years of public health research and intervention can provide insights to guide public health
professionals and institutions as they design and implement specific strategies, policies, and measures to increase resilience
to climate variability and change. This paper identifies both some modifications to public health systems that may enhance
adaptive capacity, and lessons drawn from the history of managing environmental and other threats in the public health sector
that may have relevance for other sectors as they design approaches to increase their adaptive capacity to more effectively
cope with climate variability and change.
The views expressed are the author’s own and do not represent official US EPA policy. 相似文献
219.
Pelagic crustacean zooplankton were collected from 336 Norwegian lakes covering a wide range of latitude, altitude, lake area, mean depth, production (as chlorophyll a), and fish community structure. Mean zooplankton species richness during the ice-free season was generally low at high latitudes and altitudes. Further, lower species richness was recorded in western lakes, possibly reflecting constraints on migration and dispersal. However, despite obvious spatial limitations, geographic boundaries were only weak predictors of mean zooplankton richness. Similarly, lake surface area did not contribute positively to mean richness such as seen in other ecosystem surveys. Rather, intrinsic factors such as primary production and fish community (planktivore) structure were identified by regression analysis as the major predictors of zooplankton diversity, while a positive correlation was observed between species richness and total zooplankton biomass. However, in spite of a large number of variables included in this study, the predictive power of multiple regression models was modest (<50% variance explained), pointing to a major role for within-lake properties, as yet unidentified intrinsic forces, stochasticity, or dispersal as constraints on zooplankton diversity in these lakes. 相似文献
220.
A glasshouse experiment was conducted to investigate U and As accumulation by Chinese brake fern, Pteris vittata L., in association with different arbuscular mycorrhizal fungi (AMF) from a U and As contaminated soil. The soil used contains 111 mg U kg(-1) and 106 mg As kg(-1). P. vittata L. was inoculated with each of three AMF, Glomus mosseae, Glomus caledonium and Glomus intraradices. Two harvests were made during plant growth (two and three months after transplanting). Mycorrhizal colonization depressed plant growth particularly at the early stages. TF (transfer factor) values for As from soil to fronds were higher than 1.0, while those for roots were much lower. Despite the growth depressions, AM colonization had no effect on tissue As concentrations. Conversely, TF values for U were much higher for roots than for fronds, indicating that only very small fraction of U was translocated to fronds (less than 2%), regardless of mycorrhizal colonization. Mycorrhizal colonization significantly increased root U concentrations at both harvests. Root colonization with G. mosseae or G. intraradices led to an increase in TF values for U from 7 (non-inoculation control) to 14 at the first harvest. The highest U concentration of 1574 mg kg(-1) was recorded in roots colonized by G. mosseae at the second harvest. The results suggested that P. vittata in combination with appropriate AMF would play very important roles in bioremediation of contaminated environments characterized by a multi-pollution. 相似文献