全文获取类型
收费全文 | 1417篇 |
免费 | 28篇 |
国内免费 | 3篇 |
专业分类
安全科学 | 57篇 |
废物处理 | 54篇 |
环保管理 | 284篇 |
综合类 | 126篇 |
基础理论 | 423篇 |
环境理论 | 1篇 |
污染及防治 | 333篇 |
评价与监测 | 89篇 |
社会与环境 | 70篇 |
灾害及防治 | 11篇 |
出版年
2022年 | 8篇 |
2021年 | 11篇 |
2020年 | 16篇 |
2019年 | 14篇 |
2018年 | 26篇 |
2017年 | 13篇 |
2016年 | 50篇 |
2015年 | 33篇 |
2014年 | 35篇 |
2013年 | 128篇 |
2012年 | 38篇 |
2011年 | 69篇 |
2010年 | 51篇 |
2009年 | 61篇 |
2008年 | 58篇 |
2007年 | 78篇 |
2006年 | 61篇 |
2005年 | 55篇 |
2004年 | 41篇 |
2003年 | 46篇 |
2002年 | 48篇 |
2001年 | 41篇 |
2000年 | 28篇 |
1999年 | 27篇 |
1998年 | 18篇 |
1997年 | 20篇 |
1996年 | 21篇 |
1995年 | 36篇 |
1994年 | 19篇 |
1993年 | 22篇 |
1992年 | 13篇 |
1991年 | 26篇 |
1990年 | 19篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 16篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 25篇 |
1983年 | 10篇 |
1982年 | 14篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 9篇 |
1978年 | 6篇 |
1977年 | 13篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1971年 | 7篇 |
排序方式: 共有1448条查询结果,搜索用时 783 毫秒
571.
With approximately 20 % of the world’s population living in its downstream watersheds, the Qinghai-Tibetan Plateau (QTP) is considered “Asia’s Water Tower.” However, grasslands of the QTP, where most of Asia’s great rivers originate, are becoming increasingly degraded, which leads to elevated population densities of a native small mammal, the plateau pika (Ochotona curzoniae). As a result pikas have been characterized as a pest leading to wide-spread poisoning campaigns in an attempt to restore grassland quality. A contrary view is that pikas are a keystone species for biodiversity and that their burrowing activity provides a critical ecosystem service by increasing the infiltration rate of water, hence reducing overland flow. We demonstrate that poisoning plateau pikas significantly reduces infiltration rate of water across the QTP creating the potential for watershed-level impacts. Our results demonstrate the importance of burrowing mammals as ecosystem engineers, particularly with regard to their influence on hydrological functioning. 相似文献
572.
Mitigation of two pyrethroid insecticides in a Mississippi Delta constructed wetland 总被引:1,自引:0,他引:1
Moore MT Cooper CM Smith S Cullum RF Knight SS Locke MA Bennett ER 《Environmental pollution (Barking, Essex : 1987)》2009,157(1):250-256
Constructed wetlands are a suggested best management practice to help mitigate agricultural runoff before entering receiving aquatic ecosystems. A constructed wetland system (180 m × 30 m), comprising a sediment retention basin and two treatment cells, was used to determine the fate and transport of simulated runoff containing the pyrethroid insecticides lambda-cyhalothrin and cyfluthrin, as well as suspended sediment. Wetland water, sediment, and plant samples were collected spatially and temporally over 55 d. Results showed 49 and 76% of the study's measured lambda-cyhalothrin and cyfluthrin masses were associated with vegetation, respectively. Based on conservative effects concentrations for invertebrates and regression analyses of maximum observed wetland aqueous concentrations, a wetland length of 215 m × 30 m width would be required to adequately mitigate 1% pesticide runoff from a 14 ha contributing area. Results of this experiment can be used to model future design specifications for constructed wetland mitigation of pyrethroid insecticides. 相似文献
573.
M. Carmen Casado-Martinez Brian D. Smith Samuel N. Luoma 《Environmental pollution (Barking, Essex : 1987)》2009,157(10):2743-2750
The use of biodynamic models to understand metal uptake directly from sediments by deposit-feeding organisms still represents a special challenge. In this study, accumulated concentrations of Cd, Zn and Ag predicted by biodynamic modelling in the lugworm Arenicola marina have been compared to measured concentrations in field populations in several UK estuaries. The biodynamic model predicted accumulated field Cd concentrations remarkably accurately, and predicted bioaccumulated Ag concentrations were in the range of those measured in lugworms collected from the field. For Zn the model showed less but still good comparability, accurately predicting Zn bioaccumulation in A. marina at high sediment concentrations but underestimating accumulated Zn in the worms from sites with low and intermediate levels of Zn sediment contamination. Therefore, it appears that the physiological parameters experimentally derived for A. marina are applicable to the conditions encountered in these environments and that the assumptions made in the model are plausible. 相似文献
574.
An uptake parameter u (L kg−1 d−1) and a loss rate parameter k (d−1) were estimated for the patterns of accumulation and loss of 133Cs by three fish species following an experimental 133Cs addition into a pond in South Carolina, USA. These u and k parameters were compared to similar estimates for fish from other experimental ponds and from lakes that received 137Cs deposition from Chernobyl. Estimates of u from ponds and lakes declined with increasing potassium concentrations in the water column. Although loss rates were greater in the experimental ponds, the times required to reach maximum Cs concentrations in fish were similar between ponds and lakes, because ponds and lakes had similar retentions of Cs in the water column. The maximum Cs concentrations in fish were largely determined by initial Cs concentrations in the water column. These maximum concentrations in fish and the times required to reach these maxima are potentially useful indicators for assessments of risks to humans from fish consumption. 相似文献
575.
P. B. L. Tamuno G. Howard M. D. Smith 《Environment, Development and Sustainability》2009,11(4):887-903
The Central Niger Delta is made up of a network of rivers and creeks that constitute the inland surface waters. These surface
waters have historically influenced settlement patterns and are of diverse use to residents of the Central Niger Delta. Surface
water like many ecological system are complex, whose complexity has been associated with seasonal variability. Traditional
knowledge (TK), traditional ecological knowledge (TEK) and the traditional eco-livelihood knowledge (TELK) of residents of
four rural communities in the Central Niger Delta have been explored in developing a river use profile of rural communities
of the Central Niger Delta. A questionnaire survey has been carried out in four communities, two each from the Otuoke and
Kolo Creeks. The result shows that river use varies across seasons and affected by: physico-chemical water quality and characteristics
of surface water; the hydrological characteristics; the biological/ecological characteristics; cultural use and demand; need
for development projects; and access to this vital resource. Fishing constitute one of the major livelihood source in the
Central Niger Delta and the TELK of fishers in the sample communities have specifically been explored to understanding fishing
patterns across seasons. The five seasons identified from this study are: flood season; flood recession season; dry season;
early rainy season; and rainy season. Therefore, the thesis of this paper is that there is the need to balance the current
usage of surface water in the developing world such as the Central Niger Delta with the demand for development as well as
future use if development is to meet the criteria for equitable development. The river use profile could be a promising tool
in planning for equitable development.
相似文献
M. D. SmithEmail: |
576.
Murphy JJ Dinar A Howitt RE Rassenti SJ Smith VL Weinberg M 《Journal of environmental management》2009,90(2):1089-1096
The main objective of this paper is to design and test a decentralized exchange mechanism that generates the location-specific pricing necessary to achieve efficient allocations in the presence of instream flow values. Although a market-oriented approach has the potential to improve upon traditional command and control regulations, questions remain about how these rights-based institutions can be implemented such that the potential gains from liberalized trade can be realized. This article uses laboratory experiments to test three different water market institutions designed to incorporate instream flow values into the allocation mechanism through active participation of an environmental trader. The smart, computer-coordinated market described herein offers the potential to significantly reduce coordination problems and transaction costs associated with finding mutually beneficial trades that satisfy environmental constraints. We find that direct environmental participation in the market can achieve highly efficient and stable outcomes, although the potential does exist for the environmental agent to influence outcomes. 相似文献
577.
Environmental integrated assessments are often carried out via the aggregation of a set of environmental indicators. Aggregated
indices derived from the same data set can differ substantially depending upon how the indicators are weighted and aggregated,
which is often a subjective matter. This article presents a method of generating aggregated environmental indices in an objective
manner via Monte Carlo simulation. Rankings derived from the aggregated indices within and between three Monte Carlo simulations
were used to evaluate the overall environmental condition of the study area. Other insights, such as the distribution of good
or bad values of indicators at a watershed and/or a subregion, were observed in the study. 相似文献
578.
579.
Most studies characterizing successful biological invaders emphasize those traits that help a species establish a new population.
Invasions are, however, multi-phase processes with at least two phases, dispersal and introduction, that occur before establishment.
Characteristics that enhance survival at any of these three phases will contribute to invasion success. Here, we synthesize
information on the dispersal, introduction, and establishment of fishes mediated by ship ballast-water transport. We synthesize
54 reports of at least 31 fish species collected from ballast tanks (Phase 1), including 28 new reports from our recent studies
(1986 to 1996). Our literature survey revealed 40 reports of 32 fish species whose introductions have been attributed to ballast
transport (Phase 2), of which at least 24 survived to establish persistent populations (Phase 3). We detected little overlap
at the species level between these two data sets (Phase 1 vs Phases 2 and 3), but patterns emerged at the family level. The
Gobiidae (6 species), Clupeidae (4 species), and Gasterosteidae (1 species) were the most commonly found fish families in
ballast tanks (Phase 1). The Gobiidae (13 species), Blenniidae (6 species) and Pleuronectidae (2 species) dominated the list
of ballast-mediated introductions (Phase 2); gobies and blennies were the families most frequently established (Phase 3).
The invasive success of gobies and blennies may be explained in part by their crevicolous nature: both groups seek refuge
and lay eggs in small holes, and may take advantage of the ballast-intake holes on ship hulls. This behavior, not typically
associated with invasive ability, may contribute to successful introduction and establishment by facilitating the dispersal
phase of invasion. The failure of the pleuronectids to invade may reflect poor salinity match between donor and recipient
regions. To develop a predictive framework of invasion success, organisms must be sampled at all three phases of the invasion
process. Our comparison of two ballast sampling methods suggests that fishes have been undersampled in ballast-water studies,
including our own, and that the role of ballast transport in promoting fish invasions has been underestimated.
Received: 13 January 1999 / Accepted: 24 February 2000 相似文献
580.
Brian H. Hurd Mac Callaway Joel Smith Paul Kirshen 《Journal of the American Water Resources Association》2004,40(1):129-148
ABSTRACT: Water is potentially one of the most affected resources as climate changes. Though knowledge and understanding has steadily evolved about the nature and extent of many of the physical effects of possible climate change on water resources, much less is known about the economic responses and impacts that may emerge. Methods and results are presented that examine and quantify many of the important economic consequences of possible climate change on U.S. water resources. At the core of the assessment is the simulation of multiple climate change scenarios in economic models of four watersheds. These Water Allocation and Impact Models (Water‐AIM) simulate the effects of modeled runoff changes under various climate change scenarios on the spatial and temporal dimensions of water use, supply, and storage and on the magnitude and distribution of economic consequences. One of the key aspects and contributions of this approach is the capability of capturing economic response and adaptation behavior of water users to changes in water scarcity. By reflecting changes in the relative scarcity (and value) of water, users respond by changing their patterns of water use, intertemporal storage in reservoirs, and changes in the pricing of water. The estimates of economic welfare change that emerge from the Water‐AIM models are considered lower‐bound estimates owing to the conservative nature of the model formulation and key assumptions. The results from the Water‐AIM models form the basis for extrapolating impacts to the national level. Differences in the impacts across the regional models are carried through to the national assessment by matching the modeled basins with basins with similar geographical, climatic, and water use characteristics that have not been modeled and by using hydro‐logic data across all U.S. water resources regions. The results from the national analysis show that impacts are borne to a great extent by nonconsumptive users that depend on river flows, which rise and fall with precipitation, and by agricultural users, primarily in the western United States, that use a large share of available water in relatively low‐valued uses. Water used for municipal and industrial purposes is largely spared from reduced availability because of its relatively high marginal value. In some cases water quality concerns rise, and additional investments may be required to continue to meet established guidelines. 相似文献