全文获取类型
收费全文 | 504篇 |
免费 | 11篇 |
国内免费 | 7篇 |
专业分类
安全科学 | 31篇 |
废物处理 | 6篇 |
环保管理 | 97篇 |
综合类 | 37篇 |
基础理论 | 168篇 |
污染及防治 | 134篇 |
评价与监测 | 26篇 |
社会与环境 | 17篇 |
灾害及防治 | 6篇 |
出版年
2022年 | 6篇 |
2021年 | 3篇 |
2020年 | 3篇 |
2019年 | 10篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 12篇 |
2015年 | 23篇 |
2014年 | 16篇 |
2013年 | 62篇 |
2012年 | 18篇 |
2011年 | 22篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 26篇 |
2007年 | 33篇 |
2006年 | 18篇 |
2005年 | 16篇 |
2004年 | 20篇 |
2003年 | 21篇 |
2002年 | 6篇 |
2001年 | 18篇 |
2000年 | 15篇 |
1999年 | 11篇 |
1998年 | 9篇 |
1997年 | 9篇 |
1996年 | 4篇 |
1995年 | 9篇 |
1994年 | 5篇 |
1993年 | 11篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1984年 | 3篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1980年 | 3篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有522条查询结果,搜索用时 31 毫秒
451.
Russell J. Anderson Brian P. Bledsoe W. Cully Hession 《Journal of the American Water Resources Association》2004,40(5):1159-1172
ABSTRACT: An extensive group of datasets was analyzed to examine factors affecting widths of streams and rivers. Results indicate that vegetative controls on channel size are scale dependent. In channels with watersheds greater than 10 to 100 km2, widths are narrower in channels with thick woody bank vegetation than in grass lined or nonforested banks. The converse is true in smaller streams apparently due to interactions between woody debris, shading, understory vegetation, rooting characteristics, and channel size. A tree based statistical method (regression tree) is introduced and tested as a tool for identifying thresholds of response and interpreting interactions between variables. The implications of scale dependent controls on channel width are discussed in the context of stable channel design methods and development of regional hydraulic geometry curves. 相似文献
452.
453.
454.
Russell E. Ingham James K. Detling 《Journal of environmental science and health. Part. B》2013,48(5):541-548
Abstract Growth, biomass allocation and competition between blue grama plants were examined with and without application of carbofuran, a pesticide which has been used to study insect and nematode effects on primary production. Carbofuran had no apparent effect on total plant growth, biomass allocation, or competition between neighboring plants. 相似文献
455.
In many temperate estuarine areas, ongoing climatic changes are expected to lead to higher seawater temperatures, to increased inflow of freshwater and nutrients (due to increased rainfall) and to altered light conditions. During the last two decades, several winters have been unusually mild in southern Finland, and the subsequent springs have been early. This may have consequences for the seasonality of many species, including the bladder-wrack, Fucus vesiculosus, whose reproductive cycle may be especially sensitive. In the present study, F. vesiculosus receptacles from the field were weighed regularly during three warm (early) springs and compared with receptacles from three cold (late) springs. On average, the first sign of receptacle growth in the field occurred 5–6?weeks earlier and receptacles probably matured 2–3?weeks earlier during the warm springs than during the cold springs. This may be due to differences in seawater temperatures among years, but significantly heavier receptacles at 0.8?m compared to at 3.1?m further suggests the importance of light for receptacle growth as a measure of maturation, since there were no depth-related differences in seawater temperatures. Also, when plotting receptacle wet weights against seawater temperatures, the importance of light can be seen as different regression relationships (slopes and intercepts). In an outdoor aquarium experiment, the effects of temperature and light on receptacle growth were also tested, and there were significant differences between shallow and deep specimens, but temperature and light had no effects, except on initial receptacle growth. Since oogonian development, and thereby the time for zygote release, followed the receptacle growth curve, this could mean a mismatch between the timing of F. vesiculosus zygote settlement and the cover of competing filamentous algae, but such species interactions require further investigations in order to better understand their possible consequences. 相似文献
456.
Zoltan Szantoi Arthur H. Chappelka Russell B. Muntifering 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):840-846
Cutleaf coneflower (Rudbeckia laciniata L.) seedlings were placed into open-top chambers in May, 2004 and fumigated for 12 wks. Nine chambers were fumigated with either carbon-filtered air (CF), non-filtered air (NF) or twice-ambient (2×) ozone (O3). Ethylenediurea (EDU) was applied as a foliar spray weekly at 0 (control), 200, 400 or 600 ppm. Foliar injury occurred at ambient (30%) and elevated O3 (100%). Elevated O3 resulted in significant decreases in biomass and nutritive quality. Ethylenediurea reduced percent of leaves injured, but decreased root and total biomass. Foliar concentrations of cell-wall constituents were not affected by EDU alone; however, EDU × O3 interactions were observed for total cell-wall constituents and lignocellulose fraction. Our results demonstrated that O3 altered the physiology and productivity of cutleaf coneflower, and although reducing visible injury EDU may be phytotoxic at higher concentrations. 相似文献
457.
Webster L Walsham P Russell M Hussy I Neat F Dalgarno E Packer G Scurfield JA Moffat CF 《Chemosphere》2011,83(6):839-850
Halogenated persistent organic pollutants [polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs)] along with total lipid, were measured in the liver and muscle of three species of deep water fish (black scabbard, black dogfish (liver only) and roundnose grenadier) collected from the Rockall fishing area, to the west of Scotland, between 2006 and 2008. Both contaminant groups were detected in the muscle and liver, with concentrations of PCBs being higher than PBDEs. There were no significant differences in the PCB or PBDE concentrations between the three species, or different sampling locations in the Rockall fishing area. PCB concentrations (ΣICES (International Council for the Exploration of the Sea)7 PCBs) greater than 500 μg kg−1 lipid weight were found in 26 of the 106 liver samples. PCB concentrations were compared to OSPAR assessment criteria, concentrations were above background but below Environmental Assessment Criteria. Estimated Toxic Equivalent (TEQ) concentrations, calculated using published models, in the fish muscle and liver indicated that consumption of deep water fish is unlikely to represent a risk to human health. The high squalene content in some of the black dogfish liver necessitated an additional clean-up step, involving gel permeation chromatography, when analyzing for PBDEs. Concentrations of PBDEs were low with many congeners being below detection limits, particularly in the muscle. There are currently no assessment criteria available for PBDEs. Furthermore, there is only very limited data on PBDEs in deep water fish. However, the concentrations observed in this study were similar to the concentrations recently reported in Mediterranean deep water fish. 相似文献
458.
Lelia N. Hawkins Lynn M. Russell 《Atmospheric environment (Oxford, England : 1994)》2010,44(34):4142-4154
Submicron particles were collected from June to September 2008 in La Jolla, California to investigate the composition and sources of atmospheric aerosol in an anthropogenically-influenced coastal site. Factor analysis of aerosol mass spectrometry (AMS) and Fourier transform infrared (FTIR) spectroscopy measurements revealed that the two largest sources of submicron organic mass (OM) at the sampling site were (1) fossil fuel combustion associated with ship and diesel truck emissions near the ports of Los Angeles and Long Beach and (2) aged smoke from large wildfires burning in central and northern California. During non-fire periods, fossil fuel combustion contributed up to 95% of FTIR OM, correlated to sulfur, and consisted mostly of alkane (86%) and carboxylic acid groups (9%). During fire periods, biomass burning contributed up to 74% of FTIR OM, consisted mostly of alkane (48%), ketone (25%), and carboxylic acid groups (17%), and correlated to AMS-derived factors resembling brush fire smoke, wood smoldering and flaming particles, and biogenic secondary organic aerosol. The two AMS-derived biomass burning factors were identified as oxygenated and hydrocarbon biomass burning aerosol on the basis of spectral similarities to smoldering and flaming smoke particles, respectively. In addition, the ratio of oxygenated to hydrocarbon biomass burning OM shows a clear diurnal trend with an afternoon peak, consistent with photochemical oxidation. Back trajectory analysis indicates that 2–4-day old forest fire emissions include substantial ketone groups, which have both lower O/C and lower m/z 44/OM fraction than carboxylic acid groups. Air masses with more than 4-day old emissions have higher carboxylic acid/ketone group ratios, showing that atmospheric processing of these ketone-containing organic aerosol particles results in increased m/z 44 and O/C. These observations may provide functionally-specific evidence for the type of chemical processing that is responsible for biomass burning particle composition in the atmosphere. 相似文献
459.
Seeing (and doing) conservation through cultural lenses 总被引:1,自引:1,他引:0
In this paper, we first discuss various vantage points gained through the authors’ experience of approaching conservation
through a “cultural lens.” We then draw out more general concerns that many anthropologists hold with respect to conservation,
summarizing and commenting on the work of the Conservation and Community Working Group within the Anthropology and Environment
Section of the American Anthropological Association. Here we focus on both critiques and contributions the discipline of anthropology
makes with regard to conservation, and show how anthropologists are moving beyond conservation critiques to engage actively
with conservation practice and policy. We conclude with reflections on the possibilities for enhancing transdisciplinary dialogue
and practice through reflexive questioning, the adoption of disciplinary humility, and the realization that “cross-border”
collaboration among conservation scholars and practitioners can strengthen the political will necessary to stem the growing
commoditization and ensuing degradation of the earth’s ecosystems. 相似文献
460.
A Case for Using Plethodontid Salamanders for Monitoring Biodiversity and Ecosystem Integrity of North American Forests 总被引:8,自引:0,他引:8
Abstract: Terrestrial salamanders of the family Plethodontidae have unique attributes that make them excellent indicators of biodiversity and ecosystem integrity in forested habitats. Their longevity, small territory size, site fidelity, sensitivity to natural and anthropogenic perturbations, tendency to occur in high densities, and low sampling costs mean that counts of plethodontid salamanders provide numerous advantages over counts of other North American forest organisms for indicating environmental change. Furthermore, they are tightly linked physiologically to microclimatic and successional processes that influence the distribution and abundance of numerous other hydrophilic but difficult-to-study forest-dwelling plants and animals. Ecosystem processes such as moisture cycling, food-web dynamics, and succession, with their related structural and microclimatic variability, all affect forest biodiversity and have been shown to affect salamander populations as well. We determined the variability associated with sampling for plethodontid salamanders by estimating the coefficient of variation (CV ) from available time-series data. The median coefficient of variation indicated that variation in counts of individuals among studies was much lower in plethodontids (27%) than in lepidoptera (93%), passerine birds (57%), small mammals (69%), or other amphibians (37–46%), which means plethodontid salamanders provide an important statistical advantage over other species for monitoring long-term forest health. 相似文献