全文获取类型
收费全文 | 245篇 |
免费 | 5篇 |
专业分类
安全科学 | 8篇 |
废物处理 | 4篇 |
环保管理 | 85篇 |
综合类 | 25篇 |
基础理论 | 46篇 |
污染及防治 | 66篇 |
评价与监测 | 10篇 |
社会与环境 | 4篇 |
灾害及防治 | 2篇 |
出版年
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 7篇 |
2015年 | 4篇 |
2014年 | 3篇 |
2013年 | 45篇 |
2012年 | 3篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 6篇 |
2008年 | 14篇 |
2007年 | 15篇 |
2006年 | 13篇 |
2005年 | 6篇 |
2004年 | 10篇 |
2003年 | 16篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有250条查询结果,搜索用时 31 毫秒
61.
Roger W. Parker Timothy D. Phillips Leon F. Kubena Leon H. Russell Norman D. Heidelbaugh 《Journal of environmental science and health. Part. B》2013,48(2):77-91
Abstract Penicillic acid and ochratoxin A are environmentally important toxic fungal metabolites (mycotoxins) that are synergistic in combination. The effects of penicillic acid on the pancreatic enzyme, :arboxypeptidase A were investigated in vitro and in vivo. A broad range of inhibition in vitro of the enzyme by PA was demonstrated with a half‐maximal inhibitory concentration equal to 1.1 x 10‐4M PA. Inhibition of carboxypeptidase A was time and temperature dependent, and resulted in decreased conversion of parent ochratoxin A to the non‐toxic metabolite, ochratoxin alpha. Studies in vivo demonstrated a penicillic acid‐dependent inhibition of pancreatic carboxypeptidase A activity in the mouse and the chicken following multiple oral exposure. It is postulated that the mode of toxic interaction of the two mycotoxins may be due, in part, to impaired detoxification of ochratoxin A through peni‐cillic acid depletion of carboxypeptidase A activity. 相似文献
62.
Over-stabilisation and eutrophication affect many dune systems in north-west Europe. This leads to lower diversity of typical
dune species and an accumulation of soil nutrients. Existing management techniques to remove excess nutrients include mowing,
with removal of cuttings, and turf stripping. A new restoration technique called topsoil inversion or deep ploughing may also
be able to counter some of the negative effects of eutrophication. It simulates the burial of established soils with fresh
mineral sand, by inverting the soil profile. A trial was carried out on two small blocks of eutrophic dune grassland in North
Wales, UK. Nutrient-rich surface soils were buried beneath mineral sub-sand using a double-bladed plough, designed to plough
to depths of up to 100 cm. Results show that the organic soil horizons were buried to a depth of 80 cm, and covered with 40–50 cm
of mineral sand. The pH and organic matter of the surface layers became comparable to those of mobile dunes. Fifteen months
after ploughing, bare sand cover was still 70–90%, but significant sand loss through wind erosion resulted in a thinning of
the mineral sand over-burden, leaving the buried organic layer closer to the surface. Natural vegetation colonisation was
slow, with the first surviving plants observed after 8 months. The majority of species present at 15 months were present before
ploughing and had regenerated from rhizomes or root fragments. The effect of excluding disturbance caused by rabbits, people
and dogs was assessed within fenced areas. After 11 months, vegetation cover was greater in the fenced areas than in plots
exposed to disturbance, therefore disturbance replaced physical conditions as the dominant influence on plant growth and establishment.
These early results suggest the trial has been partially successful, but that topsoil inversion could be combined with other
methods such as turf stripping or by stabilisation of the ploughed surface by planting with pioneer species, depending on
the ultimate restoration goal. 相似文献
63.
This analysis estimates willingness to pay to improve community-based rural water utilities in the Dodoma and Singida Regions of Central Tanzania, using Multinomial Logit functions. An estimate of willingness to pay provides an indication of the demand for improved services and potential for them being sustainable. Surveys were conducted in a total of 30 villages in the two regions. In the Dodoma Region, about 14% of respondents indicated that they were satisfied with the status quo, 64% suggested increasing water discharge and watering points, and 22% proposed other improvements relating to water quality. In the Singida Region, 31% of the respondents were satisfied with the status quo, 59% wanted deeper boreholes and watering points, and 10% indicated other types of improvement relating to water quality. The Multinomial Logit functions indicated that the interaction between the water quality variable and proposed bids were important in making choices with reference to the type of improvement desired. Respondents who wanted to increase water supply in Dodoma Region were willing to pay 32 Tsh above the existing tariff of 20 Tsh/bucket. In the Singida Region, the analogous amount was 91 Tsh per household per year above the existing user fee of 508 Tsh per household per year. If the tariff or user fees have to be increased, the estimated average potential revenue for the surveyed villages was 252 million Tsh/year (US$265 263) in the Dodoma Region, and 5.2 million Tsh/year (US$5474) in the Singida Region. In the future, strategic planning is needed to ensure that improvements proposed potentially improve cost recovery initiatives and increase the level of consumer satisfaction. Also, care will be needed to ensure that more disadvantaged community members do not suffer unduly from increases in tariff or user fees. 相似文献
64.
65.
One of the strategies now in vogue in hazardous waste cleanup is basing remedial strategies on future land use. The initial thrust of CERCLA for permanent and complete remedies has given way, pushed by concepts like “brownfields” and base closure and reuse, to strategies often based on “institutional controls” that attempt to stabilize future land uses at a site based on residual risk. The heart of this concept is that instead of removing all wastes from a site, some wastes can safely remain so long as in the future the site is not used in such a way that the residual contamination poses an unacceptable risk to human health and the environment. “Institutional controls” is a term for land use management strategies that do not rely on engineering approaches to reduce risk, but rather seek to ensure that the site is not used in an inappropriate way in the future. This article cautions that such a strategy has inherent residual risks that must be understood by those involved in implementing hazardous waste cleanups and those responsible for future uses of contaminated property. Simply put, institutional controls are only as good as the processes that are in place to ensure they are respected in the future. This presents particular problems for active duty installations because most of the protections commonly available to private sector sites are not useful at active installations. This article discusses an initiative by the Air Combat Command to develop a handbook on instituting and maintaining land restrictions. It will also discuss that effort in light of the April 21 EPA Region IV guidance on assuring Land Use Controls at Federal Facilities. This article is based on a paper and presentations given at the 1998 ACC Environmental Training Symposium. 相似文献
66.
Yanbo Pang Norman L. Eatough William K. Modey 《Journal of the Air & Waste Management Association (1995)》2013,63(5):563-572
Abstract The real-time ambient mass sampler (RAMS) is a continuous monitor based on particle concentrator, denuder, drier, and tapered element oscillating microbalance (TEOM) monitor technology. It is designed to measure PM2.5 mass, including the semi-volatile species NH4NO3 and semi-volatile organic material, but not to measure PM2.5 water content. The performance of the RAMS in an urban environment with high humidity was evaluated during the July 1999 NARSTO-Northeast Oxidant and Particles Study (NEOPS) intensive study at the Baxter water treatment plant in Philadelphia, PA. The results obtained with the RAMS were compared to mass measurements made with a TEOM monitor and to constructed mass obtained with a Particle Concentrator-Brigham Young University Organic Sampling System (PC-BOSS) sampler designed to determine the chemical composition of fine particles, including the semi-volatile species. An average of 28% of the fine particulate material present during the study was semi-volatile organic material lost from a filter during particle collection, and 1% was NH4NO3 that was also lost from the particles during sampling. The remaining mass was dominantly nonvolatile (NH4)2SO4 (31%) and organic material (37%), with minor amounts of soot, crustal material, and nonvolatile NH4NO3. Comparison of the RAMS and PC-BOSS results indicated that the RAMS correctly monitored for fine particulate mass, including the semi-volatile material. In contrast, the heated filter of the TEOM monitor did not measure the semi-volatile material. The comparison of the RAMS and PC-BOSS data had a precision of ±4.1 μg/m3 (±9.6%). The precision of the RAMS data was limited by the uncertainty in the blank correction for the reversible adsorption of water by the charcoal-impregnated cellulose sorbent filter of the RAMS monitor. The precision of the measurement of fine par-ticulate components by the PC-BOSS was ±6-8%. 相似文献
67.
Escalada JP Pajares A Gianotti J Massad WA Bertolotti S Amat-Guerri F García NA 《Chemosphere》2006,65(2):237-244
The present work studies the visible-light-promoted photodegradation of the colorless fungicide carbendazim (methyl 2-benzimidazolecarbamate) and several 2-substituted benzimidazoles (SBZ's), in water or water-methanol solution, in the presence of air and, as a photosensitizer, the synthetic xanthene dye Rose Bengal (RB) or the natural pigment riboflavin (Rf). The results indicate that the degradation of each particular SBZ depends on its chemical structure and on the sensitizer employed. In the presence of RB, the degradation always operates via a singlet molecular oxygen (O(2)((1)Delta(g)))-mediated mechanism, through a highly efficient process, as deduced from the comparison of the rate constants for physical and chemical quenching of O(2)((1)Delta(g)). In the presence of Rf, the visible-light irradiation of any of the studied SBZ's produces a series of competitive processes that depend on the relative concentrations of Rf and SBZ. These processes include the quenching of excited singlet and triplet Rf states by the SBZ and the generation of both O(2)((1)Delta(g)) and superoxide radical anion (O(2)(-)), the latter generated by electron transfer from excited Rf species to the dissolved oxygen. The overall result is the photodegradation of the SBZ and the photoprotection of the sensitizer. 相似文献
68.
Conservation in Brazil's Chocolate Forest: The Unlikely Persistence of the Traditional Cocoa Agroecosystem 总被引:7,自引:0,他引:7
Norman D. Johns 《Environmental management》1999,23(1):31-47
/ In southern Bahia, Brazil, the traditional cocoa agroecosystem with a dense shade canopy of native trees is now recognized as a secondary conservation route for highly endangered Atlantic Rainforest species. This "chocolate forest" of the densely shaded farms persists despite a massive 20-year Brazilian government modernization program in which shade was seen as a chief impediment to raising cocoa production. The objective of this study was to determine how this traditional agroecosystem endured. Although dense shade limits cocoa yield, it provides several agroecological benefits: control of insect pests and weeds, microclimate stability, and soil fertility maintenance. A keycomponent of modernization efforts was a shade-tree removal program designed to maximize cocoa production by using low shade and fertilizer while substituting agrochemicals for many beneficial roles of the overhead trees. This research found that many farmers rejected, or only partially accepted, the shade reduction process although it promised much higher cocoa yield and profit. Farmers employing a wide range of shading were interviewed, and it was found that decisions to remove or maintain the shade trees were linked to both agroecological and risk-minimization factors. Farmers' perceptions of the agroecological functions of the shade trees and individual willingness to entertain the economic risk associated with substituting agrochemicals for these were important. A less-profitable, but lower-risk approach of occasional fertilizer and agrochemical use with the traditional shade intact was a rational and widespread choice. Policies designed to maintain the traditional agroecosystem through the current economic crisis should heed the multiple functions of the overhead trees. KEY WORDS: Conservation; Brazil; Atlantic Rainforest; Cocoa; Agroecology; Risk; Agroforestry 相似文献
69.
Paul H. Whitfield Norman L. Wade 《Journal of the American Water Resources Association》1993,29(2):301-308
ABSTRACT: Electronic instruments are increasingly being used to gather water quality data. Quality assurance protocols are needed which provide adequate documentation of the procedures followed in calibration, collection, and validation of electronically acquired data. The level of precision of many data loggers exceeds the technology which is commonly used to make field measurements. Overcoming this problem involves using laboratory quality equipment in the field or enhanced quality control at the time of instrument servicing. Time control procedures for data loggers are needed to allow direct comparisons of data between instruments. Electronic instruments provide a mechanism to study transient events in great detail, but, without time controls, multiple loggers produce data which contain artifacts due to timing errors. Individual sensors deployed with data loggers are subject to different degrees of drift over time. Certain measurements can be measured with defined precision and accuracy for long periods of time, while other sensors are subject to loss of both precision and accuracy with increasing time of use. Adequate quality assurance requires the levels of precision and accuracy be documented, particularly those which vary with increasing time deployment. 相似文献
70.
Norman H. Pillsbury David R. DeWalle 《Journal of the American Water Resources Association》1982,18(6):989-993
ABSTRACT: Two surveys were conducted to determine the supply and demand for students trained in watershed management in the United States. The first survey of 23 educational institutions was conducted in 1978. Annual production of about 100 watershed graduates and employment success greater than 85 percent at all degree levels was indicated. The second survey of watershed employment within the U.S. Forest Service (conducted in 1979) indicated one-third of the annual supply of watershed graduates could be employed by the agency; a fact verified by employment data supplied by educational institutions. 相似文献