全文获取类型
收费全文 | 1001篇 |
免费 | 23篇 |
国内免费 | 12篇 |
专业分类
安全科学 | 53篇 |
废物处理 | 63篇 |
环保管理 | 201篇 |
综合类 | 95篇 |
基础理论 | 227篇 |
污染及防治 | 267篇 |
评价与监测 | 89篇 |
社会与环境 | 34篇 |
灾害及防治 | 7篇 |
出版年
2023年 | 14篇 |
2022年 | 11篇 |
2021年 | 15篇 |
2020年 | 17篇 |
2019年 | 21篇 |
2018年 | 21篇 |
2017年 | 26篇 |
2016年 | 22篇 |
2015年 | 24篇 |
2014年 | 33篇 |
2013年 | 153篇 |
2012年 | 51篇 |
2011年 | 53篇 |
2010年 | 30篇 |
2009年 | 43篇 |
2008年 | 48篇 |
2007年 | 57篇 |
2006年 | 40篇 |
2005年 | 35篇 |
2004年 | 31篇 |
2003年 | 31篇 |
2002年 | 30篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1998年 | 14篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 6篇 |
1994年 | 14篇 |
1993年 | 12篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1976年 | 4篇 |
1958年 | 2篇 |
1957年 | 3篇 |
1956年 | 2篇 |
1955年 | 3篇 |
排序方式: 共有1036条查询结果,搜索用时 609 毫秒
611.
Dioxin is the common name for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and is abbreviated as PCDD/Fs. In the case of Southern Vietnam, is of high concern dioxin contamination in the areas affected by past-use chemical defoliants. Our study related to the zone considered as a "hot spot"--Bien Hoa Airbase and surrounding areas (Bien Hung Lake). Although the war ended over 30 years ago, the adverse effects on this territory still continue. Soil and sediment were selected for our research as they act as a sink for PCDD/Fs. The samples were taken and analyzed in CECOTOX laboratory following certified procedures. The total amounts of PCDD/Fs (2,3,7,8 related congeners) in the samples were converted into WHO-TEQ and compared with standard values proposed by Canadian environmental quality guidelines. The obtained data shows a relatively high risk (up to 20.4 times higher than (probable effect level) PEL value for sediment and 46 times higher than standard value for soil). The research is continuing on the assessment of dioxin transport in food chain. Moreover, considering the obtained data a complete solution should be found urgently to solve the problem of dioxin contamination in the studied areas. 相似文献
612.
Processed ball clays commonly used by the ceramic art industry in the United States were collected from retail suppliers and analyzed for the presence and concentration of the 2,3,7,8-Cl substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs). The average PCDD toxic equivalent (TEQ) concentrations of these processed ball clays was approximately 800 pg/g (TEQ-WHO) with characteristic congener profiles and isomer distributions similar to patterns of previously analyzed raw and processed ball clays. The PCDF concentrations were below the average limit of detection (LOD) of 0.5 pg/g. Correlation analyses reveal no significant relationship between total organic carbon (TOC) and either individual, homologues, and total tetra-through octa-chlorinated PCDD congeners, or TEQ concentrations of the processed ball clays. The results are consistent with earlier studies on levels of PCDDs in ball clays. Data from earlier studies indicated that dioxins may be released to the environment during the processing of raw clay or the firing process used in commercial ceramic facilities. The presence of dioxin in the clays also raises concerns about potential occupational exposure for individuals involved in the mining/processing of ball clay, ceramics manufacturing and ceramic artwork. 相似文献
613.
Tsuji LJ Manson H Wainman BC Vanspronsen EP Shecapio-Blacksmith J Rabbitskin T 《Environmental monitoring and assessment》2007,127(1-3):293-306
Great concern has been raised with respect to the 13 traplines that constitute the traditional territory of the Ouje-Bougoumou
Cree located in the James Bay region of northern Quebec, Canada, with respect to mine wastes originating from three local
mines. As a result, an “Integrative Risk Assessment” was initiated consisting of three interrelated components: a comprehensive
human health study, an assessment of the existing ecological/environmental database, and a land use/potential sites of concern
study. In this paper, we document past and present land use in the traditional territory of the Ouje-Bougoumou Cree for 72
heads of households, including 13 tallymen, and use a Geographic Information System (GIS) to layer harvest/hunting and gathering/collecting
data over known mining areas and potential sites of concern. In this way, potential receptors of contamination and routes
of human exposure were identified. Areas of overlap with respect to land use activity and mining operations were relatively
extensive for certain harvesting activities (e.g., beaver, Castor canadensis and various species of game birds), less so for fish harvesting (all species) and water collection, and relatively restrictive
for large mammal harvesting and collection of firewood (and other collection activities). Potential receptors of contaminants
associated with mining activity (e.g., fish and small mammals) and potential routes of exposure (e.g., ingestion of contaminated
game and drinking of contaminated water) were identified. 相似文献
614.
We describe significant and unexpected errors in application of a conventional method for the quantitative determination of polychlorinated biphenyls (PCBs) in unusual biological tissue samples. A standard method based upon microwave-assisted extraction (MAE) and gas chromatography tandem mass spectrometry (GC-MS/MS) was applied to a variety of "invasive" freshwater organisms, representing a variety of genera. The 12 "co-planar" PCBs (co-PCBs) were determined at ng g(-1) levels in small samples (ca. 750-1000 mg) of eight freshwater species (n = 172). We found that the conventional method could lead to random and relatively large changes in retention times. A nearly five-fold increase in retention variability was observed for "lower" organisms compared to that observed in the analysis of predatory fish tissue. These unexpected retention time changes would result in misidentifications, and become problematic not only for non-selective detectors such as electron capture but also for MS-based approaches. That is, for electron impact (EI) ionization methods, molecular ions (M(+)) are produced by loss of Cl not only for congeners in the same homolog class but also for fragments of higher homologs (e.g. M - 35 and M - 37), thereby yielding false positive measurement of the target congener when the retention time windows overlap. 相似文献
615.
V. Simon C. Purcarea K. Sun J. Joseph G. Frebourg J.-P. Lechaire F. Gaill G. Hervé 《Marine Biology》2000,136(1):115-127
The obligate symbiosis of the deep-sea tube worm Riftia pachyptila with a sulphur-oxidizing bacterium raises important questions concerning its metabolism and metabolic exchanges. In this
study, the presence and properties of the enzymes synthesizing and utilizing carbamylphosphate in the arginine and pyrimidine
nucleotide pathways were investigated in this worm. The results show that the ammonium-dependent carbamylphosphate synthetase
and ornithine transcarbamylase, enzymes involved in the arginine pathway, are present in all body parts of the worm. In contrast,
the glutamine-dependent carbamylphosphate synthetase and aspartate transcarbamylase, enzymes involved in the de novo pathway
for pyrimidine nucleotides biosynthesis, are present only in the trophosome, the symbiont-harbouring tissue. Although the
bacterial nature of these enzymes is not unambigously established, these results strongly suggest that the de novo biosynthesis
of pyrimidine nucleotides is limited to the trophosome, the organ where the production of metabolic energy takes place, while
the other parts of the worm's body rely on the salvage pathway for the production of the pyrimidine triphosphate nucleotides.
Received: 22 June 1998 / Accepted: 26 October 1999 相似文献
616.
617.
Spicer CW Joseph DW Ollison WM 《Journal of the Air & Waste Management Association (1995)》2010,60(11):1353-1364
Attaining the National Ambient Air Quality Standard (NAAQS) for ozone (O3) could cost billions of dollars nationwide. Attainment of the NAAQS is judged on O3 measurements made by the Federal Reference Method (FRM), ethylene chemiluminescence, or a Federal Equivalent Method (FEM), predominantly ultraviolet (UV) absorption. Starting in the 1980s, FRM monitors were replaced by FEMs so that today virtually all monitoring in the United States uses the UV methodology. This report summarizes a laboratory and collocated ambient air monitoring study of interferences in O3 monitors. Potential interferences examined in the laboratory included water vapor, mercury, o-nitrophenol, naphthalene, p-tolualdehyde, and mixed reaction products from smog chamber simulations of urban atmospheric photochemistry. UV absorption O3 monitors modified for humidity equilibration were also collocated with UV FEM O3 monitors at six sites in Houston, TX, during the 2007 summer O3 season. The results suggest that humidity and interfering species can positively bias (overestimate) O3 measured by FEM monitors used to determine compliance with the O3 standards. The results also suggest that humidity equilibration can mitigate this bias. 相似文献
618.
Naresh?KumarEmail author Daisy?Ramirez-Ortiz Helena?M.?Solo-Gabriele Joseph?B.?Treaster Olveen?Carrasquillo Michal?Toborek Sapna?Deo Jim?Klaus Leonidas?G.?Bachas David?Whitall Sylvia?Daunert Jose?Szapocznik 《Environmental science and pollution research international》2016,23(3):2003-2013
Guánica Bay, located in southwestern Puerto Rico, has suffered oil spills and other pollution discharges since the 1960s. Previous research showed elevated concentrations of polychlorinated biphenyls (PCBs) in coral reef and sediment. This research examined PCB concentrations in sediment and fish. Sediment and fish sampling in the bay was facilitated by community members. This study identified the second highest reported PCB level (129,300 ng/g) in sediment in the USA. Fish samples also showed elevated concentrations (1623 to 3768 ng/g), which were higher than the thresholds of safe levels of PCBs in fish for human consumption. The alarmingly high concentration of PCBs calls for proactive community engagement to bring awareness about contamination of the bay and more extensive sampling to test for the concentration of PCBs in seafood and the people of Guánica. This study also underscores the value of the involvement of local communities during sampling design aimed at identifying hot spots of contaminants. 相似文献
619.
Zhen Liu Joseph P. Pinto Tao Zeng Jim Boylan Maoyi Huang 《Journal of the Air & Waste Management Association (1995)》2014,64(4):419-435
Motivated by the question of whether and how a state-of-the-art regional chemical transport model (CTM) can facilitate characterization of CO2 spatiotemporal variability and verify CO2 fossil-fuel emissions, we for the first time applied the Community Multiscale Air Quality (CMAQ) model to simulate CO2. This paper presents methods, input data, and initial results for CO2 simulation using CMAQ over the contiguous United States in October 2007. Modeling experiments have been performed to understand the roles of fossil-fuel emissions, biosphere–atmosphere exchange, and meteorology in regulating the spatial distribution of CO2 near the surface over the contiguous United States. Three sets of net ecosystem exchange (NEE) fluxes were used as input to assess the impact of uncertainty of NEE on CO2 concentrations simulated by CMAQ. Observational data from six tall tower sites across the country were used to evaluate model performance. In particular, at the Boulder Atmospheric Observatory (BAO), a tall tower site that receives urban emissions from Denver, CO, the CMAQ model using hourly varying, high-resolution CO2 fossil-fuel emissions from the Vulcan inventory and CarbonTracker optimized NEE reproduced the observed diurnal profile of CO2 reasonably well but with a low bias in the early morning. The spatial distribution of CO2 was found to correlate with NOx, SO2, and CO, because of their similar fossil-fuel emission sources and common transport processes. These initial results from CMAQ demonstrate the potential of using a regional CTM to help interpret CO2 observations and understand CO2 variability in space and time. The ability to simulate a full suite of air pollutants in CMAQ will also facilitate investigations of their use as tracers for CO2 source attribution. This work serves as a proof of concept and the foundation for more comprehensive examinations of CO2 spatiotemporal variability and various uncertainties in the future.
Implications: Atmospheric CO2 has long been modeled and studied on continental to global scales to understand the global carbon cycle. This work demonstrates the potential of modeling and studying CO2 variability at fine spatiotemporal scales with CMAQ, which has been applied extensively, to study traditionally regulated air pollutants. The abundant observational records of these air pollutants and successful experience in studying and reducing their emissions may be useful for verifying CO2 emissions. Although there remains much more to further investigate, this work opens up a discussion on whether and how to study CO2 as an air pollutant. 相似文献
620.
This study examines the bleaching responses of scleractinian corals at four sites in Kenya (Kanamai, Vipingo, Mombasa and
Nyali) representing two distinct lagoon habitats (relatively shallow and relatively deep). Bleaching incidence was monitored
for the whole coral community, while zooxanthellae densities and chlorophyll levels were monitored for target species (Pocillopora damicornis, Porites lutea, and Porites cylindrica) during a non-bleaching year (2006) and a year of mild-bleaching (2007). Differences in bleaching responses between habitats
were observed, with shallower sites Kanamai and Vipingo exhibiting lower bleaching incidence than deeper sites Nyali and Mombasa.
These shallower lagoons display more fluctuating thermal and light environments than the deeper sites, suggesting that corals
in the shallower lagoons have acclimatized and/or adapted to the fluctuating environmental conditions they endure on a daily
basis and have become more resistant to bleaching stress. In deeper sites that did exhibit higher bleaching (Mombasa and Nyali),
it was found that coral recovery occurred more quickly in the protected area than in the non-protected area. 相似文献