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191.
During Norwegian and Danish harbour porpoise projects 1987-1991, subcutaneous blubber samples of 34 male harbour porpoises (Phocoena phocoena) were collected. Animals from three geographical locations, ranging from 56 degrees N, 12 degrees E to 71 degrees N, 26 degrees E, were chosen in order to study the organochlorine (OC) contamination in this species inhabiting the northeastern part of the North Atlantic Ocean, the northern North Sea and Kattegat, at the locations of Tufjord, Vestlandet and Gilleleje, respectively. Analytical standards used consisted of the industrial chemicals PCBs (22 individual PCB congeners and 6 industrial mixtures which contained 104 PCB congeners or group of congeners) and HCB, and the organochlorine pesticides DDT, HCH, the cyclodienes endrin, dieldrin and the chlordane metabolites oxychlordane and trans-nonachlor, and heptachlor epoxide. A total of 16 PCB congeners or groups of congeners, all the DDT metabolites except o,p'-DDD, and all the pesticides were detected in all animals. The concentrations of sigmaPCB (sum of concentrations of 47 detected PCB congeners) and sigmaDDT (sum of concentrations of all DDT detected compounds) ranged from 3.7-65.3 and 3.2-45.0 microg g(-1) lipid weight, respectively. The range of mean concentrations of dieldrin, endrin and trans-nonachlor was 1-3 microg g(-1), while mean concentrations of HCHs, heptachlor epoxide, and HCB were <1 microg g(-1). No significant variation in PCB congener pattern was apparent between geographical areas. The major PCB congeners nos 147/123, 153, 138/163/164, 182/187 and 180 at Gilleleje, Vestlandet and Tufjord represented 53%, 45% and 44% of sigmaPCB, respectively. A significant difference was found between the number of PCB congeners in blubber of newborn and older porpoises. This might indicate the presence of a blood/placenta barrier and/or selective mammary transport of PCBs with specific structures. A significant OC accumulation with age was apparent, with the exception of HCB and HCHs. Geographical differences in the levels of OCs were apparent for all compounds except for dieldrin and heptachlor epoxide. Significantly higher levels of chlordane metabolites (trans-nonachlor and oxychlordane) and endrin were found in the group of animals from the northern location Tufjord, while sigmaDDT, p,p'-DDTs, HCHs and PCBs were highest in the group of animals from the southern location Gilleleje. Highest levels of the o,p'-substituted DDTs were found in specimens from the middle location Vestlandet. These findings indicate little or no regular migration of harbour porpoise between these three locations. No correlations were found between OC concentrations and blubber thickness. Although mean values of sigmaDDT and sigmaPCB were in the lower end of previously reported levels in harbour porpoise from adjacent waters in the eastern part of the North Atlantic Ocean and along the coasts of North America, these levels are relatively high. The organochlorine concentrations in harbour porpoises in the present study were 2-3 times higher than corresponding OC levels detected in harbour seals (Phoca vitulina) from the same areas.  相似文献   
192.
A cellulose acetate membrane, positioned in a passive sampler system, was coated with the perfluorinated polymer Nafion. Aqueous metal transport through the membrane and the Nafion film was investigated. The Nafion-coated membrane prevents the transport of metals bound to natural organic material to the receiving phase in the passive sampler, while copper associated with small synthetic ligands pass through the Nafion film. Increasing thickness of the Nafion film decreases the metal uptake rate to the receiving phase in the passive sampler and increases the response time. A decreased response time for the passive sampler would provide a better estimation of rapid changes in concentration, particularly for dynamic aquatic systems such as urban runoff. Limited biofouling protection with the Nafion coating was demonstrated by growth inhibition of natural periphyton communities on glass surfaces.  相似文献   
193.
Pilot-scale experiments were carried out to study the formation of chlorinated hydrocarbons through combustion of PVC. Vinyl chloride, dichloro-, trichloro-, tetrachloro-, pentachloro-, and hexachlorobenzenes were determined by GC/ECD. Furthermore, some peaks in the chromatogram were tentatively assigned to octachlorostyrene and PCB. The total amount of lipophilic organochlorinated compounds was determined by neutron activation analysis. The results indicate that incineration of PVC is not a major source of chlorinated hydrocarbons in the environment.  相似文献   
194.
This study compares diversity and abundance of birds plus abundance of butterflies, bumblebees and herbaceous plants between six small farms (<52 ha arable land) and six large farms (>135 ha arable land) in Roslagen in southeastern Sweden. Two of the large and four of the small farms were organic. Large-scale landscape mosaic and underlying bedrock were similar for all farms. Statistical analysis was performed using box-plots on medians and analysis of variance on mean values. More than twice as many bird species and territories, butterflies, and herbaceous plant species, and five times more bumblebees were found on the small compared to the large farms. The largest differences were found between small organic and large conventional farms. Differences were also noted between small and large organic farms: 56% more bird species were found on small organic than on large organic farms, although none of the farms used any pesticides. We therefore argue that the consideration of organic agriculture's effect on biodiversity should include factors affected by farm size.  相似文献   
195.
196.
While energy-sector emissions remain the biggest source of climate change, many least-developed countries still invest in fossil-fuel development paths. These countries generally have high levels of fossil-fuel technology lock-in and low capacities to change, making the shift to sustainable energy difficult. Tanzania, a telling example, is projected to triple fossil-fuel power production in the next decade. This article assesses the potential to use internationally supported Nationally Appropriate Mitigation Actions (NAMAs) to develop solar energy in Tanzania and contribute to transformational change of the electricity supply system. By assessing the cultural legitimacy of NAMAs among key stakeholders in the solar energy sector, we analyse the conditions for successful uptake of the concept in (1) national political thought and institutional frameworks and (2) the solar energy niche. Interview data are analysed from a multi-level perspective on transition, focusing on its cultural dimension. Several framings undermining legitimacy are articulated, such as attaching low-actor credibility to responsible agencies and the concept’s poor fit with political priorities. Actors that discern opportunities for NAMAs could, however, draw on a framing of high commensurability between experienced social needs and opportunities to use NAMAs to address them through climate-compatible development. This legitimises NAMAs and could challenge opposing framings.  相似文献   
197.
在野生动物物种中,乳汁在传递全氟烃基物质(PFASs)于后代中所起的作用,人类还了解甚少。本文以雌性冠海豹及其生产的一对幼崽为研究对象,在哺乳期间,对母体血浆和乳汁中的8种PFASs进行了定量检测,以及对乳汁在PFASs传递过程中所起的作用进行了分析。选择冠海豹是因为它的泌乳周期短(3~ 4 d),在此期间幼崽仅以乳汁为食。胎盘或乳汁传递成为幼崽体内PFASs的唯一来源。通过对8种PFASs的分析(Σ8PFAS),发现7种存在于所有样品中;因此,乳汁是幼崽体内PFASs的来源。在所有样本中,全氟辛烷磺酰基化合物是优势PFAS。Σ8PFAS的平均浓度为母体血浆中6.0 ng/g蛋白(36 ng/g湿重),乳汁中0.77 ng/g蛋白(3.2 ng/g湿重)以及幼崽血浆中12 ng/g蛋白(66 ng g湿重)。血浆中检测到的PFASs浓度在已有报道的其他海豹物种体内检测到的浓度范围之内,低于已知的实验啮齿动物的毒性阈值。PFASs从母体到幼崽的传递效率的个体差异,依赖于PFASs碳键长度、相对传递量最低的为中间能级键的PFASs (C9-C10)。结果显示母体通过乳汁和胎盘传递PFASs,其中胎盘传递是主导途径。
精选自Randi Gr?nnestad, Gro D. Villanger, Anuschka Polder, Kit M. Kovacs, Christian Lydersen, Bj?rn M. Jenssen, Katrine Borg?. Maternal transfer of perfluoroalkyl subastances in hooded seals. Environmental Toxicology and Chemistry: Volume 36, Issue 3, pages 763–770, July 2017. DOI: 10.1002/etc.3623
详情请见http://onlinelibrary.wiley.com/wol1/doi/10.1002/etc.3623/full
  相似文献   
198.
Eggs laid by white-tailed sea eagles (Haliaeetus albicilla), one in 1941 and five eggs between 1996 and 2001, all from the same geographical region of the Baltic Sea, were screened for organohalogen substances. The 1941 egg contained hexachlorobenzene (HCB), but did not contain either of the pesticides hexachlorocyclohexane (HCH) or p,p′-DDT, nor any metabolites of the latter. In contrast, the more recent eggs (REs) contained all of these compounds. Of the seven polychlorinated biphenyls (PCBs) analyzed (CB28, −52, −101, −118, −138/−163, −153 and 180), only the more highly chlorinated congeners were detected in the 1941 sample, with CB153 followed by CB180 showing the highest concentrations. All eggs demonstrated the same congener pattern with respect to the more highly chlorinated PCBs, but concentrations were approximately 70-230 times higher in the REs. All of the polychlorinated-p-dioxin and dibenzofuran (PCDD/Fs) congeners analyzed were detected in the eggs, with the dominant congener being 2,3,4,7,8-PeCDF (1250 pg/g l.w. in 1941 and 1540 pg/g l.w. (GM) for the REs, respectively). None of the other congeners exceeded 400 pg/g l.w., and the concentrations of 2,3,7,8-TCDD, 2,3,7,8-TCDF and 1,2,3,7,8-PeCDF were all lower in the REs. None of five congeners of polybrominated diphenyl ethers (PBDEs) found in the REs was detected in the egg from 1941. The three methoxylated brominated diphenyl ethers (MeO-BDEs) analyzed were found at similar levels and with a similar congener pattern in REs as in the egg from 1941.In conclusion, this study has shown the absence of DDE and PBDE and the presence of HCB and PCBs in a white-tailed sea eagle egg laid in 1941, and a strong increase of PCBs, DDE and PBDE in white-tailed sea eagle eggs from the same area in 1996-2001. The MeO-BDEs were found in similar concentrations in the analyzed eggs. The 1941 sample shows substantial concentrations of PCDD/Fs, noteworthy in the same magnitude as in the recent samples, illustrating the historical and recent exposure of these compounds.  相似文献   
199.
The Persian Gulf is a semi-enclosed marine system surrounded by eight countries, many of which are experiencing substantial development. It is also a major center for the oil industry. The increasing array of anthropogenic disturbances may have substantial negative impacts on marine ecosystems, but this has received little attention until recently. We review the available literature on the Gulfs marine environment and detail our recent experience in the United Arab Emirates (U.A.E.) to evaluate the role of anthropogenic disturbance in this marine ecosystem. Extensive coastal development may now be the single most important anthropogenic stressor. We offer suggestions for how to build awareness of environmental risks of current practices, enhance regional capacity for coastal management, and build cooperative management of this important, shared marine system. An excellent opportunity exists for one or more of the bordering countries to initiate a bold and effective, long-term, international collaboration in environmental management for the Gulf.  相似文献   
200.
Sustainability policy making is hampered by a tendency towards sector-based, short-term and often techno-fix perspectives. This paper describes a novel policy development and assessment framework – Integrated Sustainability Assessment (ISA) – that may help address problems of unsustainability in a more integrated and strategic manner. ISA involves two primary methods: transition analysis and stakeholder engagement. The ISA case study on sustainable passenger mobility suggests ISA is well equipped to produce a holistic analysis of mobility systems, illustrate radical alternatives to the status quo and foster social learning. Further research should explore its potential to induce long-term behavioural or institutional change.  相似文献   
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