首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   692篇
  免费   14篇
  国内免费   9篇
安全科学   66篇
废物处理   32篇
环保管理   100篇
综合类   128篇
基础理论   156篇
污染及防治   141篇
评价与监测   42篇
社会与环境   43篇
灾害及防治   7篇
  2023年   5篇
  2022年   3篇
  2021年   13篇
  2020年   14篇
  2019年   7篇
  2018年   16篇
  2017年   33篇
  2016年   27篇
  2015年   28篇
  2014年   30篇
  2013年   51篇
  2012年   30篇
  2011年   55篇
  2010年   27篇
  2009年   39篇
  2008年   42篇
  2007年   54篇
  2006年   25篇
  2005年   31篇
  2004年   27篇
  2003年   29篇
  2002年   20篇
  2001年   15篇
  2000年   10篇
  1999年   10篇
  1998年   6篇
  1997年   6篇
  1996年   5篇
  1995年   7篇
  1994年   11篇
  1993年   6篇
  1992年   2篇
  1991年   1篇
  1990年   4篇
  1989年   3篇
  1988年   2篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1984年   5篇
  1983年   3篇
  1982年   1篇
  1981年   2篇
  1975年   1篇
  1974年   1篇
  1973年   1篇
  1968年   1篇
  1958年   1篇
排序方式: 共有715条查询结果,搜索用时 15 毫秒
631.
The aim of this work is to establish baseline levels of pharmaceuticals in three wastewater treatment plant (WWTP) streams in the greater Dublin region to assess the removal efficiency of the selected WWTPs and to investigate the existence of any seasonal variability. Twenty compounds including several classes of antibiotics, acidic and basic pharmaceuticals, and prescribed medications were selected for investigation using a combination of membrane filtration, solid phase extraction (SPE) cleanup, and liquid chromatography–electrospray ionization tandem mass spectrometry. Fourteen of the selected compounds were found in the samples. Increased effluent concentrations, compared to influent concentrations, for a number of compounds (carbamazepine, clotrimazole, propranolol, nimesulide, furosemide, mefenamic acid, diclofenac, metoprolol, and gemfibrozil) were observed. The detected concentrations were generally below toxicity levels and based on current knowledge are unlikely to pose any threat to aquatic species. Mefenamic acid concentrations detected in both Leixlip and Swords effluents may potentially exert ecotoxicological effects with maximum risk quotients (i.e., ratio of predicted exposure concentration to predicted no effect concentration) of 4.04 and 1.33, respectively.  相似文献   
632.

Systematic understanding of adaptation measures utilised by households in developing countries is needed to identify the constraints they face, and the external interventions or adaptation planning needed to overcome them. Understanding of autonomous household adaptation patterns remains underdeveloped. In particular, little is known regarding whether households are implementing incremental or transformational adaptation measures as well as the implications of this for adaptation planning. We demonstrate the suitability of the risk hazard approach for understanding autonomous household adaptation patterns and discuss the implications for planned adaptation. To achieve this, we use an in-depth village case study from an area of Bangladesh particularly vulnerable to climate change, using qualitative semi-structured household interviews as primary material. We find that the risk hazard approach is ideal for exploring autonomous adaptations because of its capacity for understanding how households respond to livelihood risk, and what resources are required for it to be most effective. However, the risk hazard approach overlooks equity and fairness considerations need to be integrated due to the insufficient emphasis on these concerns.

  相似文献   
633.
The effect of heavy metals at environmentally relevant concentrations on couple fecundity has received limited study despite ubiquitous exposure. In 2005-2009, couples (n = 501) desiring pregnancy and discontinuing contraception were recruited and asked to complete interviews and to provide blood specimens for the quantification of cadmium (μg L−1), lead (μg dL−1) and mercury (μg L−1) using inductively coupled plasma-mass spectrometry. Couples completed daily journals on lifestyle and intercourse along with menstruation and pregnancy testing for women. Couples were followed for 12 months or until pregnant. Fecundability odds ratios (FORs) and 95% confidence intervals (CIs) were estimated adjusting for age, body mass index, cotinine, and serum lipids in relation to female then male exposures. FORs <1 denote a longer time to pregnancy. In adjusted models, reduced FORs were observed for both female cadmium (0.78; 95% CI 0.63-0.97) and male lead (0.85; 95% CI 0.73-0.98) concentrations. When jointly modeling couples’ exposures, only male lead concentration significantly reduced the FOR (0.82; 95% CI 0.68, 0.97), though the FOR remained <1 for female cadmium (0.80; 95% CI 0.64, 1.00). This prospective couple based cohort with longitudinal capture of time to pregnancy is suggestive of cadmium and lead’s reproductive toxicity at environmentally relevant concentrations.  相似文献   
634.
Pharmaceuticals and other anthropogenic trace contaminants reach wastewaters and are often not satisfactorily eliminated in sewage treatment plants. These contaminants and/or their degradation products may reach surface waters, thus influencing aquatic life. In this study, the behavior of five different antihypertonic pharmaceuticals from the sartan group (candesartan, eprosartan, irbesartan, olmesartan and valsartan) is investigated in lab-scale sewage plants. The elimination of the substances with related structures varied broadly from 17 % for olmesartan up to 96 % for valsartan. Monitoring data for these drugs in wastewater effluents of six different sewage treatment plants (STPs) in Bavaria, and at eight rivers, showed median concentrations for, e.g. valsartan of 1.1 and 0.13 μg L?1, respectively. Predicted environmental concentrations (PEC) were calculated and are mostly consistent with the measured environmental concentrations (MEC). The selected sartans and the mixture of the five sartans showed no ecotoxic effects on aquatic organisms in relevant concentrations. Nevertheless, the occurrence of pharmaceuticals in the environment should be reduced to minimize the risk of their distribution in surface waters, ground waters and bank filtrates used for drinking water.  相似文献   
635.
A comprehensive surveillance program was conducted to determine the occurrence of three cyclic volatile methylsiloxanes (cVMS) octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) in environmental compartments impacted by wastewater effluent discharges. Eleven wastewater treatment plants (WWTPs), representative of those found in Southern Ontario and Southern Quebec, Canada, were investigated to determine levels of cVMS in their influents and effluents. In addition, receiving water and sediment impacted by WWTP effluents, and biosolid-amended soil from agricultural fields were also analyzed for a preliminary evaluation of the environmental exposure of cVMS in media impacted by wastewater effluent and solids. A newly-developed large volume injection (septumless head adapter and cooled injection system) gas chromatography – mass spectrometry method was used to avoid contamination originating from instrumental analysis. Concentrations of D4, D5, and D6 in influents to the 11 WWTPs were in the range 0.282–6.69 μg L−1, 7.75–135 μg L−1, and 1.53–26.9 μg L−1, respectively. In general, wastewater treatment showed cVMS removal rates of greater than 92%, regardless of treatment type. The D4, D5, and D6 concentration ranges in effluent were <0.009–0.045 μg L−1, <0.027–1.56 μg L−1, and <0.022–0.093 μg L−1, respectively. The concentrations in receiving water influenced by effluent, were lower compared to those in effluent in most cases, with the ranges <0.009–0.023 μg L−1, <0.027–1.48 μg L−1, and <0.022–0.151 μg L−1 for D4, D5, and D6, respectively. Sediment concentrations ranged from <0.003–0.049 μg g−1 dw, 0.011–5.84 μg g−1 dw, and 0.004–0.371 μg g−1 dw for D4, D5, and D6, respectively. The concentrations in biosolid-amended soil, having values of <0.008–0.017 μg g−1 dw, <0.007–0.221 μg g−1 dw, and <0.009–0.711 μg g−1 dw for D4, D5, and D6, respectively, were lower than those in sediment impacted by wastewater effluent in most cases. In comparison with the no-observed-effected concentrations (NOEC) and IC50 (concentration that causes 50% inhibition of the response) values, the potential risks to aquatic, sediment-dwelling, and terrestrial organisms from these reported concentrations are low.  相似文献   
636.
The link between climate change and desertification is an important global problem for the United Nations Framework Convention on Climate Change (UNFCCC) and the United Nations Convention to Combat Desertification (UNCCD). The coastal provinces in Southern Centre Vietnam are strongly influenced by desertification, which is further exacerbated by climate change. The Delphi method was used to select sustainability indicators and then a method of an analytical hierarchy process was applied to prioritize sustainable solutions in Binh Thuan experts to elicit the causes and effects of desertification. According to the panel of 23 experts, 27 cause (e.g. rainfall and sunshine duration) and 22 effect (e.g. rice and agriculture) indicators were of particular importance to desertification and drought in the province. The highest priorities for cause are given to emigration, followed by income from industry and water supply for household use. The highest priorities for effect in the area are given to socioeconomic criteria, and in particular to the sub-criteria resettlement due to development projects, building hydropower reservoirs, and implementing irrigation schemes. The system of indicators provides useful information for the future studies. This study provides a means to uncover the most important criteria perceived as major contributors to desertification and as such enables policy-makers to prioritize solutions for Binh Thuan (Vietnam) by 2015 and a vision in 2020.  相似文献   
637.
The topic of carbon sequestration in plants has received much attention recently due to concerns about global climate change, which is being exacerbated by deforestation. In the early days of the global bioenergy boom, the private sector and non-government organizations enthusiastically promoted the planting of Jatropha curcas L. as a key candidate shrub species for the production of bioenergy in West Africa. This study investigates the aboveground biomass production and carbon sequestration potential of J. curcas, which is already widely cultivated for the production of oil seeds, biodiesel and biokerosene. The specific objective is to use a destructive method to develop allometric prediction equations of the aboveground biomass production of J. curcas plantations. 38 J. curcas shrubs were harvested and weighed in order to estimate biomass production. These data were used to develop allometric equations for the estimation of wood, leaf and total aboveground biomass production. The best-fit models found for estimating shrub component biomass and total aboveground biomass production were of the power form. All of the regression equations relating the prediction of leaf biomass, wood biomass and total aboveground biomass with J. curcas diameter at 20 cm above the ground (D) were statistically significant (p < 0.001) and also presented the highest goodness of fit (high R 2). The aboveground biomass carbon content was estimated using the ash method. Carbon content in leaves and wood was, respectively, 48 and 54 %. The current established allometric equations can be helpful to provide a rapid estimation of the aboveground biomass and C stock for J. curcas biofuel projects in semi-arid conditions.  相似文献   
638.
Oyster farmers depend on good water quality. Activities upstream from estuaries result in externalities that impact water quality. Over the last 10 years, oyster farmers have been developing estuary‐wide environmental management systems ( EMSs ) to tackle internal (i.e. industry‐related) and external (i.e. catchment) issues in N ew S outh W ales, A ustralia. Drawing on interview‐based research and document analyses, this paper shows that the process of creating an EMS for the oyster industry, as well as the creation of the EMS itself, resulted in legitimizing the industry's stewardship over the natural resource it depends on (water). For the oyster industry, this result was due to a change in the scale on which EMSs have been developed: instead of viewing issues at the individual business level, the systems expanded their viewpoint to the entire catchment, and included every oyster business in the estuary, as well as all other activities in the upper catchment. By providing a means of communicating internal efforts and with the support of local government bodies, EMSs provided a mechanism with which influence over upstream actors and activities could be exerted. We demonstrate this by using the ‘social‐ecological systems’ and ‘ ENCORE ’ frameworks, emphasizing the transitions that allowed for this change of scale to take place.  相似文献   
639.
Carbonaceous soil amendments are applied to contaminated soils and sediments to strongly sorb hydrophobic organic contaminants (HOCs) and reduce their freely dissolved concentrations. This limits biouptake and toxicity, but also biodegradation. To investigate whether HOCs sorbed to such amendments can be degraded at all, the desorption and biodegradation of low concentrations of 14C-labelled phenanthrene (?5 μg L?1) freshly sorbed to suspensions of the pure soil amendments activated carbon (AC), biochar (charcoal) and compost were compared. Firstly, the maximum abiotic desorption of phenanthrene from soil amendment suspensions in water, minimal salts medium (MSM) or tryptic soy broth (TSB) into a dominating silicone sink were measured. Highest fractions remained sorbed to AC (84 ± 2.3%, 87 ± 4.1%, and 53 ± 1.2% for water, MSM and TSB, respectively), followed by charcoal (35 ± 2.2%, 32 ± 1.7%, and 12 ± 0.3%, respectively) and compost (1.3 ± 0.21%, similar for all media). Secondly, the mineralization of phenanthrene sorbed to AC, charcoal and compost by Sphingomonas sp. 10-1 (DSM 12247) was determined. In contrast to the amounts desorbed, phenanthrene mineralization was similar for all the soil amendments at about 56 ± 11% of the initially applied radioactivity. Furthermore, HPLC analyses showed only minor amounts (<5%) of residual phenanthrene remaining in the suspensions, indicating almost complete biodegradation. Fitting the data to a coupled desorption and biodegradation model revealed that desorption did not limit biodegradation for any of the amendments, and that degradation could proceed due to the high numbers of bacteria and/or the production of biosurfactants or biofilms. Therefore, reduced desorption of phenanthrene from AC or charcoal did not inhibit its biodegradation, which implies that under the experimental conditions these amendments can reduce freely dissolved concentration without hindering biodegradation. In contrast, phenanthrene sorbed to compost was fully desorbed and biodegraded.  相似文献   
640.
The following remarks were presented by Mrs. Gorsuch at the Acid Rain Symposium conducted by the Pittsburgh Chamber of Commerce on October 6, 1982.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号