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   1895篇
  免费   15篇
  国内免费   18篇
安全科学   48篇
废物处理   138篇
环保管理   152篇
综合类   195篇
基础理论   378篇
环境理论   2篇
污染及防治   706篇
评价与监测   184篇
社会与环境   117篇
灾害及防治   8篇
  2023年   17篇
  2022年   70篇
  2021年   60篇
  2020年   37篇
  2019年   47篇
  2018年   67篇
  2017年   73篇
  2016年   102篇
  2015年   56篇
  2014年   100篇
  2013年   181篇
  2012年   132篇
  2011年   156篇
  2010年   106篇
  2009年   100篇
  2008年   101篇
  2007年   116篇
  2006年   76篇
  2005年   65篇
  2004年   61篇
  2003年   42篇
  2002年   37篇
  2001年   25篇
  2000年   23篇
  1999年   14篇
  1998年   12篇
  1997年   4篇
  1996年   5篇
  1995年   8篇
  1994年   6篇
  1993年   2篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1987年   3篇
  1986年   1篇
  1985年   1篇
  1983年   2篇
  1979年   2篇
  1978年   1篇
  1973年   1篇
  1969年   1篇
  1967年   1篇
  1961年   1篇
  1958年   1篇
  1956年   1篇
  1949年   1篇
  1915年   1篇
排序方式: 共有1928条查询结果,搜索用时 15 毫秒
51.
There is limited knowledge of the mechanisms that can inspire people's concern and engagement in the protection of unpopular and unappealing species. We analyzed Polish people's interest in themed internet memes featuring the proboscis monkey (Nasalis larvatus) and the consequences of this interest for conservation marketing. We examined Google Trends data, used Google Search, and searched popular media materials to estimate interest in the proboscis monkey in Poland. Photos of the proboscis monkey when presented with humor in internet memes attracted as much interest as usually more popular species (e.g., koala, panda, and orangutan) used in marketing by nongovernmental organizations. Amusing internet memes spread by social media positively correlated with increasing interest in the unappealing species, such as proboscis monkey. Interest in amusing internet memes positively correlated with individuals’ decisions to donate to 6 crowdfunding actions. Thus, conservation marketing that includes amusing memes and social media may provide a worthwhile complement to traditional campaigns and are likely to influence individuals who are unaffected by the usual means.  相似文献   
52.
Abstract

The main objective of this study is the degradation of a synthetic solution of atrazine by a modified vermiculite catalyzed ozonation, in a rotating packed bed (RPB) reactor. A 0.5?L RPB reactor was used to perform the experiments, using a Central Composite Design (CCD) response surface to construct the quadratic model based on the factors: pH, catalyst concentration and reactor rotation frequency. The response variable was the removal of the organic load measured in terms of Chemical Oxygen Demand (COD). After the complete quadratic model was constructed through the response surface, the COD degradation process had an optimal removal of 41% under the following conditions: pH 8.0, rotation of 1150?rpm and catalyst concentration 0.66?g L?1.  相似文献   
53.
The concentrations of cadmium, lead, nickel and copper in waters, sediments (total metal concentrations and their speciation forms) and benthic macroinvertebrates in 11 lakes of Latvia were determined using atomic absorption spectroscopy. Metal concentrations in lake waters, sediments and biota were compared with water chemistry. Compared to total concentrations, metal speciation forms in sediments were better correlated with respective metal concentrations in invertebrates. Therefore, the evaluation of potential metal bioaccumulation should consider metal speciation. The mean concentrations of trace metals in benthic invertebrates in Latvia were much lower than in other countries, which can be explained by comparatively lower anthropogenic loads. However, local areas of anthropogenic impacts were evident.  相似文献   
54.
The performance of phillipsite as a matrix for slow-release formulation of oxamyl [N,N-dimethyl-2-methylcarbamoyl-oxymino-2-(methylthio)acetamide] was tested. The adsorption kinetics followed a first-order law, and the adsorption isotherm fitted well in a two-surface Langmuir model, suggesting a double mechanism of interaction between oxamyl and the sorbent. The sorption mechanism, studied by FTIR, provided two fractions of oxamyl. The first one is sorbed on the mineral surface, linked by H-bonding, and the second one is constituted by a multilayer of oxamyl molecules linked by a water bridge between them. The release kinetics of oxamyl from a substratum zeolite-oxamyl also follows a first-order law, with two stages that correspond to both fractions of oxamyl previously detected.  相似文献   
55.
Carp (Cyprinus carpio) and barbel (Barbus graellsii) were collected from five sites along the Ebro River. The study was designed to assess levels of persistent organic pollutants and metals bioaccumulated by fish, and some biochemical responses (cytochrome P450 system, phase II activities, and metallothioneins) against those pollutants. The highest levels of PCBs and DDTs were detected in carp from industrialised areas, which also showed high levels of mercury and cadmium in the liver, and high levels of nonylphenol in bile. Significant alterations in some biochemical markers were observed and associated to combined exposure to pollutants. The activity 7-ethoxyresorufin O-deethylase ranged from 69 pmol/min/mg protein in carp from the reference site to 415 pmol/min/mg protein in those from polluted sites. Carp from the Ebro Delta, an agricultural area, had depressed acetylcholinesterase in muscle tissue. Metallothionein concentrations were positively correlated with copper residues, but no significant differences among sampling points were observed.  相似文献   
56.
The effect of hexavalent chromium on fatty acid composition was studied in two strains of Euglena gracilis; UTEX 753 (from the Culture Collection of Algae of Texas University, USA) and MAT (isolated from a highly polluted River). Both were grown in photoauxotrophic and photoheterotrophic conditions and exposed to two metal concentrations, one below and one above IC50. The high malondialdehyde (MDA) levels (3 to 7-fold) obtained with chromium concentration above IC50, suggested the existence of metal-induced lipid peroxidation. Total lipid content increased only with concentration below IC50, whereas it was inhibited by higher metal concentration. Photoheterotrophic control strains exhibited a significantly higher proportion of saturated and polyunsaturated fatty acids. Polyunsaturated acids were most affected by chromium, especially those related to chloroplast structures. Ultra-structure studies showed clear thylakoid disorganization in all treated cells. The results indicate that hexavalent chromium affects levels of fatty acids, especially those related to photosynthetic activity.  相似文献   
57.
The 18 Galician Rias, comprising 25% of the Iberian Peninsula coastline, form a unique system within the European continental Atlantic coast and provide a useful reference area for studies of metals. These rias are sensitive to anthropogenic influence due to the socioeconomic importance generated in these areas by industry, aquaculture, port activities, fishing, tourism and, accordingly, several islands lying within close proximity to the rias have recently been declared natural parks. Aquaculture in the Galician Rias is a growth industry and in 2000 the rias supported 3386 mussel rafts producing 2.5 x 10(8) kg year(-1), i.e. 40% of European Union total seafood production. The Galician Rias are partially stratified estuaries with positive residual circulation with fresh (runoff lower than 100 m3 s(-1) and salt water mixing inside the basins. This behaviour has direct consequences on metal fluxes whereby the rias behave as a barrier and accumulate metals in the sediments. Metals tend to deposit close to point sources and remobilization occurs inside the ria, leading to a seaward decrease in metal concentration. With the exception of the Ulla (Arosa Ria) and Eume (Ares-Betanzos Ria) head rivers and the Lagares river (Vigo Ria) the available data suggest that riverine freshwater inputs are not the main source of contamination. Metal studies reported in the literature mainly relate to Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn, and to a lesser extent Hg and Sn. Studies of other harmful metals such as Ag, Se and As are notably lacking. In addition, the studies have been localized and mainly restricted to the surface sediment. Data of heavy metals in the dissolved phase, suspended particulate matter and biota is scarce in the mainstream literature and should be considered in the future research. From the entire Galician coast, data from seven rias of socio-economic importance form the bulk of the published work. There is an urgent need to standardize procedures, employ 'clean' procedures to avoid contamination of samples and regular assessment of analytical accuracy with CRMs in order that results can be compared among the scientific community and produce reliable results. The continuation of coastal environmental studies requires an enlargement of the sampling locations as well as systematic and periodic analysis of known pollution sources in order to decide whether coastal regeneration action is needed. Studies dedicated to metals in the water column are lacking and need more attention in future research. The majority of the available data correspond to the fluvial front (30%) at ria head and, to a lesser extent, to the oceanic front (3%), under summer upwelling events. Current awareness of the rias suggests that they are not contaminated although there is some evidence of important localized anthropogenically induced enrichments at the outflow of the Lagares River (Pb, Zn), the San Simón inlet (Pb) and near to the harbor (Pb, Zn, Cu) in the Vigo Ria, the inner part (Cu, Zn, Hg, Pb) of the Pontevedra Ria, the Ulla River estuary (Cu, Cr, Mn, Ni; Zn) in the Arosa Ria, the inner zone (Cu, Pb, Zn) of the Coru?a Ria, the Ferrol Ria (Zn) and the Eume Estuary (Zn, Mn, Ni, Co) in the Ares-Betanzos Ria. In addition, TBT enrichment has been found along the Galician coast, being highest in the industrial bays (Vigo, Coru?a and Ferrol). Nevertheless, it is important to point out the lack of information concerning the relationship between metal concentrations in different fractions of sediments and/or water and their bioavailability and toxicity on biota in order to confirm metal contamination dangers. The present paper reviews all the information published on metals in the rias up to the year 2000 and takes a biogeochemical standpoint, i.e. metal presence in the ria reservoirs: water column, suspended particulate matter, sediments and biota, as well as the fluvial and oceanic frontiers.  相似文献   
58.
Non-mineral carbon is the main component of PM10 and PM2.5 at an urban roadside site in Madrid accounting for more than 50% of the total bulk mass in winter pollution episodes. In these cases a 70-80% of the particle mass is anthropogenic. Particles of crustal/mineral origin contribute significantly to the observed PM10 concentrations, especially in spring and summer. They have also been found in the PM2.5 fraction although secondary particles are the next most important contributor in this size. Long-range transport particle episodes of Saharan dust significantly contribute to exceedence of the new daily limiting PM10 value in the urban network and at nearby rural background stations. This type of long-range transport event also influences PM2.5 concentrations. The crustal contribution can account for up to 67 and 53% of the PM10 and PM2.5 bulk mass in such cases.  相似文献   
59.

Pyrolysis of waste materials to produce biochar is an excellent and suitable alternative supporting a circular bio-based economy. One of the properties attributed to biochar is the capacity for sorbing organic contaminants, which is determined by its composition and physicochemical characteristics. In this study, the capacity of waste-derived biochar to retain volatile fuel organic compounds (benzene, toluene, ethylbenzene and xylene (BTEX) and fuel oxygenates (FO)) from artificially contaminated water was assessed using batch-based sorption experiments. Additionally, the sorption isotherms were established. The results showed significant differences between BTEX and FO sorption on biochar, being the most hydrophobic and non-polar contaminants those showing the highest retention. Furthermore, the sorption process reflected a multilayer behaviour and a relatively high sorption capacity of the biochar materials. Langmuir and Freundlich models were adequate to describe the experimental results and to detect general differences in the sorption behaviour of volatile fuel organic compounds. It was also observed that the feedstock material and biochar pyrolysis conditions had a significant influence in the sorption process. The highest sorption capacity was found in biochars produced at high temperature (>?400 °C) and thus rich in aromatic C, such as eucalyptus and corn cob biochars. Overall, waste-derived biochar offers a viable alternative to be used in the remediation of volatile fuel organic compounds from water due to its high sorption capacity.

  相似文献   
60.
Environmental Science and Pollution Research - Lead acid battery (LAB) scrap management is an important issue both environmentally and economically. The recovery of lead from battery scrap leads to...  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