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   969篇
  免费   11篇
  国内免费   6篇
安全科学   18篇
废物处理   61篇
环保管理   55篇
综合类   182篇
基础理论   161篇
污染及防治   334篇
评价与监测   109篇
社会与环境   60篇
灾害及防治   6篇
  2023年   14篇
  2022年   36篇
  2021年   43篇
  2020年   18篇
  2019年   18篇
  2018年   51篇
  2017年   34篇
  2016年   60篇
  2015年   49篇
  2014年   52篇
  2013年   80篇
  2012年   39篇
  2011年   67篇
  2010年   51篇
  2009年   27篇
  2008年   65篇
  2007年   53篇
  2006年   44篇
  2005年   30篇
  2004年   23篇
  2003年   27篇
  2002年   23篇
  2001年   18篇
  2000年   12篇
  1999年   3篇
  1998年   3篇
  1996年   4篇
  1995年   4篇
  1994年   8篇
  1993年   5篇
  1992年   4篇
  1990年   3篇
  1988年   1篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1975年   1篇
  1964年   1篇
  1962年   1篇
排序方式: 共有986条查询结果,搜索用时 15 毫秒
81.
Aromatic DNA adducts in the livers and blood of grey mullet (Mugil sp.) have been monitored between 1993 and 1996 by the isolation of DNA and the postlabeling of the DNA adducts with 32P. The grey mullet were sampled from three well-characterised harbours, two in the northeastern Mediterranean and one in the northeastern Black Sea near Trabzon close to a site of aquaculture. One of the northeastern Mediterranean harbours was highly polluted with polynuclear aromatic hydrocarbons (PAHs) and was rich in inorganic nutrients. Larger grey mullet lived in this harbour than the other harbours and their livers possessed approximately 100 aromatic DNA adducts per 10(8) nucleotides. The livers from grey mullet in the other two harbours possessed < or = 25 aromatic DNA adducts per 10(8) nucleotides but these concentrations depended on a variety of factors. Blood cell being regenerated more rapidly than liver cells, it is found that generally the ratio of DNA adduct concentrations in piscine liver and blood will increase with the pollution of the surrounding marine environment. Fishes are acceptable models for the metabolism of xenobiotics and the associated formation of harmful aromatic DNA adducts in organisms.  相似文献   
82.
Bottom sediments reflect in general the relative contamination of a sea area. Therefore, a great deal of monitoring work has been dedicated to the analysis of bottom sediments. Izmir Bay is a very important pollution centre in Turkish Aegean coast region due to a densely populated community, industrial complex and maritime transportation, and there are many streams flowing into the bay that pass through a number of industrial and agricultural areas. It had received the majority of domestic and industrial wastewaters until the wastewater treatment plant was constructed. It is well known that sediments play an important role as reservoirs of a fraction of the pollution in aquatic systems. Therefore, sediment samples were collected monthly from three stations which are located in the inner part of the bay during the period January to December 2003. Temporal variations and seasonal changes on their 210Po and 210Pb contents were examined, and the activity concentrations of 210Po and 210Pb were found to vary from 43±6 to 132±12 and 27±5 to 91±9 Bq kg???1 dry wt, respectively. The highest values of those natural radionuclides were measured at Kar??yaka Station because of the current systems of the bay. Seasonally, the 210Pb levels were found to increase during the winter time for all the stations.  相似文献   
83.
Phyllanthus niruri is a plant that is used to prevent calcium oxalate crystallisation and to block the stone formation in urolithiasis. Contaminants in the environment can be readily taken up by medicinal plants due to their ability to absorb chemicals into their tissues. If contaminated plants are ingested, they have the potential to negatively affect human and environmental health. The aim of this study was to assess contamination in the soil and the medicinal plant P. niruri by cadmium (Cd) in ceramic industrial areas of Monte Carmelo, Brazil. Soil samples and plant samples (divided in root, shoot and leaves) were collected from a contaminated monitoring site and from a rural area (which was used as a reference site for comparative purposes). The Cd concentrations of the samples were analysed with an atomic absorption spectrometer. P. niruri was found to be sensitive to soil contamination by Cd that was attributed to ceramic industrial emissions. The results revealed that Cd bioaccumulation in the roots and shoots of P. niruri was associated with a significant increase (p?<?0.05) in the concentration of active lignan compounds (phyllanthin and hypophyllanthin) in the leaves. The identification of high concentrations of Cd and active lignan compounds suggests a risk of contamination of the site and the risk of a high dose of Cd to people exposed at the site.  相似文献   
84.
Environment, Development and Sustainability - In dry-hot areas, such as southern Tunisia, the availability of good water is very limited by the low scanty rainfall, the long dry periods and the...  相似文献   
85.
Aydin N  Daher S  Gülaçar FO 《Chemosphere》2003,52(5):937-942
The 13(2),17(3)-cyclopheophorbide a enol (CPP) is shown to convert mainly to a approximately 1:1 mixture of (13(2)R/S) chlorophyllones a (Chlone), when chromatographed over silica gel or alumina supports. 15(1)-hydroxychlorophyllonelactone a and some other chlorophyll a related compounds are also tentatively identified as minor transformation products of CPP. This raises the possibility that the chlorophyllones reported in recent sediments may be analytical artifacts from CPP. However, data for the surface sediments from Lake Motte as well as literature data for other contemporary sediments show that, (i) they are not artifacts, (ii) considering that CPP is the intermediate compound in the formation of chlorophyllones from chlorophyll a, the hydroxylation of CPP in the sedimentary environment involves an enzymatic process leading preferentially to 13(2)S chlorophyllone a.  相似文献   
86.
Environmental Science and Pollution Research - A theoretical physicochemical and thermodynamic investigation of the adsorption of heavy metals Zn2+, Cd2+, Ni2+, and Cu2+on carbon-based adsorbents...  相似文献   
87.
Nickel–metal hydride (NiMH) batteries contain high amount of industrial metals, especially iron, nickel, cobalt and rare earth elements. Although the battery waste is a considerable secondary source for metal and chemical industries, a recycling process requires a suitable pretreatment method before proceeding with recovery step to reclaim all valuable elements. In this study, AA- and AAA-type spent NiMH batteries were ground and then sieved for size measurement and classification. Chemical composition of the ground battery black mass and sorted six different size fractions were determined by an analytical technique. Crystal structures of the samples were analyzed by X-ray diffraction. Results show that after mechanical treatment, almost 87 wt% of the spent NiMH batteries are suitable for further recycling steps. Size classification by sieving enriched the iron content of the samples in the coarse fraction which is bigger than 0.25 mm. On the other hand, the amounts of nickel and rare earth elements increased by decreasing sample size, and concentrated in the finer fractions. Anode and cathode active materials that are hydrogen storage alloy and nickel hydroxide were mainly collected in finer size fraction of the battery black mass.  相似文献   
88.
An integrated system, consisting of Up-flow Anaerobic Sludge Blanket (UASB)-duckweed-tilapia ponds was used for recovery of sewage nutrients and water recycling. A UASB reactor with 40 liter working volume was used as pre-treatment unit followed by a series of three duckweed ponds for nitrogen recovery. The treated effluent and duckweed biomass was used to feed fishponds stocked with Nile tilapia (Oreochromis niloticus). The UASB reactor was fed with raw, domestic sewage at 6 h hydraulic retention time. The three duckweed ponds were stocked with Lemna gibba and fed with UASB effluent at 15 days hydraulic retention time. Nitrogen recovery from UASB effluent via duckweed biomass represented 81% of total nitrogen removal and 46.5% from the total nitrogen input to the system. In subsequent fishponds the nitrogen recovery from duckweed as fish feed was in the range of 13.4–20%. This nitrogen in fish biomass represented 10.6–11.5 g N from the total nitrogen in the raw sewage fed to the UASB reactor. The growth performance of tilapia (Oreochromis niloticus) showed specific growth rates (SGR) in the range of 0.53–0.97. The range of feed conversion ratio (FCR) and protein efficiency ratio (PER) were 1.2–2.2 and 2.1–2.28, respectively. The results of the experiments showed total fish yield and net fish yield in the range of 17–22.8 ton/ha/y and 11.8–15.7 ton/ha/y respectively. In conclusion UASB-duckweed-tilapia ponds provide marketable by-products in the form of duckweed and fish protein, which represent a cost recovery for sewage treatment.  相似文献   
89.
Different water Acts (e.g., the European Water Framework Directive) and stakeholders involved in aquatic affairs have promoted integrated river basin management over recent decades. However, few studies have provided feedback on these policies. The aim of the current article is to fill this gap by exploring how local newspapers reflect the implementation of a broad public participation within a catchment of France known for its innovation with regard to this domain. The media coverage of a water management strategy in the Drôme watershed from 1981 to 2008 was investigated using a content analysis and a geographic information system. We sought to determine what public participation and decentralized decision-making can be in practice. The results showed that this policy was integrated because of its social perspective, the high number of involved stakeholders, the willingness to handle water issues, and the local scale suitable for participation. We emphasized the prominence of the watershed scale guaranteed by the local water authority. This area was also characterized by compromise, arrangements, and power dynamics on a fine scale. We examined the most politically engaged writings regarding water management, which topics of each group emphasized, and how the groups agreed and disagreed on issues based on their values and context. The temporal pattern of participation implementation was progressive but worked by fits and starts.  相似文献   
90.
We present a case of prenatal diagnosis of a de novo (7;19)(q11.2;q13.3) translocation associated with ultrasound features, including enlarged cisterna magna, normal vermis, thick corpus callosum, micrognathia, small and low-set ears and right hyperechogenic kidney. Karyotyping was performed at 24 weeks of gestation. Termination of pregnancy was accepted at the parents' request. Postmortem examination confirmed the prenatal findings, but revealed bilateral Wilms tumors of the kidneys. Parental karyotype was normal. Copyright © 2005 John Wiley & Sons, Ltd.  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