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351.
In this present work the distribution of heavy metals in sea water and sediments of the Salerno Gulf is measured. The elements determined were Cu, Pb, Cd, Zn and Hg, employing, as instrumental techniques, either differential pulse anodic stripping voltammetry (DPASV) or graphite furnace atomic absorption spectroscopy (GFAAS). A comparison of the results of the two analytical techniques is also made. Mercury determination was carried out employing the cold vapour atomic absorption spectroscopy (CVAAS) technique, with SnCl2 as the reducing agent. The sample digestion was performed by a new procedure using concentrated suprapure H2SO4–K2Cr2O7 mixture. The accuracy and precision of the analytical procedure were evaluated employing Sea Water BCR-CRM 403 and Estuarine Sediment BCR-CRM 277 as reference materials. Accuracy, expressed as relative error e and precision, expressed as relative standard deviation sr, were in order of 2 to 5%. For both matrices, the detection limits, for all the elements, were in the range g g-1 to ng g-1.  相似文献   
352.
This paper presents the preliminary results of a study, the aim of which was to analyse the pluviometric and chemical rain data, recorded by a wet only network located in Northern Italy.More in detail, precipitations were collected on a weekly basis and chemical analysis was performed on pH, electric conductivity and Ca, Mg, Na, K, NH4, NO3, SO4, Cl concentrations.The Principal Components Analysis pointed out that the first three components are enough to explain more than 90% of the variability of the parameters. Moreover each component may have a different physical interpretation, that is the first one is mainly related to the precipitation amount, while the second to the man made and natural sources and the last one to the sea/soil contribution.  相似文献   
353.
This paper reports on a contingent valuation (CV) study eliciting willingness to pay (WTP) for a public program for the preservation of lagoon, beach and infrastructure in the island of S. Erasmo in the Lagoon of Venice, Italy. We use split samples to investigate the effect of providing a summary of reasons for voting in favor and against the program before the referendum valuation question. Reminding respondents of the reasons for voting for or against the program increases WTP among less highly educated respondents, and decreases WTP among more highly educated respondents.  相似文献   
354.
We report a case of nuchal cystic hygroma with spontaneous resolution detected by ultrasound examination at 13 weeks' gestation. Fetal karyotype and amniotic fluid alphafetoprotein levels were normal. Extreme caution in evaluating this situation is stressed.  相似文献   
355.
356.
The present paper describes the development, performance and conclusions derived from three know-how and technology transfer projects to South American countries. The first project comprised a collaborative study by European and South American universities to find sustainable solutions for Chilean and Ecuadorian leather tanneries which had underachieving process performances. The second project consisted of investigations carried out in a Brazilian municipality to enhance its municipal solid waste management system. The final collaborative programme dealt with the initial identification, evaluation and registration of suspected contaminated sites in an industrial region of Chile. The detailed objectives, methods and procedures applied as well as the results and conclusions obtained in each of the three mentioned projects are presented, giving special attention to the organizational aspects and to the practical approach of each programme, concluding with their main advantages and disadvantages for identifying a set of qualitative and quantitative suggestions, and to establish transferable methods for future applications.  相似文献   
357.
In this paper we examine the trends of nitrous oxide (N2O) emissions of the Spanish agricultural sector related to national production and consumption in the 1961–2009 period. The comparison between production- and consumption-based emissions at the national level provides a complete overview of the actual impact resulting from the dietary choices of a given country and allows the evaluation of potential emission leakages. On average, 1.5 % of the new reactive nitrogen that enters Spain every year is emitted as N2O. Production- and consumption-based emissions have both significantly increased in the period studied and nowadays consumption-based emissions are 45 % higher than production-based emissions. A large proportion of the net N2O emissions associated with imported agricultural goods comes from countries that are not committers for the United Nations Framework Convention on Climate Change Kyoto Protocol Annex I. An increase in feed consumption is the main driver of the changes observed, leading to a remarkable emission leakage in the Spanish agricultural sector. The complementary approach used here is essential to achieve an effective mitigation of Spanish greenhouse gas emissions.  相似文献   
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359.
Miscanthus. x giganteus bark was subjected to acetic and formic acid fractionation. The kinetics of the process were explained by a model of two parallel first-order reactions, for pulp yield and delignification, and by Saeman's kinetics based models, for total polysaccharides and viscosity of pulps. The influence of hydrochloric acid concentration on both organosolv processes was studied at two levels: 0.10 and 0.15% by weight. The models provided a good fit of the experimental data and helped to predict the best set of independent variables to obtain a good fractionation.Both systems achieved similar delignification levels and pulp characteristics, although the evolution in formic acid was faster than in acetic acid, mainly due to the great extent of reactions in the warming up period that accounted for about a third part of the initial dry weight of the raw material.  相似文献   
360.
Food and Environmental Virology - Norovirus (NoV) is an important etiological agent of diarrhea in children and adults. In Mexico, NoV screening is not routinely performed. NoV is highly infectious...  相似文献   
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