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   2457篇
  免费   33篇
  国内免费   40篇
安全科学   124篇
废物处理   155篇
环保管理   281篇
综合类   364篇
基础理论   435篇
环境理论   1篇
污染及防治   780篇
评价与监测   222篇
社会与环境   148篇
灾害及防治   20篇
  2023年   33篇
  2022年   71篇
  2021年   88篇
  2020年   43篇
  2019年   44篇
  2018年   94篇
  2017年   94篇
  2016年   118篇
  2015年   78篇
  2014年   107篇
  2013年   242篇
  2012年   147篇
  2011年   184篇
  2010年   128篇
  2009年   111篇
  2008年   150篇
  2007年   123篇
  2006年   143篇
  2005年   113篇
  2004年   74篇
  2003年   51篇
  2002年   49篇
  2001年   29篇
  2000年   12篇
  1999年   18篇
  1998年   10篇
  1997年   9篇
  1996年   12篇
  1995年   14篇
  1994年   10篇
  1993年   9篇
  1992年   12篇
  1991年   6篇
  1990年   14篇
  1989年   9篇
  1988年   8篇
  1987年   5篇
  1986年   5篇
  1985年   5篇
  1984年   8篇
  1983年   3篇
  1982年   4篇
  1979年   4篇
  1966年   4篇
  1962年   2篇
  1961年   2篇
  1960年   3篇
  1959年   2篇
  1953年   2篇
  1928年   2篇
排序方式: 共有2530条查询结果,搜索用时 46 毫秒
671.
We report the results of an exploratory study that examines the judgments of climate scientists, climate policy experts, astrophysicists, and non-experts (N?=?3367) about the factors that contribute to the creation and persistence of disagreement within climate science and astrophysics and about how one should respond to expert disagreement. We found that, as compared to non-experts, climate experts believe that within climate science (i) there is less disagreement about climate change, (ii) methodological factors play less of a role in generating disagreements, (iii) fewer personal or institutional biases influence climate research, and (iv) there is more agreement about which methods should be used to examine relevant phenomena we also observed that the uniquely American political context predicted experts’ judgments about some of these factors. We also found that, in regard to disagreements concerning cosmic ray physics, and commensurate with the greater inherent uncertainty and data lacunae in their field, astrophysicists working on cosmic rays were generally more willing to acknowledge expert disagreement, more open to the idea that a set of data can have multiple valid interpretations, and generally less quick to dismiss someone articulating a non-standard view as non-expert, than climate scientists were in regard to climate science.  相似文献   
672.
Environmental Science and Pollution Research - This article presents the pilot experience of an integrated biowaste management system developed in Tinos island, Greece, which promoted source...  相似文献   
673.
The research was aimed at determining the abundance of biofilm formation by Escherichia coli and Staphylococcus aureus on the surface of polycaprolactone (PCL) with polyhexamethylene guanidine (PHMG) derivatives and effect of the derivatives on extracellular hydrolytic enzymes and intracellular dehydrogenases. Biofilm abundance was determined by spectrophotometry, using crystal violet staining. Hydrolytic enzymes after contact with the film were determined with the use of non-specific substrate—fluorscein diacetate. The effect of PHMG derivatives on dehydrogenases activity was assessed using the test, where triphenyltetrazolium chloride (TTC) is reduced to triphenylformazan (TF). The PCL containing PHMG granular polyethylene wax and salt of sulfanilic acid (0.6–1% wt.) strongest inhibited biofilm formation. PHMG derivatives introduced into PCL were found to slightly affect hydrolases activity in both E. coli and S. aureus at a concentration of 0.2 and 0.6%. It was also found that dehydrogenases activity was inhibited by PCL films containing PHMG derivatives. PCL containing 1% of PHMG sulfanilate strongest inhibited hydrolases activity, whereas PCL modified with 1% of PHMG granular polyethylene wax showed the highest inhibitory effect on the activity of both enzymes. W-PCL and A-PCL composites (at concentration of 0.6%) have optimal combination of antibiofilm activity and biodegradability.  相似文献   
674.
In this paper the modifications induced in butyl rubbers (pristine, chlorinated and brominated sorts) by γ-irradiation are investigated by swelling, chemiluminescence and FT-IR. The susceptibility of butyl rubbers for the generation of radicals orders their stabilities in the following sequence: IIR?>?IIR—Cl?>?IIR—Br. The incorporation of butyl rubbers into ethylene-propylene terpolymer matrix brings about increased densities of radicals initiating modifications in the oxidation state in respect with recombination, which are intensified as the processing dose increases. Based on the variation of carbonyl and hydroxyl indices the favorable route for the recycling EPDM based formulations would be suggested in this study. The chemiluminescence spectra proving the formation of peroxyl radicals at about 100?°C prove their availability as reclaiming solutions. IIR—Br is the recommendable butyl rubber for the recovery procedure by association with EPDM. The suitability of IIRs for recycling purposes is analyzed by the variation in their crosslink densities, free volumes and swelling degrees. The crosslinking behavior of stabilized EPDM/IIR blends that runs to the improvement of durability is depicted by Charlesby–Pinner representation, which involves the different simultaneous contribution of scission and crosslinking processes.  相似文献   
675.
The objective of this study was to investigate the role of stabilized organic matter (vermicompost) and tropical soils in the sorption of naphthalene, anthracene and benzo[a]pyrene. The results obtained for the three compounds were extrapolated for the priority polycyclic aromatic hydrocarbons (PAHs) pollutants according to Environmental Protection Agency (US EPA). To evaluate the sorption process, high performance liquid chromatography was employed and the data was fitted by Freundlich isotherms. The results suggest that the sorption effect generally increases with the number of benzene rings of the PAHs, and that the persistence of PAHs in the environment is possibly related to the number of benzene rings in the PAH molecule. In addition, the pH of the vermicompost can strongly affect the adsorption process in this matrix.  相似文献   
676.
Source identification of polycyclic aromatic hydrocarbons in environmental samples has advanced greatly in the last 20 years and continues to advance. To realize potential benefits and avoid possible pitfalls, however, great care is needed as one applies published diagnostic tools to data sets. This commentary reflects some recent observations, concerns, and recommendations.  相似文献   
677.
In recent years, geophysics is increasingly used to study the flow and transport processes in the vadose zone. Particularly, when the vadose zone is made up of rocks, it is difficult to install sensors in the subsurface to measure hydrological state variables directly. In these cases, the electrical resistivity tomography (ERT) represents a useful tool to monitor the hydrodynamics of the infiltration and to estimate hydraulic parameters and state variables, such as hydraulic conductivity and water content. We propose an integrated approach aimed at predicting water content dynamics in calcarenite, a sedimentary carbonatic porous rock. The uncoupled hydrogeophysical approach proposed consists in 4D ERT monitoring conducted during an infiltrometer test under falling head conditions. Capacitance probes were installed to measure water content at different depths to validate the estimations derived from ERT. A numerical procedure, based on a data assimilation technique, was accomplished by combining the model (i.e., Richards’ equation) with the observations in order to provide reliable water content estimations. We have used a new data assimilation method that is easy to implement, based on the ensemble Kalman filter coupled with Brownian bridges. This approach is particularly suitable for strongly non-linear models, such as Richards’ equation, in order to take into account both the model uncertainty and the observation errors. The proposed data assimilation approach was tested for the first time on field data. A reasonable agreement was found between observations and predictions confirming the ability of the integrated approach to predict water content dynamics in the rocky subsoil.  相似文献   
678.
679.
Sludge generated in intensively managed tilapia fingerling breeding ponds near the Itaparica Dam in the semi-arid Brazilian northeastern region was tested as a soil conditioner to produce lettuce in an effort to mitigate the present environmental impact of the deposition of this sludge, thereby giving it a productive destiny. A greenhouse experiment was performed by mixing the sludge with a Haplic Planosol topsoil, a characteristic soil of the region, so that the sludge corresponded to 0, 25, 50, 75, and 100% of the mixture (substrate). The experiment was set up as a randomized block design with five blocks, each with three pots (5-kg substrate per pot) of the five sludge proportion treatments. One lettuce plant was transplanted into each pot, maintained under greenhouse conditions, and harvested 35 days after transplanting. Sludge, soil, and the substrates were evaluated for nutrient concentration and physical characteristics. Green and dry weights, stem diameter, and nitrogen, phosphorus, and potassium concentrations in the aboveground parts of the lettuce plants were determined. Sludge incorporation into the substrate improved its chemical and physical characteristics. The lettuce plants grew best in the substrate with 75% sludge, increasing its biomass production by 50% and more than doubling its nitrogen uptake.  相似文献   
680.
With the recommendation of the EU environmental policies, the separate waste collection issue has become more and more an object of public concern. Nevertheless, Italy’s waste management performances need further assessment processes. Until recently, some areas, especially in the South, have experienced serious waste management crises, mainly due to low rates of separate waste collection (less than 10 % of solid waste generated). The aim of this paper is to analyse the driving factors that influence the separate waste collection. Relatively to the Italian provinces in the year 2011, the analysis consists of two steps. In the first step, we characterize different institutional and socio-economic contexts through a multidimensional scaling analysis. In the second step, we provide evidence about the presence of subsets among Italian provinces using cluster analysis. Results show that contexts featuring high institutional quality promote the separate collection process. Differently, tourism-oriented environments characterized by low institutional quality don’t produce positive effects on the recycling process.  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