全文获取类型
收费全文 | 20331篇 |
免费 | 180篇 |
国内免费 | 200篇 |
专业分类
安全科学 | 534篇 |
废物处理 | 986篇 |
环保管理 | 2419篇 |
综合类 | 2666篇 |
基础理论 | 5284篇 |
环境理论 | 4篇 |
污染及防治 | 5593篇 |
评价与监测 | 1650篇 |
社会与环境 | 1453篇 |
灾害及防治 | 122篇 |
出版年
2023年 | 89篇 |
2022年 | 212篇 |
2021年 | 216篇 |
2020年 | 139篇 |
2019年 | 177篇 |
2018年 | 326篇 |
2017年 | 321篇 |
2016年 | 524篇 |
2015年 | 362篇 |
2014年 | 573篇 |
2013年 | 1744篇 |
2012年 | 672篇 |
2011年 | 859篇 |
2010年 | 802篇 |
2009年 | 785篇 |
2008年 | 886篇 |
2007年 | 977篇 |
2006年 | 870篇 |
2005年 | 717篇 |
2004年 | 723篇 |
2003年 | 704篇 |
2002年 | 670篇 |
2001年 | 911篇 |
2000年 | 631篇 |
1999年 | 393篇 |
1998年 | 274篇 |
1997年 | 246篇 |
1996年 | 291篇 |
1995年 | 270篇 |
1994年 | 250篇 |
1993年 | 233篇 |
1992年 | 240篇 |
1991年 | 208篇 |
1990年 | 214篇 |
1989年 | 219篇 |
1988年 | 197篇 |
1987年 | 158篇 |
1986年 | 126篇 |
1985年 | 138篇 |
1984年 | 169篇 |
1983年 | 153篇 |
1982年 | 193篇 |
1981年 | 134篇 |
1980年 | 119篇 |
1979年 | 152篇 |
1978年 | 118篇 |
1977年 | 107篇 |
1976年 | 100篇 |
1975年 | 83篇 |
1974年 | 88篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
911.
14C-carbofuran underwent considerable mineralization (approximately 30% of the applied activity) in Vertisol soil under moist and flooded conditions during 60 days incubation. Bound residues were formed under both the conditions, the extent being more in moist soils (approximately 55% of the applied activity) than under flooded conditions (approximately 41% of the applied activity). 3-Keto carbofuran was the only significant metabolite observed under flooded conditions. 相似文献
912.
Mineralogical compositions and their spatial distributions are important initial conditions for reactive transport modeling. However, popular Kd-based "reactive" transport models only require contaminant concentrations in the pore fluids as initial conditions, and minerals implicitly represent infinite sources and sinks in these models. That situation results in a general neglect of mineralogical characterization in site investigations. This study uses a coupled multi-component reactive mass transport model to predict the natural attenuation of a ground water plume at a uranium mill tailings site in western USA. Numerous ground water geochemistry data are available at this site, but mineralogical data are sketchy. Even given the well-defined pore fluid chemistry, variations of secondary mineral species and mineral abundances in the aquifer resulted in significantly different modeling outcomes. Results show that the amount of calcite in the aquifer determines the distances of plume migration. The possible presence of jurbanite, an aluminum sulfate phase, can store acidity temporarily but cause more severe contamination on a later date. The surfaces of iron oxyhydroxides can store significant amounts of sulfate and protons and serve as a second source for prolonged contamination. These simulations under field conditions illustrate that mineralogical compositions are an essential requirement for accurate prediction of contaminant fate and transport. 相似文献
913.
Hydroxyl radical scavenging role of chloride and bicarbonate ions in the H2O2/UV process 总被引:9,自引:0,他引:9
Simultaneous effect of inorganic anions, such as chloride and bicarbonate ions, on the scavenging of hydroxyl radicals (HO*) in the H2O2/UV process is the focus of this paper. The model compound of n-chlorobutane (BuCl) was used as the probe of HO*. By changing the pH conditions (2-9) and the concentrations of NaCl (0.25-2500 mM) and NaHCO3 (25 mM), the variation of HO* concentrations and the rate of H2O2 decomposition were compared. In general, the BuCl and H2O2 follow closely the first-order reaction within the first 10 and 40 min, respectively. In the presence of chloride alone at the pH range of 2-6, the HO* concentration in the reaction mixture increases with the increase of pH, and the HO* concentration at pH = 6 is 100 times of that at pH = 2. Including bicarbonate species in the solution, the peak HO* concentration was found at a certain pH, which shifts from 4, 5, to 5-7, as the molar ratios of chloride/bicarbonate species increase from 1 to 100. In addition, without bicarbonate species HO* concentration decreases significantly with increasing chloride concentration but remained rather unchanged beyond 1250 mM. In contrast, the HO* scavenging in the presence of bicarbonate species became relatively significant only when the chloride concentration reached beyond 250 mM. Throughout all experiments of different water quality conditions, the H2O2 decomposition rate remains rather unchanged. 相似文献
914.
Tanzarella C Degrassi F Cristaldi M Moreno S Lascialfari A Chiuchiarelli G Ieradi LA 《Environmental pollution (Barking, Essex : 1987)》2001,115(1):43-48
The Do?ana National Park (Spain), one of the most important wildlife sites in the West of Europe, was affected (25 April 1998) by the spill of acidic waste rich in toxic metals (mainly zinc, lead, copper, etc.), arsenic and aromatic amines from the Aznalcollar mine accident. Micronuclei test with May Grunwald-Giemsa and with CREST-antikinetocore staining using DAPI as counter-staining were performed on peripheral blood erythrocytes from Algerian mice to evaluate genotoxic damage. Animals were collected in four locations each differently affected by the disaster. Higher frequencies of micronuclei and CREST-positive micronuclei were observed in the sites, which were reached by toxic sludge and contaminated water in comparison with those located within the park. The results obtained applying the two methods indicate that DAPI staining is more sensitive in detecting micronuclei. Genotoxic biomonitoring should be further carried out in the area to control the mutagenetic level in natural populations. 相似文献
915.
This study involves a site characterization followed by biomonitoring with the zebra mussel, Dreissena polymorpha, at the Times Beach confined placement facility (CPF), located in Buffalo, NY. The contaminant of interest was tributyltin (TBT) and the degradation products dibutyltin (DBT) and monobutyltin (MBT). At study initiation (Day 0) TBT levels in the baseline mussels were 5.86 +/- 0.43 ng Sn/g, DBT levels were 2.25 +/- 0.37 ng Sn/g. No MBT was detected in the Day 0 baseline samples. Caged reference mussels placed back in the Black Rock Channel Lock and retrieved on Days 19 and 34 had TBT, DBT, and MBT levels which did not differ significantly from the Day 0 baseline levels. Mussels placed at the Times Beach CPF had TBT concentrations that were significantly lower at both Days 19 (3.65 +/- 0.90 ng Sn/g) and 34 (3.50 +/- 1.03 ng Sn/g) than the Day 0 baseline analysis (5.86 +/- 0.43 ng Sn/g). The results of this study indicate that butyltins were detected at the CPF site in the sediment (7.33 +/- 5.70 ng Sn/g) but not the water column (not detected at 0.01 microgram/l). In this study the zebra mussel was able to depurate TBT even in the presence of contaminated sediment. TBT may be bioaccumulated from the sediments. However, the initial levels in the mussels were so high, levels actually dropped as sediment-tissue equilibria levels were reached by the mussels. 相似文献
916.
Sivacoumar R Bhanarkar AD Goyal SK Gadkari SK Aggarwal AL 《Environmental pollution (Barking, Essex : 1987)》2001,111(3):471-477
Jamshedpur, the steel city of India situated in the eastern part of India is affected by increasing air pollution levels as a result of concentrated industrial activities. The impact of NOx emissions resulting from various air pollution sources, viz. industries, vehicles and domestic, was estimated using Industrial Source Complex Short-Term gaussian dispersion model. The contribution of NOx concentration from industrial, vehicular and domestic sources was found to be 53, 40 and 7%. Further statistical analysis was carried out to evaluate the model performance by comparing measured and predicted NOx concentrations. The model performance was found good with an accuracy of about 68%. 相似文献
917.
Monitoring laboratory-scale bioventing using synchronous scan fluorescence spectroscopy: analysis of the vapor phase 总被引:2,自引:0,他引:2
Bachman J Kanan SM Patterson HH 《Environmental pollution (Barking, Essex : 1987)》2001,113(2):155-162
Bioventing is an improved method of soil remediation that is being used with increasing frequency. In this paper, we refine techniques to measure the progress of petroleum hydrocarbon decomposition by monitoring vapor phase composition with synchronous scan fluorescence spectroscopy (SSFS). Analysis of the vapor phase has advantages compared to standard extraction techniques that require extensive sample handling and clean up. For comparison, hydrocarbon contamination in the soil was measured by analysis of Soxhlet extractions with gas chromatography-mass spectrometry (GC-MS). Comparison of the GC-MS and SSFS data showed that changes in hydrocarbon composition measured in the vapor phase provide an accurate measure of decomposition reactions taking place in the soil. 相似文献
918.
Particulate and dissolved elemental loads in the Kuji River related to discharge rate 总被引:5,自引:0,他引:5
In order to investigate influences of discharge rates on fluvial transport behavior of elements in the Kuji River, Japan, suspended and dissolved phase concentrations in the river water were measured together with the water flow rates. The concentrations of suspended particulate matter (SPM) increased by two or three orders of magnitude with the water discharge, and also had seasonal variations. Adsorptive elements or heavy metal elements, which tend to form insoluble compounds, were present generally as suspended forms in the river waters, and their dissolved form concentrations tended to increase with the water discharge. On the other hand, non-adsorptive elements such as alkali and alkaline-earth elements were present as dissolved forms under a normal flow rate condition, but equivalent quantity of suspended species also occurred under a high flow condition. In this case, the dissolved form concentrations decreased with the water discharge. Characterization of SPM with analyses of chemical compositions, scanning electron microscopy (SEM) and X-ray diffractometry (XRD) indicated that clay mineral such as montmorillonite would be the main carrier material of trace and major elements during the fluvial transport in the Kuji River. Variations of contents of selected elements in SPM with the water discharge indicated that river bottom sediments, which are probably potential sources of SPM added due to high water flow rates, would be different in chemical compositions from SPM floating under a normal flow condition. Variations of chemical compositions of SPM as well as of suspended or dissolved form concentrations of elements in the river waters were formulated as a function of the water discharge rates. 相似文献
919.
Carroll JA Caporn SJ Johnson D Morecroft MD Lee JA 《Environmental pollution (Barking, Essex : 1987)》2003,121(3):363-376
Regular applications of ammonium nitrate (35-140 kg N ha(-1) year(-1)) and ammonium sulphate (140 kg N ha(-1) year(-1)) to areas of acidic and calcareous grassland in the Derbyshire Peak District over a period of 6 years, have resulted in significant losses in both overall plant cover, and the abundance of individual species, associated with clear and dose-related increases in shoot nitrogen content. No overall growth response to nitrogen treatment was seen at any stage in the experiment. Phosphorus additions to the calcareous plots did however lead to significant increases in plant cover and total biomass, indicative of phosphorus limitation in this system. Clear and dose-related increases in soil nitrogen mineralization rates were also obtained, consistent with marked effects of the nitrogen additions on soil processes. High nitrification rates were seen on the calcareous plots, and this process was associated with significant acidification of the 140 kg N ha(-1) year(-1) treatments. 相似文献
920.
Changes of copper speciation in maize rhizosphere soil 总被引:1,自引:0,他引:1
Tao S Chen YJ Xu FL Cao J Li BG 《Environmental pollution (Barking, Essex : 1987)》2003,122(3):447-454
Chemical forms of copper in the rhizosphere and bulk soil of maize were investigated using rhizobox cultivation and sequential extraction techniques. The copper accumulations were also determined. The results demonstrated that there were continuous changes in copper fractionation within the maize rhizosphere. Initially, the amount of exchangeable copper increased before dropping below the initial level after 40 days or so. Carbonate associated copper followed a similar trend of change, but with a slower pace than the exchangeable copper. The increase in carbonate associated copper only become evident after 30 days, with the net loss occurring after 60 days. There were also initial increases in oxide bound copper as well as decreases in the organic matter associated copper, both followed by a turnover after 40-50 days. The accumulation of copper in the maize plant was found to be biomass dependent. The amount of accumulated copper absorbed in the plant material exceeded the initial quantity of the exchangeable copper in the soil, revealing a transformation from less bioavailable to more bioavailable fractions. During cultivation, decreases in redox potential and increases in pH, dissolved organic carbon (DOC), and microbial activity in the maize rhizosphere were observed. The change in copper speciation may result from root-induced changes in DOC, redox potential, and microbial activity in the rhizosphere. 相似文献