全文获取类型
收费全文 | 2106篇 |
免费 | 8篇 |
国内免费 | 11篇 |
专业分类
安全科学 | 11篇 |
废物处理 | 80篇 |
环保管理 | 104篇 |
综合类 | 818篇 |
基础理论 | 446篇 |
污染及防治 | 458篇 |
评价与监测 | 117篇 |
社会与环境 | 80篇 |
灾害及防治 | 11篇 |
出版年
2017年 | 22篇 |
2016年 | 31篇 |
2015年 | 19篇 |
2014年 | 24篇 |
2013年 | 86篇 |
2012年 | 30篇 |
2011年 | 66篇 |
2010年 | 57篇 |
2009年 | 63篇 |
2008年 | 86篇 |
2007年 | 69篇 |
2006年 | 52篇 |
2005年 | 57篇 |
2004年 | 54篇 |
2003年 | 52篇 |
2002年 | 60篇 |
2001年 | 66篇 |
2000年 | 57篇 |
1999年 | 43篇 |
1998年 | 33篇 |
1997年 | 37篇 |
1996年 | 34篇 |
1995年 | 37篇 |
1994年 | 34篇 |
1993年 | 31篇 |
1992年 | 19篇 |
1991年 | 40篇 |
1990年 | 54篇 |
1989年 | 24篇 |
1988年 | 28篇 |
1987年 | 22篇 |
1985年 | 24篇 |
1984年 | 24篇 |
1983年 | 19篇 |
1982年 | 32篇 |
1979年 | 21篇 |
1977年 | 19篇 |
1974年 | 20篇 |
1972年 | 21篇 |
1967年 | 31篇 |
1966年 | 23篇 |
1965年 | 24篇 |
1963年 | 22篇 |
1962年 | 23篇 |
1961年 | 19篇 |
1960年 | 17篇 |
1959年 | 21篇 |
1958年 | 23篇 |
1957年 | 19篇 |
1955年 | 16篇 |
排序方式: 共有2125条查询结果,搜索用时 843 毫秒
631.
Ajieh Mike U. Isagba Ebuwa S. Ihoeghian Newton Edosa Valerie I. O. Amenaghawon Andrew Oshoma Cyprian E. Erhunmwunse Nosakhare Obuekwe Ifeyinwa S. Tongo Isioma Emokaro Christopher Ezemonye Lawrence I. N. 《Environment, Development and Sustainability》2021,23(9):13182-13199
Environment, Development and Sustainability - The use of wastes for biogas production has been restricted to few feedstock like cattle manure and food waste. Increasing the feedstock base for... 相似文献
632.
633.
Sediment cores from four boreal and remote lakes in a south to north transect in central Sweden were analysed for acid leachable silver, antimony, thallium and indium in the solid sediment phase and the corresponding porewater. Dating of the cores was made by their content of acid leachable lead and the (206)Pb/(207)Pb ratio, in one lake also by (210)Pb. The impact of diagenesis on element redistribution in the sediments was included and found to be minor except for thallium. The results show lowered concentrations towards the north and most intense accumulation after the Second World War, which is taken as evidence for atmospheric deposition being the primary source. Indium has declining concentrations in recent strata while silver and antimony increase. Thallium has lowered acid-leachable concentrations in recent strata. For all metals the impact of domestic industrialisation as well as the early industrialisation of central Europe is discernible. Only thallium appears to reach a geological background at depths that correspond to the late 18th century. For the other metals elevated levels are concluded. 相似文献
634.
Polycyclic aromatic hydrocarbon (PAH) contamination of surface sediments and oysters from the inter-tidal areas of Dar es Salaam, Tanzania 总被引:1,自引:0,他引:1
Gaspare L Machiwa JF Mdachi SJ Streck G Brack W 《Environmental pollution (Barking, Essex : 1987)》2009,157(1):24-34
Surface sediment and oyster samples from the inter-tidal areas of Dar es Salaam were analyzed for 23 polycyclic aromatic hydrocarbons (PAHs) including the 16 compounds prioritized by US-EPA using GC/MS. The total concentration of PAHs in the sediment ranged from 78 to 25,000 ng/g dry weight, while oyster concentrations ranged from 170 to 650 ng/g dry weight. Hazards due to sediment contamination were assessed using Equilibrium Partitioning Sediment Benchmarks and Threshold Effect Levels. Diagnostic indices and principle component analysis were used to identify possible sources. Interestingly, no correlation between sediment and oyster concentrations at the same sites was found. This is supported by completely different contamination patterns, suggesting different sources for both matrices. Hazard assessment revealed possible effects at six out of eight sites on the benthic communities and oyster populations. The contribution of PAH intake via oyster consumption to carcinogenic risks in humans seems to be low. 相似文献
635.
636.
Ulrike Kammann Michael Vobach Werner Wosniok Andreas Schäffer Andreas Telscher 《Environmental science and pollution research international》2009,16(2):227-231
Background, aim and scope Nonylphenol (NP) can be detected in the aquatic environment all over the world. It is applied as a technical mixture of isomers
of which 353-NP is the most relevant both in terms of abundance (about 20% of total mass) and endocrine potential. 353-NP
is metabolised in sewage sludge. The aims of the present study were to determine and to compare the acute toxicity of t-NP,
353-NP and its metabolites as well as to discuss if the toxicity of 353-NP changes during degradation.
Materials and methods 353-NP and two of its metabolites were synthesised. The zebrafish embryo test was performed according to standard protocols.
Several lethal and non-lethal endpoints during embryonal development were reported. NOEL, LOEL and EC50 were calculated.
Results All tested compounds caused lethal as well as non-lethal malformations during embryo development. 353-NP showed a higher toxicity
(EC50 for lethal endpoints 6.7 mg/L) compared to its metabolites 4-(3.5-dimethyl-3-heptyl)-2-nitrophenol (EC50 13.3 mg/L) and 4-(3,5-dimethyl-3-heptyl)-2-bromophenol (EC50 27.1 mg/L).
Discussion In surface water, concentrations of NP are far below the NOEC identified by the zebrafish embryo test. However, in soils and
sewage sludge, concentrations may reach or even exceed these concentrations. Therefore, sludge-treated sites close to surface
waters should be analysed for NP and its metabolites in order to detect an unduly high contamination due to runoff events.
Conclusions The results of the present study point out that the toxicity of 353-NP probably declines during metabolisation in water, sediment
and soil, but does not vanish since the major metabolites exhibit a clear toxic potential for zebrafish embryos.
Recommendations and perspectives Metabolites of environmental pollutants should be included in the ecotoxicological test strategy for a proper risk assessment.
An erratum to this article can be found at 相似文献
637.
The optimized BCR sequential extraction procedure was applied to nine roadside soil samples for the determination of Cd, Cr,
Pb and Ni. The extractable metals were isolated into three operationally defined fractions viz: acid extractable, reducible
and oxidizable. The residue was treated with aqua regia solution. Metal analysis was done using flame atomic absorption spectrophotometry
with air–acetylene flame. Results obtained showed the concentrations of the metals as relative abundance in the mobile phases
of the samples (based on the sum of the first three fractions) are in the following order: Cd(91.9) > Pb(82.8) > Ni(49.5) > Cr(39.0).
The most non-mobilizable metals were Cr and Ni which are generally lithogenic, associated with the silicate matrix, and the
order is as follows: Cr(61.0) > Ni(50.5) > Pb(17.2) > Cd(8.1). The recovery of all the metals expressed as the ratio of total
metal concentration to fractional sum of the optimized BCR sequential extraction procedure was of the order: Cr(95.6) > Pb(95.0) > Ni(94.8) > Cd(92.4). 相似文献
638.
U.S. Korsholm A. Baklanov A. Gross J.H. Sørensen 《Atmospheric environment (Oxford, England : 1994)》2009,43(31):4805-4810
Traditionally, transport and dispersion models are offline coupled to meteorological drivers, receiving pre-processed output at regular coupling intervals. However, today meteorological models have reached urban and cloud resolving scales and online models integrating meteorological and dispersion models have been developed. In this study the online coupled model, Enviro-HIRLAM, which can also run in offline mode, was used to compare online and offline representations of meso-scale disturbances. The online model was evaluated using data from the first European Tracer Experiment (ETEX-1) and produced satisfactory results. Meso-scale influences during the simulation pertube the plume during long-range transport, leading to a double peak structure at a specific measurement station. The meso-scale influence was investigated by varying the offline coupling interval which was shown to be important in constraining the influence of meso-scale disturbances on plume structure in coarse resolution. 相似文献
639.
B. Reidy J. Webb T.H. Misselbrook H. Menzi H.H. Luesink N.J. Hutchings B. Eurich-Menden H. Döhler U. Dämmgen 《Atmospheric environment (Oxford, England : 1994)》2009,43(9):1632-1640
Six N-flow models, used to calculate national ammonia (NH3) emissions from agriculture in different European countries, were compared using standard data sets. Scenarios for litter-based systems were run separately for beef cattle and for broilers, with three different levels of model standardisation: (a) standardized inputs to all models (FF scenario); (b) standard N excretion, but national values for emission factors (EFs) (FN scenario); (c) national values for N excretion and EFs (NN scenario). Results of the FF scenario for beef cattle produced very similar estimates of total losses of total ammoniacal-N (TAN) (±6% of the mean total), but large differences in NH3 emissions (±24% of the mean). These differences arose from the different approaches to TAN immobilization in litter, other N losses and mineralization in the models. As a result of those differences estimates of TAN available at spreading differed by a factor of almost 3. Results of the FF scenario for broilers produced a range of estimates of total changes in TAN (±9% of the mean total), and larger differences in the estimate of NH3 emissions (±17% of the mean). The different approaches among the models to TAN immobilization, other N losses and mineralization, produced estimates of TAN available at spreading which differed by a factor of almost 1.7. The differences in estimates of NH3 emissions decreased as estimates of immobilization and other N losses increased. Since immobilization and denitrification depend also on the C:N ratio in manure, there would be advantages to include C flows in mass-flow models. This would also provide an integrated model for the estimation of emissions of methane, non-methane VOCs and carbon dioxide. Estimation of these would also enable an estimate of mass loss, calculation of the N and TAN concentrations in litter-based manures and further validation of model outputs. 相似文献
640.
Spermatophore characteristics in bushcrickets vary with parasitism and remating interval 总被引:4,自引:0,他引:4
Male bushcrickets provide females with a nuptial gift, a spermatophore, which is transferred to females at mating. The spermatophore
consists of a gelatinous mass, the spermatophylax, and the sperm-containing ampulla. Male spermatophore size is positively
correlated with insemination rate and female refractory period and therefore with male reproductive success. In this study,
we examined spermatophylax weight, ampulla weight and sperm number in males of Poecilimon mariannae parasitized by the acoustically orienting fly Therobia leonidei. We show that in parasitized males, spermatophylax weight decreases with the level of parasitism. In line with the hypothesis
that parasitism is a cost to reproduction, we found that spermatophylax weight was reduced at remating. In contrast, the replenishment
of the spermatophylax in unparasitized males was complete after 2 days and was increased no further after 3 days. Both sperm
number and ampulla weight showed an increase over time since last mating and sperm production was estimated at a constant
rate of 500,000 per day in all individuals, regardless of parasitism. The allocation of investment in components of the spermatophore
varies greatly with parasitism and remating. Both factors had rather independent effects on spermatophore constitution, revealing
functional constraints acting on spermatophore characteristics in bushcrickets, which are important for understanding the
selection pressures working on its components.
Received: 13 September 1999 / Received in revised form: 4 February 2000 / Accepted: 13 March 2000 相似文献