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441.
442.
Effects of 5-year application of municipal solid waste compost on the distribution and mobility of heavy metals in a Tunisian calcareous soil 总被引:2,自引:0,他引:2
Walid Ben Achiba Noureddine Gabteni Abdelbasset Lakhdar Gijs Du Laing Marc Verloo Naceur Jedidi Tahar Gallali 《Agriculture, ecosystems & environment》2009,130(3-4):156-163
It is obvious that the application of solid waste compost improves the soil fertility. These wastes, however, may also have some negative effects on the agricultural environment due to their metal content. This research aimed at evaluating the influence of Tunisian municipal solid waste compost and farmyard manure on some chemical properties and the distribution of heavy metals in a calcareous Tunisian soil (clayey–loamy soil). A field plot experiment, without vegetation, was installed since 1999 at the experimental farm of the Agronomic National Institute of Tunis (INAT) in the region of Mornag (20 km south of Tunis, Tunisia). During 5 years, the field received yearly the following treatments: 0, 40, 80 and 120 t/ha of municipal solid waste compost and 0, 40 and 120 t/ha of manure. The fractionation of heavy metals in the soil was evaluated after 5 years using a sequential extraction procedure. The application of the two amendments was found to increase the content of organic matter, the total nitrogen content and the electrical conductivity, whereas it slightly decreased the soil pH. The addition of manure did not have a significant effect on the accumulation of heavy metals in the soil, whereas compost application increased the total concentration of heavy metals in the soil. The distribution of heavy metals between the different fractions in untreated and treated soils showed the residual fraction to be dominant, followed by the fraction bound to Fe and Mn oxides. The amount of Cu bound to the organic fraction increased with the application rate, which is probably caused by the formation of organic complexes. For the other metals, the increase of the association with organic matter is very limited. The application of compost moreover increases the amount of Zn associated with Fe and Mn oxides. The “Mobility Factor (MF)” was quite low and did not change after the 5-year application of the two organic amendments. It always remained lower than 10%, although for Cd it amounted to 17%. 相似文献
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445.
The UV/Ag-TiO2/O3 process was investigated for ballast water treatment using Dunaliella salina as an indicator. Inactivation curves
were obtained, and the toxicity of e uent was determined. Compared with individual unit processes using ozone or UV/Ag-TiO2, the
inactivation e ciency of D. salina by the combined UV/Ag-TiO2/O3 process was enhanced. The presence of ozone caused an immediate
decrease in chlorophyll a (chl-a) concentration. Inactivation e ciency and chl-a removal e ciency were positively correlated with
ozone dose and ultraviolet intensity. The initial total residual oxidant (TRO) concentration of e uent increased with increasing ozone
dose, and persistence of TRO resulted in an extended period of toxicity. The results suggest that UV/Ag-TiO2/O3 has potential for
ballast water treatment. 相似文献
446.
The biosorption characteristics of Cs(I) ions from aqueous solution using exopolymers (PFC02) produced from Pseudomonas
fluorescens C-2 were investigated as a function of pH, biosorbent dosage, contact time and initial concentration. pH played a major role
in the adsorption process, and the optimum pH for the removal of Cs(I) was 8.0. Langmuir, Freundlich and Dubinin-Radushkevich (D-R)
models were applied to describe the biosorption isotherm of the Cs(I) ions by PFC02. The Lagergren first-order, pseudo second-order
kinetic and intraparticle diffusion models were used to test the kinetic data. Langmuir model and D-R model fitted the equilibrium data
better than the Freundlich isotherm. The monolayer adsorption capacities of PFC02 as obtained from Langmuir isotherm at 25°C was
found to be 32.63 mg/g. From the D-R isotherm model, the mean free energy was calculated as 26.73 kJ/mol, indicating that the
biosorption of cesium was chemisorption. The biosorption process was rapid, and the kinetic rates were best fitted to the pseudo
second-order model, which indicated the biosorption process operated through chemisorption mechanism. FT-IR analysis of PFC02
showed the possible functional groups responsible for cesium adsorption were hydroxyl, carboxyl, carbonyl and sulphonate groups.
SEM analysis showed the porous structure of the material while EDX analysis confirmed the adsorption of Cs(I) on PFC02. Cesium
adsorbed onto the PFC02 could be desorbed efficiently using 1 mol/L HNO3, and the enrichment factor was 50.0. Furthermore, PFC02
could be reused five times with only about 8.25% regeneration loss. The developed method was successfully utilized for the removal of
Cs(I) ions from aqueous solution. 相似文献
447.
A numerical study of Reciprocating Superadiabatic Combustion of Premixed gases in porous media (hereafter, referred to as RSCP) is performed. In this system the transient combustion of methane-air mixture is stabilized in a porous media combustor by periodically switching flow directions. The mass, momentum, energy and species conservation equations are solved using a two-dimensional control volume method. Local thermal non-equilibrium between the gas and the solid phases is considered by solving separate energy equations for the two phases and coupling them through a convective heat transfer coefficient. The porous media is assumed to emit, absorb and isotropically scatter radiation. The influences of the dominating operating parameters, such as filtration velocity, equivalence ratio and half cycle on the temperature profile, heat release rate, radiant flux, radiant efficiency and combustion efficiency are discussed. The results show that coupling calculating of flow field, combustion reaction and volume radiation of the optically thick media is successively achieved and heat radiation plays an important role in the overall performance of the burner. The temperature profile inside the RSCP combustor has a typical trapezoidal shape and the profile of radiation flux is similar to sinusoidal shape. Compared with the conventional premixed combustion in porous medium, combustion behavior in RSCP combustor is superior, such as better thermal structure and higher radiation efficiency and combustion efficiency. 相似文献
448.
经对鄂尔多斯市达拉特旗树林召镇的转基因试验林中的v系列转基因银中杨与非转基因对照组的生长性状的对比研究证明:该转基因系列具有较强的环境适应性,生长状况明显优于非转基因杨树。 相似文献
449.
杜红岩 《安全.健康和环境》2011,11(7):5-8
介绍了印度博帕尔农药厂异氰酸甲酯泄漏事故概况及其原因,并从工艺安全角度分析了事故教训,提出加强石化企业工艺安全管理的措施。 相似文献
450.
固相微萃取技术是一种新型的无溶剂化环境样品前处理技术,将采样、萃取、浓缩和进样集中于一个步骤完成。详细地介绍固相微萃取技术的原理、装置和萃取方式及该技术在环境空气有机污染物监测中的应用情况和国内外研究进展。 相似文献