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821.
Background Frequent application of Bordeaux mixture, which includes copper, as a fungicide in fruit and grape orchards may lead to copper accumulation in the soil, especially when orchard age and application times increase. The objectives of this study were: (i) to investigate the copper content and its spatial distribution in orchard soils; (ii) to identify the copper fractionation in soil and its relationship with plant uptake; (iii) to understand the characteristics of copper contamination in orchard soils. Materials and Methods Soil profile samples were taken in apple orchards with ages of 0, 5, 10, 20, 30 years and pot experiments were also carried out to study the effects of external copper input on copper fractionation. All soil samples were air-dried, ground and extracted with 0.43 mol L1 HNO3 for the total absorbed copper. Fractionation determination was conducted following Tessier and Shuman sequential extraction methods, and copper was measured with AAS. Plant samples were first dry ashed, dissolved with 6 mol L1 HCl and then copper and other elements were measured with ICP-MS.Results and Discussion Soil total Cu was higher in the apple orchards than that in non-orchard fields and was seen to have increased with orchard age. Soil Cu increased substantially with the average annual copper increase, ranging from 2.5 to 9 mg Cu kg1. The distribution of copper in the soil profile was uneven, decreasing from surface to deeper layers, and the differences were significant, but the contents in every layer were also significantly correlated with those in the next layers.
For all copper fractions, the organically bound, crystalline Mn oxide bound, and amorphous Fe bound fractions extracted with the Shuman method were much higher than the exchangeable and residual fractions. Using the Tessier method, organically bound, carbonate bound and Fe-Mn oxide bound fractions were much higher. With an increase in external copper input, the organically bound, crystalline Mn oxide bound and amorphous Fe bound fractions in the Shuman method and organically bound, carbonate bound and Fe-Mn oxide bound fractions in the Tessier method all increased significantly, while the changes in other fractions were not significant.
Soil total copper and copper fractions were found to have good correlations with apple tree uptake. Copper in fruit flesh had significant correlations with soil total content in the 010 cm layer, all the copper fractions in the 05 cm layer, and some fractions in the deeper layers. Conclusion Copper content in orchard soils increased significantly with intensive application of Bordeaux mixtures and orchard age. Copper content decreased sharply from the topsoil to deeper soil layers. The copper contents in different layers also significantly correlated with those in the next layers. Dominant fractions of the copper in soil were mainly associated with organic matter, iron and manganese oxides and carbonates. A close relationship was found between the copper content in soils and in apple tree organs (which contained 8.9 to 66mg kg1 Cu). Recommendation and Perspective Though most copper in the soil was specifically adsorbed or immobilized, and copper was mainly distributed in topsoil, which was essentially devoid of roots, the copper concentration of fruit still had significantly positive correlations with soil copper and most copper fractions. Therefore, measures must be taken to control copper accumulation in orchard soils and to make the apple fruit production sustainable. 相似文献
822.
823.
主要对江苏淮安盐化工循环经济发展的现状,发展的必要性、可行性及可操作性进行了分析研究,并对加快淮安盐化工循环经济发展提出了几点建议。 相似文献
824.
A new environmental chamber for evaluation of gas-phase chemical mechanisms and secondary aerosol formation 总被引:1,自引:0,他引:1
William P.L. Carter David R. Cocker III Dennis R. Fitz Irina L. Malkina Kurt Bumiller Claudia G. Sauer John T. Pisano Charles Bufalino Chen Song 《Atmospheric environment (Oxford, England : 1994)》2005,39(40):7768-7788
A new state-of-the-art indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosol (SOA) has been constructed and characterized. The chamber is designed for atmospheric chemical mechanism evaluation at low reactant concentrations under well-controlled environmental conditions. It consists of two collapsible 90 m3 FEP Teflon film reactors on pressure-controlled moveable frameworks inside a temperature-controlled enclosure flushed with purified air. Solar radiation is simulated with either a 200 kW Argon arc lamp or multiple blacklamps. Results of initial characterization experiments, all carried out at 300–305 K under dry conditions, concerning NOx and formaldehyde offgasing, radical sources, particle loss rates, and background PM formation are described. Results of initial single organic–NOx and simplified ambient surrogate–NOx experiments to demonstrate the utility of the facility for mechanism evaluation under low NOx conditions are summarized and compared with the predictions of the SAPRC-99 chemical mechanism. Overall, the results of the initial characterization and evaluation indicate that this new environmental chamber can provide high quality mechanism evaluation data for experiments with NOx levels as low as 2 ppb, though the results indicate some problems with the gas-phase mechanism that need further study. Initial evaluation experiments for SOA formation, also carried out under dry conditions, indicate that the chamber can provide high quality secondary aerosol formation data at relatively low hydrocarbon concentrations. 相似文献
825.
为了提高硝酸吸收氮氧化物的效率,对活性填料催化氧化-硝酸吸收NOx进行了研究。结果表明:活性填料能明显提高NOx的吸收效率;当NOx中NO2体积百分含量增加,其吸收效率增加;随进气浓度和液气比的增大,NOx吸收效率增加;随NO2浓度的增加,NO的吸收效率先增加后减少,在NO/NO2为3时,NO吸收效率最高;随NO的增加NO2的吸收效率先增加后减少,在NO/NO2为0.6~1之间,NO2的吸收效果较好。 相似文献
826.
827.
磷酸铵镁沉淀法脱氨机理、应用及沉淀剂循环 总被引:10,自引:0,他引:10
铵根离子可以和镁盐、磷酸根在适当的条件下生成磷酸铵镁沉淀,利用这一反应可以去除水中的氨氮。本文从磷酸铵镁的性质、反应机理、反应条件及沉淀剂循环利用等方面,对这一方法进行了介绍和总结,并对今后该技术发展提出了建议。 相似文献
828.
829.
绿色设计与绿色化学设计 总被引:7,自引:0,他引:7
根据绿色设计的基本定义,特点,过程与原则,将绿色设计与传统设计与进行比较,阐述绿色化学设计的主要内容。 相似文献
830.