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51.
52.
通过对烟道“速度场常数”的研究,提出利用速度场常数监测烟道烟气平均流速的方法,同时研制出速度场常数自动检测装置。解决烟道烟气平均流速自动监测的技术难题。 相似文献
53.
本研究以环境水文地球化学理论为基础并采用数理统计的方法,对研究区地下水样和土样的分析数据进行了处理。通过浸滤模拟试验、红外光谱和差热分析等实验手段,对京杭大运河(杭州段)两侧浅层地下水中铁、锰含量偏高的成因进行了探讨。结果表明,该区地下水中铁、锰主要来自含水粘性土层,本区还原的介质环境及特有的地质条件对铁、锰含量偏高有直接影响。 相似文献
54.
本文报道灭幼脲Ⅲ号杀虫剂在大白菜和土壤中的残留试验结果.经在南北两地连续两年的田间试验表明,灭幼脲Ⅲ号属非持久性农药,在作物和土壤中都较快地消失,在大白菜上的半衰期为3.8—14.0d,在土壤中为8.8—27.0d.用25%灭幼脲Ⅲ号胶悬剂稀释2500倍,每亩每次按常规用药10g或加倍药量20g(有效成分)施药,喷施2或3次,距最后一次施药三周时,灭幼脲Ⅲ号杀虫剂在大白菜的最大残留量为2.67ppm,在土壤中为13.81ppm.建议该农药在大白菜上的最高允许残留量(MRL)为3ppm,安全间隔期为21d. 相似文献
55.
This paper developed an approach by the synthesis of remote sensing, landscape metrics, and statistical methods to examine the effects of landscape pattern, land surface temperature, and socioeconomic conditions on the spread of West Nile virus (WNV) caused by mosquitoes and animal hosts in Chicago, USA. Land use/land cover and land surface temperature images were derived from Terra’s Advanced Spaceborne Thermal Emission and Reflection Radiometer imagery. An analytical procedure using landscape metrics was developed, applying configuration analysis of landscape patterns in the study area. The positive reports of mosquitoes and animal hosts for WNV in fall, 2001–2006, were collected from the Cook County Public Health Department. Forty-nine municipalities were found to have WNV-positive records in mosquitoes and animal hosts in fall 2004. Socioeconomic data were obtained from the 2000 US Census. Statistical analysis was applied to WNV data in fall 2004 to identify the relationship between potential predictors and WNV spread. As a result, landscape factors, such as landscape aggregation index and the urban areas and areas of grass and water, showed strong correlations with the WNV-positive records. Socioeconomic conditions, such as the population over 65 years old, also showed a strong correlation with WNV-positive records. Thermal conditions of water showed a less but still considerable correlation to WNV-positive records. This research offers an opportunity to explore the effects of landscape pattern, land surface temperature, and socioeconomic conditions on the spread of WNV caused by mosquitoes and animal hosts. Results can contribute to public health and environmental management in the study area. 相似文献
56.
A Pt/WO3/TiO2 catalyst for propane oxidation was prepared by a stepwise wet impregnation method, and was aged at 800℃ for 5 hr. Compared to the sulfate-derived titania supported catalyst, the introduction of tungsten oxide as stable Bronsted acid sites led to the formation of more metallic platinum active sites at the Pt/WO3 interface. The dissociation of surface intermediates for propane oxidation was promoted on the WO3-modified catalyst. This, as well as the inhibition effects of tungsten oxide on the sintering of anatase and the phase transformation to rutile, resulting in a high activity and thermal stability for the Pt/WO3/TiO2 catalyst. 相似文献
57.
Ngai Weng Chan 《Disasters》1997,21(3):206-222
Institutional aspects of flood hazards significantly affect their outcomes in Malaysia. Institutional arrangements to deal with floods include: legislative activity, organisational structures, attitudes and sub-culture, and policies and instruments. When assessed in terms of four specific criteria, institutional aspects of flood hazards are found to be largely inadequate. Disaster reduction programmes are over-dependent on a reactive approach based largely on technology and not even aimed at floods specifically. Structual flood reduction measures are the predominant management tool and, although the importance of non-structural measures is recognised, thus far they have been under-employed. Current laws and regulations with regard to flood management are also insufficient and both the financial and human resources of flood hazard organisations are generally found to be wanting. Finally, economic efficiency, equity and public accountability issues are not adequately addressed by institutional arrangements for flood hazards. 相似文献
58.
Climatic change will result in great changes in vegetation. In this paper, a biogeographical model, the BIOME1, was used to
predict potential vegetation distribution in China under climate change. Firstly, the BIOME1 was validated according to the
climate–vegetation relationships in China. Kappa statistics showed that the validated BIOME1 was able to capture the geographical
patterns of vegetation more accurately. Then, the validated BIOME1 was used to predict the distribution of vegetation of China
under two climatic scenarios produced by a Regional Circulation Model, RegCM2/CN. The simulation results showed obvious northward
shifts of the boreal, temperate deciduous and evergreen and tropical forests, a large expansion of tropical dry forest/savanna
and reduction of tundra on the Tibetan Plateau. Three vulnerable regions sensitive to climate changes are pointed out, i.e.,
Northern China, the Tibetan Plateau and Southwestern China (mainly Hengduan Mountains in Yunnan Province and west of Sichuan
Province). In recent decades, China has experienced dramatic industrialization and population growth, which exert strong pressure
on the environment of China. The consequences of climate changes warrant more attention for maintaining a sustainable environment
for China. 相似文献
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