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811.
Jones RK Sun WH Tang CS Robert FM 《Environmental science and pollution research international》2004,11(5):340-346
GOAL, SCOPE AND BACKGROUND: The goal of this study was to understand the interaction between plants and microorganisms during petroleum-hydrocarbon bioremediation in Pacific Islands coastal soils. Total bacteria and hydrocarbon-degrading microorganisms population dyanamics were examined in the rhizospheres of tropical trees and shrubs, which were evaluated for their phytoremediation potential in a greenhouse experiment. The respective and combined effects of plant roots and diesel contaminant on the microbial populations were determined in relation to diesel fuel depletion. An increase in the grading populations size of the hydrocarbon-degrading populations of microbes, elicited by rhizodeposition, is generally regarded as conducive to an enhanced degradation of petroleum hydrocarbon pollutants in vegetated soil. METHODS: The soil was a coastal sandy loam (pH 7.8) which was artificially contaminated with 10 g of No. 2 diesel fuel/kg soil or left uncontaminated. The pots were irrigated with fertilizer and 1% NaCl. The enumerations were carried out in the contaminated and uncontaminated rhizospheres of three trees, kiawe (Prosopis pallida), milo (Thespesia populnea), and kou (Cordia subcordata) and three shrubs, beach naupaka (Scaevola sericea), false sandalwood (Myoporum sandwicense), and oleander (Nerium oleander). Unplanted control soils were included in the experiment. Total bacteria and phenanthrene-degrading bacteria were enumerated on plates. Diesel- and pristane-degrading microorganisms were enumerated by the most-probable-number technique in tissue-culture plates. RESULTS AND DISCUSSION: All four types of microorganisms responded to the rhizosphere of the 6 plants in uncontaminated soil and to the diesel contaminant in unplanted soil. In contaminated rhizospheres, no effect of the plant on the hydrocarbon-degrader numbers was visible. Total bacteria responded more to the plant roots than to the contaminant. The phenanthrene-degrading bacteria and pristane-degrading microorganisms were more influenced by the contaminant than by the plants. The diesel-degrading microorganisms were equally stimulated by the plants and the contaminant. The numbers of hydrocarbon degraders were similar in the contaminated rhizospheres of the three effective plants (kiawe, kou, and milo) and in those of the three ineffective shrubs. CONCLUSION: The results suggest the quality of the rhizodeposition is plant-dependent and governs the type of diesel-degrader populations that will be enhanced by a given plant. RECOMMENDATIONS AND OUTLOOK: In the proposed phytoremediation-benefit model plant roots maintain high levels of hydrocaron degraders in uncontaminated soil. When the root enters a contaminated zone of soil, those hydrocarbon degraders that prefer the contaminant would switch to the contaminant as a carbon source, effectively removing the hydrocarbons. If the root exudates and the contaminant are equally attractive to the hydrocarbon degraders, the contaminant degradaton would be less effective. 相似文献
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815.
Aluminium ions hydrolyse and polymerise into different species in water. Main aluminium species in aluminium coagulant solutions are monomeric Al species (Al1) and polymeric Al species Al13O4(OH)24(7+) (Al13). The aluminium species distribution in coagulant solutions can be influenced by many parameters. This paper studies influences of concentrations of total aluminium species (Al(t)) and other species--OH-, polysilicic acid and ferric species, which were added in aluminium coagulant solutions, on the aluminium species distribution through 27Al nuclear magnetic resonance (NMR) analysis. Results show that only Al1 and no Al13 exist in coagulant solutions at higher Al(t) concentrations (over 1 mol l(-1)), while both species exist at lower Al(t) concentrations (0.1 mol l(-1)). The increase of OH/Al value (molar ratio) increases the concentration of Al13 in coagulant solutions, while the addition of polysilicic acid and ferric species decreases the concentration of Al13. 相似文献
816.
处理啤酒废水的厌氧流化床操作特性的研究 总被引:1,自引:0,他引:1
试验表明,自制厌氧流化床(AFB)反应器对温度的变化、上升流速等环境的变化都具备良好的稳定性.它的处理温度控制在30±2℃范围,上升表观流速控制为19.1 m/h左右,回流比控制为8:1,水力停留时间在6.9 h左右,废水COD去除率可达80%以上.该AFB反应器能够承受高达30.65 kg COD/m3·d的有机容积负荷,其COD去除率也达到了73%~81%,产气速率系数为0.55~0.612 m2/kg COD.同时,也对实验中出现的偏析现象进行了分析. 相似文献
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819.
PCB removal from contaminated dredged material 总被引:5,自引:0,他引:5
The purpose of this study was to evaluate the feasibility of decontaminating PCB contaminated sediment using land treatment technology. Five glass aquariums were set up to test the disappearance of polychlorinated biphenyls (PCBs) in dredged sediment under laboratory conditions that simulated photodegradation, biological transformation, and volatilization in dredged material confined disposal facilities (CDFs). A 40% decline in PCB concentration was achieved over a period of 5 months. Analysis of the variance in the data showed that periodic tilling produced a tangible effect on the disappearance of PCBs. However, the process or processes responsible for PCB disappearance could not be determined. PCB disappearance from the sediment was most likely caused by a combination of photolysis, volatilization, and biodegradation mechanisms rather than by any single process. 相似文献
820.
厌氧-吹脱-好氧-吸附法处理酱油废水 总被引:5,自引:0,他引:5
针对酱油废水的高CODCr、高色度、高挥发酸以及含盐的特点,设计了用厌氧-吹脱-好氧-吸附法处理酱油废水的工艺。实验结果表明,该工艺对酱油废水的处理有较好的处理效果。当厌氧进水的CODCr分别为6000~8000和1500~2000mg/L,色度分别为5000和1800倍左右时,厌氧反应的水力停留时间(HRT)分别为3~4和2d,吹脱池的停留时间为16h,气水比为0.01m^3/L,好氧反应器和煤渣吸附池的停留时间分别为14~18和14~16h时,该流程对废水CODCr的总平均去除率分别达到90%和82.7%左右,对色度的总平均去除率分别为76.7%和86.5%。 相似文献