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271.
通用森林火险级系统   总被引:19,自引:0,他引:19  
根据火烧试验,研究出来一套包括火险等级、火行为与火烈度等的完整系统.用公式R_0=aT bV ch-D计算日燃烧指标R_0(米/分)。此方法曾于1991年5月试用在小兴安岭伊春林区得出满意的结果。  相似文献   
272.
ABSTRACT: Road building, clearcutting 25 percent of the watershed, and slash disposal by broadcast burning or by natural decomposition caused changes in water quality of two small streams in the Bull Run Watershed in Oregon, which supplies water to the Portland, Oregon, metropolitan area. Concentrations of suspended sediment increased slightly, primarily owing to construction of a permanent logging road that crossed streams. Changes in nutrient cycling occurred due to logging and slash disposal in both watersheds where cutting was done. NO3-N concentrations, which increased most where logging residue was left to decompose naturally, increased more than sixfold and commonly exceeded 100 pg/i during the October-June high-flow season for seven years after logging. Where logging slash was broadcast burned, NO3-N concentrations increased roughly fourfold, but rarely exceeded 50 μg/l, and increases had mostly disappeared six years after slash burning. Changes in outflows of cations and other anions were not apparent. Annual maximum stream temperatures increased 2–3°C after logging, but temperature increases had mostly disappeared within three years as vegetation regrowth shaded the streams.  相似文献   
273.
含油污水中固体废物固化与燃煤混烧的可行性   总被引:3,自引:0,他引:3  
在含油污水处理过程中易产生含油污泥、活性污泥及浮渣等固体废物,利用传统的焚烧法、分离法、填埋法、生物降解法处理这些废物具有一定的缺陷和局限性。为了利用这些废物中的油及有机质的潜在能量,大庆炼化公司对固体废物进行了脱水固化试验。结果表明,脱水后的废物可以达到较好的固化状态,并具有一定的热值。固化废物经粉碎处理后,可按一定比例与燃煤混烧。在正常生产状况下,热电厂可保证混合燃烧的效果,其总体热值不会降低。混烧后的灰渣和炉渣可作为水泥厂的原料。该方法有利于环境保护,但其工业化生产可行性有待于进一步证实。  相似文献   
274.
The high degree of physical disturbance associated with conventional response options to oil spills in wetlands is driving the investigation of alternative cleanup methodologies. In March 1995, a spill of gas condensate in a brackish marsh at Rockefeller Wildlife Refuge in southwestern Louisiana was remediated through the use of in situ burning. An assessment of vegetation recovery was initiated in three treatment marshes: (1) oil-impacted and burned, (2) oil impacted and unburned, and (3) a nonoiled unburned reference. We compared percent cover, stem density, and biomass in the treatment marshes to define ecological recovery of the marsh vegetation and soil hydrocarbon content to determine the efficacy of in situ burning as a cleanup technique. Burning led to a rapid decrease in soil hydrocarbon concentrations in the impacted-and-burned marsh to background levels by the end of the first growing season. Although a management fire accidentally burned the oil-impacted-and-unburned and reference marshes in December 1995, stem density, live biomass, and total percent cover values in the oil-impacted-and-burned marsh were equivalent to those in the other treatment marshes after three years. In addition, plant community composition within the oil-impacted-and-burned marsh was similar to the codominant mix of the grasses Distichlis spicata (salt grass) and Spartina patens (wire grass) characteristic of the surrounding marsh after the same time period. Rapid recovery of the oil-impacted-and-unburned marsh was likely due to lower initial hydrocarbon exposure. Water levels inundating the soil surface of this grass-dominated marsh and the timing of the in situ burn early in the growing season were important factors contributing to the rapid recovery of this wetland. The results of this in situ burn evaluation support the conclusion that burning, under the proper conditions, can be relied upon as an effective cleanup response to hydrocarbon spills in herbaceous wetlands.  相似文献   
275.
溢油应急反应中的现场燃烧技术   总被引:3,自引:0,他引:3  
赵如箱 《交通环保》2002,23(3):39-42
介绍了溢油应急反应中的现场燃烧技术的形成、技术措施、所用设备设施以及实施现场燃烧时需要的注意事项  相似文献   
276.
不同收获与清林方式对杉木林养分的影响   总被引:4,自引:0,他引:4  
对三代杉木林全株、全木和传统收获及传统和全木收获后火烧清理迹地林分营养元素变化进行了研究 ,结果表明 :杉木林采用全株收获和全木收获的营养元素损失量分别是传统收获的1 99倍和1 64倍 ;采伐剩余物火烧导致林地生态系统中N和P2O5 大量损失 ;采用传统收获及随后火烧清理采伐剩余物 ,N和P2O5 损失量比仅采用全株或全木收获的均高。若缩短轮伐期 ,则可能导致立地N和P2O5 的严重亏缺 ;全株或全木收获导致大量盐基离子移出林地 ,可能导致土壤较为严重的酸化趋势。  相似文献   
277.
As a common practice in agricultural system, straw return has been reported to release a large number of trace gases and attracted much attention. However, the role of straw return in toluene emission remains poorly understood. In this study we measured the emissions of toluene as well as other 50 volatile organic compounds (VOCs) from wheat straw return for 66 days under flooded and non-flooded conditions, respectively. The results showed that substantial toluene was released from the returned ...  相似文献   
278.
中小型燃煤锅炉烟气除尘脱硫的分析   总被引:6,自引:1,他引:6  
较详细地介绍了干式除尘器和湿式脱硫塔串联而成的干湿两级除尘脱硫系统和湿式除尘脱硫系统的特点,这两种系统对中小型燃煤锅炉烟气的净化效果明显  相似文献   
279.
光纤pH计的设计   总被引:3,自引:0,他引:3  
针对传统pH值测试方法的局限性,提出了一种新型pH值测量方案-光纤pH计。着重讨论了传感器的敏感部件原理与制作。并将当今流行的MCS-51系列单片机用于二次仪表设计,提高信息处理速度和精度并利于数显。  相似文献   
280.
用LCA方法评估城市“白色垃圾”的处置   总被引:2,自引:0,他引:2  
牛海林 《环境工程》2001,19(1):51-52
对目前城市白色垃圾的 2种普遍处置方法———厌氧卫生填埋法和焚烧法进行了LCA分析评估 ,得出焚烧法可使环境负担相对较轻的结论。  相似文献   
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