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941.
942.
Marcelo Zeri Kristina Anderson-TeixeiraGeorge Hickman Michael MastersEvan DeLucia Carl J. Bernacchi 《Agriculture, ecosystems & environment》2011,144(1):319-329
Perennial grass biofuels may contribute to long-term carbon sequestration in soils, thereby providing a broad range of environmental benefits. To quantify those benefits, the carbon balance was investigated over three perennial grass biofuel crops - miscanthus (Miscanthus × giganteus), switchgrass (Panicum virgatum) and a mixture of native prairie plants - and a row crop control (maize-maize-soy) in Central Illinois, USA, during the establishment phase of the perennial grasses (2008-2011). The eddy covariance technique was used to calculate fluxes of carbon dioxide and energy balance components, such as latent and sensible heat fluxes. Whereas maize attained the highest maximal carbon uptake rates, the perennial grasses had significantly extended growing seasons, such that their total carbon uptake rivaled that of corn in the second growing season and greatly exceeded that of soy in the third growing season. To account for the removal of carbon through harvest, net ecosystem exchange of carbon (NEE) was combined with estimates of yields, resulting in the net ecosystem carbon balance (NECB). After 2.5 years, NECB for the maize/soybean plot was positive (a source of carbon), while the grasses were a sink of carbon. Continuous measurements over the next years are required in order to confirm whether miscanthus, switchgrass and prairie can sustain a long-term sink of carbon if managed for biofuels, i.e., if harvested annually. 相似文献
943.
温室效应与二氧化碳的控制 总被引:9,自引:1,他引:9
通过气候变暖及生态系统变化的事例简述了温室效应的危害及其起源 ,并从生物技术、能源革新、大气污染控制技术几个方面评述了近年来涌现出的二氧化碳控制技术的优缺点和发展前景。 相似文献
944.
内蒙古温带草原羊草叶片功能特性与光合特征对外源氮输入的响应 总被引:1,自引:1,他引:1
以内蒙古锡林河流域羊草草原典型植被羊草(Leymus chinensis)为研究对象,探讨了4个不同氮素输入水平(0、5、10和20g·m-·2a-1)下羊草叶片功能特性与光合特征的响应,并分析了外源氮输入背景下草地生态系统固碳潜势的变化.结果表明:中等水平施氮(10g·m-·2a-1)显著增加了羊草叶面积、叶绿素相对含量、叶氮浓度与净光合速率,但与中氮相比,高氮(20g·m-·2a-1)输入下却有所下降;施氮不仅对叶片净光合速率有一定程度的促进作用,而且延长了光合作用高峰期的持续时间;随着氮素添加梯度的增加,羊草叶片蒸腾速率降低,瞬时水分利用效率增高,气孔导度增大,胞间CO2浓度逐渐减小.从光合固碳的角度来看,适量的外源氮素输入有利于草地生态系统固定更多的CO2. 相似文献
945.
Andreas Uihlein Witold-Roger Poganietz Liselotte Schebek 《Resources, Conservation and Recycling》2006,46(4):410-429
Today, global climate change is one of the most urgent environmental problems. The atmospheric concentration of carbon dioxide (CO2) has to be stabilised by significant reductions of CO2 emissions in the next decades to keep the expected temperature rise within tolerable borders. Efforts exceeding the implemented measures to reduce CO2 emissions in Germany are desirable. An important pre-condition for such measures is a scientific-based inventory of the sources, sinks, and use of carbon.In this paper, we present CarboMoG, i.e. Carbon Flow Model of Germany. CarboMoG is a carbon flow model covering carbon flows, carbon sources and sinks in Germany and the German anthroposphere, showing concurrent energy and non-energy use of carbon sources.The model consists of seven modules in German anthroposphere following the German classification of economic sectors. Carbon flows to and from atmosphere and lithosphere as well as imports and exports were included into the model. The model comprises roughly 220 material flows determined based on material flow procedures for the base year 2000.Main sources of carbon are fossil energy carriers from lithosphere and uptake of CO2 by crops (52% resp. 48% of all carbon sources). The model calculations show that import of energy carriers dominates total carbon import to Germany (82%). Total non-energy use of carbon in Germany is significantly higher than energy use (386 Mt C and 230 Mt C, resp.). Carbon throughput of Industry is greatest (about 224 Mt C input), followed by Energy (about 129 Mt C input). Agriculture and Forestry & Industry show the highest figure for non-energy use of carbon, energy use of carbon is largest in the Energy sector. Emissions of CO2 to atmosphere account for 94% of all carbon flows to sinks in Germany. Carbon accumulates in German anthroposphere 5 Mt C in 2000. 相似文献
946.
947.
总结了国内外粉煤灰用于CO2捕集、利用和封存的不同技术研究进展,同时对今后的研究和机遇进行了展望.粉煤灰自身可通过直接干式、半干式、湿式和间接方法对CO2进行矿化捕集封存,在CO2矿化的同时降低粉煤灰自身重金属的浸出,并且矿化后的粉煤灰因有效降低游离CaO和MgO的含量而更适合于制作混凝土添加剂.粉煤灰也可制成活性炭、沸石和多孔二氧化硅等产品,并对CO2进行物理吸附捕集,制成产品的类型主要取决于粉煤灰自身的成分组成和理化性质.在CO2利用方面,粉煤灰除了可拓展建材的利用途径外,还可制作CO2多种化学工艺所需催化剂或催化剂载体,以及制作新型材料拟薄水铝石等.我国“双碳”目标的提出及燃煤电厂粉煤灰自身的理化特性为粉煤灰提供了一条新的综合利用途径. 相似文献
948.
949.
Studies concerning the emission of carbon dioxide(CO_2) were carried out in 2009–2012 for six reservoirs located in four provinces of south-eastern Poland. The CO_2 flux across the water–air interface was measured using the "static chamber" method. The measured fluxes of CO_2(FCO_2) ranged from-30.64 to 183.78 mmol/m~2/day, and the average values varied in the range from-3.52 to 82.11 mmol/m2/day. In most of the cases, emission of CO_2 to the atmosphere was observed. The obtained values of CO_2 fluxes were comparable to values typical for other temperate reservoirs. Analysis of the influence of selected environmental factors on the FCO_2 showed that it depends on parameters characterizing both the sediments and surface water. The CO_2 flux at the water–air interface was positively correlated with parameters of bottom sediments such as porosity, content of organic carbon and total nitrogen; and negatively with p H value and δ~(13)C of organic carbon. In the case of the parameters characterizing surface water, positive dependences on the concentrations of nitrate and total nitrogen, and negative relationships with water temperature and chlorophyll a concentrations, were found. 相似文献
950.
超临界CO2萃取再生活性炭技术研究进展 总被引:5,自引:0,他引:5
超临界流体由于密度大、粘度低、表面张力小,是再生活性炭的理想溶剂,文章介绍了超临界CO2萃取再生活性炭的原理,研究现状,设备和工艺流程及对该工艺的影响因素,表明了该技术在活性炭再生上的特点,优势及应用前景。 相似文献