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51.
弱势群体物质生活贫困,在市场中缺乏竞争能力,在社会和政治层面也处于弱势地位,这些特点决定了他们是公民环境权的贫困者。为此,需要设计合理的制度保护弱势群体公民环境权,需要用法律手段保护弱势群体公民环境权,还需要提高弱势群体保护公民环境权的自觉性。 相似文献
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Relation between extinction and assisted colonization of plants in the arctic‐alpine and boreal regions 下载免费PDF全文
Juha Pykälä 《Conservation biology》2017,31(3):524-530
Assisted colonization of vascular plants is considered by many ecologists an important tool to preserve biodiversity threatened by climate change. I argue that assisted colonization may have negative consequences in arctic‐alpine and boreal regions. The observed slow movement of plants toward the north has been an argument for assisted colonization. However, these range shifts may be slow because for many plants microclimatic warming (ignored by advocates of assisted colonization) has been smaller than macroclimatic warming. Arctic‐alpine and boreal plants may have limited possibilities to disperse farther north or to higher elevations. I suggest that arctic‐alpine species are more likely to be driven to extinction because of competitive exclusion by southern species than by increasing temperatures. If so, the future existence of arctic‐alpine and boreal flora may depend on delaying or preventing the migration of plants toward the north to allow northern species to evolve to survive in a warmer climate. In the arctic‐alpine region, preventing the dispersal of trees and shrubs may be the most important method to mitigate the negative effects of climate change. The purported conservation benefits of assisted colonization should not be used to promote the migration of invasive species by forestry. 相似文献
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营养限制对厌氧序批操作反应器的影响及其恢复重建过程 总被引:1,自引:0,他引:1
研究了在厌氧条件下以葡萄糖为基质的序批操作反应器(ASBR)中营养物浓度限制对基质吸收和储存的影响及其恢复重建过程。结果表明,营养物限制条件下,发酵细菌表现为过量吸收基质并储存为糖原,形成隐性增殖以维持其细胞的正常结构和代谢功能;而甲烷菌由于无储存能力,其表现为活性逐渐降低。短期营养限制条件下(1个周期),基质中无磷时,储存量增加29%;基质中无氮时,储存量增加90%;基质中既无氮也无磷时,储存量增加26%。长期(31个周期)营养限制(基质中氮磷含量减小50%)下,胞内储存糖原量可高达正常状态下的4.8倍,但甲烷活性减少为正常状态下的17.78%。营养物限制对发酵细菌影响较小,对甲烷菌影响较大。将氮磷浓度恢复正常后,反应器的产甲烷能力恢复较快,出水COD经31周期后恢复正常,而胞内糖原在85周期后恢复正常。 相似文献
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顾国培 《石油化工环境保护》2000,(1):43-47
化肥厂尿素装置对大气的环境污染主要 塔顶部排放的尾气中氮及粉尘为主,治理尿素造粒塔的尘是改善化肥厂大气环境的关键,它既是一项环境保护措施,也是一项重要的节能降耗措施。 相似文献
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Edna Granéli Paulo S. Salomon 《Journal of the American Water Resources Association》2010,46(1):108-120
Granéli, Edna and Paulo S. Salomon, 2010. Factors Influencing Allelopathy and Toxicity in Prymnesium parvum. Journal of the American Water Resources Association (JAWRA) 46(1):108-120. Abstract: Some microalgae are able to kill or inhibit nutrient-competing microalgae, a process called allelopathy. Inhibiting or killing competitors enable these species to monopolize limiting resources, such as nitrogen and phosphorus. Prymnesium parvum is known to produce such allelopathic compounds, substances that seem identical to the ichthyotoxins identified from this species. Biotic and abiotic environmental factors influence not only growth rates but also toxin/allelopathic compounds production by P. parvum cells. Toxin production, as well as allelopathy, including grazer deterrence, increases dramatically in light, temperature, or nutrient stressed P. parvum cells. Correspondingly, toxicity and allelopathy may decrease, or cease completely, if cells are grown with high amounts of N and P in balanced proportions. However, even under nutrient (N and P) sufficient conditions, P. parvum is able to produce toxins/allelopathic compounds, with negative effects on other phytoplankton species or grazers, if cells densities of P. parvum are high relative to other species. This negative effect might shift the plankton community to more toxin resistant species. Filtrates from nutrient-deficient P. parvum cultures have almost the same strong negative effect on grazers and other phytoplankton species as when Prymnesium cells are grown together with the target organisms. Eutrophication, the increased input of N and P to aquatic ecosystems, besides increasing nutrient concentrations, is usually provoking unbalanced N:P condition for the optimal growth of phytoplankton, deviating from the Redfield ratio, i.e., the phytoplankton cellular nitrogen to phosphorus ratio, N:P = 16:1 (by atoms) or 7.2:1 (by weight). Eutrophication thus both enhances P. parvum growth and increases production of toxins and allelopathic compounds. Supplying N-deficient or P-deficient P. parvum cells with the deficient nutrient reduces toxicity to less than half within 24 h after additions. As P. parvum is mixotrophic, uptake of dissolved or particulate organic N (DON or PON) can also reduce toxicity and allelopathy in the same manner as addition of inorganic N to N-starved cells. In conclusion, P. parvum, by increasing its toxicity and allelopathic ability under poor environmental conditions, outcompetes the co-occurring phytoplankton species. 相似文献
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简要说明了齐齐哈尔市中心城区地下水资源分布特征、地下水资源量、地下水补给与排放情况,根据地下水开采利用现状及存在的问题,围绕地下水水质,详细地探讨了改善与保护地下水资源的一系列有效途径。 相似文献
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纪欣 《石油化工环境保护》2006,29(2):34-36
对炼油、化工废水治理生产实践进行研究与探讨,提出应对高浓度混合污水的处理方法,对各种影响治理的因素有针对性地采取应对措施,提高了污水处理抗冲击能力和治理效果,对实现长周期平稳运行具有积极意义。 相似文献