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991.
Effect of the alkyl chain length on the anaerobic biodegradability and toxicity of quaternary ammonium based surfactants 总被引:2,自引:0,他引:2
The anaerobic biodegradability and toxicity to methanogenic gas production of different alkyl chain length homologs of quaternary ammonium based surfactants were examinated. Two series of these cationic surfactants were selected: alkyl trimethyl ammonium and alkyl benzyl dimethyl ammonium compounds. A simple anaerobic gas production test containing municipal digester solids as a source of anaerobic bacteria was used. Under the applied methanogenic conditions, the cationic surfactants tested showed a very poor primary biodegradation and no evidence of any extent of ultimate biodegradation was observed. The toxicity of quaternary ammonium based surfactants to methanogenic gas production decreased with increasing the alkyl chain length. 相似文献
992.
Detection of a Toxic Product Released by a Polyurethane-Containing Film Using a Composting Test Method Based on a Mineral Bed 总被引:1,自引:0,他引:1
Maurizio Tosin Francesco Degli-Innocenti Catia Bastioli 《Journal of Polymers and the Environment》1998,6(2):79-90
The degradation of a film containing a 4,4diphenyl methane diisocyanate (MDI) poly(€-caprolactone)-based polyurethane was followed in a test system based on a mineral solid bed designed to facilitate analysis of break-down products released under composting conditions. The use of a mineral solid bed can help extraction and analytical procedures which could be hindered by the heterogeneous nature of compost. The fermentation conditions are typical of the composting environment and generate a powerfully degradative environment. The film fully disintegrated within 30 days of treatment. Analysis on the mineral bed extracts showed that: (i) about 40% of the initial polyurethane was still present in the bed extracts; (ii) this residue was strongly degraded in the poly(€-caprolactone) part, while the urethane part was almost completely recovered (from 80 to 95%, according to the measurement method); (iii) 4,4 diamino diphenyl methane (MDA), a very dangerous product of MDI, was released during biodegradation. The results indicate that a mineral bed can be employed to study degradation and metabolites formation in solid phase fermentation and that the MDI-based polyurethanes are not susceptible of a full degradation during composting and maintain the potential of a slow release of MDA into the environment after soil application. 相似文献
993.
甲黄隆,氯黄隆,苄嘧黄隆及其降解产物对蛋白核小球藻生长的效应 总被引:5,自引:1,他引:4
本文研究了甲黄隆、氯黄隆、苄嘧黄隆及其降解产物对蛋白核小球藻(Chlorellapyrenoidosa)的96h生长抑制急性毒性和化合物氮的生物可获得性。急性毒性试验表明:黄隆的毒性比其降解产物取代磺胺和氮杂环化合物大得多(EC_(50)相差2—3个数量级),降解产物取代磺胺、均三嗪、取代嘧啶存在明显的低浓度促进生长现象,氮的生物可获得性试验表明:小球藻能有效利用低浓度取代磺胺、均三嗪、取代嘧啶化合物中的氮促进生长,促进程度:氯磺胺>苄磺胺≈二甲氧基嘧啶>甲磺胺>均三嗪。 相似文献
994.
995.
Euro Chlor Risk Assessment for the Marine Environment Osparcom Region: North Sea - Trichloroethylene
Jean-Charles Boutonnet Christ De Rooij Veronique Garny Andre Lecloux Roger Papp Roy S Thompson Dolf Van Wijk 《Environmental monitoring and assessment》1998,53(3):467-487
This risk assessment on trichloroethylene (TRI) was carried out specifically for the marine environment, according to the methodology laid down in the EU risk assessment Regulation (1488/94) and the Guidance Document of the EU New and Existing Substances Regulation (TGD, 1997). The study consists of the collection and evaluation of data on effects and environmental concentrations from analytical monitoring programs in large rivers and estuaries in the North Sea area. The risk is indicated by the ratio of the "predicted environmental concentrations" (PEC) and the "predicted no effect concentrations" (PNEC) for the marine aquatic environment. In total, 19 studies for fish, 30 studies for invertebrates and 14 studies for algae have been evaluated. Both acute and chronic toxicity studies have been taken into account and the appropriate assessment factors have been used to define a PNEC value of 150 µg/l. Most of the available monitoring data apply to rivers and estuaries and were used to calculate PECs. The most recent data (1991-1995) support a typical PEC of 0.1 µg TRI/l water and a worst case PEC of 3.5 µg TRI/l water. The calculated PEC/PNEC ratios give a safety margin of 40 to 1,500 between the predicted no effect concentration and the exposure concentration. Additional evaluation of environmental fate and bioaccumulation characteristics showed that no concern for food chain accumulation is expected. 相似文献
996.
本文测试了硫氰酸钠、二甲基甲酰胺、乙腈和丙烯腈等四种石油化工废水中常见污染物对15种水生生物的急性毒性,以考察不同时刻LC50之间的相关性。试验结果表明,24、48和72小时的LC50(或EC50)与96小时的LC50(或EC50)之间存在十分密切的相关关系,在特定情况下可以用24、48或72小时的急性毒性试验结果代替96小时毒性试验结果,比较污染物的毒性大小,进行污染物结构活性分析,完成短期生物监测。 相似文献
997.
8种拟除虫菊酯农药对稀有鲫的急性、亚慢性毒性研究 总被引:1,自引:0,他引:1
8种拟除虫菊酯对稀有鲫的急性毒性和其中2种拟除虫菊酯的亚慢性毒性研究结果表明:溴氰菊酯、高效氯氰菊酯、氯氰菊酯、甲氰菊酯、氰戊菊酯、二氯炔戊菊酯、胺菊酯、甲醚菊酯对稀有鲫均属剧毒,它们的ρ(96hLC50)/μg·L-1分别为3.16,3.24,6.31,7.21,7.35,32.45,91.75和882.6;甲氰菊酯、二氯炔戊菊酯对稀有鲫7d亚慢性毒性的最低有影响浓度ρ(LOEC)和最高无影响浓度ρ(NOEC)分别为0.88~0.44μg/L,4.0~2.0μg/L,以ρ(96hLC50)/μg·L-1为基准,2种拟除虫菊酯的安全系数均为0.06~0.125. 相似文献
998.
以二恶英类(DIOXINs, DXNs)为代表的十二项物质是在环境中具有高残留性、高生物浓缩性和高生物毒性的物质,即POPs物质(PersistentOrganicPollutants,残留性有机污染物质)。控制和治理POPs物质是我国加入斯德哥尔摩公约后应尽的义务与责任。我国加入WTO后,国内产品若走向世界,二恶英标准的制定与评价是必不可少的,否则我们国家将受到沉重的打击。同时也是保证我国人民身心健康的重要保证。本文主要叙述了二英的毒性、我国现在的污染状况以及我们应该采取的措施。 相似文献
999.
两种含氮高分子材料的热解烟气毒性评价 总被引:2,自引:0,他引:2
采用GA/T 506-2004中规定的产烟模型对2种含氮高分子材料进行热解,将实验动物动态暴露于热解烟气中并使用傅立叶变换红外分析仪(FTIR)对热解烟气进行成分分析,将成分分析的结果用模型进行计算.结果表明,在热解温度为600 ℃时,腈纶毛线的热解烟气毒性大大高于羊毛地毯的热解烟气毒性;在不考虑NO2的情况下N-气体值在0.5~1.3之间有受试动物死亡;烟气毒性的研究中数学计算方法不一定能完全替代动物实验;动物实验与成分分析、数学计算相结合在现阶段还是研究烟气毒性的较为有效的手段. 相似文献
1000.