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131.
以沈阳沈抚灌区上游指定区域为研究对象,监测分析了停灌十多年来土壤中石油烃污染残留状况;采用单项污染指数法和综合污染指数法评价了采样区域的土壤中石油烃污染现状,同时运用Arcgis软件分析绘制了采样区的单项污染指数分布图。结果表明:采样区域石油烃存在残留和污染现象,按照单项污染指数评价,60%的行政村土壤属于高污染级以上。按照综合污染指数评价,80%的行政村土壤属于重污染级。污染指数分布图显示,离主干灌渠的源头越近,污染越严重。对于土壤石油烃修复效果,旱田作业要好于水田作业。  相似文献   
132.
Novaluron, a newly introduced insecticide, is used for control of a number of field pests. However, information regarding novaluron residues and dissipation profile is limited. In this study, dissipation and residual levels of novaluron in tomato under open field conditions were investigated using high performance liquid chromatography equipped with diode array detector (HPLC-DAD) with quick, easy, cheape, effective, rugged (QuEChERS) method. The method was validated using blank samples spiked at three levels and results showed that recoveries ranged from 93% to 99%. Novaluron residues tend to dissipate following first-order rate kinetics with half-life of 2.08 days. Data demonstrated that the use of novaluron at recommended doses would not pose any hazards to consumers. The present results aid to establish the safe use of this pesticide on tomatoes, and possibly on other crops in Egypt.  相似文献   
133.
The residue dynamics of carbendazim and mancozeb in grape berries is reported. The fungicides were sprayed in accordance with the most critical use pattern i.e. 4 times at 15 days interval separately at recommended and double doses. The residues of each fungicide dissipated following 1st order rate kinetics. The half-lives of carbendazim and mancozeb were 7.3 and 8.1 days at recommended dose and 4.6 and 5.7 days at double dose. Ethylenethiourea (ETU), the toxic metabolite of mancozeb was detectable at harvest following four sprays of mancozeb at recommended dose. At double dose, however, the residues of ETU could be detected even after three sprays of mancozeb. The pre-harvest intervals for carbendazim and mancozeb were found to be 26 and 12 days at recommended dose and 33 and 17 days at double dose, respectively.  相似文献   
134.
Reclaimed water threatens the ecological safety of the Chaobai River. SMX, TMP, and SDZ were the first three abundant antibiotics in the research area. SRGs and intI1 were widespread with high abundance after reclaimed water recharge. The SRGs values followed the sequence: Summer>autumn>spring>winter. Strong correlations were detected between SRGs and environmental factors. Reclaimed water represents an important source of antibiotics and antibiotic resistance genes, threatening the ecological safety of receiving environments, while alleviating water resource shortages. This study investigated the dissemination of sulfonamide (SAs), sulfonamide resistance genes (SRGs), and class one integrons (intI1) in the surface water of the recharging area of the Chaobai River. The three antibiotics sulfamethoxazole, trimethoprim, and sulfadiazine had the highest abundance. The highest absolute abundances were 2.91×106, 6.94×106, and 2.18×104 copies/mL for sul1, sul2, and intI1 at the recharge point, respectively. SRGs and intI1 were widespread and had high abundance not only at the recharging point, but also in remote areas up to 8 km away. Seasonal variations of SRGs abundance followed the order of summer>autumn>spring>winter. Significant correlations were found between SRGs and intI1 (R2 = 0.887 and 0.786, p<0.01), indicating the potential risk of SRGs dissemination. Strong correlations between the abundance of SRGs and environmental factors were also found, suggesting that appropriate environmental conditions favor the spread of SRGs. The obtained results indicate that recharging with reclaimed water causes dissemination and enrichment of SAs and SRGs in the receiving river. Further research is required for the risk assessment and scientific management of reclaimed water.  相似文献   
135.
穆亚丽  冯淑怡  马力  雷昊  袁阳 《自然资源学报》2017,32(10):1678-1690
论文基于江苏省淮安市和连云港市沼气池使用户调查数据,运用Probit模型考察农户沼肥还田决策行为的影响因素,构建产出供给方程评价农户沼肥还田决策行为的经济效应。结果表明:沼气池使用天数越多、户主年龄越小、户主是村干部或农民专业合作社成员以及人均承包地越多的农户,越倾向于选择沼肥还田,而家庭总资产较少或较多的农户都不愿意选择沼肥还田。控制其他条件,农户沼肥还田可能性每增加1%,单位面积农地产值提高0.07%(10.81 元/hm2),若研究区域沼气池使用户全部选择沼肥还田,单位面积农地产值将提高356.55元/hm2,具有一定的经济效应,倾向得分匹配方法(PSM)的稳健性分析进一步证实这一结论。目前中国沼肥还田率总体不高且没有规范的沼肥还田管理项目,进而提出鼓励沼气池使用户充分利用沼气池,提高农户沼肥还田积极性的政策建议。  相似文献   
136.
干法烟气脱硫副产物中汞的形态分布   总被引:4,自引:3,他引:1       下载免费PDF全文
通过分析干法烟气脱硫副产物中不同形态汞的含量,研究干法脱硫灰中汞的环境稳定性. 利用逐级化学提取法,分析了锅炉底灰、锅炉飞灰、脱硫塔底灰和除尘器灰中水溶态、酸溶态、过氧化氢溶态及王水溶残渣态汞的含量,研究了不同形态汞含量的变化规律. 结果表明,锅炉底灰、锅炉飞灰、脱硫塔底灰和除尘器灰中w(总汞)分别为0.23,0.36,0.46和1.22 mg/kg,且随着脱硫除尘时间的延长w(总汞)呈增加的趋势,其中,以氯化物、硝酸盐和硫酸盐存在的水溶态汞变化明显,除尘器灰中w(水溶态汞)高达0.72 mg/kg. 分析认为,干法烟气脱硫灰吸附的大部分汞蒸气转化为可溶性的氯化物、硝酸盐和硫酸盐等,另外还有少量汞以单质状态存在.   相似文献   
137.
建立了黄瓜和土壤中啶氧菌酯残留量的检测分析方法,对啶氧菌酯在黄瓜和土壤中的消解动态及残留规律进行了研究。啶氧菌酯的最小检出量为3.5×10^-11g;在黄瓜和土壤基质中的最低检出浓度均为0.005mg·kg^-1。对黄瓜和土壤2种基质,设置了0.005、0.05、0.25 mg·kg^-13个添加水平,每个添加水平设置5个重复,啶氧菌酯在黄瓜和土壤中的添加回收率为68.61%-122.4%,变异系数为1.06%-17.2%。田间试验结果表明:啶氧菌酯在天津地区黄瓜和土壤中的残留消解半衰期分别为5.71d和12.9 d,在山东地区黄瓜和土壤中的残留消解半衰期分别为2.70d和10.3 d,在江苏地区黄瓜和土壤中的残留消解半衰期分别为9.76d和14.9 d。距最后一次施药5d时,啶氧菌酯在黄瓜中的最高残留量为0.014mg·kg^-1,远低于欧盟规定的黄瓜中啶氧菌酯最大残留限量0.05mg·kg^-1。  相似文献   
138.
半干半湿法脱硫产生的脱硫灰中混有大量有效钙和粉煤灰 ,本文对其进行了循环利用机理分析及试验研究 ,证实脱硫灰循环大大提高了钙的利用率 ,降低了钙硫比 ,但循环倍率增加到 2倍以上时 ,脱硫效率增速变缓。脱硫灰的循环利用对降低脱硫运行费用是非常有效的。  相似文献   
139.
Fragments of antifouling paint and environmental geosolids have been sampled from the island of Malta and analysed for total and bioaccessible metals. Total concentrations of Ba, Cd, Cu, Pb, Sn and Zn were two to three orders of magnitude higher in spent antifouling composites relative to respective values in background soils and road dusts. Paint fragments were visible in geosolids taken from the immediate vicinity of boat maintenance facilities and mass balance calculations, based on Ba as a paint tracer, suggested that the most contaminated soils, road dusts and boatyard dusts contained about 1%, 7% and 9%, respectively, of antifouling particles. Human bioaccessibilities of metals were evaluated in selected samples using a physiologically based extraction technique. Accessibilities of Cd, Cu, Pb and Zn in the most contaminated solids were sufficient to be cause for concern for individuals working in the boat repair industry and to the wider, local community.  相似文献   
140.
电厂脱硫灰烧成硫铝酸盐水泥的试验研究   总被引:1,自引:0,他引:1  
电厂脱硫灰由于成分复杂和高硫高钙的特点,为其综合利用造成了很多困难.试验证明,只需添加部分CaO或CaCO2,用脱硫灰作生料即可在1 300℃左右烧成硫铝酸盐水泥.这种方式可以完全利用脱硫灰中的游离CaO,CaCO3,Ca(OH)2和含硫矿物CaSO3与CaSO4,使其转化为水泥熟料矿物,如硫铝酸钙(Ca4Al6O12SO4)、硅酸二钙(Ca2SiO4)等,还能完全利用脱硫灰中的未燃烬碳,因而能达到物尽其用,是一种全新高效的利用方式,具有广阔的应用前景.  相似文献   
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