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601.
介绍免疫磁珠分离技术的原理和操作步骤,分析其主要影响因素.介绍该技术在环境样品病原菌、原虫及病毒检测中的应用及研究进展.环境样品成分复杂,需经适当分离纯化处理再进行病原微生物检测,从而保证检测结果的可信性.免疫磁珠分离技术兼具免疫反应的特异性及磁性分离的快速性,能够有效分离纯化环境水样中的病原微生物,广泛应用于病原微生物的检测. 相似文献
602.
Emission of NOx is of primary environmental concern in the oil sands industry. Selective catalytic reduction (SCR) is one of the best NOx reduction technologies. The present study discusses the testing of a mechanistic kinetic model for the SCR of NOx to describe the kinetics of V2O5/TiO2 catalysis at atmospheric pressure and a temperature of 623 K in a monolith honeycomb reactor. The modeling results impart insight into the significance of the diffusion with reaction steps and guidance for optimal monolith design for SCR. The validated expression would predict the conversion performance of the catalysts for different values of temperature inlet and ammonia concentration. A good agreement between experimental and model results has been obtained. A heterogeneous numerical model consisting of coupled mass and momentum balance equations was solved using the finite elements method without neglecting the axial dispersion term. The operating range for the catalyst relies on the NO conversion and emission. The optimum operating range for the best performance of the reactor is discussed. 相似文献
603.
Bio-economic evaluation of implementing trawl fishing gear with different selectivity 总被引:1,自引:0,他引:1
Lone Grnbk Kronbak J. Rasmus Nielsen Ole A. Jrgensen Niels Vestergaard 《Journal of environmental management》2009,90(11):3665-3674
The paper develops a biological-economic evaluation tool to analyse the consequences for trawl fishers of implementing more selective fishing technologies. This is done by merging a dynamic biological population model and an economic cost–benefit evaluation framework to describe the consequences for the fish stocks, fishermen and society. The bio-economic evaluation is applied to the case of the Danish trawl fishery in Kattegat and Skagerrak, which experiences a high level of discards and bycatches of several species. Four different kinds of selectivity scenarios are evaluated in comparison with a baseline. The results from the evaluation are indicators for the consequences on ecological and economic levels. The results show that implementation of different selective fishing gear in the Kattegat and Skagerrak mixed trawl fisheries generally implies a trade off over time between rebuilding the stocks and economic loss. Moreover, the analysis shows that implementation of more selective gear is not always beneficial. 相似文献
604.
605.
MF-UF组合工艺处理再生纸废水的实验研究 总被引:2,自引:1,他引:1
针对再生纸废水体系,采用0.2 μm陶瓷微滤膜 (MF)与截留分子量为50 000 Dalton的疏水性PS有机超滤膜 (UF)组合工艺对再生纸废水进行处理。实验结果表明,此组合工艺对再生纸废水COD的去除率可达到846%,处理的废水达到造纸工业水污染物排放标准;根据再生纸废水的性质对膜清洗再生进行了考察,陶瓷膜及超滤膜通量约分别恢复85%与80%左右。 相似文献
606.
目的研究高空风场对飞行器飞行时级间分离的影响。方法建立飞行器分离模型,仿真计算飞行器分离时下面级的横移距离、两个关键部件之间的间隙。结果在最低飞行条件风速34 m/s时,下面级横移距离和两个关键间隙均满足设计条件。在仿真计算风速40 m/s条件下,下面级横移距离、两个关键部件间隙均满足设计要求,因此最低飞行条件风速可放宽至40 m/s。在最大风速45 m/s时,三个值均超出了设计值,有可能会对分离造成影响。结论高空风对飞行器级间分离存在一定影响,随着高空风风速的增加,面级的横移距离和两个关键部件之间键间隙随之增加。 相似文献
607.
608.
采用AlCl3溶液和Na2CO3粉末在不同温度下制备了不同浓度的聚合氯化铝(PACl). 以选定的中等浓度、高Al13含量的PACl为原液,研究了Al13与硫酸盐沉淀反应过程中SO4/Al摩尔比、反应体系起始总铝浓度的影响以及Al13硫酸盐与Ba(NO3)2置换反应过程中的Ba/SO4摩尔比、超声、温度等因素的影响. 实验结果表明,在制备温度为50℃条件下,浓度在0.4~0.6 mol/L范围的PACl含有较高的Al13. 沉淀分离反应的最佳SO4/Al摩尔比为0.6∶1;生成的 Al13硫酸盐沉淀物为正四面体状晶体. 在Al13硫酸盐与Ba(NO3)2溶液置换反应过程中,Ba/SO4的最佳摩尔比为1∶1,反应温度及超声作用对置换反应的影响较小;提高Ba(NO3)2的起始浓度可以得到相应较高浓度的纯化Al13溶液. 所得Al13纯度的统计平均值为92.1%. 相似文献
609.
建立了HD-8阳离子交换树脂微色谱柱分离富集矿石中锆的方法。研究了上柱酸度、淋洗液、洗脱液、干扰离子等对锆的吸附性能的影响。结果表明,上柱最佳酸度0.5~2 mol/L HCl、淋洗液1 mol/L HCl、洗脱液1 mol/L H2SO4,锆的吸附与洗脱效果最好。选用邻氯苯基荧光酮为显色剂,直接在硫酸介质中显色,胶束增溶光度法测定,操作简便,灵敏度高,选择性好。树脂的吸附容量为81.4 mg/g。与常规柱相比,微色谱柱吸附后,洗脱体积减少了16倍,柱效高,分离速度快,试剂用量少,灵敏度高。该方法可以用于实际矿石的分离测定,经标准值验证,测定值与标准值相近,多次平行测定后,方法的相对标准偏差为1.9%~2.7%,说明此法可用于分析实际样品。 相似文献
610.
The effect of obstacle separation distance on the severity of gas explosions has received little methodical study. It was the aim of this work to investigate the influence of obstacle spacing of up to three flat-bar obstacles. The tests were performed using methane-air (10% by vol.), in an elongated vented cylindrical vessel 162 mm internal diameter with an overall length-to-diameter, L/D, of 27.7. The obstacles had either 2 or 4 flat-bars and presenting 20% blockage ratio to the flow path. The different number of flat-bars for the same blockage achieved a change of the obstacle scale which was also part of this investigation. The first two obstacles were kept at the established optimum spacing and only the spacing between the second and third obstacles was varied. The profiles of maximum flame speed and overpressure with separation distance were shown to agree with the cold flow turbulence profile determined in cold flows by other researchers. However, the present results showed that the maximum effect in explosions is experienced at 80 to 100 obstacle scales about 4 times further downstream than the position of maximum turbulence determined in the cold flow studies. Similar trends were observed for the flames speeds. In both cases the optimum spacing between the second and third obstacles corresponded to the same optimum spacing found for the first two obstacles demonstrating that the optimum separation distance does not change with number of obstacles. In planning the layout of new installations, the worst case separation distance needs to be avoided but incorporated when assessing the risk to existing set-ups. The results clearly demonstrate that high congestion in a given layout does not necessarily imply higher explosion severity as traditionally assumed. Less congested but optimally separated obstructions can lead to higher overpressures. 相似文献