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921.
文章介绍了大气环境污染源治理产业化的实施方法,这种方法介绍了大气环境污染源治理产业化管理,探讨了大气环境污染源治理项的投资,主要包括资金筹措方案,项目计划进度包括项目的总体目标、计划安排与阶段目标、企业的参与程度、产学研联合机制和其他必要的支撑和配套条件落实情况,只有在大气环境污染源治理产业化的过程中,各方面积极努力,各负其责,就一定能够做好大气环境污染源治理产业化的工作,保卫我们国家的大气环境.  相似文献   
922.
采集韶关市PM10和PM2.5样品,采用气相色谱-质谱法测定了16种PAHs的质量浓度,分析了16种PAHs在PM2.5中的时空分布特征,研究16种PAHs在PM10和PM2.5中分布的差异.结果显示:PAHs在PM2.5中的季节性分布具有冬、夏季高,春、秋季低的特点,且苯并[a]蒽、苯并[k]荧蒽、苯并[c]芘、苯并[a]芘、荧蒽等在一年四季含量均较高;在空间上的分布显示交通区>工业区>商业区>居民区>休闲区.PAHs在PM2.5中的分布明显高于在PM10中的分布,在人为活动较为频繁的季节和区域,PAHs的含量明显增加.  相似文献   
923.
An experimental study for fluid hydrodynamic characteristics in thin water films falling down the outside of a vertical tube was performed with the analysis of several factors about the uniformity and stability of the film. Liquid evaporation is of major interest for many fields in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of super heated steam is mandatory for numerous processes. Generally, this is performed by the use of classical pool boiling and evaporation process equipment, providing relatively limited performance. The performance of the film distributor will affect the production capacity and service life of the evaporator. In this publication a novel falling-film distributor which is used annular gap and inlet tube rotated tangentially 270° to guarantee the film uniformity is presented. Experimental data suggested that there is optimum annular gap distance is between 1.5 and 2.0 mm and the spray density should be controlled between 250 and 700 kg m−1 h−1. Several suggestions for evaporator design are proposed.  相似文献   
924.
针对炼化企业循环排污水中有机污染物浓度不能满足脱盐处理工艺进水水质要求的问题,开展了臭氧氧化-活性炭吸附工艺去除循环排污水中有机污染物的研究。通过对两种处理工艺进行不同组合的实验结果得知:当反应时间控制在最佳值,臭氧氧化和活性炭吸附单独处理循环排污水时,COD去除率分别约为27%和20%,处理效率偏低;当两种工艺组合后,在臭氧浓度为12 mg/L、氧化时间20 min、吸附时间为10 min时,COD去除率则达到52%,组合工艺协同作用效果明显。  相似文献   
925.
在深入分析网络管理现状的基础上,从高校管理、服务的实际情况出发,通过广泛的调研、分析,全面阐述了在高校加强网络建设、网络管理和构建网络安全的必要性和重要性。  相似文献   
926.
Sewage sludge (SS) applied to sloping fields at rates that exceed annual forest nutrient requirements can be a source of phosphorus (P) in runoff. This study investigates the effects of different slopes (18, 27, 36, and 45%) on P in runoff from plots amended with SS (120 Mg ha). Lateritic soil (pH 5.2) was exposed to five simulated rainfalls (90 mm h) on outdoor plots. When sludge was broadcast and mixed with surface soils, the concentrations and loss in runoff of total P in the mixed sample (MTP), total P in the settled sample (STP), total particulate P (TPP), total suspended P (TSP), and total dissolved P (TDP) were highest at 1 or 18 d after application. Initially, pollution risks to surface waters generally increased to different degrees with steeper slopes, and then diminished gradually with dwindling differences between the slopes. The runoff losses coefficient of MTP increased in the order 36 > 45 > 27 > 18%. The initial event (1 and 18 d) accounted for 67.0 to 83.6% of total runoff P losses. Particulate fraction were dominant carriers for P losses, while with the lower slopes there was higher content of P per unit particulate fraction in runoff. Phosphorus losses were greatly affected by the interaction of sludge-soil-runoff and the modification of soil properties induced by sludge amendment. It is recommended to choose lower slopes (<27%) to reduce risk of P losses. Thus, the risk of application sludge to sloping fields in acid soils should be studied further in the field under a wider diversity of conditions.  相似文献   
927.
The concentrations of six sulfonamides (SAs) and three tetracyclines (TCs) were investigated in Jiulongjiang River during the low water season and the high water season. They were monitored in both surface water and sediment. Total concentrations of all these antibiotics varied from 31 to 25,771 ng g(-1) in sediment samples. In water they ranged from 60 to 2607 ng L(-1) during the low water season and from ND (not detected) to 134 ng L(-1) during the high water season. At the sites nearby breeding farms, chlorotetracycline was found to have the highest concentration of 1036 ng L(-1) in water and 14,666 ng g(-1) in sediments. According to the published data, the concentrations of sulfamethazine, sulfameter and TCs at these sites were higher than that in most rivers. The concentrations during the low water season were tens to hundreds of times higher than that in the high water season. The lower concentrations of TCs in the high water season might result from both dilution and photo-degradation, while dilution and bio-degradation might lead to the lower concentrations of SAs. However, further study is needed to clarify the specific reasons. Concerning the relationship between sediment and water samples, the pseudo-partitioning values of TCs were much higher than SAs. It indicates that the TCs are prone to accumulate in the sediment.  相似文献   
928.
陈建峰  汪嘉嘉  徐超 《灾害学》2011,26(3):52-55
加筋土挡墙表现出很好的抗震性能,对于加筋土挡墙的动力特性研究有利于更好地弄清楚其工作机理,为加筋土挡墙在动荷区特别是地震区的更广泛应用奠定基础。根据大量文献资料,从试验研究、数值模拟和传统的拟静力方法等三个方面阐述了目前加筋土挡墙动力特性的研究进展,并对今后的研究作了展望。  相似文献   
929.
Titanium nanomaterials are likely to sink into sediments in substantial quantities due to their wide use in a number of applications for decades. To assess the potential environmental consequences, a better understanding is required of the occurrence and sources of titanium (Ti) nanomaterials in sediments. In this research, we provide the first report of the Ti concentrations and the morphology and composition of Ti-based solids in surface sediments from Xiamen Bay, China. Results indicated that the anthropogenic Ti concentrations in the surface sediments from Xiamen Bay reached approximately 2.74 g kg(-1). Ti nanomaterials could be found in sediments with elevated Ti concentrations, which were often aggregated to a few hundred nanometers (<300 nm) and were composed of several spherical particles, less than 50 nm in size, that were made solely of TiO(x). However, Ti particles (approx. 300-700 nm) could be also found in sediments with lower Ti concentrations, which were presumably components of the natural clay mineral kaolinite. Ti nanomaterials could be easily distributed in sediments associated with elevated levels of organic matter and preferentially attach to those sediments with elevated fine fractions. As a sentinel, or tracer, for other nanomaterials, the field-scale investigation of Ti nanomaterials would contribute to increasing our knowledge on the behavior of engineered nanomaterials in an aquatic environment.  相似文献   
930.
Diphenylarsinic acid(DPAA) is formed during the leakage of aromatic arsenic chemical weapons in soils,is persistent in nature,and results in arsenic contamination in the field.The adsorption and desorption characteristics of DPAA were investigated in two typical Chinese soils,an Acrisol(a variable-charge soil) and a Phaeozem(a constant-charge soil).Their thermodynamics and some of the factors influencing them(i.e.,initial pH value,ionic strength and phosphate) were also evaluated using the batch method in order to understand the environmental fate of DPAA in soils.The results indicate that Acrisol had a stronger adsorption capacity for DPAA than Phaeozem.Soil DPAA adsorption was a spontaneous and endothermic process and the amount of DPAA adsorbed was affected significantly by variation in soil pH and phosphate.In contrast,soil organic matter and ionic strength had no significant effect on adsorption.This suggests that DPAA adsorption may be due to specific adsorption on soil mineral surfaces.Therefore,monitoring the fate of DPAA in soils is recommended in areas contaminated by leakage from chemical weapons.  相似文献   
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