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951.
Little EE Calfee RD Theodorakos P Brown ZA Johnson CA 《Environmental science and pollution research international》2007,14(5):333-337
Background Cobalt cyanide complexes often result when ore is treated with cyanide solutions to extract gold and other metals. These have
recently been discovered in low but significant concentrations in effluents from gold leach operations. This study was conducted
to determine the potential toxicity of cobalt-cyanide complexes to freshwater organisms and the extent to which ultraviolet
radiation (UV) potentiates this toxicity. Tests were also conducted to determine if humic acids or if adaptation to UV influenced
sensitivity to the cyanide complexes.
Methods Rainbow trout (Oncorhynchus mykiss), Daphnia magna, and Ceriodaphnia dubia were exposed to potassium hexacyanocobaltate in the presence and absence of UV radiation, in the presence and absence of
humic acids. Cyano-cobalt exposures were also conducted with C. dubia from cultures adapted to elevated UV.
Results With an LC50 concentration of 0.38 mg/L, cyanocobalt was over a 1000 times more toxic to rainbow trout in the presence of
UV at a low, environmentally relevant irradiance level (4 μW/cm2 as UVB) than exposure to this compound in the absence of UV with an LC50 of 112.9 mg/L. Toxicity was immediately apparent,
with mortality occurring within an hour of the onset of exposure at the highest concentration. Fish were unaffected by exposure
to UV alone. Weak-acid dissociable cyanide concentrations were observed in irradiated aqueous solutions of cyanocobaltate
within hours of UV exposure and persisted in the presence of UV for at least 96 hours, whereas negligible concentrations were
observed in the absence of UV. The presence of humic acids significantly diminished cyanocobalt toxicity to D. magna and reduced mortality from UV exposure. Humic acids did not significantly influence survival among C. dubia. C. dubia from UV-adapted populations were less sensitive to metallocyanide compounds than organisms from unadapted populations.
Conclusions The results indicate that metallocyanide complexes may pose a hazard to aquatic life through photochemically induced processes.
Factors that decrease UV exposure such as dissolved organic carbon or increased pigmentation would diminish toxicity. 相似文献
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953.
核废物的安全和环境影响 总被引:8,自引:0,他引:8
本论述了核废物特性,核废物安全管理原则,核废物的安全处理、处置技术、废放射源的安全管理、乏燃料的安全管理和核废物的环境影响等6方面问题。特别强调了废物管理9条原则,核废物最少化,豁免和清洁解控,核废物处理、处置技术的发展动向,我国核废物管理40字方针,国际社会关注的废放射源和乏燃料安全处理和处置等,并以我国大亚湾和秦山核电站为例,说明核废物可以被安全地控制和管理,保证环境的安全。 相似文献
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955.
为研究宁波市大气污染状况及其影响因素,利用2013—2018年宁波市国控站点实时监测污染物数据以及气象数据,探讨分析了宁波市大气污染特征以及所受气象因素的影响概况。结果表明:宁波市颗粒物污染和O3污染呈现典型的季节性特征,颗粒物浓度冬季最高,O3最大滑动8 h平均质量浓度春、秋季最高。宁波市O3污染问题越来越突出,且呈现出春、秋季O3超标天数最多的季节变化特征。O3小时质量浓度与气温和太阳辐射成正相关关系,NO2和颗粒物浓度与气温成负相关关系。NO2与O3浓度成负相关关系,与颗粒物浓度成正相关关系。 相似文献
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958.
液化气体容器在火灾环境下由于内部压力升高和容器本身强度的下降,爆炸的危险性极大。研究容器在喷射火焰作用的响应规律是预防事故发生的关键。本文研究了由于气体泄漏引起的喷射火焰在有风条件下的火焰形状和温度变化规律,以及对于水平圆柱形容器的热辐射影响,并用编制计算程序进行了数值计算。计算结果表明,容器表面的热辐射随风速、容器表面的位置等因素而变化。风速越大,容器表面的热辐射会减少;轴向距离越大,热辐射减少,周向角度增加,热辐射减少。 相似文献
959.
Mingjin Wang Nan Zheng Tong Zhu Jing Shang Ting Yu Xiaojuan Song Defeng Zhao Yong Guan Yangchao Tian 《环境科学学报(英文版)》2018,30(7):23-32
Heterogeneous reactions on the aerosol particle surface in the atmosphere play important roles in air pollution, climate change, and global biogeochemical cycles. However, the reported uptake coefficients of heterogeneous reactions usually have large variations and may not be relevant to real atmospheric conditions. One of the major reasons for this is the use of bulk samples in laboratory experiments, while particles in the atmosphere are suspended individually. A number of technologies have been developed recently to study heterogeneous reactions on the surfaces of individual particles. Precise measurements on the reactive surface area, volume, and morphology of individual particles are necessary for calculating the uptake coefficient, quantifying reactants and products, and understanding the reaction mechanism better. In this study, for the first time we used synchrotron radiation X-ray computed tomography(XCT) and micro-Raman spectrometry to measure individual CaCO_3 particle morphology, with sizes ranging from 3.5–6.5 μm. Particle surface area and volume were calculated using a reconstruction method based on software threedimensional(3-D) rendering. The XCT was first validated with high-resolution fieldemission scanning electron microscopy(FE-SEM) to acquire accurate CaCO_3 particle surface area and volume estimates. Our results showed an average difference of only 6.1% in surface area and 3.2% in volume measured either by micro-Raman spectrometry or X-ray tomography. X-ray tomography and FE-SEM can provide more morphological details of individual Ca CO3 particles than micro-Raman spectrometry. This study demonstrated that X-ray computed tomography and micro-Raman spectrometry can precisely measure the surface area, volume, and morphology of an individual particle. 相似文献
960.
大气扩散模型和容量测算工具有多种选择.一个关键的问题是对各种模型进行比较和检验,选择一种适合当地实际的模型或工具,进行参数选择和调整,得到相对比较准确、合理的大气环境容量测算结果.计算SO2环境容量是区域环境影响评价的重要组成部分.本研究对区域大气SO2环境容量测算进行了两种设计,针对这两种容量设计,选择了两种测算模式,比例模式和线性规划模式.分别计算出现状排放源布局及排放状况不变的条件下的SO2现状环境容量;以及对现状排放源进行合理分配的规划环境容量. 相似文献