全文获取类型
收费全文 | 395篇 |
免费 | 34篇 |
国内免费 | 129篇 |
专业分类
安全科学 | 61篇 |
废物处理 | 4篇 |
环保管理 | 47篇 |
综合类 | 213篇 |
基础理论 | 123篇 |
污染及防治 | 32篇 |
评价与监测 | 5篇 |
社会与环境 | 31篇 |
灾害及防治 | 42篇 |
出版年
2024年 | 6篇 |
2023年 | 12篇 |
2022年 | 18篇 |
2021年 | 27篇 |
2020年 | 25篇 |
2019年 | 14篇 |
2018年 | 15篇 |
2017年 | 21篇 |
2016年 | 23篇 |
2015年 | 27篇 |
2014年 | 18篇 |
2013年 | 45篇 |
2012年 | 23篇 |
2011年 | 26篇 |
2010年 | 23篇 |
2009年 | 28篇 |
2008年 | 24篇 |
2007年 | 24篇 |
2006年 | 18篇 |
2005年 | 20篇 |
2004年 | 22篇 |
2003年 | 23篇 |
2002年 | 14篇 |
2001年 | 9篇 |
2000年 | 11篇 |
1999年 | 4篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有558条查询结果,搜索用时 15 毫秒
171.
进入新世纪,作为信息载体的应用写作越来越受到社会重视,然而目前高职院校中的应用写作教学现状却与这种重视不相适应。为此,本文试就目前高职教学中如何改革应用写作教学方法的问题,从“应用写作课与相关课程互动”、“写作理论和写作实践互动”、“应用写作文种之间互动”、“促使教学主体进行互动”四个方面提出了看法,以期对高职应用写作教学改革有所裨益。 相似文献
172.
以焦作市某电厂粉煤版堆放场为研究对象,通过模拟试验,探讨灰场耿水入渗过程中,氟化物及总硬度与基底灰岩发生的水一岩作用。结果表明,在灰水入渗过程中,发生了溶滤及吸附等水一岩作用;灰岩中Ca^2+、Mg^2+的淋溶,可能会造成地下水硬度超标;吸附作用表明,石袄岩对灰水中氟有一定的吸附能力,吸附达到饱和后,灰场灰水中的氟继续下渗,导致氟对地下水污染。研究表明,该粉煤灰堆放场对焦作市饮用水水源构成了潜在威胁。 相似文献
173.
Potential synergistic interactions between polycyclic aromatic hydrocarbons in a household sewage sludge compost extract were investigated using the Dioxin-Responsive Chemical-Activated Luciferase gene eXpression (DR-CALUX) assay and reverse-phase high-performance liquid chromatography (RP-HPLC) fractionation. The biological activity of the crude extract was measured in vitro using the CALUX assay. The CALUX activity of the extract was as potent as 360-pg CALUX-TEQ (2,3,7,8-TCDD equivalent value) per g sample, this was 70 times above the WHO-TEQ value which was derived from chemical analyses of dioxins/furans and dioxin-like PCBs of the mixture. The CALUX activity pattern of the crude extract and the retention times of 26 polycyclic aromatic compounds (PACs), as determined by RP-HPLC on an octadecylsilica column, suggested that the dioxin-like compounds with the log K(OW) (n-octanol/water partition coefficient) values corresponding to 6.0-7.0 contributed highly to the whole activity. The CALUX activity of the crude extract was three times the sum of the CALUX activities of the RP-HPLC separated fractions. Mixture effects were assessed by co-exposure of each HPLC fraction and 2,3,7,8-TCDD to the cells. The four concentration levels of added 2,3,7,8-TCDD corresponded to the TEQ value in the original compost sample. The experimental CALUX activity was higher than the predicted CALUX activity for some fractions. It was demonstrated that some compounds in the compost sample interacted synergistically with 2,3,7,8-TCDD in terms of dioxin-like activity. This finding points out the necessity for detailed investigation of synergistic effects in environmental samples. 相似文献
174.
Efficient environmental protection requires global, as well as regional ecological strategies. During the last decade numerous attempts at regional and global environmental protection have been made. But industrial environmental protection is still, above all, a national matter. National emission limit values and international technological standards still neglect to a large extent the regional aspects of pollution prevention. Recent normative texts (international standards, European directives) can be seen as the first step to filling this gap. They represent different evolutionary stages on the way from merely technocentric to regionally integrated environmental protection. We investigate the potential of some of these normative texts to operationalise regional environmental strategies. For this purpose we will provide a framework for evaluation centred on the following questions: ? Is the installation/project/organisation perceived as part of its specific environment? ? Can local immission standards be developed on the basis of a functional classification of ecosystems? ? Are methods of integrated ecological evaluation supported? The framework will be applied to examine the European directives on Environmental Impact Assessment and Integrated Pollution Prevention and Control and two ISO (International Standardisation Organisation) standards on Environmental Management Systems (ISO 14001 and 14004) with regard to basic requirements for operationalising integrated regional environmental protection. 相似文献
175.
三维原子场全息作用矢量用于芳香类化合物的三维QSAR研究 总被引:1,自引:1,他引:0
采用新型的的三维原子场全息作用矢量(3D-HoVAIF)研究了200种芳香化合物的化学结构与其生物毒性的定量构效关系(QSAR).首先对芳香化合物进行了结构参数化表达,然后采用逐步回归(SMR)对变量进行筛选,建立了三维定量构效关系模型.其87个无氢键分子的模型和113个有氢键分子的模型的复相关系数和标准偏差分别为R2=0.801,SD=0.473和R2=0.929,SD=0.318.模型具有良好的稳定性和预测能力,证明了该三维原子场全息作用矢量在分子结构表征和生物毒性预测上的适用性. 相似文献
176.
Sze Yin Kwok David Harrison Alessio Malizia 《International Journal of Sustainable Engineering》2017,10(6):302-312
Eco-labelling is the practice of eco information provision that most directly addresses consumer behaviour. Nowadays, consumers are facing difficulties in perceiving and understanding existing eco labels. In previous work, we proposed the conceptual framework of eco information individualisation which tailors eco labels according to the specific needs of individual users using contextual technologies. This paper extends the conceptual framework by introducing a more structured way of considering the personal data and product data requirements, and reports the development of a design toolkit that aims to support designers in the designing of individualised eco information. A design workshop was carried out to introduce the concept to designers, and evaluate the usability and usefulness of the toolkit. Positive responses were received. The design outputs generated from the workshop were considered largely feasible and have the potential to be developed into digital prototypes. These indicate that it is possible for designers to learn to design eco information individualisation in a short time. This paper is a step towards a greater understanding of designing individualised eco information. 相似文献
177.
选用海伦黑土、咸宁棕红壤和长武黑垆土这3种土壤,分别设置4组不同含量配比的Pb和Cd复合处理,进行为期5个月的小麦种植(郑麦9023号)盆栽试验,结合小麦植株各部位Pb和Cd含量,分析3种土壤-小麦体系中Pb和Cd交互作用对小麦富集转运重金属的影响.结果表明,低pH棕红壤水溶态Cd和Pb含量最高,且土壤颗粒表面Pb和Cd交互作用显著,高有机质黑土及高碳酸钙含量的黑垆土中Cd和Pb活性较低.3种土壤中黑垆土种植小麦的株高和干重表现最差,但Pb和Cd复合作用使其株高较对照增加了2.68~8.49 cm, Pb和Cd交互作用对黑土中小麦的株高和干重影响最小,但抑制了棕红壤中小麦生长.3种土壤-小麦体系的Pb和Cd交互作用差异较大,棕红壤中Pb和Cd间存在协同作用,125 mg·kg-1和250 mg·kg-1Pb处理下棕红壤种植的小麦籽粒Pb含量随Cd添加量升高分别显著增加73.2%和19.1%;黑土中Pb和Cd间存在拮抗作用,0.3 mg·kg-1和0.6 mg·kg-1 Cd处理下黑土中小麦籽粒Cd含... 相似文献
178.
基于遥感反演数据,研究了2016年长三角地区PM2.5浓度空间分布特征,从气象因素、地形、植被和大气污染物排放清单等方面选取评价因子,以0.25°×0.25°网格为评价单元,利用GAM模型研究了长三角PM2.5空间分布的影响因素及交互效应.结果表明:①长三角PM2.5浓度总体呈北高南低、西高东低的分布态势,但以南北向差异为主.长三角南部PM2.5浓度多低于35 μg·m-3,PM2.5超标零星出现在城镇周围,呈孤岛状分布.北部PM2.5浓度多超过35μg·m-3,PM2.5污染多呈连片状分布.②长三角PM2.5浓度分布具有显著的正的空间自相关性,高高集聚区集中分布在长三角北部,低低集聚区集中分布在南部.③ GAM模型分析表明,地形起伏度、气温和降水量对PM2.5浓度主要呈负向影响;污染物排放量主要呈正向影响;风速<2.5 m·s-1时影响不显著,风速≥2.5 m·s-1后有显著的负向影响.地形起伏度、气温和降水量南高北低是造成长三角PM2.5北高南低的重要原因,风速东高西低是造成长三角PM2.5浓度东西向差异的原因之一.④除地形起伏度-PM2.5排放量外,其余因素两两间的交互项均通过了显著性检验,对PM2.5分布有显著的交互效应. 相似文献
179.
Co基催化剂在低碳烷烃直接脱氢及氧化脱氢制烯烃方面表现出良好的应用潜力.为了探究Co物种的价态对CO2氧化乙烷脱氢制乙烯的影响,以共沉淀法制备的TiZrO4固溶体为载体,采用浸渍法制备了一系列X%Co/TiZrO4(X=0.5、1、3、5和7.5)催化剂.结果表明,0.5%Co/TiZrO4和1%Co/TiZrO4催化剂的催化活性较差,但保持了相当高的C2H4选择性(>90%)和碳平衡(≈100%);3%Co/TiZrO4催化剂在反应过程中表现出良好的C2H6和CO2活化能力,在650℃、质量空速WHSV=9000 mL?g-1?h-1的反应条件下获得了约25%的乙烯收率;而5%Co/TiZrO4和7.5%Co/TiZrO4催化剂则在600℃及以上温度反应... 相似文献
180.
水中的溴离子(Br-)和溴酸根离子(BrO3-)由于难挥发、易溶解、稳定性好而难以除去,因此,制备了一种对较低浓度的Br-和BrO3-都有良好吸附去除效果的季铵碱树脂(Quaternary ammonium base resin,QABR)并表征了其物化结构.同时,考察了初始浓度、QABR投加量、溶液pH、离子强度、吸附接触时间和吸附温度等因素对QABR吸附Br-和BrO3-性能的影响.结果表明,在0.05~4.00 mmol·L-1浓度范围内,在298 K、pH=7.0时QABR对Br-和BrO3-的吸附能力最佳,其最大吸附量分别为1.78 mmol·g-1和1.65 mmol·g-1;QABR对Br-和BrO3 相似文献