全文获取类型
收费全文 | 2602篇 |
免费 | 181篇 |
国内免费 | 756篇 |
专业分类
安全科学 | 220篇 |
废物处理 | 128篇 |
环保管理 | 240篇 |
综合类 | 1468篇 |
基础理论 | 373篇 |
污染及防治 | 717篇 |
评价与监测 | 145篇 |
社会与环境 | 145篇 |
灾害及防治 | 103篇 |
出版年
2024年 | 9篇 |
2023年 | 57篇 |
2022年 | 149篇 |
2021年 | 140篇 |
2020年 | 113篇 |
2019年 | 110篇 |
2018年 | 134篇 |
2017年 | 145篇 |
2016年 | 141篇 |
2015年 | 169篇 |
2014年 | 211篇 |
2013年 | 265篇 |
2012年 | 215篇 |
2011年 | 222篇 |
2010年 | 174篇 |
2009年 | 175篇 |
2008年 | 143篇 |
2007年 | 148篇 |
2006年 | 118篇 |
2005年 | 98篇 |
2004年 | 70篇 |
2003年 | 82篇 |
2002年 | 74篇 |
2001年 | 76篇 |
2000年 | 56篇 |
1999年 | 43篇 |
1998年 | 25篇 |
1997年 | 32篇 |
1996年 | 23篇 |
1995年 | 20篇 |
1994年 | 15篇 |
1993年 | 17篇 |
1992年 | 20篇 |
1991年 | 15篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有3539条查询结果,搜索用时 0 毫秒
151.
152.
为了解决煤矿掘进面风筒出风口参数不能动态变化,而传统风幕全断面控尘效果不理想引起的粉尘浓度高等问题,通过分析风幕和出风口参数对粉尘分布规律的影响,以此得到合理的出风口风流与风幕综合调控方案,降低粉尘浓度。以陕西神木柠条塔煤矿N1212巷道为研究对象,利用Fluent软件建立出风口风流与风幕综合调控的粉尘场有限元模型,设计出风口风流及风幕综合调控响应曲面实验,得到最佳综合调控方案为:风幕射流出口宽度为0.16 m,风幕射流出口速度为6 m/s,出风口口径为0.9 m,出风口右偏角度为3°。搭建相似模拟实验平台来验证最佳综合调控方案,研究结果表明:调控后回风侧行人呼吸处和司机位置处粉尘平均浓度分别降低89%和81%,有效改善掘进面作业环境。 相似文献
153.
Hui Zhou Aihong Meng Yanqiu Long Qinghai Li 《Journal of the Air & Waste Management Association (1995)》2014,64(5):597-616
Municipal solid waste (MSW) has been normally sorted into six categories, namely, food residue, wood waste, paper, textiles, plastics, and rubber. In each category, materials could be classified further into subgroups. Based on proximate and ultimate analysis and heating value, statistical methods such as analysis of variance (ANOVA) and cluster analysis were applied to analyze the characteristics of MSW in every subgroup and to try to distinguish their relative properties. The chemical characteristics analysis of MSW showed that polyethylene (PE), polypropylene (PP), and polystyrene (PS) had the highest volatile matter content, with almost no ash and fixed carbon, while polyethylene terephthalate (PET) had high carbon content but low hydrogen content. Bones and vegetables had the highest ash content, while nutshells and rubber had the highest fixed carbon content. Paper and starch food had the highest oxygen content, and wool and bones had the highest nitrogen and sulfur content. Polyvinyl chloride (PVC) had the highest chlorine content at about 55%. PE, PP, and PS had the highest heating value, followed by chemical products such as rubber and chemical fiber. Conversely, paper, vegetables and bones had the lowest heating value. The results of cluster analysis of MSW components showed that fruit peel, weeds, wood, bamboo, leaves and nutshells could be classified as the lignocellulose category; starch food, cotton, toilet paper, printing paper and cardboard could be classified as the glucose monomer category; wood and chemical fiber could be classified as the high nitrogen and sulfur category; and PE, PP, and PS could be cluster as the polyolefin category.
Implications: The yield of municipal solid waste (MSW) is constantly increasing and waste to energy (WTE) has been used extensively all over the world. During the processes of incineration, pyrolysis, or gasification, the impact of physical and chemical properties of MSW is of great significance. However, the traditional classification of MSW is too general to provide more detailed information in many investigations. It is necessary to perform the investigation of characteristics of combustible MSW to distinguish different categories of MSW and find out their subclassification. 相似文献
154.
磷酸微波活化多孔生物质炭对亚甲基蓝的吸附特性 总被引:1,自引:0,他引:1
以甘蔗渣为原料,采用微波辅助H3PO4活化法制备富含含氧酸官能团的中孔生物质炭。通过扫描电子显微镜SEM、傅立叶变换红外光谱FT-IR等技术对生物质炭物理化学性质进行表征,并通过静态实验法,探讨炭样对亚甲基蓝的吸附行为及热力学性质。结果表明,H3PO4活化制备蔗渣生物质炭的适宜条件为浸渍比1:1,烘干时间10h,活化功率900W,活化时间22min,在此条件下制得的生物质炭得率为39.2%,碘值为817mg/g,亚甲基蓝值为229mg/g,为国家一级品标准的1.7倍。红外光谱分析表明,炭样表面以羟基、羰基、羧基等酸性官能团为主。静态吸附实验表明,Freundlich方程与Redlich—Peterson方程能较好地描述等温吸附行为,表现为优惠吸附。热力学研究表明,吸附吉布斯自由能(△G0)〈0,说明吸附反应是自发过程,而吸附标准焓变(△H0)〉70KJ/mol,表明亚甲基蓝在制备炭样上的吸附是吸热反应,升温有利于吸附,且化学反应在吸附过程中发挥了重要作用。 相似文献
155.
西安是空气污染监控和防治有代表性的西部大型城市。研究了西安市及周边地区上空气溶胶光学厚度与PM10浓度的关系模型。利用2011—2012年MODIS卫星气溶胶光学厚度(AOD)遥感产品,通过数据匹配,利用地面气象观测站点的能见度数据和相对湿度数据对AOD产品进行垂直标高订正和湿度订正,2项订正显著提高了AOD和地面PM10浓度的相关性,相关系数从0.36提高到0.65,按季节分类统计和订正春至冬四季的相关系数分别为0.57、0.71、0.62和0.87,夏季和冬季的订正更为有效,可用性更高,这可能由于受到不同季节气溶胶来源和特征的影响。为研究中国西部大型城市,特别是西安市空气环境监测和区域联防联控提供了一种有效方法。 相似文献
156.
Robinson MS Zhao M Zack L Brindley C Portz L Quarterman M Long X Herckes P 《Atmospheric environment (Oxford, England : 1994)》2011,45(12):2087-2094
Prescribed burning, in combination with mechanical thinning, is a successful method for reducing heavy fuel loads from forest floors and thereby lowering the risk of catastrophic wildfire. However, an undesirable consequence of managed fire is the production of fine particulate matter or PM(2.5) (particles ≤2.5 μm in aerodynamic diameter). Wood-smoke particulate data from 21 prescribed burns are described, including results from broadcast and slash-pile burns. All PM(2.5) samples were collected in situ on day 1 (ignition) or day 2. Samples were analyzed for mass, polycyclic aromatic hydrocarbons (PAHs), inorganic elements, organic carbon (OC), and elemental carbon (EC). Results were characteristic of low intensity, smoldering fires. PM(2.5) concentrations varied from 523 to 8357 μg m(-3) and were higher on day 1. PAH weight percents (19 PAHs) were higher in slash-pile burns (0.21 ± 0.08% OC) than broadcast burns (0.07 ± 0.03% OC). The major elements were K, Cl, S, and Si. OC and EC values averaged 66 ± 7 and 2.8 ± 1.4% PM(2.5), respectively, for all burns studied, in good agreement with literature values for smoldering fires. 相似文献
157.
Chan WH Mak YL Wu JJ Jin L Sit WH Lam JC Sadovy de Mitcheson Y Chan LL Lam PK Murphy MB 《Chemosphere》2011,84(1):117-123
Ciguatera is food poisoning caused by human consumption of reef fish contaminated with ciguatoxins (CTXs). The expanding international trade of tropical fish species from ciguatera-endemic regions has resulted in increased global incidence of ciguatera, and more than 50 000 people are estimated to suffer from ciguatera each year worldwide. The Republic of Kiribati is located in the Pacific Ocean; two of its islands, Marakei and Tarawa, have been suggested as high-risk areas for ciguatera. The toxicities of coral reef fish collected from these islands, including herbivorous, omnivorous and carnivorous fish (24% [n = 41], 8% [n = 13] and 68% [n = 117], respectively), were analyzed using the mouse neuroblastoma assay (MNA) after CTX extraction. The MNA results indicated that 156 fish specimens, or 91% of the fish samples, were ciguatoxic (CTX levels >0.01 ng g−1). Groupers and moray eels were generally more toxic by an order of magnitude than other fish species. All of the collected individuals of eight species (n = 3-19) were toxic. Toxicity varied within species and among locations by up to 10 000-fold. Cephalapholis argus and Gymnothorax spp. collected from Tarawa Island were significantly less toxic than those from Marakei Island, although all individuals were toxic based on the 0.01 ng g−1 threshold. CTX concentrations in the livers of individuals of two moray eel species (Gymnothorax spp., n = 6) were nine times greater than those in muscle, and toxicity in liver and muscle showed a strong positive correlation with body weight. The present study provides quantitative information on the ciguatoxicity and distribution of toxicity in fish for use in fisheries management and public health. 相似文献
158.
胶带输送机运输事故树可靠性的计算机模拟 总被引:1,自引:2,他引:1
以胶带输送机运输事故树的计算机模拟过程为例 ,介绍了对事故树可靠性进行计算机模拟的原理、算法以及程序运行步骤 ,编制了模拟程序。用笔者提出的理论、方法及模拟程序 ,对平顶山煤业集团一矿胶带输送机运输事故进行了事故树分析与求解 ,同时将模拟程序运行结果与最小割集法求得的理论值进行了对比 ,计算结果误差小 ,所得结论准确可靠 ,为类似事故的模拟分析提供了一种新的方法和途径 相似文献
159.
介绍了金山店铁矿通风系统多级站和机站设计;阐述了该项目的施工,检测及通风效果评估情况;对安全生产提出了全面,系统的建议。 相似文献
160.