全文获取类型
收费全文 | 5072篇 |
免费 | 412篇 |
国内免费 | 1639篇 |
专业分类
安全科学 | 505篇 |
废物处理 | 254篇 |
环保管理 | 431篇 |
综合类 | 2960篇 |
基础理论 | 773篇 |
环境理论 | 2篇 |
污染及防治 | 1448篇 |
评价与监测 | 280篇 |
社会与环境 | 228篇 |
灾害及防治 | 242篇 |
出版年
2024年 | 17篇 |
2023年 | 107篇 |
2022年 | 284篇 |
2021年 | 302篇 |
2020年 | 249篇 |
2019年 | 201篇 |
2018年 | 203篇 |
2017年 | 262篇 |
2016年 | 306篇 |
2015年 | 314篇 |
2014年 | 395篇 |
2013年 | 495篇 |
2012年 | 463篇 |
2011年 | 495篇 |
2010年 | 361篇 |
2009年 | 343篇 |
2008年 | 346篇 |
2007年 | 337篇 |
2006年 | 298篇 |
2005年 | 218篇 |
2004年 | 147篇 |
2003年 | 163篇 |
2002年 | 126篇 |
2001年 | 102篇 |
2000年 | 96篇 |
1999年 | 85篇 |
1998年 | 75篇 |
1997年 | 76篇 |
1996年 | 54篇 |
1995年 | 42篇 |
1994年 | 35篇 |
1993年 | 24篇 |
1992年 | 29篇 |
1991年 | 16篇 |
1990年 | 18篇 |
1989年 | 15篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1958年 | 2篇 |
排序方式: 共有7123条查询结果,搜索用时 15 毫秒
321.
退火炉采取小燃烧室,对工件实行侧下加热、强化绝热措施复合炉衬、二次均热风管、扩张室沉降等五项措施.目的是为了提高炉的热效率和炉温的均匀度.在耗煤量较低的情况下能保持较高的燃烧室强度.有利于强化燃烧和减少蓄散热损失.实行扩张室沉降,在不加任何除尘装置的条件下烟尘排放浓度达到了国家标准新规定的排放要求,而且大大改善了工人的劳动条件. 相似文献
322.
废水中有机物生物降解性数据库系统的研究 总被引:1,自引:0,他引:1
在全面分析废有机物生物降解性数据库系统的需求状态及特点的基础上,采用软件工程的方法,面向用户完成了该数据系统的系统分析和系统设计,为系统的进一步全面实施奠定了基础。 相似文献
323.
324.
325.
326.
327.
本文以标准GB/T 29309-2012为基础,以某款开关电源为例,对HALT试验设备、工作极限与破坏极限、试验步骤及设备运行中注意点等方面展开介绍,为电子产品可靠性测试提供相关探讨。 相似文献
328.
329.
Mobilization and plant accumulation of prometryne in soil by two different sources of organic matter
Prometryne is a selective herbicide of the s-triazine chemical family. Due to its weak absorption onto soil, it readily leaches down through the soil and contaminates underground water. Application of organic manure to soil has become a widespread practice as a disposal strategy to improve soil properties. In this study, we demonstrated the effect of pig manure compost (PMC) and lake-bed sludge (SL) on the sorption/desorption, mobility and bioavailability of prometryne in soil using comprehensive analysis approaches. Downward movement of prometryne was monitored in the packed soil column. Addition of PMC or SL decreased considerably the mobility and total concentration of prometryne in the soil leachate. Bioavailability analyses with wheat plants revealed that addition of the organic matter reduced accumulation of prometryne in tissues and increased plant elongation and biomass. These results indicate that the organic amendments are effective in modifying adsorption and mobility of the pesticide in soil. 相似文献
330.
Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface soils from the Qinghai-Tibetan plateau 总被引:4,自引:0,他引:4
Tao S Wang W Liu W Zuo Q Wang X Wang R Wang B Shen G Yang Y He JS 《Journal of environmental monitoring : JEM》2011,13(1):175-181
Eighty eight surface soil samples were collected from the Qinghai-Tibetan Plateau (QTP) for determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs). The measured concentrations were 51.8 ± 38.5 ng g(-1), 0.329 ± 0.818 ng g(-1), and 0.467 ± 0.741 ng g(-1) as means and standard deviations of PAHs, DDXs, and HCHs, respectively, which were 1-2 orders of magnitude lower than those reported for eastern China. Significant differences were also revealed among four sub-areas within QTP. PAHs detected in the samples from the remote sub-areas of T'ang-ku-la/Hoh Xil Mountains and along the Qinghai-Tibet highway in the west and northwest of QTP were 1 order of magnitude lower than those from Lhasa and east Qinghai. The differences in soil OCPs among the sub-areas were 2-7 times. Soil PAHs were significantly correlated with emission density and soil organic carbon content (SOC), while OCPs were correlated significantly with the population density and SOC. Based on the calculated backward air mass trajectories and geographical distributions of emission and population, it was revealed that PAHs and OCPs accumulated in the soils in the west and northwest QTP were primarily from long-range transport and may represent the background levels of East Asia. This part of QTP can also serve as an important receptor area for regional or even global long-range transport study. The elevated concentrations of PAHs and OCPs in Lhasa and east Qinghai were mainly from local sources, while PAHs from adjacent Lanzhou area also contributed considerably to the accumulation of PAHs in east Qinghai. 相似文献