全文获取类型
收费全文 | 14344篇 |
免费 | 666篇 |
国内免费 | 5057篇 |
专业分类
安全科学 | 1026篇 |
废物处理 | 917篇 |
环保管理 | 1080篇 |
综合类 | 8129篇 |
基础理论 | 2278篇 |
环境理论 | 6篇 |
污染及防治 | 4848篇 |
评价与监测 | 553篇 |
社会与环境 | 584篇 |
灾害及防治 | 646篇 |
出版年
2024年 | 9篇 |
2023年 | 231篇 |
2022年 | 690篇 |
2021年 | 596篇 |
2020年 | 456篇 |
2019年 | 434篇 |
2018年 | 571篇 |
2017年 | 659篇 |
2016年 | 613篇 |
2015年 | 810篇 |
2014年 | 1111篇 |
2013年 | 1470篇 |
2012年 | 1181篇 |
2011年 | 1373篇 |
2010年 | 1009篇 |
2009年 | 984篇 |
2008年 | 1024篇 |
2007年 | 791篇 |
2006年 | 802篇 |
2005年 | 576篇 |
2004年 | 408篇 |
2003年 | 490篇 |
2002年 | 439篇 |
2001年 | 361篇 |
2000年 | 396篇 |
1999年 | 436篇 |
1998年 | 362篇 |
1997年 | 333篇 |
1996年 | 314篇 |
1995年 | 286篇 |
1994年 | 189篇 |
1993年 | 167篇 |
1992年 | 125篇 |
1991年 | 102篇 |
1990年 | 69篇 |
1989年 | 59篇 |
1988年 | 47篇 |
1987年 | 21篇 |
1986年 | 25篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 11篇 |
1981年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
871.
In this paper, we addressed the utilization of photochemical method as an innovative technology for the destruction and removal of two potent greenhouse gases, SF(6) and SF(5)CF(3). The destruction and removal efficiency (DRE) of the process was determined as a function of excitation wavelength, irradiation time, initial ratio of acetone to SF(5)X (X represented F or CF(3)), initial SF(5)X concentration, additive oxygen and water vapor concentration. A complete removal was achieved by a radiation period of 55min and 120min for SF(6)-CH(3)COCH(3) system and SF(5)CF(3)-CH(3)COCH(3) system respectively under 184.9nm irradiation. Extra addition of water vapor can enhance DRE by approximately 6% points in both systems. Further studies with GC/MS and FT-IR proved that no hazardous products such as S(2)F(10), SO(2)F(2), SOF(2), SOF(4) were generated in this process. 相似文献
872.
Deng DM Shu WS Zhang J Zou HL Lin Z Ye ZH Wong MH 《Environmental pollution (Barking, Essex : 1987)》2007,147(2):381-386
To investigate the variation of Zn and Cd accumulation and tolerance of Sedum alfredii (a newly reported Zn/Cd hyperaccumulator), field surveys and hydroponic experiments were conducted among three populations of this species: two originating from old Pb/Zn mines in Zhejiang (ZJ) and Hunan (HN) Provinces and one from a "clean" site in Guangdong (GD) Province, China. Under field conditions, up to 12,524 and 12,253 mg kg(-1) Zn, and 1400 and 97 mg kg(-1) Cd in shoots of ZJ and HN plants were recorded respectively. Under hydroponic conditions, ZJ and HN plants accumulated significantly higher Zn and Cd in their leaves and stems, and possessed significantly higher Zn and Cd tolerance than GD plants. Among the two contaminated populations, ZJ plants showed higher Cd tolerance and accumulation (in leaves) than HN plants. The present results indicate that significant differences in Zn and Cd accumulation and tolerance exist in populations of S. alfredii. 相似文献
873.
874.
875.
876.
Assessing the Geographic Representativeness of Genebank Collections: the Case of Bolivian Wild Potatoes 总被引:5,自引:0,他引:5
R. J. Hijmans K. A. Garrett Z. Huamán D. P. Zhang M. Schreuder M. Bonierbale 《Conservation biology》2000,14(6):1755-1765
Abstract: Genebank collection databases can be used for ecogeographical studies under the assumption that the accessions are a geographically unbiased sample. We evaluated the representativeness of a collection of wild potatoes from Bolivia and defined and assessed four types of bias: species, species-area, hotspot, and infrastructure. Species bias is the sampling of some species more often than others. Species-area bias is a sampling that is disproportionate to the total area in which a species is found. Hotspot bias is the disproportionate sampling of areas with high levels of diversity. Infrastructure bias is the disproportionate sampling of areas near roads and towns. Each of these biases is present in the Bolivian wild potato collection. The infrastructure bias was strong: 60% of all wild potato accessions were collected within 2 km of a road, as opposed to 22%, if collections had been made randomly. This analysis can serve as a guide for future collecting trips. It can also provide baseline information for the application of genebank data in studies based on geographic information systems. 相似文献
877.
王东莲 《城市环境与城市生态》2000,13(2):48-50
文章对我国污染预防现状进行了评估,并对如何进一步实施污染预提出初步建议,形成污染预防框架行动计划,试图人们从行为和观念转向污染预防提供方向。框架行计划着重从政策和法律,组织和人力资源,研究和开发,污染预防活动和实践到评估、推广等方面进行了建议。 相似文献
878.
中国煤电和核电的环境影响与健康风险比较 总被引:1,自引:0,他引:1
将煤电与核电的环境影响和健康风险从全燃料链角度进行比较 ,结果表明 ,煤电燃料链的环境影响和健康风险比核电燃料链大。 相似文献
879.
提出了以GM(1,1)模型拟合发展的趋势、傅里叶变换撮周期分量AR(p)模型模拟随机过程的集成预报模型,并用于黄河三角洲人工草场群落土壤盐分的定量研究中,经理论和应用检验证明:该模型能以较高的精度模拟或预报土壤盐分在较长时期内的动态变化过程,方法简单,计算工作量小,并优于传统的单一预报模型。 相似文献
880.
张民侠 《生态与农村环境学报》2000,16(4):15-19
根据秦岭保护区群的生物多样性和保护管理现状 ,提出了加强保护区群生物多样性保护和促进保护区发展的对策 ,其主要措施为 :一、合理划分和调整功能区 ;二、强化内部管理 ,加强对自然资源的巡护、监测 ;三、协调周边社区关系 ,积极开展社区共管工作 ;四、加强对外合作 ,积极开展科学研究 ;五、开展环境教育 ,提高全民保护意识 ;六、开展资源适度开发利用 ,增强自养能力。 相似文献