全文获取类型
收费全文 | 3222篇 |
免费 | 91篇 |
国内免费 | 1111篇 |
专业分类
安全科学 | 171篇 |
废物处理 | 209篇 |
环保管理 | 254篇 |
综合类 | 1714篇 |
基础理论 | 538篇 |
污染及防治 | 1196篇 |
评价与监测 | 104篇 |
社会与环境 | 102篇 |
灾害及防治 | 136篇 |
出版年
2024年 | 1篇 |
2023年 | 50篇 |
2022年 | 160篇 |
2021年 | 124篇 |
2020年 | 86篇 |
2019年 | 85篇 |
2018年 | 120篇 |
2017年 | 149篇 |
2016年 | 150篇 |
2015年 | 164篇 |
2014年 | 299篇 |
2013年 | 324篇 |
2012年 | 262篇 |
2011年 | 298篇 |
2010年 | 229篇 |
2009年 | 214篇 |
2008年 | 280篇 |
2007年 | 200篇 |
2006年 | 178篇 |
2005年 | 122篇 |
2004年 | 78篇 |
2003年 | 95篇 |
2002年 | 82篇 |
2001年 | 83篇 |
2000年 | 73篇 |
1999年 | 70篇 |
1998年 | 84篇 |
1997年 | 68篇 |
1996年 | 63篇 |
1995年 | 55篇 |
1994年 | 28篇 |
1993年 | 36篇 |
1992年 | 31篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 15篇 |
1988年 | 9篇 |
1987年 | 11篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 3篇 |
1970年 | 1篇 |
排序方式: 共有4424条查询结果,搜索用时 650 毫秒
441.
The effects of sediment-laden waters on irrigated lands along the lower Yellow River in China 总被引:1,自引:0,他引:1
Mingzhou Q Jackson RH Zhongjin Y Jackson MW Bo S 《Journal of environmental management》2007,85(4):858-865
Expansion of irrigation in the Yellow River (Huang He in Chinese) Basin of China is a major accomplishment of the post-revolutionary period in China. Irrigation reliance on the Yellow River was anticipated to not only supply greater reliability of water for crops, but also to improve the productivity of aeolian, saline and alkali soils because of the high sediment loads in the river. Irrigation expansion also was a significant factor in affecting human modification of the landscape ecosystem in the lower reaches of the Yellow River. Based on field investigation and sampling of the amount and distribution of used suspended sediment load in irrigated areas, this paper analyzes the impact of the suspended sediment on soil texture, fertility and salinity and the consequences to the landscape ecosystem. Results indicate that soil quality has indeed been improved through irrigation and related deposition of sediment, but some local problems created by long periods of irrigation should not be ignored in the future. 相似文献
442.
Polycyclic aromatic hydrocarbons(PAHs), as persistent toxic substances(PTS), have been widely monitored in coastal environment, including seawater and sediment. However, scientific monitoring methods, like ecological risk assessment and integrated biomarker response, still need massive researches to verify their availabilities. This study was performed in March, May, August and October of 2018 at eight sites, Yellow River estuary(S1), Guangli Port(S2), Xiaying(S3), Laizhou(S4), Inner Bay(S5), Ou... 相似文献
443.
High efficient removal of antibiotics during nutriments recovery for biomass production poses a major technical challenge for photosynthetic microbial biofilm-based wastewater treatment since antibiotics are always co-exist with nutriments in wastewater and resist biodegradation due to their strong biotoxicity and recalcitrance. In this study, we make a first attempt to enhance metronidazole (MNZ) removal from wastewater using electrochemistry-activated binary-species photosynthetic biofilm of Rhodopseudomonas Palustris (R. Palustris) and Chlorella vulgaris (C. vulgaris) by cultivating them under different applied potentials. The results showed that application of external potentials of -0.3, 0 and 0.2 V led to 11, 33 and 26-fold acceleration in MNZ removal, respectively, as compared to that of potential free. The extent of enhancement in MNZ removal was positively correlated to the intensities of photosynthetic current produced under different externally applied potentials. The binary-species photoelectrogenic biofilm exhibited 18 and 6-fold higher MNZ removal rate than that of single-species of C. vulgaris and R. Palustris, respectively, due to the enhanced metabolic interaction between them. Application of an external potential of 0V significantly promoted the accumulation of tryptophan and tyrosine-like compounds as well as humic acid in extracellular polymeric substance, whose concentrations were 7.4, 7.1 and 2.0-fold higher than those produced at potential free, contributing to accelerated adsorption and reductive and photosensitive degradation of MNZ. 相似文献
444.
445.
孙景民 《中国环境管理干部学院学报》2014,(5):81-84
2011年教育部一号文件明确规定要把思想政治理论课(以下简称"思政课")实践教学纳入正式教学环节。只有对思政课实践教学进行科学定义,厘清思政课实践教学与其他教学的区别和联系,找准当前存在的问题和不足,提炼出思政课实践教学的特点,进而建立科学规范的教学内容、教学方法、教学形式和考评机制,才能使其落到实处。 相似文献
446.
447.
448.
Based on the analysis on the global economic crisis,climate change crisis and their mutual underlying reasons,the authors believe that low-carbon economy has become an inevitable choice to break through the dual crises,coordinate the economic development,and protect the global climate.The global trend of low-carbon economy finds expression in Green Recovery currently,while,in a long run,it will give rise to a new pattern of world competition in politics,economy,technology,trade and finance.The impact of the... 相似文献
449.
Yuan Ma Shan Zhai Shi Yun Mao Shi Lei Sun Ying Wang Zhong Hua Liu 《Journal of environmental science and health. Part. B》2013,48(9):661-670
A new imidacloprid (IMI) degrading bacterium Z-9 (deposited number CGMCC 6648) was isolated and identified as Pseudoxanthomonas indica by 16S rRNA gene analysis. Two metabolites were identified as olefin and 5-hydroxy IMI by liquid chromatography-mass spectrometry and nuclear magnetic resonance analysis. P. indica CGMCC 6648 degraded 70.1% of IMI (1.22 mmol L?1) and formed 0.93 mmol L?1 5-hydroxy IMI and 0.05 mmol L?1 olefin IMI in 6 days and in the presence of 100 mmol L?1 glucose. The half-life of IMI degradation was 3.6 days. P. indica CGMCC 6648 transforms IMI via a co-metabolism mechanism and different carbohydrates have significant effects on 5-hydroxy IMI formation, whereas different organic acids have substantial effects on olefin IMI production. Lactose is the best co-substrate for IMI degradation and 5-hydroxy IMI formation with 0.77 mmol L?1 degraded and 0.67 mmol L?1 formed in 48 h, respectively. Pyruvate is the best co-substrate for olefin IMI formation with 0.17 mmol L?1 produced in 96 h for all carbon sources tested. Pyruvate significantly stimulates the conversion of 5-hydroxy IMI to olefin IMI, whereas glucose slightly inhibits this reaction. P. indica CGMCC 6648 rapidly degrades IMI and forms olefin IMI, which may enhance its potential for biodegradation of IMI and increase its insecticidal activity, which can decrease the IMI dosage required. 相似文献
450.
孙增荣 《中国安全科学学报》1995,(2)
提出利用市场机制的作用,实现劳动安全监察任务的观点。简析计划经济体制下实现劳动安全监察任务的模式;利用市场机制的功能和特性,分析判别计划经济体制下形成的实现劳动安全监察任务途径及其手段、有效性和必然性;提出了具体进行工作的思路、方法。 相似文献