全文获取类型
收费全文 | 2579篇 |
免费 | 282篇 |
国内免费 | 849篇 |
专业分类
安全科学 | 299篇 |
废物处理 | 81篇 |
环保管理 | 362篇 |
综合类 | 1727篇 |
基础理论 | 361篇 |
环境理论 | 1篇 |
污染及防治 | 427篇 |
评价与监测 | 213篇 |
社会与环境 | 198篇 |
灾害及防治 | 41篇 |
出版年
2024年 | 16篇 |
2023年 | 45篇 |
2022年 | 114篇 |
2021年 | 107篇 |
2020年 | 132篇 |
2019年 | 121篇 |
2018年 | 115篇 |
2017年 | 163篇 |
2016年 | 179篇 |
2015年 | 174篇 |
2014年 | 184篇 |
2013年 | 253篇 |
2012年 | 252篇 |
2011年 | 261篇 |
2010年 | 170篇 |
2009年 | 180篇 |
2008年 | 131篇 |
2007年 | 189篇 |
2006年 | 156篇 |
2005年 | 109篇 |
2004年 | 80篇 |
2003年 | 103篇 |
2002年 | 79篇 |
2001年 | 65篇 |
2000年 | 68篇 |
1999年 | 52篇 |
1998年 | 38篇 |
1997年 | 28篇 |
1996年 | 23篇 |
1995年 | 24篇 |
1994年 | 9篇 |
1993年 | 19篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有3710条查询结果,搜索用时 265 毫秒
1.
Ling R. Zeng Li H. Shi Xin G. Meng J. Xu Gui F. Jia T. Gui 《Journal of environmental science and health. Part. B》2019,54(4):317-325
This study evaluated the hydrolysis and photolysis kinetics of pyraclostrobin in an aqueous solution using ultra-high-performance liquid chromatography–photodiode array detection and identified the resulting metabolites of pyraclostrobin by hydrolysis and photolysis in paddy water using high-resolution mass spectrometry coupled with liquid chromatography. The effect of solution pH, metal ions and surfactants on the hydrolysis of pyraclostrobin was explored. The hydrolysis half-lives of pyraclostrobin were 23.1–115.5?days and were stable in buffer solution at pH 5.0. The degradation rate of pyraclostrobin in an aqueous solution under sunlight was slower than that under UV photolysis reaction. The half-lives of pyraclostrobin in a buffer solution at pH 5.0, 7.0, 9.0 and in paddy water were less than 12?h under the two light irradiation types. The metabolites of the two processes were identified and compared to further understand the mechanisms underlying hydrolysis and photolysis of pyraclostrobin in natural water. The extracted ions obtained from paddy water were automatically annotated by Compound Discoverer software with manual confirmation of their fragments. Two metabolites were detected and identified in the pyraclostrobin hydrolysis, whereas three metabolites were detected and identified in the photolysis in paddy water. 相似文献
2.
按照国家环保部文件要求,大唐集团河北某电厂600 MW机组湿法脱硫系统需进行增容改造。该电厂根据实际情况,归纳了3种可行的脱硫增容改造方案,即原吸收塔增加喷淋层和高度、双吸收塔串联、双吸收塔双循环,阐述了各自的技术特点,结合性能保证、工程投资、施工周期等影响因素,比较了各方案的优缺点。经过对比和论证,双吸收塔方案比单吸收塔方案更适合于本次工程改造。 相似文献
3.
建立了土壤和沉积物中8种多溴联苯醚(PBDEs,BDE-28、BDE-47、BDE-99、BDE-100、BDE-153、BDE-154、BDE-183和BDE-209)加速溶剂同时萃取和净化-气相色谱-三重四极杆串联质谱(ASE-GC-MS-MS)的分析方法。通过优化加速溶剂萃取与弗罗里硅土在线净化和串联质谱多反应监测模式的条件,较好地去除基质干扰,并提高了三重四极杆串联质谱定性的准确性及定量的灵敏性。该方法采用改进的色谱柱能同时分析包括高溴代联苯醚BDE-209在内的8种PBDEs,其浓度范围为1~100 ng/mL(BDE-209为10~1 000 ng/mL),线性良好,线性回归系数均大于0.997。方法检出限为0.004~0.1 ng/g,方法回收率为75%~110%,方法精密度为2.4%~15.6%。适于批量处理土壤和沉积物中含有多组分痕量PBDEs的样品。 相似文献
4.
When accounting the CO2 emissions responsibility of the electricity sector at the provincial level in China,it is of great significance to consider the scope of both producers’ and the consumers’ responsibility,since this will promote fairness in defining emission responsibility and enhance cooperation in emission reduction among provinces.This paper proposes a new method for calculating carbon emissions from the power sector at the provincial level based on the shared responsibility principle and taking into account interregional power exchange.This method can not only be used to account the emission responsibility shared by both the electricity production side and the consumption side,but it is also applicable for calculating the corresponding emission responsibility undertaken by those provinces with net electricity outflow and inflow.This method has been used to account for the carbon emissions responsibilities of the power sector at the provincial level in China since 2011.The empirical results indicate that compared with the production-based accounting method,the carbon emissions of major power-generation provinces in China calculated by the shared responsibility accounting method are reduced by at least 10%,but those of other power-consumption provinces are increased by 20% or more.Secondly,based on the principle of shared responsibility accounting,Inner Mongolia has the highest carbon emissions from the power sector while Hainan has the lowest.Thirdly,four provinces,including Inner Mongolia,Shanxi,Hubei and Anhui,have the highest carbon emissions from net electricity outflow- 14 million t in 2011,accounting for 74.42% of total carbon emissions from net electricity outflow in China.Six provinces,including Hebei,Beijing,Guangdong,Liaoning,Shandong,and Jiangsu,have the highest carbon emissions from net electricity inflow- 11 million t in 2011,accounting for 71.44% of total carbon emissions from net electricity inflow in China.Lastly,this paper has estimated the emission factors of electricity consumption at the provincial level,which can avoid repeated calculations when accounting the emission responsibility of power consumption terminals(e.g.construction,automobile manufacturing and other industries).In addition,these emission factors can also be used to account the emission responsibilities of provincial power grids. 相似文献
5.
能源短缺和环境污染已成为中国推行全面协调可持续发展的重要制约因素,作为能源消耗的主体和环境污染的控制重点,在城市层面推动能源发展战略的转变和强化环境保护是发展的基本要求.鉴于能源与环境之间的高度关联性,在管理方面要求对能源发展和环境保护进行统筹考虑和综合管理,充分强调能源经济效率和环境制约因素在能源发展中的作用.通过制定合理的产业能效标准和排放绩效标准,为城市经济、能源和环境的可持续性发展提供科学性、系统性决策支持. 相似文献
6.
7.
对武钢第一炼钢厂100t转炉OG系统设备存在的问题进行了分析、研究,结合生产实际进行了一系列的技术改进和工艺参数调整,提高了OG系统效率。 相似文献
8.
V. I. Kolmakov N. A. Gaevskii E. A. Ivanova O. P. Dubovskaya I. V. Gribovskaya E. S. Kravchuk 《Russian Journal of Ecology》2002,33(2):97-103
In the periods of summer and autumn bloom of the Stephanodiscus hantzschii Crun. in recreational water bodies, studies on the vertical distribution of chlorophyll a, its contents per unit biomass, efficiency in using photosynthetically active radiation (EPhAR), and assimilative activity of microalgae were performed. The results confirmed the existence of two ecophysiological forms of St. hantzschii and provided evidence that both forms are typically autotrophic and can efficiently use low-intensity PhAR for photosynthesis. 相似文献
9.
Mamoru Morikawa Kazutoshi Cho Soromon Kataoka Emi H. Kato Takashi Yamada Hideto Yamada Hisanori Minakami 《黑龙江环境通报》2005,25(3):250-252
Two cases with a large cystic mass within the placenta are reported. By ultrasonography, it was found that both women had a subchorionic hypoechoic lesion (11.0 × 4.8 × 4.0 cm and 6.6 × 3.7 × 2.2 cm, respectively) at 24 and 35 weeks of gestation, respectively. In both cases, turbulent blood flow generated by a pulsatile jet flow (pulse rate; 40 to 60 beats per minute) into the cystic lesion seen on real-time imaging and lesions being low intensity on T1-weighted and isointensity on T2-weighted magnetic resonance image suggested that they contained fresh maternal blood. In both cases, the sonolucency of the lesions did not change until cesarean deliveries of females, both of whom were small-for-gestational-age infants (1940 g at 37 weeks and 2195 g at 37 weeks, respectively). Biochemical analysis of the fluid in the cystic lesion sampled during the cesarean section in the latter case confirmed that the fluid had originated from the maternal blood. These lesions histologically corresponded to large avillous areas surrounded by normal villi. Thus, a huge placental lake was diagnosed in both cases. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
10.
采集太原市城北和城南区域环境空气和5类污染源挥发性有机物样品,测定样品中典型单环芳烃稳定氢同位素(δD)组成,基于同位素质量平衡原理计算单环芳烃从源到环境空气受体的δD初始混合值,探讨单环芳烃来源.结果表明,柴油挥发源、溶剂挥发源、汽油挥发源(97#)、汽油挥发源(95#)、机动车尾气(97#)、机动车尾气(95#)和民用燃煤源中单环芳烃δD范围依次为:(-138.7‰~-115.5‰)、(-147.0‰~-121.0‰)、(-150.8‰~-117.6‰)、(-131.8‰~-113.8‰)、(-171.2‰~-120.0‰)、(-138.9‰~-102.7‰)和(-168.3‰~-142.3‰),民用燃煤源中单环芳烃δD显著贫重氢同位素(D)组成,机动车尾气源与汽油挥发源中苯的δD相比显著贫D,可用于探索污染物转化过程;城北和城南环境空气中δD范围为(-131.7‰~-115.1‰)和(-131.9‰~-74.9‰),δD初始混合值为-138.4‰和-173.9‰,体现了其来源差异. 相似文献