首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   50278篇
  免费   574篇
  国内免费   607篇
安全科学   1552篇
废物处理   2262篇
环保管理   6506篇
综合类   8259篇
基础理论   13565篇
环境理论   29篇
污染及防治   12973篇
评价与监测   3283篇
社会与环境   2704篇
灾害及防治   326篇
  2022年   456篇
  2021年   448篇
  2020年   343篇
  2019年   412篇
  2018年   717篇
  2017年   739篇
  2016年   1143篇
  2015年   857篇
  2014年   1293篇
  2013年   3989篇
  2012年   1600篇
  2011年   2219篇
  2010年   1813篇
  2009年   1841篇
  2008年   2211篇
  2007年   2291篇
  2006年   2030篇
  2005年   1711篇
  2004年   1608篇
  2003年   1704篇
  2002年   1521篇
  2001年   1972篇
  2000年   1384篇
  1999年   851篇
  1998年   612篇
  1997年   627篇
  1996年   642篇
  1995年   754篇
  1994年   707篇
  1993年   597篇
  1992年   637篇
  1991年   608篇
  1990年   664篇
  1989年   618篇
  1988年   528篇
  1987年   495篇
  1986年   429篇
  1985年   466篇
  1984年   525篇
  1983年   470篇
  1982年   494篇
  1981年   433篇
  1980年   358篇
  1979年   390篇
  1978年   345篇
  1977年   282篇
  1975年   292篇
  1974年   279篇
  1972年   272篇
  1971年   268篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Environment, Development and Sustainability - The current study explores the role of green trust, green perceived risk and green perceived quality in changing green purchase intention....  相似文献   
2.
Russian Journal of Ecology - A study of the anthropogenic impacts on the on-shore aggregation of true seals was carried out at a haul-out located at the mouth of Piltun Bay (the northeastern part...  相似文献   
3.
Environmental Science and Pollution Research - Heavy metals are well known for their toxicity and become significant environmental pollution with a continually rising technology and public outcry...  相似文献   
4.
Environmental Science and Pollution Research - A current environmental problem is the uncontrolled use of various pesticides that are harmful to the environment and public health. The herbicide...  相似文献   
5.
Russian Journal of Ecology - Climate change entails shifts in the ranges of woody plants along both latitudinal and altitudinal gradients in the boreal forest biome. In this study,...  相似文献   
6.
Russian Journal of Ecology - In this paper, Ellenberg’s indicator values were estimated in order to soil nitrogen (N), pH (R) and soil moisture (M) in different subalpine grassland...  相似文献   
7.
Journal of Material Cycles and Waste Management - Power generation from municipal solid waste plays significant role to mitigate the environmental pollution. The power generation potential of...  相似文献   
8.
Nano-ZnO-chitosan bio-composite beads were prepared for the sorption of \({\text{UO}}_{2}^{{2+}}\) from aqueous media. The resulting nano-ZnO/CTS bio-composite beads were characterized by TEM, XRD etc. The sorption of \({\text{UO}}_{2}^{{2+}}\) by bio-composite beads was optimized using RSM. The correlation between four variables was modelled and studied. According to RSM data, correlation coefficients (R2?=?0.99) and probability F-values (F?=?2.24?×?10??10) show that the model fits the experimental data well. Adsorption capacity for nano-ZnO/CTS bio-composite beads was obtained at 148.7 mg/g under optimum conditions. The results indicate that nano-ZnO/CTS bio-composite beads are appropriate for the adsorption of \({\text{UO}}_{2}^{{2+}}\) ions from aqueous media. Also, the suitability of adsorption values to adsorption isotherms was researched and thermodynamic data were calculated.  相似文献   
9.
The chemical recycling of cellulosic fibres may represent a next-generation fibre–fibre recycling system for cotton textiles, though remaining challenges include how to accommodate fibre blends, dyes, wrinkle-free finishes, and other impurities from finishing. These challenges may disrupt the regeneration process steps and reduce the fibre quality. This study examines the impact on regenerated viscose fibre properties of a novel alkaline/acid bleaching sequence to strip reactive dyes and dimethyloldihydroxyethyleneureas (DMDHEU) wrinkle-free finish from cotton textiles. Potentially, such a bleaching sequence could advantageously be integrated into the viscose process, reducing the costs and environmental impact of the product. The study investigates the spinning performance and mechanical properties (e.g., tenacity and elongation) of the regenerated viscose fibres. The alkaline/acid bleaching sequence was found to strip the reactive dye and DMDHEU wrinkle-free finish from the cotton fabric, so the resulting pulp could successfully be spun into viscose fibres, though the mechanical properties of these fibres were worse than those of commercial viscose fibres. This study finds that reactive dyes and DMDHEU wrinkle-free finish affect the viscose dope quality and the regeneration performance. The results might lead to progress in overcoming quality challenges in cellulosic chemical recycling.  相似文献   
10.
The current study is interested in evaluating the decay of cotton, Whatman and chemical pulp caused by Trichoderma harzianum and Paecilomyces variotii. The structural changes of the paper were evaluated by Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). The SEM results show differences in hyphae colonization and paper decay patterns between studied species under the current study; P. variotii caused an eroded structure in the cotton (cavity forming), whereas the initial T. harzianum colonization produced rupture and erosion (soft-rot decay type II) for the three types of paper ,the gaps were elongated with sharp pointed ends, which consisted either of individual cavities or in chains. Moreover, FTIR results confirmed that there a relationship could be observed between fungal decay and crystalline cellulose content because the intensity of peaks at 1335 and 1111 cm?1 significantly decreased due to the fungal decay. Furthermore, the intensity of O–H stretching absorption slightly decreased, and this may be attributed to hydrolysis of cellulose molecules.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号