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   1806篇
  免费   24篇
  国内免费   36篇
安全科学   57篇
废物处理   93篇
环保管理   202篇
综合类   280篇
基础理论   341篇
环境理论   3篇
污染及防治   592篇
评价与监测   197篇
社会与环境   94篇
灾害及防治   7篇
  2023年   25篇
  2022年   83篇
  2021年   92篇
  2020年   34篇
  2019年   44篇
  2018年   76篇
  2017年   76篇
  2016年   82篇
  2015年   69篇
  2014年   76篇
  2013年   147篇
  2012年   76篇
  2011年   126篇
  2010年   94篇
  2009年   86篇
  2008年   94篇
  2007年   84篇
  2006年   52篇
  2005年   66篇
  2004年   39篇
  2003年   41篇
  2002年   38篇
  2001年   29篇
  2000年   16篇
  1999年   15篇
  1998年   18篇
  1997年   7篇
  1996年   12篇
  1995年   20篇
  1994年   11篇
  1993年   7篇
  1992年   12篇
  1991年   7篇
  1990年   8篇
  1989年   9篇
  1988年   7篇
  1987年   7篇
  1986年   8篇
  1985年   5篇
  1984年   4篇
  1983年   5篇
  1982年   6篇
  1981年   4篇
  1980年   5篇
  1979年   5篇
  1978年   3篇
  1977年   4篇
  1963年   3篇
  1959年   3篇
  1958年   3篇
排序方式: 共有1866条查询结果,搜索用时 15 毫秒
1.
Environmental Science and Pollution Research - The present research article uses simultaneous equation modelling approach to investigate the three-way linkages between economic growth, energy...  相似文献   
2.
Environmental Science and Pollution Research - Buildings account for nearly 2/5ths of global energy expenditure. Due to this figure, the 90s witnessed the rise of green buildings (GBs) that were...  相似文献   
3.
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   
4.
Environmental Chemistry Letters - Water desalination and recycling of wastewater is a key challenge to meet water shortage issues. Thin film composite polyamide membranes are widely used for...  相似文献   
5.
6.
The structure of the choroid plexus was studied in five normal human embryos, three normal fetuses and three fetuses with choroid plexus cysts. These were detected by ultrasound and the fetuses were karyotypically normal. The choroid plexus appears in the lateral cerebral ventricles at the seventh developmental week. The early structure is lobulated with vessels running in the mesenchymal stroma and forming capillary nets under the single-layered ependymal epithelium. This embryonal structure is converted into the fetal type during the ninth developmental week as the embryonal capillary net is replaced by elongated loops of wavy capillaries that lie under regular longitudinal epithelial folds. The choroid plexus cysts exhibited accumulation of fluid within distended mesenchymal stroma and did not show the wavy folds on this surface, which was smooth. Within this connective tissue of the cyst wall were distended angiomatous interconnecting thin-walled capillaries. Therefore, filled cavities were not lined by any epithelium. We suggest that fetal choroid plexuses cysts (at least in many cases) are in fact pseudocysts exhibiting angiomatous patterns of capillaries in their walls. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   
7.
The production of brominated aromatics from combustion was shown to be influenced by the operating conditions. Brominated aromatics also showed high yields compared to their chlorinated analogues.  相似文献   
8.
9.
Summary Genetic parentage of 135 nestlings from 27 broods of polygynous and monogamous pied flycatchers Ficedula hypoleuca was analyzed by means of multilocus DNA fingerprinting. The minisatellite probe alpha-globin 3HVR detected approximately 12 scorable bands per fingerprint, and the proportion of bands shared between presumably unrelated adults averaged 0.22+0.08 SD. The fingerprints of 125 of the 135 nestlings made a complete match to those of their putative parents. In 4 nestlings a single mismatched band occurred, but since band sharing with both putative parents was high, the single mismatches were assumed to be caused by mutation. The 6 remaining nestlings had 5 or more mismatched bands each, low band-sharing proportions with their putative father and high band-sharing proportions with their putative mother. We thus conclude that they were all sired through extra-pair copulations (EPCs). Hence, only 4% of nestlings were sired through EPCs, and none resulted from intraspecific brood parasitism. One of the cuckolding males was identified, explaining all 5 mismatched bands in the nestling's fingerprint. Three of the illegitimate nestlings were from primary nests of polygynous males; 3 were from nests of monogamous males. The fact that many males in this study started to advertise for a second female in a distant territory several days before their first mate began egglaying, and still managed to secure almost exclusive paternity in their first brood, suggests that male polyterritoriality is not costly in terms of lost paternity. Common anti-cuckoddry tactics performed by male birds, like high rate of within-pair copulation and continuous mate-guarding thoughout the female's fertilizable period, do not seem to be important in pied flycatchers.Offprint requests to: J.T. Lifjeld  相似文献   
10.
One third of the territory of Czechoslovakia is covered by forests. A substantial part of them is damaged in various degrees by air pollution. The air pollution influence on forests developed to a very serious problem during the last 40 years. The main pollutant at present is SO2 acting directly, but the improtance of soil changes due to acid deposition increases. The consequences are increased mortality and decreased increment in the forests, further consequences are the loss of valuable ecotypes, impact on water management and decreased stability of the landscape. There are limited possibilities of the forest sector to reduce the consequences.Contribution from Fourth World Wilderness Congress—Acid Rain Symposium, Denver (Estes Park), Colorado, September 11–18, 1987.  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