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   50026篇
  免费   827篇
  国内免费   3541篇
安全科学   1789篇
废物处理   2103篇
环保管理   6432篇
综合类   10818篇
基础理论   13116篇
环境理论   24篇
污染及防治   14436篇
评价与监测   2889篇
社会与环境   2143篇
灾害及防治   644篇
  2023年   332篇
  2022年   710篇
  2021年   676篇
  2020年   519篇
  2019年   618篇
  2018年   848篇
  2017年   943篇
  2016年   1294篇
  2015年   1206篇
  2014年   1684篇
  2013年   4132篇
  2012年   1954篇
  2011年   2514篇
  2010年   2003篇
  2009年   2012篇
  2008年   2414篇
  2007年   2369篇
  2006年   2163篇
  2005年   1752篇
  2004年   1671篇
  2003年   1638篇
  2002年   1629篇
  2001年   1875篇
  2000年   1448篇
  1999年   1017篇
  1998年   798篇
  1997年   794篇
  1996年   798篇
  1995年   808篇
  1994年   712篇
  1993年   661篇
  1992年   629篇
  1991年   584篇
  1990年   539篇
  1989年   567篇
  1988年   488篇
  1987年   435篇
  1986年   385篇
  1985年   411篇
  1984年   397篇
  1983年   433篇
  1982年   446篇
  1981年   397篇
  1980年   332篇
  1979年   371篇
  1978年   302篇
  1977年   254篇
  1976年   258篇
  1975年   254篇
  1972年   273篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Chen  Yan  Su  Xuewei  Ma  Mingliang  Hou  Yongbo  Lu  Chenggang  Liu  Peizhe  Ma  Yong  Wan  Fei  Yang  Ying  Hu  Xinru  Yu  Zhenqi 《Environmental science and pollution research international》2022,29(58):87310-87318
Environmental Science and Pollution Research - In this work, the 3D magnetic flower-like Fe3O4@SiO2@Co3O4@BiOCl heterojunction photocatalyst was successfully prepared. The combination of BiOCl with...  相似文献   
912.
913.
Sea ice continues to decline across many regions of the Arctic, with remaining ice becoming increasingly younger and more dynamic. These changes alter the habitats of microbial life that live within the sea ice, which support healthy functioning of the marine ecosystem and provision of resources for human-consumption, in addition to influencing biogeochemical cycles (e.g. air–sea CO2 exchange). With the susceptibility of sea ice ecosystems to climate change, there is a pressing need to fill knowledge gaps surrounding sea ice habitats and their microbial communities. Of fundamental importance to this goal is the development of new methodologies that permit effective study of them. Based on outcomes from the DiatomARCTIC project, this paper integrates existing knowledge with case studies to provide insight on how to best document sea ice microbial communities, which contributes to the sustainable use and protection of Arctic marine and coastal ecosystems in a time of environmental change.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01658-z.  相似文献   
914.
As the two largest countries by population, China and India have pervasive effects on the ecosphere. Because of their human population size and long international boundary, they share biodiversity and the threats to it, as well as crops, pests and diseases. We ranked the two countries on a variety of environmental challenges and solutions, illustrating quantitatively their environmental footprint and the parallels between them regarding the threats to their human populations and biodiversity. Yet we show that China and India continue to have few co-authorships in environmental publications, even as their major funding for scientific research has expanded. An agenda for collaboration between China and India can start with the shared Himalaya, linking the countries’ scientists and institutions. A broader agenda can then be framed around environmental challenges that have regional patterns. Coordinated and collaborative research has the potential to improve the two countries’ environmental performance, with implications for global sustainability.  相似文献   
915.
针对秸秆类农业废弃物干法厌氧发酵过程中易产生物料分层、表面结垢以及存在“死角”等问题,通过改进横卧推流式中试厌氧反应器搅拌工艺,探索了连续运行条件下机械搅拌、前端气动搅拌和全程气动搅拌等3种单一搅拌方式对稻秸干法厌氧发酵产气规律、底物降解特性及系统稳定性的影响,并通过进一步设置不同的搅拌频次优化了机械搅拌和前端气动搅拌组合工艺,综合考察了发酵效率和能源消耗情况。结果表明,在单一搅拌工艺条件下,稻秸干法厌氧发酵40 d总产气量呈现出“机械搅拌>前端气动搅拌>全程气动搅拌”的规律,分别为75.5、66.5和61.9 m3,对应的单位VS产气量分别为441.9、389.3和362.3 L·kg−1,这说明采用改进型框型叶片的机械搅拌可有效翻动物料,以促进其与发酵液的充分接触。在进一步优化“机械+前端气动”的组合搅拌工艺后发现,稻秸40 d产气量与单一机械搅拌模式较为接近,尤其是“机械搅拌(每天4次)+前端气动搅拌(每天4次)”的组合搅拌方式,单位VS产气量高达447.2 L·kg −1,纤维素和半纤维素降解率分别可达14.9%和15.1%;但从能源损耗角度来看,“机械搅拌(每天2次)+前端气动搅拌(每天4次)”的组合搅拌方式中能耗最低,仅为单一机械搅拌方式能耗的约40%。在稻秸干法厌氧发酵工程实际运行过程中,可根据厌氧发酵效率和能耗节省需求,因地制宜地选择合适的组合搅拌工艺。本研究结果可为木质纤维素类废弃物干法厌氧发酵工程中的搅拌方式改进提供参考。  相似文献   
916.
Ambio - The Circumpolar North has been changing rapidly within the last decades, and the socioeconomic systems of the Eurasian Arctic and Siberia in particular have displayed the most dramatic...  相似文献   
917.
Felton  Adam  Löfroth  Therese  Angelstam  Per  Gustafsson  Lena  Hjältén  Joakim  Felton  Annika M.  Simonsson  Per  Dahlberg  Anders  Lindbladh  Matts  Svensson  Johan  Nilsson  Urban  Lodin  Isak  Hedwall  P. O.  Sténs  Anna  Lämås  Tomas  Brunet  Jörg  Kalén  Christer  Kriström  Bengt  Gemmel  Pelle  Ranius  Thomas 《Ambio》2020,49(5):1065-1066
Ambio - In the original published article, the sentence “Nevertheless, semi-natural forest remnants continue to be harvested and fragmented (Svensson et al. 2018; Jonsson et al. 2019), and...  相似文献   
918.
Environmental Science and Pollution Research - The total cultivated area in Brazil reached to 62 million ha in 2018, with the predominance of genetically modified soybean and corn (36 and 17...  相似文献   
919.
ABSTRACT

Near-road measurements in Rochester, NY with a Portable Air Quality Monitoring System indicate a significant plume control of PM2.5 black carbon (BC) concentrations. This study evaluates the performance of two portable air quality enclosures deployed at collocated research sites to determine their accuracy and usefulness in field deployments, and specifically in pollution plume analysis. One system deployed collocated sensors for measurement of particulate matter mass concentration (Thermo pDR 1500 against Tapered Element Oscillating Microbalance (TEOM) measurement) and the second system deployed sensors for measurement of black carbon (Magee AE33 aethalometer and Brechtel Tricolor Absorption Photometer) in ambient and near-road locations in Rochester, New York, respectively. While the optical PM2.5 sensors tended to be biased in their determination of concentration by ~15%, they followed changes and trends in concentration very well. The black carbon sensors in the portable systems agreed very well with each other and with the collocated sensor. As a case study to determine the contribution from statistically significant short-lived excursions of pollutant concentration, Morlet wavelet analysis was performed on data from the portable system sensors. Black carbon was found to be strongly influenced by plume behavior with significant plume excursions representing just over 12% of all data points and contributing on average 1 µg/m3 of black carbon above ambient concentrations.

Implications: This paper first evaluates two air pollutant monitoring enclosures with wide applicability including near-road detection of pollutants. Then, we present a novel method to designate isolate statistically significant excursions in air pollution concentration which can be used to determine the impact of pollutant plumes as observed in PM and black carbon behavior near road.  相似文献   
920.
Environmental Science and Pollution Research - Biochar has been applied widely as an amendment in the remediation of contaminated soil to immobilize the heavy metals. However, the role of...  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