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   6095篇
  免费   50篇
  国内免费   35篇
安全科学   122篇
废物处理   368篇
环保管理   491篇
综合类   731篇
基础理论   1354篇
环境理论   7篇
污染及防治   2128篇
评价与监测   540篇
社会与环境   422篇
灾害及防治   17篇
  2023年   65篇
  2022年   180篇
  2021年   203篇
  2020年   88篇
  2019年   98篇
  2018年   253篇
  2017年   232篇
  2016年   325篇
  2015年   181篇
  2014年   323篇
  2013年   529篇
  2012年   379篇
  2011年   451篇
  2010年   305篇
  2009年   255篇
  2008年   346篇
  2007年   373篇
  2006年   279篇
  2005年   228篇
  2004年   191篇
  2003年   149篇
  2002年   133篇
  2001年   106篇
  2000年   77篇
  1999年   48篇
  1998年   28篇
  1997年   24篇
  1996年   16篇
  1995年   33篇
  1994年   27篇
  1993年   17篇
  1992年   19篇
  1991年   16篇
  1990年   14篇
  1989年   9篇
  1988年   14篇
  1985年   7篇
  1983年   4篇
  1982年   4篇
  1980年   4篇
  1967年   5篇
  1966年   7篇
  1965年   7篇
  1964年   12篇
  1962年   7篇
  1961年   5篇
  1960年   5篇
  1959年   8篇
  1958年   18篇
  1957年   8篇
排序方式: 共有6180条查询结果,搜索用时 234 毫秒
71.
Three groups of data entry female visual display terminal (VDT) workers from Norway (n = 30), Poland (n = 33) and the USA (n = 29) were compared. Before intervention, the Norwegian group reported more neck pain compared with the Polish group. The Polish group reported less shoulder pain than both the U.S. and the Norwegian groups. The clinical examination documented fewer symptoms and signs of musculoskeletal illness among the Polish participants compared with the Norwegian and the U.S. groups. After intervention, the Norwegian group reported a reduction in neck pain while the U.S. group reported a reduction in shoulder pain. The Polish group reported an increase in neck, shoulder and forearm pain at follow-up compared to after intervention. The Polish group recorded higher flexion of the upper arm at follow-up parallel with an increase of pain in the upper part of the body. Visual discomfort showed variable results in the 3 countries.  相似文献   
72.
Recent research has focused on establishing the values of preserving biodiversity both in agriculture and in less managed ecosystems, and in showing the importance of the role of cultural diversity in preserving biodiversity in food production systems. A study of the philosophy embedded in cultural systems can reveal the importance of the technological information for preserving genetic biodiversity contained in such systems and can be used to support arguments for the protection/preservation of cultural diversity. For example, corn or maize can serve as a paradigm of Native American thinking and can provide one of the few areas from which common philosophical conceptions can emerge. An examination of the cultivation of corn or maize as an agricultural activity and as a cultural activity in Native American literature reveals a philosophy that recognizes the importance of biodiversity and provides techniques for its preservation. Corn, and the food and the materials derived from it, is something thought out, not by specialists, but by the entire tribe and its ancestors, even if this thinking is done within what we might consider a framework of highly mythical notions. Importantly, this framework yields an understanding of both the genetics and nutrition of corn. A survey of these mythical notions (myths and stories) and agricultural practices makes this thought explicit and exemplifies the value of cultural diversity and biodiversity.  相似文献   
73.
The microalgae Chlamydomonas reinhardtii was used for the biosorption of Hg(II), Cd(II) and Pb(II) ions. The maximum adsorption of Hg(II) and Cd(II) ions on Chlamydomonas reinhardtii biomass was observed at pH 6.0 and the corresponding value for Pb(II) ions was 5.0. The biosorption of Hg(II), Cd(II) and Pb(II) ions by microalgae biomass increased as the initial concentration of Hg(II), Cd(II) and Pb(II) ions increased in the biosorption medium. The maximum biosorption capacities of microalgae for Hg(II), Cd(II) and Pb(II) ions were 72.2+/-0.67, 42.6+/-0.54 and 96.3+/-0.86 mg/g dry biomass, respectively. The affinity order for algal biomass was Pb(II)>Hg(II)>Cd(II). FT-IR analysis of algal biomass revealed the presence of amino, carboxyl, hydroxyl and carbonyl groups, which were responsible for biosorption of metal ions. Biosorption equilibrium was established in about 60 min and the equilibrium was well described by the Freundlich biosorption isotherms. Temperature change in the range of 5-35 degrees C did not affect the biosorption capacity. The microalgae could be regenerated using 0.1 M HCl, with up to 98% recovery, which allowed the reuse of the biomass in six biosorption-desorption cycles without any considerable loss of biosorption capacity.  相似文献   
74.
Biological treatment of clogged emitters in a drip irrigation system   总被引:1,自引:0,他引:1  
This study was conducted to investigate microbial organisms that can be used for preventing clogging in drip irrigation systems caused by biological factors. A total of 25 fungi isolate and 121 bacterial strains were isolated from water samples collected from drip irrigation systems in tomato greenhouses in the eastern Anatolia region of Turkey in the spring season of 2001. Biological clogging of emitters in a model drip irrigation system was experimentally caused by application of the microorganisms (fungi and bacteria) isolated in the study. Three antagonistic bacterial strains in the genus Bacillus spp (ERZ, OSU-142) and Burkholdria spp (OSU-7) were used for treatment of biological clogging of the emitters. The results showed that the antagonistic bacterial strains tested have the potential to be used as anti-clogging agents for treatment of emitters in drip irrigation system. This is the first study that demonstrated that antagonistic microorganisms can be utilized for treatment of clogging in drip irrigation systems.  相似文献   
75.
76.
How do youth learn through participation in efforts to study and change the school food system? Through our participatory youth action research (YPAR) project, we move beyond the “youth as consumer” frame to a food justice youth development (FJYD) approach. We track how a group of youth learned about food and the public policy process through their efforts to transform their own school food systems by conducting a participatory evaluation of farm-to-school efforts in collaboration with university and community partners. We used the Photovoice research method, placing cameras in the hands of young people so that they themselves could document and discuss their concerns and perspectives. The research was designed to gain insight about youths’ knowledge of food, health, and community food systems. Drawing upon the youth group’s insights, we build a framework for building critical consciousness through FJYD.  相似文献   
77.
Environmental Science and Pollution Research - The assessment of productivity change over time and its drivers is of great significance for water companies and regulators when setting urban water...  相似文献   
78.
The fifth meeting of INRA’s national network of ecotoxicologists took place on 25 to 27 November 2014 in Biarritz, France. The main aim of the meeting was to bring together ecotoxicologists from INRA and associated partners, providing them ample opportunity to share and discuss their latest scientific results as well as the national policy of research in ecotoxicology and to precise perspectives for the network.  相似文献   
79.
80.
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