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   5569篇
  免费   28篇
  国内免费   26篇
安全科学   136篇
废物处理   310篇
环保管理   442篇
综合类   835篇
基础理论   1367篇
环境理论   1篇
污染及防治   1390篇
评价与监测   405篇
社会与环境   710篇
灾害及防治   27篇
  2023年   45篇
  2022年   88篇
  2021年   70篇
  2020年   35篇
  2019年   44篇
  2018年   79篇
  2017年   96篇
  2016年   116篇
  2015年   72篇
  2014年   147篇
  2013年   426篇
  2012年   174篇
  2011年   242篇
  2010年   217篇
  2009年   221篇
  2008年   255篇
  2007年   251篇
  2006年   241篇
  2005年   208篇
  2004年   189篇
  2003年   215篇
  2002年   176篇
  2001年   255篇
  2000年   161篇
  1999年   101篇
  1998年   41篇
  1997年   58篇
  1996年   53篇
  1995年   61篇
  1994年   64篇
  1993年   59篇
  1992年   58篇
  1991年   61篇
  1990年   66篇
  1989年   52篇
  1988年   56篇
  1987年   54篇
  1986年   55篇
  1985年   41篇
  1984年   50篇
  1983年   48篇
  1982年   49篇
  1980年   32篇
  1979年   32篇
  1978年   29篇
  1977年   28篇
  1976年   28篇
  1974年   31篇
  1973年   30篇
  1972年   27篇
排序方式: 共有5623条查询结果,搜索用时 0 毫秒
431.
A Spanish ecodesign standard (the UNE 150301) is being used as a basic reference point in paving the way for the future ISO 14006 ecodesign standard which may foreseeably be passed in 2011. This article aims to analyze the experience regarding adoption of the UNE 150301 in Spain.Following an analysis of the standard’s structure, its objectives and scope, its real implementation process is then analyzed based on an exploratory qualitative study carried out in four Spanish companies that have been pioneers in adopting this environmental standard. The conclusion is drawn in the article that in all the cases analyzed, the greatest source of impact occurs in the phase in which the product is used and is related to energy consumption. Companies appear to be satisfied with the adoption of this standard and, in particular, point out that they have managed to reduce the environmental impact of their products. However, they draw attention to the fact that, to deal with certain instances of impact that increases in cost entail, administrative bodies need to establish mandatory regulations, as environmentally-friendly companies would otherwise lose competitiveness.  相似文献   
432.
Although many parasites are known to manipulate the behavior of their hosts, the mechanisms underlying such manipulations are largely unknown. Baculoviruses manipulate the behavior of caterpillar hosts by inducing hyperactivity and by inducing climbing behavior leading to death at elevated positions (tree-top disease or Wipfelkrankheit). Whether hyperactivity and tree-top disease are independent manipulative strategies of the virus is unclear. Recently, we demonstrated the involvement of the protein tyrosine phosphatase (ptp) gene of the baculovirus Autographa californica multiple nucleopolyhedrovirus (AcMNPV) in the induction of hyperactivity in Spodoptera exigua larvae. Here we show that AcMNPV ptp is not required for tree-top disease, indicating that in S. exigua baculovirus-induced hyperactivity and tree-top disease are independently induced behaviors that are governed by distinct mechanisms.  相似文献   
433.
Food and Environmental Virology - Saffold virus as a newly discovered virus, which seems to be related to acute gastroenteritis as with other enteric viruses and to human airway diseases in...  相似文献   
434.
435.
436.
437.
The evaluation of biospheric role of the boreal forests in the accumulation of carbon is connected with the evaluation of organic matter (OM) pool in soils. The research sites were larch forests, they are situated on Nizhne-Tungusskoe Plateau. Larch forests of feather-moss and lichen types (110 and 380 years old) were formed on 'ochric podbur' soils. Litter stocks are 3.5–4.5 kg m− 2 with thickness 10–25 cm. Cryomezomorphic northern taiga soils contains 38–73 t (carbon) ha− 1. Pool of fast mineralized OM has average value 38.1 t (carbon) ha− 1, including 20.5 and 6.4 t (Carbon) ha− 1 of labile compounds on surface and in the soil, and 11.2 t (carbon) ha− 1 of mobile OM. Microbial mass reaches 1.78–3.47 t (carbon) ha− 1, its proportion is 3.6–4.9% of the total OM carbon. Zoomass of feather-moss larch forest is 0.20–0.61 * 10− 2, in lichen larch forest −0.01–0.07 * 10− 2 t (carbon) ha− 1. A pool of resistant to biological decomposition and bonded to mineral soil matrix OM is 17.7 t (carbon) ha− 1 and it varies from 18.6 to 29.0 in feather-moss larch forest, and from 6.4 to 17.0 t (carbon) ha− 1 in lichen larch forest. Two-years field experiment has been performed to determine transformation rates of various plant litter fractions and to clarify the role of soil biota in these processes. The results showed participation of all biota groups in the decomposition of plant residues caused weight loss of larch-needles and root mortmass. Isolation of organic matter from all-size invertebrate groups leads to some decrease of decomposition activity.  相似文献   
438.
439.
440.
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