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   3327篇
  免费   81篇
  国内免费   31篇
安全科学   138篇
废物处理   143篇
环保管理   876篇
综合类   364篇
基础理论   759篇
环境理论   1篇
污染及防治   792篇
评价与监测   208篇
社会与环境   122篇
灾害及防治   36篇
  2023年   22篇
  2022年   35篇
  2021年   51篇
  2020年   25篇
  2019年   42篇
  2018年   77篇
  2017年   79篇
  2016年   102篇
  2015年   77篇
  2014年   90篇
  2013年   347篇
  2012年   138篇
  2011年   190篇
  2010年   143篇
  2009年   147篇
  2008年   191篇
  2007年   185篇
  2006年   150篇
  2005年   116篇
  2004年   98篇
  2003年   111篇
  2002年   102篇
  2001年   64篇
  2000年   50篇
  1999年   27篇
  1998年   45篇
  1997年   31篇
  1996年   43篇
  1995年   48篇
  1994年   32篇
  1993年   45篇
  1992年   38篇
  1991年   18篇
  1990年   24篇
  1989年   18篇
  1988年   26篇
  1987年   17篇
  1986年   22篇
  1985年   30篇
  1984年   23篇
  1983年   25篇
  1982年   34篇
  1981年   35篇
  1980年   32篇
  1979年   23篇
  1978年   23篇
  1977年   12篇
  1976年   8篇
  1974年   7篇
  1972年   10篇
排序方式: 共有3439条查询结果,搜索用时 46 毫秒
1.
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   
2.
The Science of Nature - We present the first study that compares phenological variation in parasite load and inflammatory response in a lizard with asynchronous male and female gonadal cycles....  相似文献   
3.
Introduced and cryptogenic species in Port Phillip Bay, Victoria, Australia   总被引:4,自引:0,他引:4  
Port Phillip Bay (PPB) is a large (1,930 km2), temperate embayment in southern Victoria, Australia. Extensive bay-wide surveys of PPB have occurred since 1840. In 1995/1996 the Commonwealth Scientific and Industrial Research Organization (CSIRO) Centre for Research on Introduced Marine Pests (CRIMP) undertook an intensive evaluation of the region with the aims of developing a comprehensive species list of native and introduced biota and contrasting previous bay-wide assessments with a current field survey in order to detect new incursions and discern alterations to native communities. Two methods were used to meet these aims: a re-evaluation of regional museum collections and published research in PPB to identify and determine the timing of introductions; and field surveys for benthic (infauna, epifauna and encrusting) organisms between September 1995 to March 1996. One hundred and sixty introduced (99) and cryptogenic (61) species were identified representing over 13% of the recorded species of PPB. As expected, the majority of these are concentrated around the shipping ports of Geelong and Melbourne. Invasions within PPB appear to be increasing, possibly due to an increase in modern shipping traffic and an increase in aquaculture (historically associated with incidental introductions); however the records of extensive biological surveys suggest that this may, in part, be an artefact of sampling effort. In contrast to Northern Hemisphere studies, PPB (and Southern Hemisphere introductions in general) have significantly different suites of successfully invading taxa. PPB is presented as one of the most invaded marine ecosystems in the Southern Hemisphere.Communicated by M.S. Johnson, Crawley  相似文献   
4.
5.
Quick fix. Putting out firs. Do it over. Fix it again. Bottlenecks. Come back to it later. Out of stock. Back order. Not what we ordered. Is that the best you can do? It's the contractor's fault. Not within specs. Defective. Nobody's perfect. Lost in the system. Over budget. Delayed. Late penalities. Fines.  相似文献   
6.
7.
Three monoclonal antibodies (MAbs) against trophoblast (GB17, GB21, and GB25) and flow cytometry were used to sort trophoblast-like cells (TLCs) from peripheral blood of pregnant women. Sorted TLCs were processed for electron microscopy and fetal DNA amplification of the Y-specific sequences from mothers carrying male fetuses. At the ultra-structural level, most of the nucleated cells had the morphology of leucocytes, suggesting maternal contaminants, and we did not find the characteristic features of the free inter-villous trophoblast cells. Nevertheless, polymerase chain reaction (PCR) analysis showed an amplification of Y-specific sequences in two out of three samples of sorted TLCs. These results suggest that besides the maternal leucocytes, sufficient trophoblast nucleated fetal cells can be obtained using cell enrichment by sorting. This sensitive method holds promise for non-invasive prenatal diagnosis of fetal sex and if sufficient Y(positive) nuclei are found, for the diagnosis of selected numerical chromosome abnormalities.  相似文献   
8.
9.
Critical loads offer a unique way of evaluating impacts of acid deposition by quantifying environmental sensitivity. The critical loads of acidity for UK peat soils have been based upon an arbitrary reduction in pH of 0.2 units. This chemical shift needs to be better related to adverse effects on sensitive biological receptors. It is known that effective precipitation pH equates closely to soil solution pH, and the latter is directly linkable to biotic effects of pH change. On continuation of a long-term experiment assessing impacts of simulated acid rain on peat microcosms in a realistic outdoor environment, Calluna vulgaris continued to flourish at acid deposition loads well above the existing critical load. Calluna plants were harvested and analysed, and acid deposition treatments to the microcosms continued to allow natural vegetation to regenerate. A diverse mixture of moorland plants and bryophytes established at acidity treatments well above the existing critical load, and only a very high acid load resulted in no natural regeneration. A critical effective rain pH value of 3.6 is suggested as a basis for setting critical loads. At this pH, Calluna grows well, and a healthy diverse vegetation community re-establishes when harvested. It is suggested that the peat critical load should be set at the acid load that, at any specific site, would result in a mean effective precipitation pH of 3.6.  相似文献   
10.
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