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   7700篇
  免费   65篇
  国内免费   41篇
安全科学   178篇
废物处理   316篇
环保管理   699篇
综合类   1209篇
基础理论   1606篇
环境理论   6篇
污染及防治   1933篇
评价与监测   608篇
社会与环境   1219篇
灾害及防治   32篇
  2023年   35篇
  2022年   86篇
  2021年   107篇
  2020年   56篇
  2019年   72篇
  2018年   160篇
  2017年   179篇
  2016年   214篇
  2015年   144篇
  2014年   267篇
  2013年   599篇
  2012年   291篇
  2011年   365篇
  2010年   289篇
  2009年   324篇
  2008年   387篇
  2007年   420篇
  2006年   316篇
  2005年   322篇
  2004年   276篇
  2003年   263篇
  2002年   245篇
  2001年   266篇
  2000年   214篇
  1999年   99篇
  1998年   83篇
  1997年   79篇
  1996年   72篇
  1995年   100篇
  1994年   77篇
  1993年   63篇
  1992年   69篇
  1991年   65篇
  1990年   77篇
  1989年   61篇
  1988年   48篇
  1987年   44篇
  1986年   54篇
  1985年   48篇
  1984年   55篇
  1983年   40篇
  1982年   49篇
  1981年   38篇
  1980年   47篇
  1979年   46篇
  1977年   33篇
  1974年   32篇
  1973年   33篇
  1972年   39篇
  1969年   33篇
排序方式: 共有7806条查询结果,搜索用时 31 毫秒
71.
Regional Environmental Change - Increased dieback and mortality of “dark needle conifer” (DNC) stands (composed of fir (Abies sibirica), Siberian pine (Pinus sibirica) and spruce (Picea...  相似文献   
72.
73.
74.
75.
Based on 30-year monitoring of Ni2+ and Cu2+ concentrations in the organic horizon of Albic Rustic Podzols and the foliage of six plant species, a dynamic trend in the level of heavy metal accumulation in the components of forest ecosystems of the Kola Peninsula has been revealed against the background of five- to eightfold reduction of pollutant emissions. The direction of the trend has been found to differ: the size of polluted area and pollution level increase with time, while the concentrations of heavy metals in plants decrease due to reduction in their input from the polluted air.  相似文献   
76.
The role of the Siberian musk deer in the diets of the Amur tiger, brown bear, and Asian black bear has been studied in the Sikhote-Alin State Biosphere Reserve in 1992 to 2016. Information has been collected from 763 tiger feeding sites, and the contents of tiger feces have been analyzed. Radiotelemetry has been used to evaluate tiger–musk deer relationships. The musk deer accounted for 0.26% of all animal species found to be eaten by the tiger. Musk deer remains in feces of the tiger, brown bear, and Asian black bear occurred with frequencies of 1.3, 0.2, and 0.3%, respectively. A case of musk deer avoiding the presence of brown bear is described.  相似文献   
77.
The flora of Siberia includes 4500 species, 815 genera, and 123 families of angiosperms. The causes of the relationship between sexual forms and such ecological and biological features of plants as the life form, the mode of pollination, pericarp’s consistency, habitat type, zonal group, and the ecological group in relation to moistening were analyzed and discussed. For the first time, we demonstrated that gynomonoecy in the flora of Siberia was associated with a semiwoody growth form, pollination by wind, and propagation in zonal communities. It was revealed that gynodioecy in Siberia was associated with a semiwoody growth form, circumpolar or Eurasian distribution, and floodplain meadows. It was found that the ratio of dioecious and hermaphrodite plants in the ecological-biological complexes of species directly depends on the frequency of the abundance of species with endemic areas.  相似文献   
78.
A methodology of substantiating the ecological risk of technogenic soil pollution has been described according to the results of bioindication using microfungal communities. At the first state, the values of the factors under which the frequency of each species is maximal were estimated using ordination methods. The statistical distribution of the species sensitivity was simulated according to these data. The methodology was illustrated using the results of analysis of the toxicity of soil samples from uranium mine dumps (the village of Kadzhi-Sai, Kyrgyzstan). The preliminary estimates of the critical values of six soil pollution indices that provide the defined allowable probability of the ecological risk have been given.  相似文献   
79.
Data on the ratio of stable carbon isotopes in xylotrophic fungi and their xylic substrates are presented for the first time. It is shown that coniferous substrates are more enriched in the heavy carbon isotope, compared to deciduous substrates. In both cases, however, their carbon isotope composition is characterized by low variability and does not correlate with the species or physiological type of decomposer fungus but shows a statistically significant correlation with the degree of wood mineralization. The ratio of stable carbon isotopes in the fungi depends on that in their substrates but is shifted in favor of the heavier isotope. This trophic shift lacks species specificity, is equally manifested in decomposers of deciduous and coniferous substrates, remains unchanged along the latitudinal climatic gradient, and is positively correlated with the carbon isotope composition of substrates, in the absence of correlation with the degree of their mineralization.  相似文献   
80.
While rural transformations are nothing new in human history, current processes of rural change occur under multiple forces at an unprecedented pace, involving profound and unexpected changes in land use and users, and rapid transformations in the metabolic patterns of rural systems. The present special section aims to shed light on current drivers and pathways of rural change by analyzing, under a common conceptual and theoretical framework, examples of new ruralities that are emerging as responses across different world regions. Within this context, this introduction presents: (1) common research questions of the six presented cases of rural change; (2) the general theoretical and methodological framework of integrated assessment of societal metabolism adopted to analyze rural systems and (3) the main contributions and conclusions that could be drawn from six context-specific case studies from Asia, Latin America and Europe.  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