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   20846篇
  免费   183篇
  国内免费   204篇
安全科学   549篇
废物处理   1001篇
环保管理   2478篇
综合类   2954篇
基础理论   5327篇
环境理论   4篇
污染及防治   5675篇
评价与监测   1664篇
社会与环境   1459篇
灾害及防治   122篇
  2023年   96篇
  2022年   215篇
  2021年   220篇
  2020年   140篇
  2019年   178篇
  2018年   332篇
  2017年   326篇
  2016年   527篇
  2015年   374篇
  2014年   584篇
  2013年   1761篇
  2012年   681篇
  2011年   870篇
  2010年   819篇
  2009年   800篇
  2008年   900篇
  2007年   994篇
  2006年   885篇
  2005年   734篇
  2004年   731篇
  2003年   717篇
  2002年   681篇
  2001年   916篇
  2000年   636篇
  1999年   402篇
  1998年   277篇
  1997年   247篇
  1996年   294篇
  1995年   277篇
  1994年   252篇
  1993年   235篇
  1992年   241篇
  1991年   210篇
  1990年   218篇
  1989年   219篇
  1988年   199篇
  1987年   158篇
  1986年   127篇
  1985年   142篇
  1984年   174篇
  1983年   155篇
  1982年   197篇
  1981年   136篇
  1980年   120篇
  1979年   153篇
  1978年   120篇
  1977年   107篇
  1976年   101篇
  1975年   85篇
  1974年   89篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
891.
Concerns about climate change as a result of anthropic actions have led to an increase in the volume of information disclosed about it in the reports of companies that are members of the Carbon Disclosure Project (CDP). In this context, the factors most disclosed remain obscure due to both the complexity of climate change impacts and the stakeholders’ different interests. This study aims to identify which factors are most disclosed in the reports of companies that are members of CDP. For this purpose, it is necessary to investigate if the factors indicated by managers and experts are the main ones disclosed in the reports of Brazilian companies that are members of CDP, as well as to identify which companies stand out in climate change disclosure based on these factors. To this end, 463 reports submitted by 48 companies between 2014 and 2016 were examined and 32 factors were investigated using the NVivo® software. Some companies submitted reports with unified titles, which reduced the sample. The results indicate that certain factors—prevention of pollution, prevention of loss, management of environmental assets, volume of greenhouse gas (GHG) emissions, and climate change strategy—account for 50.03% of the total volume of information disclosed about climate change. The main lesson learned from this research is that climate change mitigation strategy is strongly supported by the evidence of corporate annual reports, and it has relation with the following determinant factors: pollution prevention, loss prevention, environmental asset management, GHG emissions, and the strategy chosen by the companies to deal with climate change. Due to the low volume of research related to loss prevention and pollution prevention, we have identified that little attention has been paid to these items. Based on our results, we recommend that climate change mitigation strategies begin to consider these determinant factors in their structure because both have a strong influence in demonstrating how companies are managing these factors for stakeholders. Therefore, companies can benefit from this data to manage their resources for the maintenance of the social contract (legitimacy) through the factors most disclosed, especially companies with lower scores on the scale of ranking presented. Hence, stakeholders can have access to more information on strategies that mitigate climate change and help companies improve the disclosure of the actions that contribute to reduction of GHG emissions.  相似文献   
892.
893.
There was a widespread misconception about the causes of vegetation and land fires in Indonesia. At a certain point, the public perceived that fires and the associated haze pollution were primarily caused by smallholders' agricultural activities. In fact, there was a variety of land-use activities including large-scale land clearing following deforestation for further land development. El Niño events and the associated dry weather were sometimes quoted by officials and the media as the cause of fires. The fire episodes from 1980 to 2000 were analysed in connection with climate anomalies and the implementation of land-use policies related to forest conversions. The analysis employs long-term climatic and sea surface temperature data to reconstruct climate distributions and anomalies including Southern Oscillation Index (SOI), Sea Surface Temperature (SST) and Outgoing Long-wave Radiation (OLR). In this study, the terrestrial carbon emissions from vegetation fires were estimated based on official statistical data on area burnt. The possible incentives for sustainable land management were discussed in the light of fire prevention. The underlying cause neglected in the discussion of Indonesian vegetation fires was forest and land development policy. Legitimated in the early 1980s, it drove massive forest conversions and the use of fires for land clearing. El Niño Southern Oscillation (ENSO) provided dry weather suitable for biomass burning and widespread fire, but it was hardly the cause of fires. The estimate of area burnt in the big fires in 1997 was about 11.6 Mha, resulting in carbon release of 1.45 Gt, equivalent to 0.73 ppmv of CO2, or almost half the annual global atmospheric CO2 growth. Based on the current carbon market price such emissions by the 1997 fire episode were worth around US$ 3.6 billion.  相似文献   
894.
895.
896.
897.
898.
899.
900.
Among 5315 prenatal diagnoses performed for various indications (maternal age, neural tube defect, metabolic diseases, X-linked diseases, pathologic pregnancies) 29 unexpected structural chromosome rearrangements were found in fetal cells. Fourteen were de novo chromosome rearrangements, six unbalanced, and eight balanced. Fifteen were inherited and balanced rearrangements. This high frequency of structural anomalies is discussed.  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