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排序方式: 共有1046条查询结果,搜索用时 234 毫秒
921.
不同复合人工湿地对高污染河流有机污染物的去除 总被引:1,自引:0,他引:1
为了研究复合人工湿地对高污染河流污水中有机污染物的去除效果及规律,实验构建了不同水力负荷下的潜流+潜流、潜流+表面流、潜流+潜流+表面流、表面流+表面流等人工湿地单元组合成的5个复合人工湿地.连续运行一年以来,各复合人工湿地对BOD5、COD和SS的去除效果分别为91.9% ~94.7%、69.3% ~75.8%和92.3% ~ 93.9%,相对于多级表流湿地,多级潜流湿地更利于有机污染物和悬浮物的去除;BOD5、COD和SS主要在各复合湿地的第一级湿地单元内得到去除;复合人工湿地对COD去除效果秋夏季两季好,春冬两季差;复合人工湿地能有效去除悬浮态BOD5和COD,出水中部分溶解态有机物难以有效降解. 相似文献
922.
根据2015年1月7日至14日在长江口南槽中段主槽内获得的流速和悬沙观测资料,运用机制分解法分析了从大潮到小潮连续变化过程中南槽中段的水沙输运机制,通过小波分析方法探讨了悬沙浓度和流速的周期性对悬沙输运的影响。研究结果表明:(1)在一个大小潮周期过程中各潮周期的单宽净输水以向海为主,斯托克斯余流和欧拉余流的强度由大潮到小潮呈减小趋势;(2)各潮周期的单宽净输沙以向陆为主,与净输水方向相反,输沙强度从大潮至小潮呈现"小-大-小"的变化特征,该特征的产生与潮泵效应输沙的剧烈潮周期变化有关,平流输沙、潮泵效应输沙与垂向净环流输沙项是影响潮周期净输沙的主要成分;(3)小波分析表明,悬沙浓度和流速具有多个时间周期的变化,它们与水位的联合作用导致瞬时输沙率具有2个明显的时间周期变化。 相似文献
923.
Yves Pepermans Pieter Maeseele 《Environmental Communication: A Journal of Nature and Culture》2014,8(2):216-232
Starting from a risk conflicts perspective, this article challenges two common assumptions of existing research on climate change in public and media discourses. It argues that the evaluation of these discourses on the extent to which these either accurately reflect a scientific consensus or contribute to achieving social consensus insufficiently takes account of the exclusionary mechanisms it starts from. A conceptual and empirical framework is subsequently put forward which allows one to evaluate mediated discourses in terms of the extent to which democratic debate and citizenship are encouraged. Such analysis can reveal the discursive strategies underlying processes of politicization and depoliticization. This perspective is illustrated by an analysis of a local case study: the “Sing for the Climate” campaign. We conclude by calling for a broad systematic research agenda revealing the extent to which de/politicizing discourses are found to influence public and media discourses. 相似文献
924.
Ulrika Olausson Peter Berglez 《Environmental Communication: A Journal of Nature and Culture》2014,8(2):249-265
This paper suggests some further avenues of empirical and theoretical investigation for media research on climate change. “Old” suggestions, whose significance, as we see it, needs to be further reinforced, are included, as are “new” ones, which we hope will generate innovative research questions. In order to integrate the analysis with knowledge generated by media research at large, we revisit four research challenges that media scholars have long grappled with in the investigation of journalism: (1) the discursive challenge, i.e. the production, content and reception of media discourse; (2) the interdisciplinary challenge, i.e. how media research might engage in productive collaboration with other disciplines; (3) the international challenge, i.e. how to achieve a more diverse and complex understanding of news reporting globally; and (4) the practical challenge, i.e. how to reduce the theory–practice divide in media research. 相似文献
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928.
Alberto Acerbi John Burns Unal Cabuk Jakub Kryczka Bethany Trapp John Joseph Valletta Alex Mesoudi 《Conservation biology》2023,37(4):e14060
The role of nature documentaries in shaping public attitudes and behavior toward conservation and wildlife issues is unclear. We analyzed the emotional content of over 2 million tweets related to Our Planet, a major nature documentary released on Netflix, with dictionary and rule-based automatic sentiment analysis. We also compared the sentiment associated with species mentioned in Our Planet and a set of control species with similar features but not mentioned in the documentary. Tweets were largely negative in sentiment at the time of release of the series. This effect was primarily linked to the highly skewed distributions of retweets and, in particular, to a single negatively valenced and massively retweeted tweet (>150,000 retweets). Species mentioned in Our Planet were associated with more negative sentiment than the control species, and this effect coincided with a short period following the airing of the series. Our results are consistent with a general negativity bias in cultural transmission and document the difficulty of evoking positive sentiment, on social media and elsewhere, in response to environmental problems. 相似文献
929.
This study, based on data collected from a representative sample of adults in the United States, explores the social cognitive variables that motivated Americans to validate rumours on social media about Hurricanes Harvey and Irma, both of which struck in August/September 2017. The results indicate that risk perception and negative emotions are positively related to systematic processing of relevant risk information, and that systematic processing is significantly related to rumour validation through search engines such as Google. In contrast, trust in information about the hurricane is significantly related to validation through official sources, such as FEMA (Federal Emergency Management Agency), and major news outlets such as The New York Times. Trust in information is also significantly related to systematic processing of risk information. The findings of this study suggest that ordinary citizens may be motivated to validate rumours on social media, which is an increasingly important issue in contemporary societies. 相似文献
930.
总悬浮微粒中的沥青成分在植物中的累积 总被引:2,自引:0,他引:2
在参照美国试验与材料协会标准分析方法(ASTM D4124)的基础上,对邻近高速公路的多种植物样品和大气中总悬浮颗粒样品中的沥青成分极性芳烃、环烷芳烃和饱和物进行了分析。将分析结果与取自高速公路表面的沥青样品和相应的背景植物样品的分析结果对比得知:3种有机组分在植物中的累积过程中,沥青起了主要作用。在实验所分析的植物样品中,3种有机组分在每g干植物样品中的含量分别为0.29-3.07mg(极性芳烃 相似文献