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   39308篇
  免费   392篇
  国内免费   418篇
安全科学   889篇
废物处理   1991篇
环保管理   5237篇
综合类   6842篇
基础理论   10265篇
环境理论   13篇
污染及防治   9307篇
评价与监测   2747篇
社会与环境   2660篇
灾害及防治   167篇
  2022年   255篇
  2021年   261篇
  2020年   232篇
  2019年   229篇
  2018年   1822篇
  2017年   1691篇
  2016年   1734篇
  2015年   620篇
  2014年   742篇
  2013年   2304篇
  2012年   1356篇
  2011年   2579篇
  2010年   1667篇
  2009年   1703篇
  2008年   2122篇
  2007年   2484篇
  2006年   1190篇
  2005年   1026篇
  2004年   1058篇
  2003年   1029篇
  2002年   1011篇
  2001年   1159篇
  2000年   828篇
  1999年   551篇
  1998年   360篇
  1997年   401篇
  1996年   412篇
  1995年   460篇
  1994年   404篇
  1993年   385篇
  1992年   345篇
  1991年   369篇
  1990年   344篇
  1989年   314篇
  1988年   301篇
  1987年   266篇
  1986年   273篇
  1985年   270篇
  1984年   341篇
  1983年   296篇
  1982年   315篇
  1981年   282篇
  1980年   236篇
  1979年   252篇
  1978年   212篇
  1977年   199篇
  1976年   167篇
  1975年   183篇
  1974年   192篇
  1972年   170篇
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
991.
Salinity levels vary spatially in coastal areas, depending on proximity to freshwater sources, and may also be slowly decreasing as a result of anthropogenic climatic changes. The impact of salinity on host–parasite interactions is potentially a key regulator of transmission processes in intertidal areas, where trematodes are extremely common parasites of invertebrates and vertebrates. We investigated experimentally the effects of long-term exposure to decreased salinity levels on output of infective stages (cercariae) and their transmission success in the trematode Philophthalmus sp. This parasite uses the snail Zeacumantus subcarinatus as intermediate host, in which it asexually produces cercariae. After leaving the snail, cercariae encyst externally on hard substrates to await accidental ingestion by shorebirds, which serve as definitive hosts. We found that at reduced salinities (25 or 30 psu), the cercarial output of the parasite was lower, the time taken by cercariae to encyst was longer, fewer cercariae successfully encysted and encysted parasites had lower long-term survival than at normal seawater salinity (35 psu). The strong effect of salinity on the replication and transmission of this parasite suggests that there may be sources and sinks of transmission to birds along coastal areas, depending on local salinity conditions. Also, unless it evolves to adapt to changing conditions, the predicted reduction in salinity as a consequence of climate change may have negative impact on the parasite’s abundance.  相似文献   
992.
Loss of zooxanthellae (dinoflagellate Symbiodinium) from corals will sometimes lead to mass mortality of corals. To detect and quantify Symbiodinium released from corals, we developed a zooxanthellae “trap” and a quantitative PCR (qPCR) system with Symbiodinium clades A–F-specific primer sets. The trap was attached to a branch or the surface of several wild stony corals, and the water samples within the traps, including released Symbiodinium, were subjected to qPCR. All tested corals released clade C Symbiodinium at estimates of ~5,900 cells h−1 cm−2 of coral surface. Although all tested Pocillopora eydouxi harboured both clades C and D, some of these colonies released only clade C or released a lesser amount of clade D than that in the tissues. Our Symbiodinium quantification system revealed that wild hermatypic corals constantly release Symbiodinium to the environment. Our result suggests that some corals may discharge certain clades of Symbiodinium alternatively.  相似文献   
993.
994.
995.
Mountain ecosystems are considered vulnerable to early impacts of climate change. Whether and how local residents of these areas perceive these changes, however, remain under-studied questions. By conducting a household survey in the Khumbu region of Nepal, this study assessed local residents’ experience-based perception of changes in climate trends and patterns, perceived risk, and attitudes towards climate issues. Multivariate cluster analysis based on residents’ climate change beliefs revealed three segments: “Cautious,” “Disengaged,” and “Alarmed.” A comparison of these segments along key psychosocial constructs of Protection Motivation Theory (PMT) revealed significant inter-segment differences in residents’ perception of severity, vulnerability, response efficacy, self-efficacy, and response cost associated with engaging in mitigating behavior. Results shed light on how residents of high elevation areas that are considered to be exposed to early impacts of climate change perceive the risk and intend to respond. These findings could also assist stakeholders working in other similar mountain ecosystems in understanding vulnerability and in working towards climate readiness.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01369-x) contains supplementary material, which is available to authorized users.  相似文献   
996.
Environmental Science and Pollution Research - The order Odonata has been regularly used as an indicator of the ecosystem’s condition. The objective of this review was to analyze the...  相似文献   
997.
Environmental Science and Pollution Research - The scientific knowledge produced by academic research can be valued in all sectors of human activity, including private sector. The ROVALTAIN...  相似文献   
998.
Environmental Science and Pollution Research - The process TiO2/PAC/UV-vis has been under study and compared with the isolated treatments of adsorption and photocatalysis determining possible...  相似文献   
999.
Environmental Science and Pollution Research - This paper presents the synthesis of a hybrid material through the use of natural pozzolan and titanium(IV) isopropoxide using the sol-gel method and...  相似文献   
1000.
Nature-based solutions (NbS) are increasingly recognized as sustainable approaches to address societal challenges. Disaster risk reduction (DRR) has benefited by moving away from purely ‘grey’ infrastructure measures towards NbS. However, this shift also furthers an increasing trend of reliance on public acceptance to plan, implement and manage DRR measures. In this review, we examine how unique NbS characteristics relate to public acceptance through a comparison with grey measures, and we identify influential acceptance factors related to individuals, society, and DRR measures. Based on the review, we introduce the PA-NbS model that highlights the role of risk perception, trust, competing societal interests, and ecosystem services. Efforts to increase acceptance should focus on providing and promoting awareness of benefits combined with effective communication and collaboration. Further research is required to understand interconnections among identified factors and how they can be leveraged for the success and further uptake of NbS.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-021-01502-4.  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