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   69篇
  免费   1篇
  2022年   1篇
  2021年   3篇
  2020年   2篇
  2018年   2篇
  2016年   2篇
  2015年   1篇
  2014年   2篇
  2013年   11篇
  2012年   4篇
  2011年   3篇
  2010年   6篇
  2009年   8篇
  2008年   15篇
  2007年   4篇
  2006年   4篇
  2005年   2篇
排序方式: 共有70条查询结果,搜索用时 15 毫秒
1.
VandenBerg, Alfons H.M., November 2017. Fragmentation as a novel propagation strategy in an Early Ordovician graptolite. Alcheringa 42, 1–9. ISSN 0311-5518.

Catenagraptus communalis gen. nov. sp. nov. is a late Floian (Early Ordovician) graptolite from Victoria, Australia, only found as fragments, with each fragment resembling an assemblage of uniserial tubarium-like structures (pseudotubaria) connected by threads (aulons). Individual pseudotubaria consist of a fallosicula and a stipe, both of which are linked by aulons to other pseudotubaria. Adjacent pseudotubaria are in a parent–offspring relationship. Aulons can be generated from both the proximal and distal extremities of fallosiculae, and from the ends of stipes. The aulons are interpreted to have been grown by the zooid that occupied either the fallosicula or the terminal theca of the stipe. Aulons were pathways for a zooid that built a fallosicula at the end of the aulon. This process was repeated to form the assemblage. None of the assemblages contain a true sicula, which suggests that the assemblages present evidence of a new, asexual propagation strategy that involved fragmentation and dispersal. As this interpretation is radical, other models explored are partial sclerotization and modified sicular spines.

Alfons H.M. VandenBerg [], Museum Victoria, GPO Box 666, Melbourne 3001, Victoria, Australia.  相似文献   

2.
X. Zhou  T. J. Burbey 《Geofluids》2014,14(2):174-188
The initiation of hydraulic fractures during fluid injection in deep formations can be either engineered or induced unintentionally. Upon injection of CO2, the pore fluids in deep formations can be changed from oil/saline water to CO2 or CO2 dominated. The type of fluid is important not only because the fluid must fracture the rock, but also because rocks saturated with different pore fluids behave differently. We investigated the influence of fluid properties on fracture propagation behavior by using the cohesive zone model in conjunction with a poroelasticity model. Simulation results indicate that the pore pressure fields are very different for different pore fluids even when the initial field conditions and injection schemes (rate and time) are kept the same. Low viscosity fluids with properties of supercritical CO2 will create relatively thin and much shorter fractures in comparison with fluids exhibiting properties of water under similar injection schemes. Two significant times are recognized during fracture propagation: the time at which a crack ceases opening and the later time point at which a crack ceases propagating. These times are very different for different fluids. Both fluid compressibility and viscosity influence fracture propagation, with viscosity being the more important property. Viscosity can greatly affect hydraulic conductivity and the leak‐off coefficient. This analysis assumes the in‐situ pore fluid and injected fluid are the same and the pore space is 100% saturated by that fluid at the beginning of the simulation.  相似文献   
3.
《明书》由傅维鳞参修《明史》而引发,自顺治四年开始撰写,到十年基本完成。以完成时间论,是第一部明代全史。《明书》的刊布、流传,经历了一个比较坎坷的历程,这与清廷的文化政策,与《四库全书总目》的苛评,与《明史》的独尊地位,都有着千丝万缕的联系。  相似文献   
4.
虚假新闻折射新闻职业道德——加强新闻职业道德之我见   总被引:1,自引:0,他引:1  
刘娜娜 《攀登》2008,27(4):203-204
新闻职业道德,是新闻工作者在长期的职业实践中形成的调整和处理新闻机构内外相互关系的行为规范或准则。当前,一些新闻工作者违背职业道德,给新闻事业造成了不良的影响。虚假新闻的出现,就是一些新闻工作者职业道德与操守缺失的表现。对此,笔者分析了产生虚假新闻的主要原因,认为要减少、杜绝虚假新闻现象,必须要加强新闻工作者的道德修养,树立正确的职业道德观。  相似文献   
5.
Much scholarly work on the literary culture of the early Qing dynasty has focused on notions of memory, trauma, and nostalgia. In contrast, this essay investigates the "contemporary operas" (shishi xiqu) of the seventeenth-century Suzhou playwright Li Yu to argue for the importance of the notion of"the present day." How is this notion of the present day given dramatic form in Li Yu's operas and what implications does this interest in the contemporary have for the broader cultural scene of the early Qing dynasty? This paper will answer these questions by investigating one dramatic technique favored by Li Yu: the inclusion of snippets of rumor and "news" reports into the play. By including such contemporary media reports, Li Yu not only generates a constantly evolving sense of the present, he also projects this sense of immediacy beyond the fiction of the stage into the "reality" of the audience, creating a form of opera eminently suited for both reflecting and producing local Suzhou activism, as evidenced in Li Yu's most famous work, Qing zhong pu (Registers of the pure and loyal), a work chronicling the popular Suzhou protests of the mid-1620s and Wanli yuan (Reunion over ten thousand miles), which stages the dissolution and reintegration of family and empire right after the fall of the Ming.  相似文献   
6.
Tuvalu, a place whose image in the ‘West’ is as a small island state, insignificant and remote on the world stage, is becoming remarkably prominent in connection with the contemporary issue of climate change‐related sea‐level rise. My aim in this paper is to advance understanding of the linkages between climate change and island places, by exploring the discursive negotiation of the identity of geographically distant islands and island peoples in the Australian news media. Specifically, I use discourse analytic methods to critically explore how, and to what effects, various representations of the Tuvaluan islands and people in an Australian broadsheet, the Sydney Morning Herald, emphasize difference between Australia and Tuvalu. My hypothesis is that implicating climate change in the identity of people and place can constitute Tuvaluans as .tragic victims. of environmental displacement, marginalizing discourses of adaptation for Tuvaluans and other inhabitants of low‐lying islands, and silencing alternative constructions of Tuvaluan identity that could emphasize resilience and resourcefulness. By drawing attention to the problematic ways that island identities are constituted in climate change discourse in the news media, I advocate a more critical approach to the production and consumption of representations of climate change.  相似文献   
7.
在日本侵华战争中,被军国主义狂热笼罩的日本新闻传媒失去了理智与道德.在1937年12月侵华日军进攻中国首都南京的战役中,日本随军记者与日本各大新闻传媒多次作了不实报道:既凭空捏造中国军民防守的南京"完全变成了一个鬼魂哭叫的死亡街道",又在日军尚被阻击在南京远郊时,几次虚报日军"占领"南京的"胜利消息",引起了日本的"举国狂欢".此举遭到一些知情者的质疑与批驳,成为世界新闻史上的丑闻与笑料.  相似文献   
8.
杨晓冬 《攀登》2010,29(3):100-105
本文就新时期如何全面准确理解新闻党性原则,牢牢把握和坚持新闻党性原则的时代要求,科学处理新闻党性与人民性的关系、党性原则与尊重规律的关系、社会效益与经济效益的关系以及主旋律与多样化的关系进行了论述,阐明了只有把握新闻党性原则的时代特色,才能不断开创社会主义新闻事业的新局面。  相似文献   
9.
关青兰 《攀登》2010,29(4):122-124
中共青海省委十一届六次全体会议提出的跨越发展、绿色发展、和谐发展和统筹发展是具有青海特点的科学发展模式。新闻宣传在实现四个发展中担负着重要责任。文章通过新闻宣传与“四个发展”关系的论述,阐明新闻媒体及其工作者要准确把握和理解“四个发展”的深刻内涵、基本特征和内在联系,把四个发展的要求贯穿到宣传报道之中,在建设富裕文明、和谐的新青海中做好舆论引导,为推动“四个发展”发挥应有的作用。  相似文献   
10.
龙燕宁 《攀登》2009,28(4):122-124
做好经济新闻报道对于贯彻党和国家有关经济方面的方针、政策,对于客观理性地分析世界经济局势、评判我国经济现状和走向、保持经济平稳较快发展、满足人民群众日益增长的信息需求都具有十分重要的意义。文章指出了长期以来我们在经济新闻报道方面存在的问题,并就这些问题提出了改进方法。  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