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   273篇
  免费   32篇
  2024年   1篇
  2023年   4篇
  2022年   6篇
  2021年   7篇
  2020年   14篇
  2019年   11篇
  2018年   9篇
  2017年   16篇
  2016年   22篇
  2015年   14篇
  2014年   10篇
  2013年   43篇
  2012年   12篇
  2011年   22篇
  2010年   15篇
  2009年   10篇
  2008年   19篇
  2007年   14篇
  2006年   11篇
  2005年   12篇
  2004年   7篇
  2003年   9篇
  2002年   4篇
  2001年   3篇
  2000年   4篇
  1999年   1篇
  1996年   3篇
  1994年   1篇
  1993年   1篇
排序方式: 共有305条查询结果,搜索用时 15 毫秒
1.
Scientists advise limiting global warming to 1.5°C with substantial actions by 2030. Our viewpoint argues that climate response strategies in Canada have underemphasized and underestimated the potential contribution deep energy retrofits can make to greenhouse gas (GHG) emissions reductions, leading to inadequate responses in the building sector, and that Canada can (and should) be ambitious with building retrofits over the next decade. GHG savings from building retrofits can be realized more quickly than GHG reductions from other sectors, and either deliver net cost savings or are cost‐effective when compared to other mitigation measures. Retrofits can also provide social and economic benefits, such as improved health and comfort, and lower energy costs. This paper reviews energy use and building retrofits in Canada and argues the following should be implemented: (1) focus innovation on deep energy retrofit processes, not singular retrofit actions; (2) maximize both social and environmental benefits; (3) improve data gathering and availability for analysis and delivery; (4) innovate for a process of decisions and to avoid “dropouts” during the retrofit process; and (5) focus innovation on business models that maximize benefits.  相似文献   
2.
高颐阙是东汉晚期的红色砂岩的建筑物。位于四川省雅安市。阙檐东面残缺.导致日晒雨淋加剧,苔藓丛生,从而引起严重风化。为此,对残损阙檐进行了修复。根据高颐阙的结构.雅安市的气候特征及阙石的化学组成和物理性质.讨论了薄片检查和 X 衍射分析的结果、修复残缺阙檐的理论基础以及计算、修复的程序和效果。  相似文献   
3.
This paper investigates the function of beauty in David and Bathsheba’s encounter in 2 Sam 11,1-5. It argues that the female bather’s pleasant appearance, rather than simply kindling king David’s desire, focalizes the woman as sexually available (and vulnerable) and wraps the whole episode in a royal fantasy of shared intimacy. The focus on Bathsheba’s beautiful body—her wash, her motion towards the king, her self-sanctification and her pregnancy—frames the episode in a very erotic way, suggesting adultery. It conceals the sexual violence committed by the king who sends, takes and sleeps with the woman. David’s violent entitlement to Bathsheba reveals the beauty politics at play in his royal House.  相似文献   
4.
ABSTRACT

Along Florida’s nearly 13,000 km of shoreline, nearly 4000 archaeological sites and over 600 recorded historic cemeteries are at risk from climate change impacts including coastal erosion and a 2-metre rise in sea level. In 2016, the Florida Public Archaeology Network (FPAN) created the Heritage Monitoring Scouts (HMS Florida) programme to engage the public in monitoring sites at risk. The programme grew quickly during the first year of operation to include 233 volunteers who submitted 312 monitoring forms. The programme exists beyond the singular act of a volunteer reporting site conditions; across Florida, varied combinations of local partnerships present unique opportunities for programmes, for example, the pilot program at the Guana Tolomato Matanzas National Estuarine Research Reserve. Preliminary outcomes from the first year of HMS Florida and the pilot indicate the programme is effective in public engagement and a powerful management tool for tracking change to sites over time.  相似文献   
5.
Capillary trapping is a physical mechanism by which carbon dioxide (CO2) is naturally immobilized in the pore spaces of aquifer rocks during geologic carbon sequestration operations, and thus a key aspect of estimating geologic storage potential. Here, we studied capillary trapping of supercritical carbon dioxide (scCO2), and the effect of initial scCO2 saturation and flow rate on the storage/trapping potential of Berea sandstone. We performed two‐phase, scCO2‐brine displacements in two samples, each subject to four sequential drainage–imbibition core‐flooding cycles to quantify end‐point saturations of scCO2 with the aid of micro‐ and macro‐computed tomography imaging. From these experiments, we found that between 51% and 75% of the initial CO2 injected can be left behind after the brine injection. We also observed that the initial scCO2 saturation influenced the residual scCO2 saturation to a greater extent than the rate of brine injection under the experimental conditions examined. In spite of differences in the experimental conditions tested, as well as those reported in the literature, initial and residual saturations were found to follow a consistent relationship.  相似文献   
6.
G. Etiope  A. Ionescu 《Geofluids》2015,15(3):438-452
Metal‐catalysed CO2 hydrogenation is considered a source of methane in serpentinized (hydrated) igneous rocks and a fundamental abiotic process germane to the origin of life. Iron, nickel, chromium and cobalt are the catalysts typically employed in hydrothermal simulation experiments to obtain methane at temperatures >200°C. However, land‐based present‐day serpentinization and abiotic gas apparently develop below 100°C, down to approximately 40–50°C. Here, we document considerable methane production in thirteen CO2 hydrogenation experiments performed in a closed dry system, from 20 to 90°C and atmospheric pressure, over 0.9–122 days, using concentrations of non‐pretreated ruthenium equivalent to those occurring in chromitites in ophiolites or igneous complexes (from 0.4 to 76 mg of Ru, equivalent to the amount occurring approximately in 0.4–760 kg of chromitite). Methane production increased with time and temperature, reaching approximately 87 mg CH4 per gram of Ru after 30 days (2.9 mgCH4/gru/day) at 90°C. At room temperature, CH4 production rate was approximately three orders of magnitude lower (0.003 mgCH4/gru/day). We report the first stable carbon and hydrogen isotope ratios of abiotic CH4 generated below 100°C. Using initial δ13CCO2 of ‐40‰, we obtained room temperature δ13CCH4 values as 13C depleted as ?142‰. With time and temperature, the C‐isotope separation between CO2 and CH4 decreased significantly and the final δ13CCH4 values approached that of initial δ13CCO2. The presence of minor amounts of C2‐C6 hydrocarbons is consistent with observations in natural settings. Comparative experiments at the same temperatures with iron and nichel catalysts did not generate CH4. Ru‐enriched chromitites could potentially generate methane at low temperatures on Earth and on other planets.  相似文献   
7.
While Sunnism is the largest sect of Islam, Sunnism itself is divided into many strands. The two main strands of Sunnism for the last few centuries are the Atharī (or Salafī) strand, and the Ash?arī strand. This papers seeks to examine the earliest recorded controversies that signal this intra‐Sunnī divide. While each of these two groups has historically attempted to claim true Sunnī ‘orthodoxy’ by denying the legitimacy, and at times even the early existence, of the other, it will be shown that the genesis of this intra‐Sunnī divide dates back to the first century of Sunnism itself, viz., the 3rd AH/8th CE centuries, and that there are specific historic incidents that indicate theological tensions within the nascent Sunnī movement that would later be manifested in the two streams of Ash?arism and Salafism. Hence, it can be argued that Sunnism was never truly unified to begin with, and that these incidents demonstrate theological tensions that existed from its very origins.  相似文献   
8.
Since the 1980s there is an overall agreement that German academic and applied geography between 1933 and 1945 were closely linked to the ideology and practice of National Socialism. There is very little historical work, however, on how geography was reestablished in Germany after the end of National Socialism. This paper deals with West German geography after 1945 and the attempts to reestablish geography as a legitimate discipline within academia. Taking the influential paper by German geographer Carl Troll as a starting point, this paper deals, on the one hand, with the way geographers positioned geography in relation to National Socialism, and how they told the history of their recent past. It then asks what the defeat of Germany and the experiences of the war in general meant for how geographers in Germany thought about the relation between the discipline and politics. It is argued that a number of cleansing and legitimating strategies that freed geography from direct involvement with National Socialism, went hand in hand with a very quick adaption to the new world order and a rebranding of geography as a science of peace.  相似文献   
9.
According to the Hebrew version of the transport of the ark to Jerusalem in 2 Samuel 6, King David is so scantily dressed that he publicly exposes himself while dancing before G*d (????). David?s wild, gay and possibly sexual conduct can evoke associations with the behavior of gay persons of today. Queer readers may identify with David and like him turn their backs on dominant rulers—like the members of Saul?s dynasty—if they are not respected because of their queer way of life, but persecuted—as David was persecuted by King Saul. Such an interpretation implies that G*d (????) is on the side of persons like King David, who—from the point of view of other people as well as of David?s wife Michal—behave in a strange fashion, thus act queerly.  相似文献   
10.
Kicking in soccer has been the subject of scientific research for more than 40 years yet review articles summarizing the biomechanical fundamentals of kick optimization as a guide to coaching are scarcely to be found. The current review article aims to bridge the gap between scientific research into the maximal instep kick (including studies employing 3D motion capture and full-body biomechanical modelling) and the application of such research in coaching. It does so by supplying a scientifically founded, coaching-friendly article explaining identifiable characteristics and motor control sequencing that define this skill. Relevant biomechanical factors are identified in a way that should help coaches better develop training programmes and, at the same time, foster better understanding of the skill among athletes. Such information will contribute to both accelerated skill acquisition and, by concomitant gains in skill efficiency, the development of programmes that minimize risk of injury to athletes during training.  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