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   201篇
  免费   12篇
  2023年   1篇
  2021年   3篇
  2020年   7篇
  2019年   9篇
  2018年   10篇
  2017年   12篇
  2016年   11篇
  2015年   3篇
  2014年   11篇
  2013年   41篇
  2012年   7篇
  2011年   6篇
  2010年   6篇
  2009年   11篇
  2008年   8篇
  2007年   2篇
  2006年   2篇
  2005年   6篇
  2004年   3篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  2000年   3篇
  1999年   2篇
  1998年   5篇
  1997年   4篇
  1996年   3篇
  1995年   4篇
  1994年   3篇
  1992年   3篇
  1991年   4篇
  1990年   2篇
  1989年   4篇
  1988年   4篇
  1987年   3篇
  1986年   1篇
  1981年   1篇
  1979年   1篇
  1972年   1篇
  1969年   1篇
排序方式: 共有213条查询结果,搜索用时 31 毫秒
21.
22.
In his Sociology of music, Max Weber stressed the importance of the invention of notation on lines by Guido of Arezzo (c. 990–1035). This article traces the beginnings of musical notation. Although Guido of Arezzo proposed a system of lines in which each note is always in the same place, he also placed the neumes invented before him on these lines. The first annotators sought to note with precision the rhythmic nuances and ornaments of the melodies; but those subtle indications disappeared little by little from the notation, betraying an inflexibility of the tradition, which contributed to the orientation of western music towards paths which did not know other music of oral tradition.  相似文献   
23.
24.
25.
26.
27.
28.
The Palmottu hydrosystem is located in a granitic host rock in southern Finland. Along well‐defined pathways in the fractured crystalline rock, strontium isotopes are used to trace the degree of water–rock interaction (WRI) and mixing processes in groundwaters. The 87Sr/86Sr ratios range between 0.716910 and 0.735606 in the surface waters and between 0.719991 and 0.750787 in the groundwaters, but are between 0.720 and 0.735 in most of the samples. Moreover, the results show a lack of correlation between the water chemistries determining the classification into different water‐types (Na–Cl, Na–SO4, etc.) and the results of the strontium (Sr) contents and Sr isotopic ratios. From a WRI standpoint, this implies that the Sr behaviour is independent of the water chemistry; the occurrence of large 87Sr/86Sr variations is site specific and mainly dependent on the lithology. A model to determine the 87Sr/86Sr ratio of water after interaction with granite was developed. This model is based on the assumption that Sr was derived from three minerals: plagioclase, K‐feldspar and biotite. The results of the calculation indicate that around half of the water analysed within the Palmottu hydrosystem can be explained by the weathering of the granites. However, clearly lower 87Sr/86Sr are observed in waters when compared to the calculated 87Sr/86Sr and other sources of Sr, with low 87Sr/86Sr, rather than the calculated granite–water interaction, which may be suspected. When comparing the 87Sr/86Sr and ion ratios (Ca/Na, Mg/Na, Sr/Na, Cl/Na), the scattering of the data can be explained by the presence of four end‐members: a brine component (low 87Sr/86Sr and Ca/Na ratios…), a deep granitic component (high 87Sr/86Sr ratios and low Ca/Na ratios…), a subsurface component (intermediate 87Sr/86Sr ratios associated with high Ca/Na ratios…) and a surface end‐member:snow and river drainage (low 87Sr/86Sr and low Ca/Na ratios…). These extreme end‐members define a series of WRI‐mixing line within a rather complex hydrosystem.  相似文献   
29.
Mineralised fruits and seeds are frequently found in archaeological sediments but their chemical nature has not been often examined. The nature and the origin of these archaeobotanical remains have to be investigated to understand their taphonomic history. Fruits or seeds can be mineralised not only by replacement mineralisation but also by biomineralisation during the plant life. The mineral components of three fossil fruits sampled on the Pleistocene site of Dmanisi were analysed and compared with their modern analogues. Analyses were carried out by means of an environmental scanning electron microscope, equipped with an energy dispersive X-ray device and by means of a Fourier transform infrared spectrometer. Biogenic carbonates and/or biogenic silica were identified in the fossil and modern fruits of some taxa. Comparison between fossil and modern specimens has shown that molecular reorganisation occurred in carbonate and in biogenic silica during fossilisation, through diagenetic processes. The resulting stable mineral structures confer an exceptional preservation to fruits in sediments. Taking into account these taphonomic specificities (transformation and differential preservation), the chronological and palaeoenvironmental aspects of the mineralised fruits are discussed.  相似文献   
30.
On 12 July 2006, Hezbollah's kidnapping of two young Israeli soldiers was the catalyst for a sudden escalation of the conflict between Israel and Hezbollah. Lebanon was host to more citizens and permanent residents from Australia than any other country in the world. This article examines the monumental challenge faced by the Australian authorities in rescuing and repatriating its citizens who were caught up in the conflict. It does so through the conceptual lens of ‘remote crisis management’ i.e. episodes where one country's traditional crisis management challenges of rapid threats, uncertainty and the need for swift decision making are compounded by ‘political remoteness’. In other words, it lacks both political sovereignty and local infrastructure capacity for crisis resolution in a faraway county. The article focuses particularly on the remote crisis management challenges of making sense of the crisis, communication with a range of interests, and the logistical challenges of arranging and installing rescue and evacuation procedures. It also addresses the significance of Australia's prior evacuation experiences, as well as the capacity it had built in local and international networks. The article draws on a range of primary and secondary sources, including interviews with public servants and community representatives.  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