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   10654篇
  免费   392篇
  2020年   137篇
  2019年   192篇
  2018年   243篇
  2017年   274篇
  2016年   337篇
  2015年   225篇
  2014年   230篇
  2013年   3028篇
  2012年   306篇
  2011年   330篇
  2010年   343篇
  2009年   297篇
  2008年   273篇
  2007年   248篇
  2006年   242篇
  2005年   153篇
  2004年   140篇
  2003年   118篇
  2002年   136篇
  2001年   162篇
  2000年   127篇
  1999年   149篇
  1998年   100篇
  1997年   93篇
  1996年   104篇
  1995年   100篇
  1994年   105篇
  1993年   109篇
  1992年   104篇
  1991年   87篇
  1990年   77篇
  1989年   97篇
  1988年   89篇
  1987年   104篇
  1986年   90篇
  1985年   119篇
  1984年   99篇
  1983年   149篇
  1982年   115篇
  1981年   114篇
  1980年   117篇
  1979年   101篇
  1978年   106篇
  1977年   117篇
  1976年   109篇
  1975年   103篇
  1974年   81篇
  1973年   79篇
  1972年   77篇
  1970年   61篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Palace lanterns were important and highly visible decorations in the imperial palace in Beijing, China, during the Qing dynasty (1636–1912). Most lanterns had colourful tassels made of fibres. The study performed a comprehensive investigation of the materials and dyes used for palace lantern tassels preserved in The Palace Museum, Beijing. Eight samples with different colours, including yellow, green and red, from five palace lanterns were analysed. By using ultra-performance liquid chromatography combined with time-of-flight mass spectrometry, the compositions of the dyes were identified quickly, and thus the dyes' origins were explored. A X-ray fluorescence spectrometer assisted in the detection of whether a mordant was used during the dyeing process. As a result, the tassels were all made of silk, discovered through the use of microscopic observation and micro-Fourier transform infrared spectrometry analysis. Different dyeing techniques were found in these tassels: yellow tassels were dyed by cork tree or turmeric by a direct dyeing method; greens were dyed by pagoda bud with an iron mordant, or by the combination of cork tree and indigo using multi-dyeing method; and red tassels were coloured with different acid red industrial dyes. These results provide valuable data for the conservation of ancient textile tassels and contribute to the investigation of other hanging tags.  相似文献   
5.
6.
7.
8.
9.
Trigger levels for fine suspended sediment (FSS) load in streams are required to identify rainfall-runoff events that have significantly elevated FSS loads, compared with expected background loads, as a result of catchment disturbance. Stream FSS load data collected in the mine-impacted Magela Creek catchment in the wet-dry tropics were used to derive water quality management trigger levels for two approaches – a Before-After-Control-Impact Paired difference design (BACIP) and a regression relationship between observed FSS load and corresponding event discharge characteristics. The results indicate that both the BACIP and regression relationship approaches behave similarly, with similar FSS load events elevated above trigger levels. Notwithstanding this, it is recommended that in order to reliably assess the location and magnitude of a catchment disturbance on FSS load, a combination of BACIP and regression relationship approaches must be adopted. In this study, an event with a FSS load above trigger levels associated with both BACIP and the regression relationship fitted for the downstream site is considered to be significantly elevated as a result of a disturbance within the mine-impacted region. While this technique cannot conclusively determine whether the cause of the disturbance is mine-related or natural (such as fire or bank erosion), it is an efficient statistical method of identifying events that warrant further investigation and management action, if required.  相似文献   
10.
This paper examines the comparatively patchy evidence for the pastoral provision and personal faith of late medieval Scottish combatants below the rank of knight. By examining such sources as papal supplications, royal financial accounts, parliamentary rolls, chronicles, poetry and the cartularies of Scottish monastic houses and burgh collegiate churches, it is possible to identify elite and parish provision of churchmen serving the needs of Scottish troops as they mustered, trained and prepared for battle. In addition, this evidence also highlights a number of cults and relics popular with the social ranks of the ordinary Scottish soldiery, including those of SS Ninian, Leonard, Thomas Becket, Columba, the Blessed Virgin Mary and — often cast as the nemesis of Scottish troops — Cuthbert. However, this survey also points to some tensions between the spiritual interests of Scottish servicemen and their ruling elites.  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