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   15928篇
  免费   173篇
  国内免费   19篇
教育   10352篇
科学研究   2674篇
各国文化   130篇
体育   1146篇
综合类   12篇
文化理论   143篇
信息传播   1663篇
  2021年   144篇
  2020年   236篇
  2019年   370篇
  2018年   513篇
  2017年   509篇
  2016年   428篇
  2015年   287篇
  2014年   382篇
  2013年   2791篇
  2012年   418篇
  2011年   408篇
  2010年   359篇
  2009年   307篇
  2008年   280篇
  2007年   334篇
  2006年   245篇
  2005年   263篇
  2004年   227篇
  2003年   221篇
  2002年   208篇
  2001年   270篇
  2000年   253篇
  1999年   225篇
  1998年   148篇
  1997年   143篇
  1996年   170篇
  1995年   114篇
  1994年   129篇
  1993年   115篇
  1992年   175篇
  1991年   194篇
  1990年   174篇
  1989年   202篇
  1988年   160篇
  1987年   146篇
  1986年   197篇
  1985年   189篇
  1984年   167篇
  1983年   149篇
  1982年   135篇
  1981年   116篇
  1980年   102篇
  1979年   158篇
  1978年   132篇
  1977年   116篇
  1976年   104篇
  1974年   116篇
  1973年   92篇
  1972年   94篇
  1971年   107篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
ABSTRACT

The preservation of artefacts in museum collections is profoundly affected by fluctuations in temperature and, especially, relative humidity (RH). Since the late nineteenth century, many studies have been carried out on the best way to control hygrothermal conditions. In old buildings located in maritime temperate climate zones (such as Portugal) with strong thermal inertia, and which have low ventilation rate (relative to the volume and number of visitors), daily and seasonal hygroscopic inertia may help to assure the maintenance of RH stabilization conditions. The use of expensive active systems may be minimized through the passive behaviour of internal finishing building materials. This work presents the results of an experimental laboratory study conducted in a flow chamber to demonstrate the enormous potential of hygroscopic materials in stabilizing interior relative humidity. Based in these results and in-situ monitoring in a museum housed in a building, located in Porto, with a typical construction of the 1950s (granite masonry and reinforced concrete slabs), a numerical analysis was done to quantify the influence of hygroscopic materials in stabilizing the interior relative humidity.  相似文献   
3.
The value that willed body donors provide to medical education is priceless. Their precious gift helps to teach anatomy, spatial relationships between morphological structures, anatomical variation, and professionalism to medical students in a way that plastic models, podcasts, and lectures cannot. They are also an important resource for medical research and a wide variety of postgraduate training opportunities. While many body donation programs throughout the world are nonprofit organizations, there are body donation companies in the United States that sell donors for-profit. These “body brokers” have accumulated large profits from this business. It is incongruous that others would profit from such a priceless, freely donated gift. To prevent this incongruity, it is proposed that the international anatomical community develop a normative culture (a bioethos) for body donation programs. This would involve the conscious and systematic development of ethical principles for the day-to-day policies and practices of institutions that collect and use human bodies. With the development of this bioethos, a cultural shift in how donors are treated would occur and, over time, this would become the normal practice. These principles would become fundamental and foundational for the procurement and use of priceless human tissues.  相似文献   
4.
5.
6.
7.
8.
9.
10.
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