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   42037篇
  免费   1631篇
  2020年   532篇
  2019年   819篇
  2018年   936篇
  2017年   1136篇
  2016年   1229篇
  2015年   938篇
  2014年   913篇
  2013年   14110篇
  2012年   1059篇
  2011年   1105篇
  2010年   1087篇
  2009年   1073篇
  2008年   1020篇
  2007年   923篇
  2006年   823篇
  2005年   580篇
  2004年   573篇
  2003年   537篇
  2002年   510篇
  2001年   517篇
  2000年   469篇
  1999年   551篇
  1998年   465篇
  1997年   425篇
  1996年   407篇
  1995年   423篇
  1994年   364篇
  1993年   418篇
  1992年   394篇
  1991年   300篇
  1990年   301篇
  1989年   312篇
  1988年   311篇
  1987年   333篇
  1986年   310篇
  1985年   432篇
  1984年   454篇
  1983年   469篇
  1982年   394篇
  1981年   404篇
  1980年   433篇
  1979年   429篇
  1978年   403篇
  1977年   429篇
  1976年   379篇
  1975年   384篇
  1974年   299篇
  1973年   274篇
  1972年   247篇
  1970年   229篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
There is no doubt that medical semiotics are having a revival at the moment. Different aspects of yesterday's and today's interest in semiotics and in the historical interpretation of signs of disease in the context of theory and history of medicine can be illuminated: their deciphering as the history of the sign in medicine by historic science, their overestimation by philosophy during the Age of Enlightenment, their reduction to a phenomenology of medicine and natural science during the first half of the 19th century and their transformation to medical diagnostics since the middle of the 19th century and recently even their functionalization as methodical instrument within the history of science. The following will show the change in meaning of medical semiotics. Modern development and especially the transition to medicine, based on natural science, will be emphasized.  相似文献   
982.
983.
984.
985.
The characterization of the products of international cooperation as public goods has been severely challenged, undermining a central pillar of theories of international cooperation. I review the criticism of public goods assumptions, identifying the need to account for both exclusion and rival consumption in international cooperative arrangements. Drawing on the recent debate of states as relative versus absolute gains maximizers, I offer a characterization of international cooperative arrangements as discriminatory clubs. I develop a refined relative gains model, which focuses on relative net gains, and apply it to a hypothetical situation to illustrate its usefulness in predicting patterns of exclusion and distribution in international trade.  相似文献   
986.
987.
988.
The Campania was a fertile area, with a growing population during the eleventh and twelfth centuries, and was economically more advanced than most of the rest of southern Italy. This essay examines the impact of the Norman conquest of the south upon this region, with special reference to the settlement pattern and the aristocracy. It concludes that the role of incastellamento in changing the pattern of settlement was relatively limited, and the extensive incastellamento of the Montecassino lands (a product of Norman pressure upon the abbey) cannot be taken as typical. Furthermore, while the Norman conquest led to colonisation by French aristocrats, this did not entirely displace existing Lombard families, and widespread intermarriage led to a blurring of the distinction between Lombards and Normans. The impact of political crises during the twelfth century was also more limited than might be supposed, and continuity rather than change characterised the nobility of the Norman period.  相似文献   
989.
We develop a new conceptual approach to locating inspection stations for hazardous vehicles, prevention, and compare it to the previous, punitive, philosophy of the flow-capturing location model. We implement this preventive protection philosophy with a new mixed integer program that maximizes hazard avoidance by locating a number of inspection stations to detect and remove hazardous vehicles as early in their trips as possible. We test the model's performance and analyze the spatial characteristics of solutions simulating several potential applications. Our computations demonstrate that a relaxed integer-linear program is overly demanding computationally and that a simple greedy heuristic lacks robustness. We suggest further approaches to developing more powerful and efficient solution methods.  相似文献   
990.
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