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   5479篇
  免费   247篇
  2020年   90篇
  2019年   127篇
  2018年   162篇
  2017年   162篇
  2016年   181篇
  2015年   116篇
  2014年   137篇
  2013年   1569篇
  2012年   154篇
  2011年   170篇
  2010年   157篇
  2009年   146篇
  2008年   148篇
  2007年   125篇
  2006年   110篇
  2005年   85篇
  2004年   74篇
  2003年   90篇
  2002年   74篇
  2001年   99篇
  2000年   79篇
  1999年   81篇
  1998年   64篇
  1997年   59篇
  1996年   50篇
  1995年   67篇
  1994年   59篇
  1993年   52篇
  1992年   45篇
  1991年   41篇
  1990年   45篇
  1989年   36篇
  1988年   46篇
  1987年   51篇
  1986年   47篇
  1985年   56篇
  1984年   65篇
  1983年   63篇
  1982年   67篇
  1981年   56篇
  1980年   44篇
  1979年   42篇
  1978年   46篇
  1977年   50篇
  1976年   40篇
  1975年   28篇
  1974年   42篇
  1971年   24篇
  1970年   26篇
  1969年   24篇
排序方式: 共有5726条查询结果,搜索用时 15 毫秒
991.
Breathtaking parades of black kings and their courts enlivened the streets of cities in Europe and the Americas between the fifteenth and the eighteenth centuries. Sumptuously dressed queens and kings and their resplendent attendants processed to the sound of music, lifted, temporarily, from the grim the life of enslavement or institutionalized inferiority many of them lived in the age of Atlantic slavery. Drawing from a recent analysis of a prominent ritual performance from the central African kingdom of Kongo called sangamento, this article offers a new interpretation of the black kings festivals, beyond their interpretation as carnivalesque pomp emulating and destabilizing European rule. On both shores of the Atlantic, the performances combined African and European regalia and pageantry to express and enact central African collective identity, political power, and social unity. Restaging performances and reshaping ideas honed in the Kongo, enslaved central Africans not only preserved the memory of their region of origins, but also crafted empowered responses to enslavement and the colonial system at large.  相似文献   
992.
The article examines the first official, national Holocaust memorial day in Italy, the so-called Giorno della memoria (Day of memory), marked on the 56th anniversary of the liberation of Auschwitz on 27 January 2001. It looks at the ways in which the day acted as a filter for issues of national collective memory and identity, in particular state and public negotiation of the legacy of Fascism, as well as addressing broader issues of Holocaust remembrance. The article looks first at the origins of the Giorno della memoria in political and in legislative terms. Then it sketches in the events of the day itself, at national and local levels, in political, educational and cultural terms. This is followed by an analysis of media coverage and contemporary commentary, showing how various lines of interpretation addressed general issues related to the Holocaust and specifically Italian historical, ideological and contemporary questions.  相似文献   
993.
This article offers an account of a recent debate in the cultural pages of the Italian press on a polemical work of literary criticism entitled Pasolini contro Calvino, in which the two authors are shown to represent emblematically different attitudes towards literature, cultural institutions and the culture industry in post‐war Italy. The debate surrounding this claim is examined in substance, but also as an illustration of the workings of culture in 1990s Italy.  相似文献   
994.
995.
996.
Northwestern Italian weak-motion data were used to study attenuation characteristics of horizontal peak ground acceleration (PGA) and horizontal peak ground velocity (PGV) from earthquakes of local magnitudes (M l ) up to 5.1. Data have been provided by the RSNI (Regional seismic network of Northwestern Italy) and RSLG (Regional seismic network of Lunigiana-Garfagnana) waveform database. The database consists of more than 14000 horizontal components recorded in the period 1999-2002 by both broadband and enlarged band seismometers. The accuracy of the procedure used to extract PGA values from the velocity recordings was verified comparing observed and derived PGA values at station STV2, which was equipped with both a temporary K2 Kinemctrtcs accelerometer and Guralp CMG40 broadband sensor. The attenuation of both peak ground acceleration and peak ground velocity was found to be logarithmically distributed with a strong attenuation for low distances (less than 50 km) and low M l values (<3.0). The resulting equations are:

Log(PGA)=?3.19+0.87M?0.042M 2?1.92 Log(R)+0.249S,

Log(PGA)=?4.23+0.76M?0.018M2?1.56 Log(R)+0.230S,

where PGA is expressed in g, PGV is expressed in m/s, M is local magnitude, R is the hypocentral distance in kilometers and S is a dummy variable assuming values of 0 and 1 for rock and soil respectively. For increasing distance and magnitude, both PGA and PGV values show a linear distribution. The validity range of the obtained attenuation relationships is 0–200 km for distances and M l up to 4.5. Sensitivity studies performed by analysis of residuals, showed that predicted PGA and PGV values are stable with respect to reasonable variations of the model and distances providing the data. Comparisons with attenuation relationships proposed for Italian region, derived from strong motion records, are also presented.  相似文献   
997.
A novel sampling technique for the analysis of glass is described, which involves the removal of minute particles from an object with a diamond‐coated file, followed by energy‐dispersive X‐ray analysis in the scanning electron microscope (SEM/EDXA). The particles are fixed to adhesive carbon discs and carbon coated without grinding or polishing. Mean compositions are determined for 10 arbitrarily selected particles above a minimum grain size of 150 mm and normalized to totals of 100%. Tests were carried out on two standard soda–lime–silica glasses of well‐characterized composition, using two files of different grade. The analyses showed good agreement with the accepted values of all elements. Although the precision is somewhat reduced, this highly portable and quasi non‐destructive microsampling procedure provides almost the same information as that gained from samples embedded and polished in the normal way. Its application is thought to be especially useful for the investigation of intact glass objects and ceramic glazes.  相似文献   
998.
The lead isotope compositions of many different samples from lead ingots of Roman age from two relicts (from Cabrera, and from Saintes‐Maries‐de‐la‐Mer) of the Western Mediterranean have been measured. Other lead isotope analyses of ores, metals or lead ingots from mines of Sierra Morena and from Cartagena and Sardinia have been accomplished. All the lead isotope measurements have been performed at the Joint Research Centre of the European Union, Ispra (Va), Italy. The samples have been prepared in a class 100 clean room, using only ultrapure reagents and FEP materials. In view of the archaeological arguments, it was possible to believe that the Roman lead ingots of the Saintes‐Maries‐de‐la‐Mer 1 wreck came from Spanish lodes, as well as those of the Cabrera 5 wreck. In fact, while the comparison between the first group of ingots (Cabrera 5) and the lead from Sierra Morena is consistent, the correspondence between the second group of ingots (Saintes‐Maries‐de‐la‐Mer 1) and the Cevennes ores (southern France) gives rise to several problems concerning the archaeological and physical origins. These problems are discussed.  相似文献   
999.
There is an increasing awareness of the potentials of nonlinear modeling in regional science. This can be explained partly by the recognition of the limitations of conventional equilibrium models in complex situations, and also by the easy availability and accessibility of sophisticated computational techniques. Among the class of nonlinear models, dynamic variants based on, for example, chaos theory stand out as an interesting approach. However, the operational significance of such approaches is still rather limited and a rigorous statistical-econometric treatment of nonlinear dynamic modeling experiments is lacking. Against this background this paper is concerned with a methodological and empirical analysis of a general misspecification test for spatial regression models that is expected to have power against nonlinearity, spatial dependence, and heteroskedasticity. The paper seeks to break new research ground by linking the classical diagnostic tools developed in spatial econometrics to a misspecification test derived directly from chaos theory—the BDS test, developed by Brock, Dechert, and Scheinkman (1987). A spatial variant of the BDS test is introduced and applied in the context of two examples of spatial process models, one of which is concerned with the spatial distribution of regional investments in The Netherlands, the other with spatial crime patterns in Columbus, Ohio.  相似文献   
1000.
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