全文获取类型
收费全文 | 5233篇 |
免费 | 252篇 |
出版年
2023年 | 39篇 |
2020年 | 109篇 |
2019年 | 111篇 |
2018年 | 188篇 |
2017年 | 193篇 |
2016年 | 217篇 |
2015年 | 138篇 |
2014年 | 138篇 |
2013年 | 1523篇 |
2012年 | 167篇 |
2011年 | 196篇 |
2010年 | 178篇 |
2009年 | 147篇 |
2008年 | 119篇 |
2007年 | 113篇 |
2006年 | 123篇 |
2005年 | 81篇 |
2004年 | 59篇 |
2003年 | 65篇 |
2002年 | 71篇 |
2001年 | 76篇 |
2000年 | 67篇 |
1999年 | 81篇 |
1998年 | 62篇 |
1997年 | 44篇 |
1996年 | 36篇 |
1995年 | 49篇 |
1994年 | 35篇 |
1993年 | 50篇 |
1992年 | 33篇 |
1991年 | 43篇 |
1990年 | 47篇 |
1989年 | 42篇 |
1988年 | 33篇 |
1987年 | 44篇 |
1986年 | 47篇 |
1985年 | 47篇 |
1984年 | 52篇 |
1983年 | 47篇 |
1982年 | 41篇 |
1981年 | 47篇 |
1980年 | 42篇 |
1979年 | 39篇 |
1978年 | 36篇 |
1977年 | 36篇 |
1975年 | 27篇 |
1974年 | 27篇 |
1973年 | 29篇 |
1972年 | 29篇 |
1970年 | 27篇 |
排序方式: 共有5485条查询结果,搜索用时 15 毫秒
121.
Lead-glazed pottery from the medieval workshop of Les Olleries Majors (Paterna, Spain) has been studied by Mössbauer spectroscopy, X-ray diffraction, X-ray fluorescence and optical spectroscopy. Yellow, brown and honey-coloured glazes occur on pots glazed on only one surface. They have virtually identical compositions and transmittance spectra, their apparent differences in colour are due to the colours of the underlying pastes. Yellow glazes occur on cream-coloured calcareous bodies, honey-coloured glazes occur on less calcareous bodies with some development of hematite, while brown glazes occur on red siliceous cooking-pots. Green glazes are found on pots glazed on both surfaces; the glazes trapped CO2 evolved by decomposing carbonates, resulting in an internal reducing environment. This caused the reduction of iron to the ferrous state which coloured the glaze green by diffusion. 相似文献
122.
SPATIAL DEPENDENCY OF SEGREGATION INDICES 总被引:3,自引:0,他引:3
David W.S. Wong 《The Canadian geographer》1997,41(2):128-136
A few researchers have mentioned the scale sensitivity of segregation index, D. In this paper, I discuss analytically and empirically why using large enumeration areal units usually results in low segregation measures, and using small areal units produces relatively high segregation measures. The discussion is also applicable to the multi-group variant of D. A major finding is that if people of the same ethnic groups are positively spatially auto-correlated, increasing the size of areal units of analysis may not lower D initially, because only people of the same group are added. But enlarging the areal units subsequently may include population of other ethnic groups, and therefore could lower D. However, if the boundaries of the larger enumeration units are drawn to include only population of the same group, then D will not change significantly. Both the spatial autocorrelation of ethnic group population and zonal pattern are critical factors in determining the scale sensitivity of D. 相似文献
123.
The present paper surveys the discussions conducted by official statisticians regarding the ideal structure according to which a national data collection system should have been designed if it was to meet the challenges put up by the various transformation Western countries have undergone since the beginning of the 19th century. Arguments in favour of coordination, centralization, or decentralization have emerged for the first time in 1832 Britain, when the Statistical Bureau of the Board of Trade was created. Up to 1945, this debate went on, the industrial take-off, the economic crises, and the world wars all being occasions for its protagonists to put forward their preferred view. The perspective we take here is original in two respects: on the one hand, instead of confining ourselves to the major statistical systems (those of France, Britain, and the USA), we intend to evoke a large number of cases and, from this comparative standpoint, propose a general account of the drive towards centralization; on the other hand, instead of restraining our-selves to the 19th century, we cover the entire time-frame extending from 1800 to 1945. 相似文献
124.
Jean-Marc Drouin Patrick Gautier Dalché Fabien Chareix Charles Lenay Monique Cottret Bernard Vandewalle François Laplanche Françoise Waquet Agnès Spiquel Ariane Poulantzas Olivier Martin Sophie Roux Ilana Löwy Françoise Waquet Isabelle Brian Michel Cassan Jean-Marc Rohrbasser Jean-Michel Vienne Marc Renneville Bernard Lahire Mikhaäl Xifaras Bertrand Binoche Stéphane Haber Jean-François Pradeau Noël Bonneuil Marie Jaisson 《Revue de synthèse / Centre international de synthèse》1997,118(4):551-613
125.
126.
127.
128.
129.
The idea that there are certain "laws" of learning (similarity, contrast, contiguity) can be traced to Aristotle. He maintained that external stimuli cause small movements in the vessels to the dominant heart, the vestiges of which can be linked to one another. Aristotle's laws of learning were incorporated into the writings of Hobbes, Locke, and Berkeley, men who said nothing about the physiological correlates of mental associations. This left the door open for David Hartley to combine mental associationism with the Newtonian idea that sensations can cause minute particle vibrations in the nerves. Hartley's amalgam of psychology, philosophy, and neurology was first presented in 1746, as a "trial balloon" at the end a little-known monograph on a treatment for kidney stones. It was repeated three years later in his better-known Observations on Man. In many ways, modern psychobiological connectionism can be traced back to Hartley's Conjectures of 1746, in which Aristotle's original thoughts were modified with then current ideas about functions of the mind and the nervous system. 相似文献
130.
Gusein-zade SM 《Journal of regional science》1993,33(4):547-558
ABSTRACT. The paper is devoted to modeling the relationship between the density of service centers and the density of population (or on the density of demand). Several models lead to an exponential function with the exponent equal to ⅔. For a number of real systems of centers, the power is considerably different from ⅔ (more often it is nearer to 1). I describe a series of models that explain this difference. 相似文献