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   398篇
  免费   19篇
  2024年   2篇
  2023年   11篇
  2022年   2篇
  2021年   1篇
  2020年   18篇
  2019年   21篇
  2018年   32篇
  2017年   40篇
  2016年   30篇
  2015年   17篇
  2014年   24篇
  2013年   107篇
  2012年   11篇
  2011年   7篇
  2010年   10篇
  2009年   13篇
  2008年   13篇
  2007年   3篇
  2006年   2篇
  2005年   2篇
  2004年   1篇
  2001年   2篇
  2000年   3篇
  1999年   1篇
  1998年   6篇
  1997年   1篇
  1996年   5篇
  1995年   3篇
  1993年   4篇
  1992年   3篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   4篇
  1986年   6篇
  1985年   1篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1974年   1篇
  1957年   1篇
排序方式: 共有417条查询结果,搜索用时 15 毫秒
1.
ABSTRACT. We determine the location equilibria in a duopoly model under a novel solution concept. Typically, spatial equilibrium is described as either a simultaneous price and location game, or else as a two-stage location-then-price game. We introduce a new alternative, a two-stage price-then-location game. It is well known that no (pure strategy) equilibrium usually exists under the two standard solution concepts when products are homogeneous. We show this is also true for the new concept. We then provide numerical results for a specific functional form (the logit model) which introduces product heterogeneity into the standard framework, restoring equilibrium when the degree of substitutability between products is not too small.  相似文献   
2.
3.
The results obtained from the multi-analytic compositional characterization of ceramic pastes and paints of the Santa María style, from the El Bolsón valley (Belén Department, Catamarca Province, Argentina), are presented here. This pottery style had a wide regional distribution in Northwestern Argentina between ca. 1000 and1600 ce and is characterized by its complex iconography painted in black, cream and red. The analyses show that the containers correspond to the technical tradition of using grog temper and suggest that its manufacture involved a double firing process. This reveals a new practice for the time.  相似文献   
4.
Faunal remains from archeological sites worldwide, especially feces and regurgitated pellets, are usually subjected to paleoparasitological examination, allowing the identification of past animal parasites. In this study, we analyzed 10 samples of South American camelid dung, which played an important role for the ancient human groups in the South-Central Andes, dated between 341 and 1635 calCE, from the Iluga Túmulos site (Pampa del Tamarugal, Tarapacá region, Atacama Desert, Chile). Microscopy examination revealed parasite remains in seven samples, in which oocysts of Eimeria macusaniensis and eggs of Lamanema chavezi/Nematodirus lamae, Trichuris sp., Moniezia sp., capillariids, strongylids, and unidentified nematodes were found. Although some of these species pose a potential health risk to camelids, most are not considered to be of major zoonotic importance, which could explain the absence of these parasites on human coprolites from this site analyzed previously. This first paleoparasitological study on camelid fecal remains from northern Chile sheds light on the occurrence of gastrointestinal parasites and its relationship with Andean ancient human populations and the environment.  相似文献   
5.
ABSTRACT. We reexamine the price structures and their welfare implications in three pricing regimes (mill, uniform and discriminatory) for a monopoly. We show that spatial price discrimination could provide the highest social welfare and, when consumers tastes are heterogeneous enough, also the highest consumer surplus. The superiority of spatial price discrimination is partially due to the larger output produced and partially due to differential treatment for consumers with heterogeneous tastes.  相似文献   
6.
A region's technology potential can be developed in three ways: public finding; private investment (by business); and an intermediate area which ensures coherence between the public and private sectors, and which is mainly to be seen in interface structures between universities and business. After presenting these ways for Rhône‐Alpes, the paper introduces the regional policy to promote science and technology. According to French centralized political structure, the regional government acts as a lever. The region's innovation‐oriented policy, which should not be confused with a research‐oriented policy, has the impact of aiming all action at improving the technological environment of business, and at facilitating their economic development by integrating new technologies. Similarities between Rhône‐Alpes and Baden‐Würtemberg have led these two regions to cooperate increasingly in the fields of science and technology. The ‘four motor‐regions for Europe’ (with Lombardia and Catalonia) experiment in the field of new‐material investment cooperation could be useful if we think of the process aimed at strengthening integration in the European Community.  相似文献   
7.
8.
9.
This paper studies the territorial effects of the LEADER approach in Southern Europe, by analysing the region of Andalusia (Spain). Our research has revealed that, in many cases, projects were concentrated in the most dynamic, most populated areas, with a well-established business network with the financial and organizational capacity required to access European funding. In these areas, the economic leadership of the most dynamic municipalities has been reinforced at the expense of more depressed areas with little social capital and few businesses. These programmes have not, therefore, helped to mitigate territorial imbalances. In a minority of rural areas, however, this trend was not observed, which shows that although territorial inequality is a widespread problem in the practice of neo-endogenous rural development, it does not affect all areas to the same degree.  相似文献   
10.
The defining element of island regions is their isolation, the separation of the islands from the mainland; there is an inherent notion of natural border. This condition has preserved ecosystems and protected against outside threats, stimulating ‘coevolution’ between man and the environment, a fundamental ingredient of sustainability. But insularity also means the evident added costs of access to markets which, together with territorial limits and the scarcity of basic resources, especially on small islands, hinders their socioeconomic development. These costs are even greater in the case of outlying islands, which suffer from a ‘double insularity’ in the form of both external and internal borders. For this reason, it is common for governments to establish various forms of support, from tax exemptions to the creation of permanent aid funds, like those implemented by the European Union for the outermost regions. This article discusses these aspects in the case of the Canary Islands, an example of a European outermost island region. The findings show that the support measures have not always been favourable for all the islands.  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