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   23篇
  免费   0篇
  2023年   1篇
  2021年   1篇
  2019年   2篇
  2018年   1篇
  2013年   4篇
  2009年   1篇
  2005年   1篇
  2004年   1篇
  1999年   1篇
  1997年   1篇
  1995年   1篇
  1992年   1篇
  1991年   1篇
  1987年   1篇
  1984年   3篇
  1983年   2篇
排序方式: 共有23条查询结果,搜索用时 15 毫秒
1.
This paper explores, theoretically and empirically, the influence of interregional migration on regional fertility differentials. Specifically, it tests the hypothesis that regions that are closely linked through migration have, all else held constant, a lower differential in fertility than regions that are relatively isolated from one another. A model linking the fertility differential between two states to migration as well as a number of socioeconomic variables is articulated. The model is tested by means of a randomization procedure using U.S. state-level data for 1980. Results support the hypothesis that an increasing volume of interregional migration tends to lower regional fertility differentials.  相似文献   
2.
ABSTRACT Increasing strains on self-sufficiency within the block of East European command economies resulted in the dramatic decision to change over to an economic system largely based on market forces. The painfulness of the ensuing transformation process will be mitigated somewhat by supportive economic policies of the West, including the European Community which is itself aiming at complete economic integration by the end of 1992. The consequences for the developing countries of these far-reaching policy changes in East and West are likely to be negative, at least in the immediate future. This is true for the volume of development assistance given by East and West, as well as for the export prospects of developing countries. Favourable effects might at best be expected in the longer run.  相似文献   
3.
Scientists advise limiting global warming to 1.5°C with substantial actions by 2030. Our viewpoint argues that climate response strategies in Canada have underemphasized and underestimated the potential contribution deep energy retrofits can make to greenhouse gas (GHG) emissions reductions, leading to inadequate responses in the building sector, and that Canada can (and should) be ambitious with building retrofits over the next decade. GHG savings from building retrofits can be realized more quickly than GHG reductions from other sectors, and either deliver net cost savings or are cost‐effective when compared to other mitigation measures. Retrofits can also provide social and economic benefits, such as improved health and comfort, and lower energy costs. This paper reviews energy use and building retrofits in Canada and argues the following should be implemented: (1) focus innovation on deep energy retrofit processes, not singular retrofit actions; (2) maximize both social and environmental benefits; (3) improve data gathering and availability for analysis and delivery; (4) innovate for a process of decisions and to avoid “dropouts” during the retrofit process; and (5) focus innovation on business models that maximize benefits.  相似文献   
4.
India’s recognition of West, but not East, Germany was the foundation of an inconsistent policy on Germany from India and many other non-aligned countries. It was the outcome of a lack of professionalism, indecisiveness, the pragmatic considerations of a junior Indian diplomat in Berlin, and the laconic approval of the anti-communist secretary-general of the Ministry of External Affairs, Girja Shankar Bajpai. Neither Prime Minister Jawaharlal Nehru nor his advisor V.K. Krishnan Menon were involved at all. Officials around Foreign Secretary K.P.S. Menon held that the GDR should also be recognised in due course, but did not exercise sufficient influence. India would stand by its decision for 23 years and thereby set an example for other non-aligned countries.  相似文献   
5.
Comparative study of numerically and experimentally obtained seismic responses of un-reinforced masonry building supported on in-house designed un-bonded fibre reinforced elastomeric isolator (U-FREI) are presented in this article. The effectiveness of U-FREI is established very clearly in terms of controlled dynamic response of the model building. Experimental studies are carried out on a shake table with elaborate instrumentations for measurement of acceleration and displacements at different floor levels. Numerical study of the model building supported on U-FREI is carried out to compare the results with experimental investigation. Multi-linear pivot hysteretic plasticity model is used to simulate the behavior of FREI, while plate elements are used for brick-masonry walls. Experimentally obtained force-displacement curves of FREI are used for defining the properties of multi-linear model representing FREI. The dynamic responses obtained from the numerical studies are compared with those from experimental investigations. This study indicates that the seismic responses of building supported on U-FREI can be numerically evaluated with quite reasonable accuracy. A good numerical model can be judiciously used at the preliminary design stage, followed by actual testing and construction of the base isolated building.  相似文献   
6.
7.
How has the history of the twentieth century affected the extent of female disadvantage in child survival in China, South Korea and India, and how has this in turn shaped spousal availability and marriage payments? These three countries have similar kinship systems which generate discrimination against girls, and they show the highest levels of excess female child mortality in the world. This article explores how the extent of excess female child mortality was influenced by historical events in these countries in the period 1920–90, and discusses some of the substantial social ramifications of resulting changes in sex ratios. The authors hypothesize that these changes encouraged the retention of brideprice in China while dowry became the norm in India, and illustrate how these demographic changes have influenced the extent and manifestations of violence against women.  相似文献   
8.
9.
10.
The records of fabulous stones associated with birds are here examined systematically for the first time. Some were purported to be obtained from within the bird and others obtained from the nest. Zahir mora, the Adjutant Bird Stone, was used against snake bite, whilst Alectorius (the Cock Stone), Aetites (the Eagle Stone) and Vulturis (the Vulture Stone) shared a multiplicity of medicinal applications. Quirin (the Hoopoe Stone), Chloritis (the Wagtail Stone) and Corvina (the Crow Stone) supposedly possessed occult powers. The Penguin Stone, Ostrich Stone and Pigeon Stone were probably gastroliths.  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