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   16886篇
  免费   565篇
  国内免费   138篇
管理学   1679篇
民族学   434篇
人口学   848篇
丛书文集   846篇
理论方法论   1072篇
综合类   6766篇
社会学   4548篇
统计学   1396篇
  2023年   85篇
  2022年   167篇
  2021年   246篇
  2020年   254篇
  2019年   221篇
  2018年   258篇
  2017年   329篇
  2016年   305篇
  2015年   376篇
  2014年   511篇
  2013年   1947篇
  2012年   689篇
  2011年   849篇
  2010年   810篇
  2009年   810篇
  2008年   896篇
  2007年   935篇
  2006年   865篇
  2005年   815篇
  2004年   658篇
  2003年   519篇
  2002年   547篇
  2001年   499篇
  2000年   345篇
  1999年   180篇
  1998年   147篇
  1997年   130篇
  1996年   132篇
  1995年   138篇
  1994年   144篇
  1993年   137篇
  1992年   150篇
  1991年   165篇
  1990年   183篇
  1989年   149篇
  1988年   168篇
  1987年   144篇
  1986年   138篇
  1985年   139篇
  1984年   147篇
  1983年   137篇
  1982年   99篇
  1981年   84篇
  1980年   94篇
  1979年   119篇
  1978年   90篇
  1977年   71篇
  1976年   84篇
  1975年   56篇
  1974年   76篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Objectives: In the United States, HIV continues to disproportionately affect men who have sex with men. One promising area of research that may inform the development of behavioral interventions among male–male couples is within the realm of sexual agreements. Methods: The purpose of our analysis was to determine whether respondents who report having an open agreement or an agreement breakage also report a higher incidence of recent (within the previous 12 months) intimate-partner violence (IPV) compared to respondents who report having a monogamous agreement or no agreement breakage after controlling for demographic variables. Results: Results showed that men who have an open agreement are less likely to report recent physical IPV. Conclusions: The results highlight the need to develop dyadic behavior interventions that address sexual agreements and stress management.  相似文献   
2.
Population Research and Policy Review - The welfare state can be perceived as a safety net which helps individuals adjust to situations of risk or transition. Starting from this idea of the welfare...  相似文献   
3.
4.
5.
6.
We find “green” labels increase residential property values by an average of 5%. This premium varies by label stringency and across market segments. Builders respond to the stringency of labels by strategically incorporating green features to achieve higher ratings. This strategy seems reasonable as there is no market premium for green features that lead to scores between label rating cutoff values. These results raise important questions as to how green label policies should be designed in order to foster the supply of green features. Gradations of green attributes are influential, particularly for highly rated homes. The most stringent labels have the greatest role at the high price end of the market. (JEL Q20, Q40, R31)  相似文献   
7.
在零售4.0时代,渠道的多样化不仅丰富了数据源,还能迅速生成大量数据,需要通过分析大数据,为决策提取有意义的信息,通过分析先行发货的重要性,提出了一种基于遗传算法(GA)的优化模型,预测顾客何时购买,然后在顾客线下单前将产品运送到距顾客最近的配送中心,解决先行发货中存在的问题。研究认为,需要先部署云计算来存储所有渠道生成的大数据,再应用基于集群的关联规则挖掘研究顾客的购买行为,根据“如果-那么”预测规则预测未来的采购情况,最后利用修正的遗传算法生成最优的先行发货计划;这种遗传算法考虑了其在运输成本和运输距离之外,还有预测规则的置信度,利用大量的数值实验权衡了先行发货中的不同因素,验证了模型的最优可靠性  相似文献   
8.
9.
From the inception of the proportional representation movement it has been an issue whether larger parties are favored at the expense of smaller parties in one apportionment of seats as compared to another apportionment. A number of methods have been proposed and are used in countries with a proportional representation system. These apportionment methods exhibit a regularity of order, as discussed in the present paper, that captures the preferential treatment of larger versus smaller parties. This order, namely majorization, permits the comparison of seat allocations in two apportionments. For divisor methods, we show that one method is majorized by another method if and only if their signpost ratios are increasing. This criterion is satisfied for the divisor methods with power-mean rounding, and for the divisor methods with stationary rounding. Majorization places the five traditional apportionment methods in the order as they are known to favor larger parties over smaller parties: Adams, Dean, Hill, Webster, and Jefferson. Received: 5 August 2000/Accepted: 24 October 2001  相似文献   
10.
Conflict over water resources is a major problem throughout the world. This essay describes the long-standing and often successful effort to insulate decisions on how to allot water among contending users, and how to reduce water pollution along a 5000-mile international border. The effort has been fraught with political and scientific complexity. Yet, after more than 90 years of experience, it provides a model that other nations are beginning to examine as relevant to their own efforts to find solutions.  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