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   206篇
  免费   3篇
管理学   36篇
民族学   2篇
人口学   11篇
丛书文集   1篇
理论方法论   23篇
综合类   4篇
社会学   99篇
统计学   33篇
  2023年   3篇
  2022年   4篇
  2021年   2篇
  2020年   9篇
  2019年   11篇
  2018年   10篇
  2017年   8篇
  2016年   8篇
  2015年   8篇
  2014年   9篇
  2013年   29篇
  2012年   16篇
  2011年   9篇
  2010年   11篇
  2009年   15篇
  2008年   4篇
  2007年   6篇
  2006年   9篇
  2005年   5篇
  2004年   4篇
  2003年   3篇
  2002年   2篇
  2001年   5篇
  2000年   2篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1989年   1篇
  1988年   1篇
  1984年   2篇
  1973年   1篇
  1965年   1篇
排序方式: 共有209条查询结果,搜索用时 0 毫秒
201.
This study investigated the effects of a 1-h nap on subsequent performance in spatial memory (SM) and logical reasoning (LR) tasks. The objective was to evaluate the duration of the effects of sleep inertia (SI). The performance was measured in two independent groups of subjects. The 1-h nap took place at 00:00 h in group 1 and at 03:00 h in group 2. In each task, the experimental design comprised one no-nap condition in which subjects had no sleep before the night tests, and a nap condition that comprised the 1-h nap followed by the test sessions. To measure the duration of SI effects, the subjects were tested in two 30-min sessions and the data in each session were analysed in sub-units of time of 3 min each. In each task the results showed no effects on accuracy, and no circadian effects of napping were found. In each task, analyses of pooled data of the two groups showed that the performance in the 1-h nap condition exhibited significant reductions of speed immediately following awakening, when compared with no-nap, reflecting SI effects. In SM, the slowing lasted 24 min, and 27 min in LR. Practical implications of the results are discussed.  相似文献   
202.
Lindley's measure of experimental information is utilized to determine the optimal sample-size that is required to obtain a prescribed level of accuracy about the parameter of a binomial distribution. The measure is expressed through its approximate limiting relationship to the posterior variance of the parameter, and a simple application of the methodology is presented.  相似文献   
203.
In this article I will aim to present results of research which deals with the French word ‘chanson’ and song theory. My observations will be conducted within a metalinguistic and a linguistic corpora. My corpora was largely constituted by works published in France in addition to other countries in Europe. The study of European dictionaries has shown me how important the French song culture has become in German dictionaries (in which chansonnier and chanson de geste sometimes appear) and in Italian dictionaries (in which chansonnier as a synomym of cantaautore appears). This presentation contains some diachronical and theoretical observations. The research appears to be the first significant research conducted about the vocabulary of song in French. This will finally lead us to present the theoretical vocabulary that we have created to study song phenomena.  相似文献   
204.
The Precautionary Principle has provided the foundations for building a new risk regulatory pattern under scientific uncertainty. This paper investigates how classical economic theory may, or may not, justify the Precautionary Principle. It examines the link between irreversibility, the prospect of increasing information over time and risk management. In doing so, it brings closer the notion of option value to that of precaution. Using a general modelling framework, it identifies the conditions so that the Precautionary Principle is an efficient economic guideline. It also explains why precautionary policies are not likely to emerge in a competitive economy or in the presence of a global pollution problem.  相似文献   
205.
Many studies indicate that adolescents are hypersensitive to rewards in salient socio‐emotional contexts. However, little is known about adolescents' sensitivity to complex negative emotions. To study the development of the ability to experience regret and relief, children, adolescents, and young adults performed a gambling task in a socio‐emotional context of competition, in which they were informed that their outcome would be compared with that of a competitor. The context of competition impacted the feelings of regret and relief in adolescents. When adolescents experienced an initial negative outcome, their feeling of relief was reinforced. However, they did not seem to experience regret in the social context of competition. These results provide a possible explanation for adolescents' enhanced risk seeking.  相似文献   
206.
Journal of Risk and Uncertainty - This paper introduces the Prince incentive system for measuring preferences. Prince combines the tractability of direct matching, allowing for the precise and...  相似文献   
207.
208.
Coalescence processes have received a lot of attention in the context of conditional branching processes with fixed population size and non-overlapping generations. Here, we focus on similar problems in the context of the standard unconditional Bienaymé–Galton–Watson branching processes, either (sub)-critical or supercritical. Using an analytical tool, we derive the structure of some counting aspects of the ancestral genealogy of such processes, including: the transition matrix of the ancestral count process and an integral representation of various coalescence times distributions, such as the time to most recent common ancestor of a random sample of arbitrary size, including full size. We illustrate our results on two important examples of branching mechanisms displaying either finite or infinite reproduction mean, their main interest being to offer a closed form expression for their probability generating functions at all times. Large time behaviors are investigated.  相似文献   
209.
We use a French firm‐level data set containing 13,000 firms over the period 1994–2004 to analyze the relationship between credit constraints and firms’ R&D behavior over the business cycle. Our main results can be summarized as follows: (i) R&D investment is countercyclical without credit constraints, but it becomes procyclical as firms face tighter credit constraints; (ii) this result is only observed for firms in sectors that depend more heavily upon external finance, or that are characterized by a low degree of asset tangibility; (iii) in more credit‐constrained firms, R&D investment plummets during recessions but does not increase proportionally during upturns.  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