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   624篇
  免费   17篇
管理学   67篇
人口学   32篇
丛书文集   2篇
理论方法论   47篇
综合类   8篇
社会学   344篇
统计学   141篇
  2023年   4篇
  2022年   3篇
  2021年   5篇
  2020年   10篇
  2019年   6篇
  2018年   27篇
  2017年   21篇
  2016年   21篇
  2015年   11篇
  2014年   19篇
  2013年   138篇
  2012年   24篇
  2011年   18篇
  2010年   13篇
  2009年   9篇
  2008年   20篇
  2007年   16篇
  2006年   24篇
  2005年   16篇
  2004年   10篇
  2003年   16篇
  2002年   16篇
  2001年   16篇
  2000年   18篇
  1999年   16篇
  1998年   10篇
  1997年   6篇
  1996年   11篇
  1995年   5篇
  1994年   6篇
  1993年   3篇
  1992年   7篇
  1991年   4篇
  1990年   5篇
  1989年   5篇
  1988年   4篇
  1987年   5篇
  1986年   7篇
  1985年   4篇
  1984年   5篇
  1982年   4篇
  1981年   9篇
  1980年   6篇
  1979年   5篇
  1978年   7篇
  1977年   3篇
  1975年   5篇
  1973年   3篇
  1970年   3篇
  1968年   3篇
排序方式: 共有641条查询结果,搜索用时 646 毫秒
141.
142.
Occasionally, scientific reports have omitted information on standard deviations, making estimates of effect sizes very difficult to impossible. In such situations, several scholars have recommended obtaining an estimate of the standard deviation of distributions by dividing the range of the distribution (highest value minus lowest value) by four. However, there appears to be little evidence to confirm the validity of this approach. Articles from 2012 to 2015 in the journal Marriage & Family Review were surveyed to find instances where demographic variables (age, education, duration of relationship, number of children) were reported with both standard deviations and ranges. Ratios between range and standard deviations were calculated by several rules of thumb or more complex formulas and compared with the actual ratios obtained. Results indicated that dividing by five in general provided a more accurate estimate of actual standard deviations but accuracy in predicting the true ratio between range and standard deviation was substantially related to the position of the mean score within the range of scores with larger divisors needed as the mean approached either the minimum or the maximum values of the demographic variable (skew). Other recent formulae for estimating the standard deviation were also evaluated, but the skew-based approach appeared to be more accurate than the others. However, further investigation in other samples is needed because the skew-based approach was derived from observation of the data here, which might not replicate in different sets of data.  相似文献   
143.
Hoaglin and Andrews (1975) proposed standards for computational practice and the reporting of computation-based studies. They observed that “statisticians … often pay too little attention to their own principles of design.” To see if the design and reporting had improved, we surveyed five major statistical journals for 1975, 1978, and 1981 to ascertain whether reported simulation studies involved a specified design, justified the choice of the number of iterations, and specified the random number generator(s) used. Eighteen percent of the 1,198 papers surveyed included results based on simulation. We found that 9% of the papers including a simulation study justified the choice of the number of iterations and 44% at least partially specified the random number generator. Hoaglin and Andrews's observation appears still to be true.  相似文献   
144.
The Polya-Eggenberger distribution Involves drawing a ball from an urn containing black and white balls and, after each drawing, returning the ball together with s balls of the same color, The model represents positive contagion since the added balls are the same color as the one drawn, See Johnson and Kotz, (1977),

This paper derives and examines the probability distribution which results from the Polya-Eggenberger model with only one change namely, the s additional balls added after each drawing are of the opposite color, producing a negative contagion model.

Formulas in closed form are presented for the probability distribution function, the mean and variance, all binomial moments and, where s is greater than or equal to the number of balls in the urn at start, the mode, A formula for the mode is conjectured where s is less than the number of balls in the urn at start.

Finally, the probability of obtaining k black balls in n drawings is shown in certain instances to be equal to Ank/n!

where Ank are the Eulerian numbers.  相似文献   
145.
Sexual excitement can be seen as an action disposition. In this study sexual arousal was expected to generate sexual action and to increase interest and responsiveness to sexual stimuli. In two experiments, male and female participants were exposed to a neutral or a sexual film. We measured genital and subjective responses to the film, and sexual behavior following the laboratory visit. In Experiment 2, film exposure was followed by a task in which participants rated the sexual arousability of neutral and sexual pictures. Rating time of the sexual pictures served as an index for sexual interest. Responsiveness to the sexual pictures was measured by modulation of spinal tendinous (T) reflexes. Sexual activity, but not sexual desire, was higher for participants in the sexual film condition than for participants in the neutral condition. Sexual interest and responsiveness to still pictures were not higher for participants in the sexual film condition than for those in the neutral film condition. In addition, men who saw the neutral film showed a greater responsiveness to still pictures than men who saw the sexual film. The results support the view of sexual arousal as an emotional state generating action tendencies and actual sexual behavior.  相似文献   
146.
Procedures such as group testing and fractional replication can greatly reduce the workload. The former is especially efficient when the presence of a characteristic in samples is low. Fractional replication can greatly reduce the amount of experimentation when some of the parameters associated with a factorial are nonexistent or negligible. Supersaturated fractional replication can be used to efficiently screen factors when it is suspected that they may not affect a process but it is desired to check this suspicion. There are many types of grouping and pooling material in an investigation. Some of these are discussed as are the interrelationships among the above procedures.  相似文献   
147.
148.
Twelve of the novels of Charles Dickens provide a sample of 349 characters whose occupational achievement and mobility are investigated. The mobility patterns indicate more inheritance than in the United States. This cannot be accounted for by education, material inheritance, or morality (being a good or bad person). A model of quasi-perfect mobility, taking all diagonal frequencies as given, more closely represents the patterns. Determinants of achievement considered are social origins, number of siblings, education, marital status, morality. The characters from large families do better occupationally than those from small. Education functions primarily to redistribute success. The married are superior to the unmarried, with marriage functioning not as a selective mechanism, but exerting causal impact of its own. The evil are rewarded in this life. The basic path model of the stratification system of Dickens is similar to that of the United States.  相似文献   
149.
150.
Summary The re-emergence of a majority of centre-left governments incountries of the European Union was associated with the hopethat, after the neo-liberal attempts at its marginalizationand de-institutionalization, social work could regain a morevalued position in society. There are indeed indications thatthe growth of the profession continues and that social workis returning to a more explicit and official role in nationalsocial policies. However, this tends to be associated with anexpectation that social work would play its part in ‘activating’the recipients of welfare benefits in the context of the NewLeft project of shifting from social rights to social obligations.The practical and political effects of this new agenda are,however, modified greatly by the prevailing ‘welfare cultures’as well as the professional and academic discourses. This paperexplores the dilemmas and opportunities for the social professionsin Europe associated with the ‘pull’ to become incorporatedinto these new social policy agendas.  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