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   19936篇
  免费   1626篇
  国内免费   1051篇
  22613篇
  2024年   37篇
  2023年   304篇
  2022年   282篇
  2021年   356篇
  2020年   712篇
  2019年   709篇
  2018年   680篇
  2017年   835篇
  2016年   820篇
  2015年   568篇
  2014年   769篇
  2013年   2282篇
  2012年   454篇
  2011年   630篇
  2010年   497篇
  2009年   786篇
  2008年   964篇
  2007年   1017篇
  2006年   875篇
  2005年   738篇
  2004年   636篇
  2003年   529篇
  2002年   466篇
  2001年   296篇
  2000年   275篇
  1999年   235篇
  1998年   191篇
  1997年   150篇
  1996年   124篇
  1995年   108篇
  1994年   104篇
  1993年   87篇
  1992年   67篇
  1991年   47篇
  1990年   50篇
  1989年   30篇
  1988年   40篇
  1985年   368篇
  1984年   421篇
  1983年   348篇
  1982年   452篇
  1981年   442篇
  1980年   443篇
  1979年   396篇
  1978年   446篇
  1977年   352篇
  1976年   354篇
  1975年   275篇
  1974年   279篇
  1973年   236篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
971.
972.
A questionnaire study involving white collar workers (n=48) investigated the effects of the threat of retaliation, seriousness of malpractice and occupational status of the observer on the likelihood and method of whistle-blowing chosen. In line with previous whistle-blowing and bystander intervention research, the likelihood of whistle-blowing was greater for serious malpractices and where threatened retaliation was low. The effect of retaliation was only significant for serious white collar malpractices and in every situation internal whistle-blowing was more likely than external. The general likelihood of whistle-blowing was positively correlated with the perception that reporting the malpractice would result in change.  相似文献   
973.
In this article it is argued that the attributional literature concerning explanations of poverty is inadequate due to its theoretical presuppositions. It is proposed that a discursive approach is better able to withstand criticism and contribute to a more adequate understanding of poverty accounts. Some examples are given of how a discursive approach might work in practice.  相似文献   
974.
Multiple-criteria decision aid almost always requires the use of weights, importance coefficients or even a hierarchy of criteria, veto thresholds, etc. These are importance parameters that are used to differentiate the role devoted to each criterion in the construction of comprehensive preferences. Many researchers have studied the problem of how to assign values to such parameters, but few of them have tried to analyse in detail what underlies the notion of importance of criteria and to give a clear formal definition of it. In this paper our purpose is to define a theoretical framework so as to analyse the notion of the importance of criteria under very general conditions. Within this framework it clearly appears that the importance of criteria is taken into account in very different ways in various aggregation procedures. This framework also allows us to shed new light on fundamental questions such as: Under what conditions is it possible to state that one criterion is more important than another? Are importance parameters of the various aggregation procedures dependent on or independent of the encoding of criteria? What are the links between the two concepts of the importance of criteria and the compensatoriness of preferences? This theoretical framework seems to us sufficiently general to ground further research in order to define theoretically valid elicitation methods for importance parameters.  相似文献   
975.
The association between the life orientation and attributional styles of a mother and the aggressiveness of her child were studied in 61 mothers and their children, 23 boys and 38 girls, mean age 6.6 years (range 4–13 years). The mother's life orientation and attributional styles were established during interviews using the life-style questionnaire, and a child's aggressiveness was evaluated by the mother using the Health Examination Survey. The factors assessing life orientation were lack of personal control, causal unstability, internal locus of causality, personal responsibility, and democratic educational attitudes. The mother's personal responsibility and internal causal attributions were related to nonaggressiveness in the child, whereas mothers with a lack of personal control were likely to have aggressive children. Educational attitudes were of no importance. The results showed no sex- or age-related variance.  相似文献   
976.
This study assessed whether two types of non-aggressive “standard opponents” (“intact” and “anosmic” group-housed males) produced similar behavioral changes in isolated OF1 male mice given several experiences of victory. Experimental groups confronted either intact or anosmic opponents every two days until they had completed four encounters. The behavioral changes were recorded using a detailed ethologically inspired analysis. These changes were clearly different depending on the opponent type. When intact opponents were used, experimental subjects increased the time spent in digging, non-social exploration, explore from a distance, and attack over encounters, but showed decreased time spent in threat and a decreased latency to the first attack. In encounters with anosmic opponents, only declines in the latencies to threat and attack were noted. Moreover, the experimental groups differed in their behaviors over encounters. Those confronting intact opponents spent less time in social investigation, more time in explore from a distance and threat, and showed a shorter latencies to threat and attack than counterparts confronting anosmics. These results suggest that, although both types of “standard opponents” are similar in their non-aggressiveness, they elicit rather different behavioral responses in their adversaries. These findings provide additional support for the view that the type of opponent used in studies on intermale aggression is of paramount importance. Indeed, the use of different types of “standardized non-aggressive opponents” appears to be an important source of variability between studies. © 1994 Wiley-Liss, Inc.  相似文献   
977.
In expected utility many results have been derived that give necessary and/or sufficient conditions for a multivariate utility function to be decomposable into lower-dimensional functions. In particular, multilinear, multiplicative and additive decompositions have been widely discussed. These utility functions can be more easily assessed in practical situations. In this paper we present a theory of decomposition in the context of nonadditive expected utility such as anticipated utility or Choquet expected utility. We show that many of the results used in conventional expected utility carry over to these more general frameworks. If preferences over lotteries depend only on the marginal probability distributions, then in expected utility the utility function is additively decomposable. We show that in anticipated utility the marginality condition implies not only that the utility function is additively decomposable but also that the distortion function is the identity function. We further demonstrate that a decision maker who is bivariate risk neutral has a utility function that is additively decomposable and a distortion function q for which q(½) = ½.  相似文献   
978.
Analysis of the body targets attacked and defended during play-fighting by juvenile Djungarian hamsters Phodopus campbelli revealed that about 70% of all attacks were directed at the mouth. If successfully contacted, the mouth was briefly licked and nuzzled. The remaining playful attacks were gentle bites directed at the rump, and to a lesser extent, the top of the head. During serious fighting the top of the head and the rump are targets of attack, whereas the mouth is not. Licking and nuzzling the mouth was found to be a behavior performed by adult males at the beginning of sexual encounters. Therefore, play-fighting in juvenile hamsters cannot be thought of merely as a form of “mock fighting” since the principal target is seemingly sexual, not agonistic. The data also show that of the sexual body targets contacted, adult females are more likely to defend the mouth. In this way it is suggested that targets attacked and defended during juvenile play-fighting are derived from adult contexts in which such targets are defended. This hypothesis accounts for the prevalence of agonistic targets in the play-fighting of many species, and may provide a rationale for classifying those amicable targets that are competed for during play-fighting.  相似文献   
979.
The Wilcoxon–Mann–Whitney procedure is invariant under monotone transformations but its use as a test of location or shift is said not to be so. It tests location only under the shift model, the assumption of parallel cumulative distribution functions (cdfs). We show that infinitely many monotone transformations of the measured variable produce parallel cdfs, so long as the original cdfs intersect nowhere or everywhere. Thus there are infinitely many effect sizes measured as shifts of medians, invalidating the notion that there is one true shift parameter and thereby rendering any single estimate dubious. Measuring effect size using the probability of superiority alleviates this difficulty.  相似文献   
980.
Sanders et al.'s proposal for a management framework for conflicting interests among program developers is very welcome. The underlying principles of such a framework must nevertheless prioritise the need for researchers and commissioners of services to make objective assessments of the impact of interventions reported in journal articles. This is particularly important in the field of randomised trials which may influence public sector expenditure. Using a strict definition derived from known financial conflict of interest, we have demonstrated that child-based effect sizes are much lower for independent studies than for studies with developer involvement. On this basis, we propose that journals publishing evaluations of psychosocial interventions should agree a standardised format for declarations of conflicts of interest based on that recommended by the International Committee of Medical Journal Editors.  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