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   176篇
  免费   5篇
管理学   34篇
民族学   2篇
人口学   13篇
理论方法论   10篇
综合类   1篇
社会学   63篇
统计学   58篇
  2022年   3篇
  2021年   6篇
  2020年   8篇
  2019年   3篇
  2018年   7篇
  2017年   10篇
  2016年   11篇
  2015年   7篇
  2014年   11篇
  2013年   26篇
  2012年   13篇
  2011年   8篇
  2010年   9篇
  2009年   7篇
  2008年   3篇
  2007年   2篇
  2006年   5篇
  2005年   3篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  2001年   3篇
  2000年   1篇
  1999年   4篇
  1998年   1篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   1篇
  1991年   1篇
  1990年   2篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1976年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有181条查询结果,搜索用时 93 毫秒
51.
52.
From 2005 through 2008, we undertook a participatory research project involving graziers from 8 farms in Southern Wisconsin, all of whom practice management intensive grazing. We used semi-structured interviews and participant observation during research and field days to investigate graziers’ engagement with university research. Grazing farms demonstrate rich variability and individuality as a result of their position within a number of biophysical and social contexts. Graziers emphasized the importance of finding ways to work with the variables of their specific context, rather than trying to control that variability. This effort entails the development and use of local knowledge, as graziers respond to the idiosyncrasies of their farms. It also leads graziers to reject mainstream agricultural research that has produced formulas for agricultural uniformity. The picture of grazing that emerged from our interviews leads us to propose the search for agroecological principles and agroecological tools, embedded in context, as an alternative to conventional research. We argue that this proposal speaks to the greater conundrum of how to relate the general knowledge of science to the place-specific, experience-based knowledge of grass-based farmers.  相似文献   
53.
Usual fitting methods for the nested error linear regression model are known to be very sensitive to the effect of even a single outlier. Robust approaches for the unbalanced nested error model with proved robustness and efficiency properties, such as M-estimators, are typically obtained through iterative algorithms. These algorithms are often computationally intensive and require robust estimates of the same parameters to start the algorithms, but so far no robust starting values have been proposed for this model. This paper proposes computationally fast robust estimators for the variance components under an unbalanced nested error model, based on a simple robustification of the fitting-of-constants method or Henderson method III. These estimators can be used as starting values for other iterative methods. Our simulations show that they are highly robust to various types of contamination of different magnitude.  相似文献   
54.
The paper starts with a theoretical reinterpretation of some classical topics in the public choice literature, where specific elements of contract theory and the theory of the firm are introduced. By putting into contact these completely different fields of economics, it defines a general theoretical framework for political behaviors whose implications go beyond those determined by the standard self-interest assumption. Political organizations, as suppliers of public policies, are supposed to maximize a residual quantum consisting in the public authority that can actually be exercised after all the electoral commitments, with voters and interests groups, have been fulfilled. This residual right—which can be seen also as a degree of discretion necessary for ruling parties to deal with unforeseen contingencies—is based on the reputational capital (goodwill) accumulated over time by political organizations and represents the intangible asset that secures voters’ loyalty and, consequently, the legitimacy to exercise public authority in the long run. When a deficit of goodwill occurs, a chain of “exit” strategies by voters can lead to undesirable results unless an effective “voice” option for citizens exists.  相似文献   
55.
AStA Advances in Statistical Analysis - This paper deals with the estimation of kurtosis on large datasets. It aims at overcoming two frequent limitations in applications: first, Pearson's...  相似文献   
56.
Logical principles, in particular the law of noncontradiction and the law of exclusion of middle term, play different roles at different levels of discourse: valid formulae in an axiomatic calculus, methodological requirements (of consistency and completeness) for formalized systems. When postulated as formal laws, —pvp and —(p·—p), they are totally interdefinable and equivalent as well (DeMorgan's transformations are proof of this). If postulated as methodological requirements, the principles are not equivalent, although they could still be said in some sense to be interdefinable (the existence of consistent yet incomplete systems shows that the requirements are not equivalent; still, completeness of a system can be defined in terms of consistency of another system which keeps a definite relationship with the first one).There exists a third level of discourse: scientific praxis. At this level, the principles come even farther apart: they neither have the same logical value nor is one definable in terms of the other. However, they keep a family resemblance which justifies our dealing with them jointly. Let us call the principles at this level pragmatic imperatives. They deal with paradoxes, which are of two types: knots (conflicts) and blanks (gaps in the scientific pattern). The left-hand pragmatic imperative says: Be intolerant with knots, try to remove (dissolve) them. The right-hand pragmatic imperative says: Try to remove (fill) all blanks. The knot-removing and the blank-dissolving imperatives are prior to and more important than the laws of noncontradiction and excluded middle and the requirements of consistency and completeness. Logical principles are not prime categories: pragmatic imperatives are primordial.  相似文献   
57.
In situations where continuous prolonged work demands exist, the habitual nocturnal monophasic (6-8h duration) sleep pattern can rarely be accomplished, and performance effectiveness may sometimes be severely compromised by accumulation of sleep debt. Several studies have shown that naps can be disproportionately effective in recovering functioning during continuous work (CW).

In this study, sleep-wake patterns and their relationship to performance were studied for 99 sailors involved in solo and double-handed ocean sailing races (a model of a highly demanding CW situation). Most sailors spontaneously adopted multiple nap sleep-wake schedules and adapted without major difficulties to such polyphasic patterns. 66.5% had mean sleep episode durations (SEDs) ranging from 20 min to 2h. Overall mean Total Sleep Time (TST) per 24h was reduced from a baseline of 7.5 to 6.3h. Race performance correlated negatively and significantly with mean SEDs and TSTs. Best performance results were obtained by those sleeping for periods of between 20 min and 1 h and for a total of 4.5 to 5.5h of sleep per day.

The results are discussed together with several chronobiological, phylogenetic and experimental studies and issues, all of which suggest that adult humans may have a damped polyphasic sleep-wake tendency. It is also proposed that polyphasic sleep schedules could become promising and feasible solutions for the management of sleep requirements under prolonged CW situations.  相似文献   
58.
This paper uses quasi-unit record data on expenditures and incomes of New Zealand households of different demographic profiles to estimate consumption equivalence scales which measure the relative levels of spending required by households of different composition to attain given levels of utility. The equivalence scales with respect to specific items of consumption, as well as total consumption, have been obtained from the parameters of the preference-consistent Extended Linear Expenditure System and a few alternative versions of a rank 3 complete demand system with demand shifters. Among the demographic variables included in the models, the type of housing tenure and the actual age of children have special relevance. For the sake of comparison, a few heuristic scales are also computed. The results are largely in line with those found in similar studies of Australia and New Zealand. The analysis is developed within the framework of hypothesized utility-maximizing behaviour of households.  相似文献   
59.
Marina Tsvetaeva’s 1934 “Chërt” (The Devil) forms a central part of the cycle of autobiographical prose she wrote in emigration. This article assembles clues to the hidden origins of the Devil she describes in prose about her grandfathers, some of it censored in pre-1990 editions of her works. Tsvetaeva’s Devil is not simply metaphysical: it has the unusual appearance of a Great Dane. Though she goes on to trace its appearances in the literature and culture of her childhood, some of its physical features (eyes, nose, colour and posture) link it with other people in her life. The vivid details of the Devil suggest relationships, though peculiarly mediated ones, to members of her own family, especially her maternal grandfather, Aleksandr Danilovich Mein. The poet describes herself using Pushkin’s poem “Utoplennik” to camouflage her own sense of self from her mother. Much of the rest of “The Devil” describes her recognition of the Devil in varying symbolic or even phonetic guises, tracing how the poet stayed faithful to him even after he ceased to appear visibly, how she found and read his symbols in surrounding reality—e.g., card games, toys, rituals for finding lost objects—and in unexpected, otherwise respectable, parts of society, including her own grandfather. As always, Tsvetaeva creates a story that affirms her identity as a poet and illustrates the work she had to do to achieve that identity.  相似文献   
60.
The attachment pattern of a sample of 168 internationally adopted children was explored in this study using the semi‐structured Friends and Family Interview. The pattern was analysed in relation to the development of adaptive skills as an expression of the children's resilience. The secure attachment pattern rates were slightly lower and the insecure attachment patterns were considerably higher than those of normative samples from the previous studies. The children from Eastern Europe demonstrated a more insecure attachment pattern (odds ratio [OR]= 2.46; confidence interval [CI]= 1.23–3.94), and their scores on the adaptive skills scales were lower than the scores of children from other countries (OR = 2.62; 95% CI = 1.02–6.72). These results help to identify the groups at risk of failing to develop secure attachment patterns and appropriate adaptive skills, and should provide valuable information for designing effective interventions.  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