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   683篇
  免费   37篇
  2024年   1篇
  2023年   10篇
  2022年   5篇
  2021年   9篇
  2020年   19篇
  2019年   24篇
  2018年   36篇
  2017年   27篇
  2016年   33篇
  2015年   19篇
  2014年   26篇
  2013年   68篇
  2012年   48篇
  2011年   45篇
  2010年   21篇
  2009年   25篇
  2008年   31篇
  2007年   32篇
  2006年   36篇
  2005年   24篇
  2004年   19篇
  2003年   12篇
  2002年   18篇
  2001年   16篇
  2000年   14篇
  1999年   5篇
  1998年   7篇
  1997年   12篇
  1996年   10篇
  1995年   6篇
  1994年   8篇
  1993年   11篇
  1992年   5篇
  1991年   7篇
  1990年   4篇
  1989年   4篇
  1988年   1篇
  1987年   2篇
  1986年   2篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   3篇
  1981年   1篇
  1979年   2篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1968年   1篇
排序方式: 共有720条查询结果,搜索用时 15 毫秒
1.
2.
Currently available methods for the analysis of circadian rhythms provide little help in the evaluation of the circadian rhythm of body temperature because they either assume that the circadian rhythm of body temperature approximates a cosine wave (which for many species is not true) or simply do not address important parameters, such as the amplitude and the shape of the temperature rhythm. The present paper presents methods for the computation and statistical evaluation of the period, amplitude, mean level, and general shape of the circadian rhythm of body temperature. The period is analyzed by the periodogram procedure, whereas the other parameters are analyzed by the histogram method. Both procedures are simple to implement and relatively insensitive to spurious data points. A simplified but fully operational program in BASIC is provided.  相似文献   
3.
4.
People hold different perspectives about how they think the world is changing or should change. We examined five of these “worldviews” about change: Progress, Golden Age, Endless Cycle, Maintenance, and Balance. In Studies 1–4 (total N = 2733) we established reliable measures of each change worldview, and showed how these help explain when people will support or oppose social change in contexts spanning sustainability, technological innovations, and political elections. In mapping out these relationships we identify how the importance of different change worldviews varies across contexts, with Balance most critical for understanding support for sustainability, Progress/Golden Age important for understanding responses to innovations, and Golden Age uniquely important for preferring Trump/Republicans in the 2016 US election. These relationships were independent of prominent individual differences (e.g., values, political orientation for elections) or context-specific factors (e.g., self-reported innovativeness for responses to innovations). Study 5 (N = 2140) examined generalizability in 10 countries/regions spanning five continents, establishing that these worldviews exhibited metric invariance, but with country/region differences in how change worldviews were related to support for sustainability. These findings show that change worldviews can act as a general “lens” people use to help determine whether to support or oppose social change.  相似文献   
5.
6.
In rats, pretraining ip administration of the central benzodiazepine receptor antagonist, flumazenil (5.0 mg/kg), or of the inverse agonist, n-butyl-beta-carboline-3-carboxylate (BCCB) (0.2 or 0.5 mg/kg), facilitated retention of a step-down inhibitory avoidance task; the central agonists, clonazepam and diazepam (0.4 or 1.0 mg/kg), had an opposite effect, and the peripheral agonist, 4'-chlordiazepam (1.25 or 6.25 mg/kg), was without effect. Pre- but not post-training flumazenil (2.0 mg/kg) blocked the effect of BCCB (0.5 mg/kg), clonazepam (1.0 mg/kg), or diazepam (1.0 mg/kg) given also pretraining. The post-training administration of all of these drugs had no effect on retention of the avoidance task. Flumazenil (5.0 mg/kg) and BCCB (0.5 mg/kg), given before training, enhanced retention test performance of habituation to a buzzer but not of habituation to an open field. In the three tasks studied, none of the drugs used had any appreciable effect on training session parameters. These results suggest that there is an endogenous mechanism mediated by benzodiazepine agonists, sensitive to inverse agonists, that normally down-regulates acquisition of certain behaviors; this mechanism becomes activated only when the tasks involve or occur with a certain degree of stress or anxiety (i.e., inhibitory avoidance or habituation to the buzzer) and not in less stressful or anxiogenic tasks (i.e., habituation to an open field).  相似文献   
7.
This article presents a series of personal guidelines for promoting the culturally sensitive psychiatric diagnosis of Mexican American/Chicano clients. These guidelines are primarily based on the authors' collective experiences in diagnosing and treating this population.  相似文献   
8.
The notion of unsharp orthoalgebra is introduced and it is proved that the category of unsharp orthoalgebras is isomorphic to the category of D-posets. A completeness theorem for some partial logics based on unsharp orthoalgebras, orthoalgebras and orthomodular posets is proved.  相似文献   
9.
This article sets out the overall framework within which American music phenomenologists operates. A widely accepted definition of the word phenomenology, together with a basically eclectic attitude and a boundary issue between musicology and philosophy, is identified. The impetus to the article is provided by an anti-positivistic polemic and a plea in defence of the meaning and concreteness of musical experience. These aspects then combine in a critique of traditional musical analysis in its positivistic matrix. S.K. Langer's philosophy, as the inspiration of this polemic, is examined in the central part of the article. However, the author's distancing from the idealistic aspects of his esthetics is covered, in particular the downplaying of the sound-sensitive level and the condemnation of musicology in general. Sense and sensitive materials, wide philosophical options and concrete procedures of music analysis are what these authors look for in phenomenology as a means to reconcile humanistic and technical culture. Therefore, the article is not so much a condemnation as an attempt to refound musicology in its entirety, with particular reference to contemporary music.  相似文献   
10.
Zellini (1979, Theorem 3.1) has shown how to decompose an arbitrary symmetric matrix of ordern ×n as a linear combination of 1/2n(n+1) fixed rank one matrices, thus constructing an explicit tensor basis for the set of symmetricn ×n matrices. Zellini's decomposition is based on properties of persymmetric matrices. In the present paper, a simplified tensor basis is given, by showing that a symmetric matrix can also be decomposed in terms of 1/2n(n+1) fixed binary matrices of rank one. The decomposition implies that ann ×n ×p array consisting ofp symmetricn ×n slabs has maximal rank 1/2n(n+1). Likewise, an unconstrained INDSCAL (symmetric CANDECOMP/PARAFAC) decomposition of such an array will yield a perfect fit in 1/2n(n+1) dimensions. When the fitting only pertains to the off-diagonal elements of the symmetric matrices, as is the case in a version of PARAFAC where communalities are involved, the maximal number of dimensions can be further reduced to 1/2n(n–1). However, when the saliences in INDSCAL are constrained to be nonnegative, the tensor basis result does not apply. In fact, it is shown that in this case the number of dimensions needed can be as large asp, the number of matrices analyzed.  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