全文获取类型
收费全文 | 5263篇 |
免费 | 269篇 |
国内免费 | 4篇 |
专业分类
5536篇 |
出版年
2024年 | 10篇 |
2023年 | 60篇 |
2022年 | 86篇 |
2021年 | 103篇 |
2020年 | 141篇 |
2019年 | 135篇 |
2018年 | 263篇 |
2017年 | 248篇 |
2016年 | 227篇 |
2015年 | 145篇 |
2014年 | 164篇 |
2013年 | 701篇 |
2012年 | 401篇 |
2011年 | 403篇 |
2010年 | 249篇 |
2009年 | 165篇 |
2008年 | 314篇 |
2007年 | 255篇 |
2006年 | 225篇 |
2005年 | 210篇 |
2004年 | 121篇 |
2003年 | 129篇 |
2002年 | 124篇 |
2001年 | 58篇 |
2000年 | 76篇 |
1999年 | 44篇 |
1998年 | 25篇 |
1997年 | 18篇 |
1996年 | 21篇 |
1995年 | 18篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 30篇 |
1991年 | 20篇 |
1990年 | 24篇 |
1989年 | 23篇 |
1988年 | 26篇 |
1987年 | 16篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1979年 | 15篇 |
1978年 | 11篇 |
1976年 | 13篇 |
1974年 | 10篇 |
1971年 | 10篇 |
1970年 | 10篇 |
1968年 | 11篇 |
1966年 | 9篇 |
1965年 | 10篇 |
排序方式: 共有5536条查询结果,搜索用时 15 毫秒
951.
Helena Cassol Charlotte Martial Jitka Annen Géraldine Martens Vanessa Charland-Verville Steve Majerus 《Memory (Hove, England)》2013,21(8):1122-1129
ABSTRACTNear-death experiences (NDEs) are usually associated with positive affect, however, a small proportion are considered distressing. We aimed to look into the proportion of distressing NDEs in a sample of NDE narratives, categorise distressing narratives according to Greyson and Bush’s classification (inverse, void or hellish), and compare distressing and “classical” NDEs. Participants wrote down their experience, completed the Memory Characteristics Questionnaire (assessing the phenomenology of memories) and the Greyson scale (characterising content of NDEs). The proportion of suicidal attempts, content and intensity of distressing and classical NDEs were compared using frequentist and Bayesian statistics. Distressing NDEs represent 14% of our sample (n?=?123). We identified 8 inverse, 8 hellish and 1 void accounts. The proportion of suicide survivors is higher in distressing NDEs as compared to classical ones. Finally, memories of distressing NDEs appear as phenomenologically detailed as classical ones. Distressing NDEs deserve careful consideration to ensure their integration into experiencers’ identity. 相似文献
952.
An enhancement of the UV-visible optical absorption spectra of Ag nanoparticles (NPs) deposited on indium tin oxide (ITO) surfaces of different resistance by a seed-mediated growth technique is presented. A bicolour coherent beam, obtained from a pulsed Nd:YAG laser providing a 1060-nm fundamental wavelength and a double-frequency one at 530?nm, was used. A significant change in the optical density is observed for Ag NPs on low-resistance ITO surfaces (≈4?Ω/square), while almost nothing occurs with high-resistance (≈50?Ω/square surfaces). The spectral position of the maximal absorption at 440?nm is almost preserved in both cases. This result is explained in terms of a local photoinduced static field and surface-plasmon polaritons interacting with photoexcited phonons. A grating effect, arising from the coherent bicolour light forming a superstructure as for quantum crystals, could be another contribution. 相似文献
953.
Antoine Jérusalem 《Philosophical Magazine Letters》2013,93(9):599-609
Owing to their very high strength, nanocrystalline metals have been extensively studied over the recent years. The direct Hall–Petch law, empirically proportioning the material strength to the inverse square root of its grain size has been shown to break down below a grain size of the order of tenths of nanometers. This phenomenon has been widely rationalized as a gradual switch from intragrain mediated deformation mechanisms to grain boundary mediated deformation mechanisms. This transition has been observed in many finite element simulations, despite the intrinsic restriction of necessarily limiting the nanocrystalline representative assembly to only a few grains. Such a limitation is generally overlooked, and its influence on an uniaxial tension test – when compared to a complete sample of millions of grains – ignored. We propose here to quantify the approximation done by considering a finite number of grains by means of a simple analytical model based on the early work of Stevens [R.N. Stevens, Philos. Mag. 23 (1971) p. 265]. The finite element approximation is demonstrated to be relatively good, even down to only three grains in width, and a method to “correct” the stress-strain curves of small representative volumes is proposed. 相似文献
954.
The current study incorporated principles from the acculturation literature to specify an ethnically relevant general strain theory (GST). This study argues that the acculturation process exposes Hispanics to unique types of strain (e.g., prejudice and discrimination) that may increase the likelihood of delinquency. Further varying levels of Hispanic concentration can moderate the effect of acculturative strain on delinquency, whereby the effect of ethnic-specific strains may be more pronounced where ethnic concentration is low. Responses from self-administered questionnaires of 1,729 Hispanic adolescents were analyzed to test various hypotheses regarding the effects of traditional and acculturation-related strains on violent delinquency. The findings indicated that GST is generalizable to Hispanic adolescents. The analyses also found support for the prediction that, conditional on the level of Hispanic concentration, ethnic-specific strain measures increased the likelihood of violent delinquency among Hispanic adolescents. This study provided a foundation for future empirical analyses of criminological theories among Hispanic populations. 相似文献
955.
Cédrick T. Bonnet Cédric Morio Sébastien Szaffarczyk Patrice R. Rougier 《Journal of motor behavior》2013,45(6):397-405
Medialateral postural control mechanisms (bodyweight distribution and center of pressure location) have been studied in static conditions. Our objective was to determine how these mechanisms are adjusted to perform voluntary movements, in our case 80° lateral gaze shifts at 0.125 Hz and 0.25 Hz. In healthy, young adults, we expected body marker (neck, lower back) and center of pressure displacements to be significantly greater in gaze shift conditions than in the stationary gaze condition. To explain these changes in center of pressure displacement, the amplitude contribution of both mechanisms was expected to increase significantly. All these results were found accordingly. Unexpectedly, the active contribution of the bodyweight distribution mechanism was negatively related to body marker displacements in the gaze shift conditions (ns in stationary condition). Moreover, changes in the contribution of the mechanisms were statistically weaker in effect size than changes in body displacement. However, the participants were not unstable because they performed the visual tasks as requested. We propose that the strength of medialateral postural control mechanisms may not only be strengthened to control challenging ML stance conditions but also slightly weakened to allow the performance of adequate body motions in ongoing tasks. 相似文献
956.
Andréa Baraldi Cunha Michele A. Lobo Elena Kokkoni James C. Galloway Eloisa Tudella 《Journal of motor behavior》2013,45(2):132-142
The purpose of this study was to test the effect of short-term training on reaching behavior in infants at the onset of reaching. The study was a single-blind, parallel group design, randomized controlled clinical trial. Thirty healthy infants were randomly assigned to a social control group (n = 15) or a reaching training group (n = 15). Infants began the study up to 3 days after the onset of reaching and were assessed three times across 2 days: pretraining (before training), posttraining 1 (after 1 session of training), and posttraining 2 (after 3 sessions of training). The reaching training group received 3 sessions of training by a physical therapist while the control group received a similar amount of time sitting in the therapist's lap. The data were analyzed using repeated-measures analyses of variance, and independent-samples tests with Bonferroni adjustments. Short-term training resulted in increased frequency of object contacts, shorter and smoother reaches, and improved hand positioning. The few short training sessions likely provided opportunities for infants to explore and learn to select movements from their existing movement repertoire. These results demonstrate that adaptive changes in infants' novel behaviors can emerge rapidly, and highlight the need for increased understanding of how to most effectively time early interventions. 相似文献
957.
958.
Nicolas Sihlé 《Religion》2013,43(2):284-287
959.
András Pöstényi M.D. 《Scandinavian Psychoanalytic Review》2013,36(1):35-48
In differentiation of early and mature shame, the phenomenological content of shame changes with the development of a stable self-state. In this hypothesis, early shame refers to a person's dependence upon mirroring himself and in being mirrored by an outer object, while mature shame refers to introspection and self-reflection. From a developmental psychological point of view, the connection between self-development and mirroring is expounded. Mirroring is defined as a psychic dialectic process between the inner psychic reality and the outer reality. Early shame is connected to dyadic mirroring, which refers to attachment and empathy. Mature shame is connected to triadic mirroring, which refers to separation and reflection. Early shame emerges from discrepancies between the infant's expectations of a complementary affective response and the mother's response, and is defined as an early marker of differences in the mother/infant unit. It is argued that early shame in smaller ‘doses’ has a regulating function on self-development by maintaining the psychic dialectic process, while in larger ‘doses’, it has a disturbing effect on the self-development, resulting in pathological shame. In the therapeutic process, early shame appears as shame scenarios illustrated in the text by a clinical vignette. 相似文献
960.
Angela Conchillo Jiménez 《Estudios de Psicología》2013,34(27-28):59-75
RESUMENLa autora comienza exponiendo una síntesis de los modelos de Thurstone y Anderson -Ley del Juicio Comparativo y Teoría de la Integración de la Información, respectivamente- los cuales, desde supuestos distintos, permiten establecer una escala de intervalos en la medición de estímulos subjetivos. En esta investigación el objetivo es descubrir la existencia de una transformación admisible para la escala de intervalos que permita pasar de la escala de medida proporcionada por un modelo a la proporcionada por el otro, utilizando los mismos estímulos y los mismos sujetos. El trabajo concluye considerando que los resultados son esperanzadores aunque se sugiere aceptarlos con cierta cautela ya que se utilizaron pocas categorías de estímulos. 相似文献