全文获取类型
收费全文 | 1446篇 |
免费 | 177篇 |
国内免费 | 367篇 |
专业分类
1990篇 |
出版年
2024年 | 6篇 |
2023年 | 30篇 |
2022年 | 53篇 |
2021年 | 52篇 |
2020年 | 78篇 |
2019年 | 74篇 |
2018年 | 82篇 |
2017年 | 83篇 |
2016年 | 78篇 |
2015年 | 50篇 |
2014年 | 66篇 |
2013年 | 125篇 |
2012年 | 106篇 |
2011年 | 116篇 |
2010年 | 95篇 |
2009年 | 112篇 |
2008年 | 121篇 |
2007年 | 128篇 |
2006年 | 119篇 |
2005年 | 100篇 |
2004年 | 52篇 |
2003年 | 44篇 |
2002年 | 27篇 |
2001年 | 29篇 |
2000年 | 15篇 |
1999年 | 18篇 |
1998年 | 9篇 |
1997年 | 10篇 |
1996年 | 7篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 9篇 |
1991年 | 7篇 |
1990年 | 1篇 |
1989年 | 9篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 7篇 |
1981年 | 6篇 |
1980年 | 3篇 |
1979年 | 4篇 |
1975年 | 3篇 |
1972年 | 1篇 |
1964年 | 1篇 |
1959年 | 1篇 |
排序方式: 共有1990条查询结果,搜索用时 0 毫秒
141.
Fei Gu Kristopher J. Preacher Wei Wu Yiu-Fai Yung 《Multivariate behavioral research》2013,48(2):119-129
Although the state space approach for estimating multilevel regression models has been well established for decades in the time series literature, it does not receive much attention from educational and psychological researchers. In this article, we (a) introduce the state space approach for estimating multilevel regression models and (b) extend the state space approach for estimating multilevel factor models. A brief outline of the state space formulation is provided and then state space forms for univariate and multivariate multilevel regression models, and a multilevel confirmatory factor model, are illustrated. The utility of the state space approach is demonstrated with either a simulated or real example for each multilevel model. It is concluded that the results from the state space approach are essentially identical to those from specialized multilevel regression modeling and structural equation modeling software. More importantly, the state space approach offers researchers a computationally more efficient alternative to fit multilevel regression models with a large number of Level 1 units within each Level 2 unit or a large number of observations on each subject in a longitudinal study. 相似文献
142.
HaiYing Wu YaHong Chen XinFang Su ChengRong Deng Zi-Jiang Liu 《Philosophical Magazine Letters》2013,93(4):198-204
A phase transition of MgS under high pressure is investigated using a first-principles method. It is found from energy-volume calculations that the rock-salt (B1) phase of MgS transforms into a FeSi-type (B28) phase at 143?GPa. The calculated ground-state parameters in the B1 phase are in excellent agreement with available experimental and theoretical data. Ab initio phonon calculations are also performed to investigate the structural behaviour of MgS under high pressure. An unstable transverse acoustic mode and a phase transition from B1 to B28 phase at ~143.7?GPa driven by this soft mode are predicted. The B28 structure of MgS is stable up to 350?GPa according to lattice dynamics calculations. 相似文献
143.
High-resolution grazing-incidence parallel-beam powder diffraction has been used to detect the subsurface damage below alumina surfaces subjected to polishing with cerium oxide or diamond. Despite very significant evolution of the surface morphology, no changes in the subsurface strains were observed over a 20min period of polishing with ceria. For both polishing materials, the variation with angle in the full-width at half-height maximum was successfully modelled by a strain distribution that fell exponentially with increasing depth. Although the surface amplitude and depth dependence parameter are coupled, we have been able to place upper limits on the depth to which the damage extends. Under realistic assumptions, the depth of damage induced by 1µm diamond paste is comparable with that from 3µm ceria polish. 相似文献
144.
The average velocities of screw dislocations in Ni 3 Al single crystals have been directly measured as a function of resolved shear stress (RSS) and orientation in the temperature domain of the flow stress anomaly using the etch-pit technique. The velocity was found to be extremely sensitive to the RSS in all cases. In contrast with ordinary metals, the screw dislocation velocities in Ni 3 Al show anomalous behaviour; under a constant RSS, the velocities decrease dramatically with increasing temperature. Furthermore, the velocities and the tension-compression asymmetry of the velocities depend on the orientation of applied stress. 相似文献
145.
Chunxiao Li C.K. John Wang Do Young Pyun Ying Hwa Kee 《Psychology of sport and exercise》2013,14(5):692-700
ObjectivesThe present study is a review on studies about the relationships between the three basic psychological needs/motivational regulations (i.e., amotivation, controlled regulation, extrinsic autonomous regulation, and intrinsic motivation) and burnout.DesignA systematic review and meta-analysis.MethodStudies were identified through five electronic databases and manual search using combinations of three groups of keywords. Three inclusion criteria were then used to screen the searched articles.ResultsEighteen studies met the inclusion criteria and these studies varied considerably in terms of their study characteristics (e.g., characteristics of participants, study designs, and outcome measures). The results also showed that the three basic psychological needs, intrinsic motivation, extrinsic autonomous regulation, and amotivation had small to large effects on predicting global burnout and its three dimensions. However, controlled regulation showed no or weak correlations with the burnout subscales.ConclusionsSelf-determination theory was generally supported in explaining athlete burnout. 相似文献
146.
Yanbo Wang Hongbiao Wang Ji Wang Jing Wu Xiaohong Liu 《Journal of clinical psychology in medical settings》2013,20(1):3-12
This study examined prevalence and predictors of posttraumatic growth in 180 accidentally injured patients of mainland China in their convalescence stage, investigating its relationships with demographic and accidental injury variables, personality, posttraumatic stress disorder (PTSD) symptoms, and coping styles. Our results showed that posttraumatic growth (PTG) presented mostly in the domain of Relating to Others and indicated that PTG was significantly related to marital status, educational level, personality, coping styles, and PTSD symptoms. Avoidance of PTSD symptoms, Openness to experience, and positive coping were significant predictors of PTG. The findings emphasize that when promoting PTG of accidentally injured patients, healthcare providers should facilitate patients utilizing personal resources, understand PTG coexists with PTSD symptoms, and adjust interventions based on the coping styles the patients have adopted. 相似文献
147.
Lars O. White Jia Wu Jessica L. Borelli Linda C. Mayes Michael J. Crowley 《Developmental science》2013,16(6):850-863
Reunion behavior following stressful separations from caregivers is often considered the single most sensitive clue to infant attachment patterns. Extending these ideas to middle childhood/early adolescence, we examined participants' neural responses to reunion with peers who had previously excluded them. We recorded event‐related potentials among nineteen 11‐ to 15‐year‐old youth previously classified on attachment interviews (11 secure and 8 insecure‐dismissing) while they played a virtual ball‐toss game (Cyberball) with peers that involved fair play, exclusion and reunion phases. Compared to secure participants, dismissing participants displayed a greater increment in the N2 during reunion relative to fair play, a neural marker commonly linked to expectancy violation. These data suggest a greater tendency toward continued expectations of rejection among dismissing children, even after cessation of social exclusion. In turn, the link between self‐reported ostracism distress and neural signs of negative expectancy at reunion was moderated by attachment, such that self‐reports were discordant with the neural index of expectancy violation for dismissing, but not for secure children. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=qzoRel5c-4s . 相似文献
148.
C. Harry Hui Stephanie W.Y. Chan Esther Y.Y. Lau Shu-Fai Cheung Doris Shu Ying Mok 《Mental health, religion & culture》2013,16(1):52-61
How would religion and a life event carrying an existential threat (LEET) jointly impact a person's life goals of becoming wealthy and successful in one's career? Goal reprioritisation, socioemotional selectivity, and gerotranscendence theories predict a shift away from material goals following a LEET, independent of the effect of religion. However, terror management theory (TMT) predicts that the effect of death thoughts depends on one's prevailing cultural values. As religion can be regarded as a culture, it is possible that Christians' and non-believers' material life goals would be differentially altered by LEET. Data from 1259 young Chinese adults reveal no main effect of LEET, but a strong effect of religion. Moreover, there was an interaction effect between LEET and religion on material life goals: LEET weakened material goals for Christians but not for non-believers. These findings suggest that TMT is more suitable than the other theories for predicting life goal changes. 相似文献
149.
本工作对两例先天性无痛症患者对于致痛性强刺激的知觉和反应进行了研究(例1女,10岁,例2男,13岁)。对照组为20例正常儿童,性别和年龄均与患儿相匹配。 结果:1),生活中痛:两例患儿均无(包括痛感觉和痛反应)。2)实验性痛:①痛感觉:两例患儿均无;②“痛”反应:例1有“痛”反应(脉搏和呼吸的变化以及行为反应明显,大致与正常儿童相似)。例2无“痛”反应(脉搏和呼吸的变化轻微,无行为反应,与正常儿童不同)。 由结果看来,先天性无痛症患者似乎可分为两种类型:不完全型(如同例1)和完全型(如同例2)。存在有“痛”反应而无痛感觉的无痛症患者。 本工作结果从另一侧面为痛的两成分学说提供了依据。 相似文献
150.
汉语词类歧义解决初探 总被引:1,自引:0,他引:1
采用自定步速移动窗口阅读实验范式,考察汉语词类歧义解决过程。阅渎材料为含有单字词类歧义词的句子,歧义词前面的语境不提供明确的偏向性信息.后语境提供解歧信息。结果发现,主要用法和次要用法的句子都在解歧区比控制句阅读时间加长,表明汉语词类歧义解决没有即时受到歧义词两种用法的相对频率影响,而是在歧义词处暂时不进行完全的句法分配,延迟到获得充分解歧信息的时候才分配句法角色。这一结果支持词类歧义解决的延迟模型。 相似文献