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   536篇
  免费   56篇
  国内免费   42篇
  2023年   19篇
  2022年   10篇
  2021年   10篇
  2020年   38篇
  2019年   38篇
  2018年   36篇
  2017年   41篇
  2016年   38篇
  2015年   16篇
  2014年   26篇
  2013年   82篇
  2012年   20篇
  2011年   25篇
  2010年   11篇
  2009年   17篇
  2008年   19篇
  2007年   25篇
  2006年   24篇
  2005年   15篇
  2004年   14篇
  2003年   5篇
  2002年   12篇
  2001年   13篇
  2000年   9篇
  1999年   6篇
  1998年   8篇
  1997年   15篇
  1996年   5篇
  1995年   4篇
  1994年   8篇
  1993年   4篇
  1991年   5篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1980年   1篇
  1979年   1篇
  1978年   2篇
  1977年   1篇
  1976年   2篇
排序方式: 共有634条查询结果,搜索用时 15 毫秒
61.
Based on the Theory of Planned Behaviour (TPB), the purpose of this investigation was to examine the directionality of the association among condom use, intention, attitudes, subjective norms and perceived behavioural control. The present study investigated the nature of these relationships using a longitudinal cross-lagged design applied to data from a cohort of 958 randomly selected Italian adults. Using structural equation modelling, two cross-lagged panel analyses revealed reciprocal relationships between intention and attitudes and between intention and condom use. Contrary to expectations, baseline subjective norms and perceived behavioural control did not predict subsequent intention to use condom when controlled for the autoregressive effect of intention at T1 on the same variable at T2. Also, perceived behavioural control at T1 did not influence condom use at T2 after controlling for the effect of baseline intention. The possibility of reciprocity was also tested for all relations and significant results were found. The moderation effect of perceived behavioural control on the relationship between intention and condom use was not significant. The differences in age, gender and partnership status were taken into account in the analyses.  相似文献   
62.
This article describes an example of making pediatric neuropsychological assessments more time-efficient. Empirical support, including new data, for the utilization of an eight-subtest short form of the Wechsler Intelligence Scale for Children-Third Edition (WISC-III; Wechsler, 1991) is reviewed. It is concluded that this short form of the WISC-III is a valid substitute for the complete version under most clinical circumstances, allowing the practitioner to expand on interview, history or more specific neuropsychological tests without adding financial or time burdens to the evaluation.  相似文献   
63.
A key challenge in the fabrication of superhard nanocomposite films is how to control the distribution of grain sizes in these materials. High-resolution transmission electron microscopy has been used to measure nanograin-size distributions in the Ti–B–N films with various B contents. The results show that the mean grain size decreases with increase of B content and the grain-size distribution conforms to a log-normal function when the hardness approaches a maximum value. The transition from normal to log-normal distributions can be determined by analysis in terms of a minimum information criterion. The origin of a log-normal size distribution probably results from heterogeneity arising from a diffusion-drift process.  相似文献   
64.
We report on the effect of cooling rate on the size-dependent atomic ordering of CoPt nanoparticles using aberration corrected high-resolution transmission electron microscopy. It was found that cooling rate plays a crucial role in promoting atomic ordering during the cooling process after annealing. Nanoparticles of ≈3?nm in diameter show the A1-disordered phase after annealing at 873?K for 1?h followed by rapid cooling (110?K/min), while the L10-ordered phase is obtained when the cooling rate is slow (1.5?K/min). The disordered phase is also obtained by rapid cooling after annealing at 973?K for 1?h. These results unambiguously indicate that the order–disorder transformation temperature is reduced to a temperature at least lower than 873?K for CoPt nanoparticles smaller than 3?nm in diameter. The slow cooling process promotes the atomic ordering, which resulted in an enhancement of magnetic coercivity as high as 2200?Oe. This study demonstrates that hard magnetic properties of the CoPt nanoparticles can be improved by controlling the cooling rate after heat treatments.  相似文献   
65.
This article describes the possible impact of emotional intelligence on identity negotiation of a racial minority group in a majority school context. The study investigated the adjustment and functioning of racial minority groups in majority school contexts, as well as the identity negotiation associated with it, and determined whether there is a correlation between the former and the Emotional Intelligence (EI) of the participants. Participants were 16 black and 21 white learners attending two schools where they were in the minority (mean age = 16.23 years; SD = 1.49 years). The learners attended Grades 9–12. Data were first organised, after which themes and patterns were identified, and the data appraised and categorised (Creswell, 2007), after which a comparison was drawn between the identified categories of existing knowledge. Findings suggest that racial integration in both high schools actually occurred in name only; most participants chose to mingle within their own racial groups and the black participants in particular were exposed to racism, discrimination and prejudice on a regular basis. Despite the necessary steps taken and implemented by government in order to oppose racism in the country and promote racial integration in schools, it seems that the consequences of apartheid remain for the foreseeable future.  相似文献   
66.
We show that perceived size of visual stimuli can be altered by matches between the contents of visual short-term memory and stimuli in the scene. Observers were presented with a colour cue (to hold in working memory or to merely identify) and subsequently had to indicate which of the two different-coloured objects presented simultaneously on the screen appeared bigger (or smaller). One of the two objects for size judgements had the same colour as the cue (matching stimulus) and the other did not (mismatching stimulus). Perceived object size was decreased by the reappearance of the recently seen cue, as there were more size judgement errors on trials where the matching stimulus was physically bigger (relative to the mismatching stimulus) than on trials where the matching stimulus was physically smaller. The effect occurred regardless of whether the visual cue was actively maintained in working memory or was merely identified. The effect was unlikely generated by the allocation of attention, because shifting attention to a visual stimulus actually increased its perceived size. The findings suggest that visual short-term memory, whether explicit or implicit, can decrease the perceived size of subsequent visual stimuli.  相似文献   
67.
Two models of second-order ZFC need not be isomorphic to each other, but at least one is isomorphic to an initial segment of the other. The situation is subtler for impure set theory, but Vann McGee has recently proved a categoricity result for second-order ZFCU plus the axiom that the urelements form a set. Two models of this theory with the same universe of discourse need not be isomorphic to each other, but the pure sets of one are isomorphic to the pure sets of the other.This paper argues that similar results obtain for considerably weaker second-order axiomatizations of impure set theory that are in line with two different conceptions of set, the iterative conception and the limitation of size doctrine.  相似文献   
68.
许百华  傅亚强 《心理科学》2003,26(3):397-399
采用一台有源矩阵彩色液晶显示器作为主要实验装置,对低色温、低强度背景光照射下液晶显示颜色编码范围及其与色标大小的关系进行了研究。实验结果表明:(1)液晶显示器上色标大小对绝对辨认效果有显著影响,随着色标的增大,辨认错误率随之下降,但下降率则随色标的增大而递减。(2)在色温为3100K的低强度背景光照射下,液晶显示的颜色编码范围因色标大小不同而存在显著差异,当色标面积减小到1×1mm2至2×2mm2时,编码色数目仅限于3-4种。  相似文献   
69.
This paper is an introduction to a special issue on Nationalism, Multiculturalism and Liberal Democracy. It attempts to describe the state of the debate on issues of multiculturalism and nationalism within liberal-democratic theory. I suggest that there may be an emerging consensus on liberal culturalism – the view that certain group-specific rights or policies aimed at recognizing or accommodating ethnic and national groups are legitimate so long as they operate within certain constraints of liberal justice. I explore the possible reasons for this emerging consensus (including the lack of clear alternatives), and conclude with some suggestions about the likely avenues for future research in this area.  相似文献   
70.
Two studies tested a model, whereby, identification with the minority group was predicted to impact on acculturation preferences, which in turn were proposed to impact involvement in intragroup friendships with other minority members, intergroup friendships with majority members and stress experienced by minority members. A direct path from minority identification to stress was also included in the model. The model was tested using structural equation modelling on survey data collected from Muslim women (N = 250) and from Somali minority members (N = 198) in Britain. Results supported predictions and revealed that identification was associated with more culture maintenance preference and less culture adoption preference. Culture maintenance preference was associated with involvement in intragroup friendships, and culture adoption preference was associated with involvement in intergroup friendships and increased stress. Practical applications of the findings are discussed.  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