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   3426篇
  免费   204篇
  国内免费   142篇
  2023年   53篇
  2022年   37篇
  2021年   79篇
  2020年   117篇
  2019年   90篇
  2018年   131篇
  2017年   134篇
  2016年   155篇
  2015年   96篇
  2014年   114篇
  2013年   385篇
  2012年   184篇
  2011年   201篇
  2010年   130篇
  2009年   138篇
  2008年   148篇
  2007年   187篇
  2006年   146篇
  2005年   136篇
  2004年   111篇
  2003年   96篇
  2002年   88篇
  2001年   73篇
  2000年   62篇
  1999年   61篇
  1998年   40篇
  1997年   38篇
  1996年   26篇
  1995年   22篇
  1994年   22篇
  1993年   24篇
  1992年   36篇
  1991年   32篇
  1990年   17篇
  1989年   18篇
  1988年   17篇
  1987年   19篇
  1986年   27篇
  1985年   23篇
  1984年   23篇
  1983年   15篇
  1981年   15篇
  1980年   16篇
  1979年   20篇
  1978年   12篇
  1977年   12篇
  1975年   17篇
  1974年   12篇
  1973年   14篇
  1966年   15篇
排序方式: 共有3772条查询结果,搜索用时 15 毫秒
181.
In two experiments using spatial probes, we measured the temporal and spatial interactions between top-down control of attention and bottom-up interference from a salient distractor in visual search. The subjects searched for a square among circles, ignoring color. Probe response times showed that a color singleton distractor could draw attention to its location in the early stage of visual processing (before a 100-msec stimulus onset asynchrony [SOA]), but only when the color singleton distractor was located far from the target. Apparently the bottom-up activation of the singleton distractor's location is affected early on by local interactions with nearby stimulus locations. Moreover, probe results showed that a singleton distractor did not receive attention after extended practice. These results suggest that top-down control of attention is possible at an early stage of visual processing. In the long-SOA condition (150-msec SOA), spatial attention selected the target location over distractor locations, and this tendency occurred with or without extended practice.  相似文献   
182.
The relations between temperament and empathy in 2-year-olds.   总被引:2,自引:0,他引:2  
The role of infant and toddler temperament in the prediction of empathy in 2-year-old children was examined. Assessments of temperament included reactivity and affect observed at 4 months of age, as well as inhibition at Age 2. Empathy was measured in 2-year-old children's responses to simulations of distress performed by their mothers and by an unfamiliar person. Children showed relatively more concern for the mother's distress, but they were also responsive to unfamiliar victims. Infants who were unreactive and showed little affect also showed less empathy toward the unfamiliar adult almost 2 years later. Inhibition toward an unfamiliar adult (but not toward the mother) at 2 years of age was negatively related to empathy. Inhibited temperament may thus have a major impact on young children's empathy in unfamiliar contexts. Findings also highlight the need to consider early underarousal as another dimension of temperament that may dampen expressions of empathic concern.  相似文献   
183.
依据Rayleigh颜色匹配方法研制人眼颜色视觉定量测量实验装置,并对20名色觉正常和30名色觉异常大学生的颜色视觉进行测量。结果表明,色觉异常被试在Rayleigh匹配中点和匹配范围测量值上均与色觉正常被试者存在明显的差异。  相似文献   
184.
Kim L. Beckmann 《Zygon》1999,34(3):537-541
This Christian sermon uses a DNA lab experience as a basis for theological reflection on ourselves and our offering. Who are we to God? What determines the self that we offer? Can the alphabet of DNA shed light for us on the Word of God in our lives? This first attempt to introduce the language and laboratory environment of genetic testing (represented by DNA fingerprinting) within a parish preaching context juxtaposes liturgical, scientific, and biblical language and settings for fresh insights.  相似文献   
185.
In 3 experiments, the authors examined movement space-time variability as a function of the force-time properties of the initial impulse in a movement timing task. In the range of motion and movement time task conditions, peak force, initial rate of force, and force duration were manipulated either independently or in combination across a range of parameter values. The findings showed that (a) impulse variability is predicted well by the elaboration of the isometric force variability scaling functions of L. G. Carlton, K. H. Kim, Y. T. Liu, and K. M. Newell (1993) to movement, and (b) the movement spatial and temporal outcome variability are complementary and well predicted by an equation treating the variance of force and time in Newton's 2nd law as independent random variables. Collectively, the findings suggest that movement outcome variability is the product of a coherent space-time function that is driven by the nonlinear scaling of the force-time properties of the initial impulse.  相似文献   
186.
分析中国伪生命科学产生的文化原因和背景,指出其致命的谎言、骗术与危害;揭露其理论上的荒谬与科学上的无知。并强调开展对这类伪科学产品进行批判运动的意义;同时重新对科学、非科学、伪科学、宗教、神话、迷信等进行划界和定义。医学研究需要正义、需要哲学的引导;在事实的世界之上,必须由价值和意义的世界来把握;医学理论不允许任意杜撰和加工,从这个意义上,医学科学还需要法律来维护其正义  相似文献   
187.
Seventeen-month-old infants were presented with pairs of images, in silence or with the non-directive auditory stimulus ‘look!’. The images had been chosen so that one image depicted an item whose name was known to the infant, and the other image depicted an image whose name was not known to the infant. Infants looked longer at images for which they had names than at images for which they did not have names, despite the absence of any referential input. The experiment controlled for the familiarity of the objects depicted: in each trial, image pairs presented to infants had previously been judged by caregivers to be of roughly equal familiarity. From a theoretical perspective, the results indicate that objects with names are of intrinsic interest to the infant. The possible causal direction for this linkage is discussed and it is concluded that the results are consistent with Whorfian linguistic determinism, although other construals are possible. From a methodological perspective, the results have implications for the use of preferential looking as an index of early word comprehension.  相似文献   
188.
Infants under 7 months of age fail to reach behind an occluding screen to retrieve a desired toy even though they possess sufficient motor skills to do so. However, even by 3.5 months of age they show surprise if the solidity of the hidden toy is violated, suggesting that they know that the hidden toy still exists. We describe a connectionist model that learns to predict the position of objects and to initiate a response towards these objects. The model embodies the dual-route principle of object information processing characteristic of the cortex. One route develops a spatially invariant surface feature representation of the object whereas the other route develops a feature blind spatial–temporal representation of the object. The model provides an account of the developmental lag between infants’ knowledge of hidden objects and their ability to demonstrate that knowledge in an active retrieval task, in terms of the need to integrate information across multiple object representations using (associative) connectionist learning algorithms. Finally, the model predicts the presence of an early dissociation between infants’ ability to use surface features (e.g. colour) and spatial–temporal features (e.g. position) when reasoning about hidden objects. Evidence supporting this prediction has now been reported.  相似文献   
189.
In two experiments using spatial probes, we measured the temporal and spatial interactions between top-down control of attention and bottom-up interference from a salient distractor in visual search. The subjects searched for a square among circles, ignoring color. Probe response times showed that a color singleton distractor could draw attention to its location in the early stage of visual processing (before a 100-msec stimulus onset asynchrony [SOA]), but only when the color singleton distractor was located far from the target. Apparently the bottom-up activation of the singleton distractor’s location is affected early on by local interactions with nearby stimulus locations. Moreover, probe results showed that a singleton distractor did not receive attention after extended practice. These results suggest that top-down control of attention is possible at an early stage of visual processing. In the long-SOA condition (150-msec SOA), spatial attention selected the target location over distractor locations, and this tendency occurred with or without extended practice.  相似文献   
190.
Intervening on the development of adolescent addiction requires an understanding of the role of precursors. In a community sample of youth with and without early childhood speech/language (S/L) impairments, 12.7% of participants had a substance use disorder (SUD). Among these participants, 42.0% met criteria for more than 1 SUD. Interestingly, rates of SUDs did not differ by S/L status. However, S/L-impaired participants did show greater psychiatric comorbidity and poorer functioning. A total of 80% of S/L participants with SUDs had a concurrent diagnosis of antisocial personality disorder, compared with 43.8% of SUDs controls. In a logistic regression analysis, we found age 5 mother-rated problem behavior scores and an interaction between S/L status and teacher-rated conduct problem scores were predictive of SUDs. High conduct scores were predictive of SUDs development among control participants but not among S/L-impaired participants. First substance use and initial SUDs symptoms suggest that a window of opportunity exists to reach these troubled young people before they spiral into addiction.  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