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   38242篇
  免费   863篇
  国内免费   15篇
  39120篇
  2023年   124篇
  2021年   185篇
  2020年   327篇
  2019年   426篇
  2018年   3846篇
  2017年   3234篇
  2016年   2697篇
  2015年   615篇
  2014年   584篇
  2013年   2143篇
  2012年   1414篇
  2011年   3222篇
  2010年   2976篇
  2009年   2014篇
  2008年   2416篇
  2007年   2858篇
  2006年   789篇
  2005年   891篇
  2004年   790篇
  2003年   767篇
  2002年   683篇
  2001年   341篇
  2000年   322篇
  1999年   283篇
  1998年   283篇
  1997年   283篇
  1996年   260篇
  1995年   213篇
  1994年   217篇
  1993年   192篇
  1992年   180篇
  1991年   193篇
  1990年   184篇
  1989年   142篇
  1988年   117篇
  1987年   144篇
  1986年   151篇
  1985年   203篇
  1984年   197篇
  1983年   154篇
  1982年   175篇
  1981年   171篇
  1980年   162篇
  1979年   143篇
  1978年   154篇
  1977年   146篇
  1976年   142篇
  1975年   125篇
  1974年   125篇
  1973年   109篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
A total of 50 elderly individuals and 48 college students were tested on several measures of processing speed and of working memory capacity. Language processing was tested with an on-line measure of sentence processing efficiency, an end-of-sentence acceptability judgement task, and a paragraph comprehension test. Elderly individuals performed more poorly than college students on the speed of processing and working memory measures and had longer listening times overall on the sentence processing measures. Elderly individuals did not, however, have overall longer listening times at the most capacity-demanding regions of the harder sentence types. Correlational analyses failed to establish a relationship between the increase in syntactic processing load at the capacity-demanding region of the harder sentence type and the measures of working memory capacity, but did establish a relationship between paragraph comprehension and working memory capacity. The data are argued to provide evidence that the WM system used to structure sentences syntactically is separate from that used in other aspects of language comprehension.  相似文献   
912.
Basic fact acquisition is an important component for developing higher-order math skills. However, getting students with a history of academic noncompliance to engage in activities related to skills acquisition can be difficult. Prior research demonstrates that engagement increases when nonpreferred activities are preceded by a series of brief activities with a high probability of completion. This technique, called high-p task/request sequences, was not fully explored within the context of skill acquisition. The purpose of this study was to examine the effects of adding high-p sequences to explicit instruction on the math fact acquisition of three elementary-age students in a learning support classroom. Results showed no differences in fact acquisition between explicit instruction and explicit instruction with an added high-p component. However, the high-p sessions took nearly twice as long to complete when compared to explicit instruction alone. Implications for instructional efficiency and limitations of the high-p procedures for acquisition tasks are discussed.  相似文献   
913.
The standard behavioral index for human consciousness is the ability to report events with accuracy. While this method is routinely used for scientific and medical applications in humans, it is not easy to generalize to other species. Brain evidence may lend itself more easily to comparative testing. Human consciousness involves widespread, relatively fast low-amplitude interactions in the thalamocortical core of the brain, driven by current tasks and conditions. These features have also been found in other mammals, which suggests that consciousness is a major biological adaptation in mammals. We suggest more than a dozen additional properties of human consciousness that may be used to test comparative predictions. Such homologies are necessarily more remote in non-mammals, which do not share the thalamocortical complex. However, as we learn more we may be able to make "deeper" predictions that apply to some birds, reptiles, large-brained invertebrates, and perhaps other species.  相似文献   
914.
Two experiments exploring the effects of social category membership on real-life helping behavior are reported. In Study 1, intergroup rivalries between soccer fans are used to examine the role of identity in emergency helping. An injured stranger wearing an in-group team shirt is more likely to be helped than when wearing a rival team shirt or an unbranded sports shirt. In Study 2, a more inclusive social categorization is made salient for potential helpers. Helping is extended to those who were previously identified as out-group members but not to those who do not display signs of group membership. Taken together, the studies show the importance of both shared identity between bystander and victim and the inclusiveness of salient identity for increasing the likelihood of emergency intervention.  相似文献   
915.
Three conditioned taste aversion experiments with rats investigated superconditioning. In each experiment, alternate exposures of 2 flavor compounds with a common element (i.e., AB/AS) were administered to establish an inhibitory relationship between the 2 unique elements, B and S, and prior to testing, S was paired with lithium chloride (LiCl). In Experiment 1, pairings of a neutral cue (X) with S in compound with B after the AB/AS exposures resulted in superconditioning between X and S. Extinction of the common element (A) just before the S-LiCl pairing attenuated both the inhibitory relationship between B and S (Experiment 2) and superconditioning between X and S (Experiment 3). These observations suggest that superconditioning consists of enhanced performance rather than enhanced associative acquisition.  相似文献   
916.
Partial reinforcement, compared with continuous reinforcement, is widely considered detrimental to Pavlovian conditioned responding. However, time-accumulation models predict an invariance in acquisition when learning is assessed as a function of number of reinforcements, not trials, and intertrial interval is held constant. Three experiments examined this prediction in a rat magazine-approach procedure. All experiments showed superior responding with continuous reinforcement. Experiments 1 and 3 used common tests in between- and within-subject designs, respectively. Experiment 2 showed the same pattern in a discrimination. Earlier results are reanalyzed informally and in a meta-analysis. Contrary to previous summaries of the literature, evidence points to superior conditioned responding with continuous reinforcement in a number of procedures. Results are generally consistent with traditional associative models of learning.  相似文献   
917.
W. T. Maddox, F. G. Ashby, and C. J. Bohil (2003) found that delayed feedback adversely affects information-integration but not rule-based category learning in support of a multiple-systems approach to category learning. However, differences in the number of stimulus dimensions relevant to solving the task and perceptual similarity failed to rule out 2 single-system interpretations. The authors conducted an experiment that remedied these problems and replicated W. T. Maddox et al.'s findings. The experiment revealed a strong performance decrement for information-integration but not rule-based category learning under delayed feedback that was due to an increase in the number of observers using hypothesis-testing strategies to solve the information-integration task, and lower accuracy rates for the few observers using information-integration strategies.  相似文献   
918.
The Collaborative Assessment and Management of Suicidality (CAMS) is a novel clinical approach used to identify, assess, and manage suicidal outpatients (Jobes & Drozd, 2004). The results of a retrospective study evaluating the impact of CAMS versus treatment as usual (TAU) on suicidal outpatients are presented. Patients in the CAMS treatment group (n = 25) resolved their suicidality significantly more quickly than TAU patients (n = 30). CAMS was also significantly associated with decreased medical health care utilization in the 6 months after the start of suicide-related mental health treatment. These results provide promising preliminary support for the effectiveness of CAMS and a foundation for prospective research.  相似文献   
919.
Physicians frequently are early adopters of healthy behaviors based on their knowledge and economic resources. The mortality patterns of physicians in the United States, particularly suicide, have not been rigorously described for over a decade. Previous studies have shown lower all-cause mortality among physicians yet reported conflicting results about cause-specific mortality such as suicide. In this study, we compared all-cause and cause-specific mortality in a sample of physicians to the age-gender matched general U.S. population from 1948 through 1998. We also compared the mortality experience across medical specialties. The risk of all-cause mortality was 56% lower than expected in men, and 26% lower in women, compared to the general population. Standardized mortality ratios (SMRs) were markedly lower for diseases strongly linked to smoking, e.g., cardiovascular diseases, respiratory diseases, and lung cancer. Suicide was the only cause of death where risk was greater than the general population. Overall, we found that physicians are at substantially lower risk of dying compared to the general population for all causes of death except suicide. The findings for suicide are strikingly different than other causes of death and should provide impetus for new research on the mental health of physicians.  相似文献   
920.
Both avoidant and borderline personality disorder (APD and BPD) are theoretically associated with temperamental vulnerabilities, adverse attachment experiences, and negative (pessimistic or catastrophic) reactions to the threat of perceived rejection; however, more work is needed to differentiate how these processes account for the etiology and maintenance of both disorders. In this study, 156 adults completed questionnaires measuring APD and BPD features, temperament (sensory-processing sensitivity), mood, and attachment experiences. A vignette task was devised to examine pessimistic cognitive-affective reactions in situations signaling potential rejection. Both APD and BPD were associated with temperamental sensitivity, but BPD was uniquely linked with a subscale measuring sensitivity to mental and emotive stimuli, whereas APD was uniquely linked with a subscale measuring the control and avoidance of aversive stimulation. Compared to APD, BPD was more strongly linked with negative moods (anxiety, anger, sadness) and insecure attachment to parents, whereas APD was more strongly linked (than BPD) to pessimistic cognitive-affective responses to rejection-related situations.  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