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   50362篇
  免费   2004篇
  国内免费   29篇
  2020年   524篇
  2019年   622篇
  2018年   926篇
  2017年   918篇
  2016年   917篇
  2015年   635篇
  2014年   804篇
  2013年   3810篇
  2012年   1406篇
  2011年   1558篇
  2010年   945篇
  2009年   1016篇
  2008年   1377篇
  2007年   1332篇
  2006年   1248篇
  2005年   1064篇
  2004年   1006篇
  2003年   1029篇
  2002年   947篇
  2001年   1818篇
  2000年   1778篇
  1999年   1318篇
  1998年   575篇
  1997年   489篇
  1996年   465篇
  1992年   1115篇
  1991年   1045篇
  1990年   1053篇
  1989年   952篇
  1988年   898篇
  1987年   892篇
  1986年   872篇
  1985年   979篇
  1984年   770篇
  1983年   619篇
  1982年   488篇
  1979年   748篇
  1978年   571篇
  1977年   504篇
  1976年   478篇
  1975年   676篇
  1974年   718篇
  1973年   786篇
  1972年   630篇
  1971年   525篇
  1970年   483篇
  1969年   527篇
  1968年   638篇
  1967年   560篇
  1966年   619篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
851.
Teacher-rated adjustment differences among young elementary school children from (a) a recent sample and a 1974 cohort, and (b) urban/suburban, male/female, and grade-level subgroups were examined. A problem behavior checklist (Classroom Adjustment Rating Scale) and a school competence measure (Health Resources Inventory) for 974 children from 5 urban and 5 suburban schools were completed by 101 first- to fourth-grade teachers. Children from the more current cohort were rated as significantly more maladjusted than those from the earlier sample on 8 of 10 adjustment variables. In the recent sample, girls and suburban children evidenced a greater number of school competencies and fewer problem behaviors than boys and urban children, respectively. The implications of these findings for the future use of the teacher rating scales are discussed.  相似文献   
852.
853.
Processing of lexical ambiguities in aphasia   总被引:2,自引:2,他引:0  
Wernicke's and Broca's aphasics performed a lexical decision task wherein they had to decide whether the third word of an auditorily presented triplet series of words was "real" or not. The first and third words of each triplet were related to one, both, or neither meaning of the second word which was semantically ambiguous. The performance pattern of the Wernicke's aphasics was similar to that of normals. They showed selective access to different meanings of the ambiguous words, as demonstrated by the fact that the context provided by the first word affected semantic facilitation on the third word. In contrast, Broca's aphasics showed no semantic facilitation in any priming condition. These results are consistent with previous findings, suggesting that semantic representations may be largely spared in Wernicke's aphasics. The failure of the Broca's aphasics to demonstrate facilitation is consistent with the view that they have a processing deficit in automatically accessing the lexical representation of words.  相似文献   
854.
The purpose of this paper is to present a new electromagnetic device which uses alternating magnetic fields for tracking movements of multiple points inside and outside the vocal tract. It is biologically safe, noninvasive, it does not interfere with speech movements, allows for multiple recording in the same subject, and for easy collection of large amounts of data. It is especially suitable for evaluation of patients with speech motor impairments.  相似文献   
855.
Experiment 1 of the current research failed to replicate Toppino and Di George’s (1984) finding that older children but not preschoolers showed a spacing effect. Instead, we obtained the spacing effect in all the age groups tested (preschool, kindergarten, first-grade, and third-grade children). The effect was demonstrated with two types of material, words and pictures. Experiment 2 focused on the role that very brief spacings, with no intervening items between repetitions, play in later retention. Age groups and materials were the same as in Experiment 1. Four different levels of spacing were included (0-, 1.1-,2.5-, and 5-sec intervals). The spacing effect was again obtained for all age groups with both words and pictures. The results of both experiments suggest that the spacing effect does not emerge with development.  相似文献   
856.
To be pertinent to democratic practice, collective choice functions need not apply to all possible constellations of individual preference, but only to those that are humanly possible in an appropriate sense. The present paper develops a theory of humanly possible preference within the context of the mathematical theory of learning. The theory of preference is then exploited in an attempt to resolve Arrow's voting paradox through restriction of the domain of majoritarian choice functions.  相似文献   
857.
In this study, verbal memory and naming abilities were investigated in reading disabled (RD) and control children who were characterized according to the presence or absence of attention deficit disorder (ADD). Results indicate that deficits in learning and memory for recently acquired information occur as a function of ADD rather than RD while deficits in naming are specific to RD rather than ADD. We conclude that ADD is a major source of additional and separate cognitive morbidity in RD children.  相似文献   
858.
Specific language impairment in children: A cross-linguistic study   总被引:1,自引:0,他引:1  
A common profile in English-speaking specifically language-impaired children is a moderate deficit across a broad range of linguistic features and a more marked, selective impairment in using bound morphemes and components of the verb system. To gain a clearer understanding of the nature of these more serious problems, we examined the speech of monolingual Italian-speaking as well as English-speaking children with specific language impairment. The evidence suggested that phonological factors contributed significantly to these children's extraordinary problems with particular linguistic features. Contrary to expectations, other marked deficits seemed more related to the opacity of the rules involved and homonymity with other morphemes than to problems with formal grammatical devices in general or components of the verb system in particular.  相似文献   
859.
Regional cerebral blood flow (rCBF) may be measured with inhalation techniques that use end-expired values of radioactivity to estimate the isotope concentration in arterial blood. These end-expired data are used as an input function in a mathematical equation to derive rCBF. End-expired air is assumed normally to be in equilibrium with the arterial blood at the alveolar surface of the lung during regular (passive) breathing; this assumption may not be valid during continuous phonation. We therefore have analyzed breathing (inhalation/exhalation) patterns and end-expired radioactivity (133Xe) during (1) speaking, (2) singing, and (3) humming of the national anthem, and also during (4) passive breathing. Statistically significant differences in breathing patterns were measured between a group of nonmusicians and two groups of musicians (singers) during the phonation tasks: The nonmusicians breathed more often (and more rapidly) and exhibited less variability in their breathing patterns than did the musicians. Notwithstanding these differences, the shapes of smoothed functions derived from the end-expired values were not influenced appreciably during phonation (except possibly during talking). The latter finding suggests that estimates of rCBF derived with these data should not be confounded seriously because of the continuous phonation.  相似文献   
860.
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