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   31567篇
  免费   1236篇
  国内免费   13篇
  32816篇
  2020年   409篇
  2019年   398篇
  2018年   629篇
  2017年   666篇
  2016年   652篇
  2015年   458篇
  2014年   538篇
  2013年   2665篇
  2012年   1054篇
  2011年   1129篇
  2010年   707篇
  2009年   607篇
  2008年   943篇
  2007年   863篇
  2006年   782篇
  2005年   639篇
  2004年   616篇
  2003年   597篇
  2002年   627篇
  2001年   951篇
  2000年   960篇
  1999年   713篇
  1998年   328篇
  1997年   276篇
  1992年   551篇
  1991年   529篇
  1990年   546篇
  1989年   508篇
  1988年   487篇
  1987年   477篇
  1986年   500篇
  1985年   522篇
  1984年   421篇
  1983年   368篇
  1982年   288篇
  1981年   269篇
  1979年   489篇
  1978年   329篇
  1977年   298篇
  1976年   278篇
  1975年   414篇
  1974年   464篇
  1973年   438篇
  1972年   405篇
  1971年   367篇
  1970年   333篇
  1969年   390篇
  1968年   426篇
  1967年   401篇
  1966年   379篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Cognitive neuropsychology provides a theoretical framework and methods that can be of value in the study of developmental disorders, but the "dissociation" logic at the centre of this approach is not well suited to the developmental context. This is illustrated with examples from specific language impairment. Within the developing language system there is ample evidence for interaction between levels of representation, with modularity emerging in the course of development. This means that one typically is seeking to explain a complex pattern of associated impairments, rather than highly selective deficits. For instance, a selective impairment in auditory processing can have repercussions through the language system and may lead to distinctive syntactic deficits that are seen in written as well as spoken language. Changes in the nature of representations and in the relationships between components of a developing system mean that cross-sectional data at a single point in development may be misleading indicators of the primary deficit. Furthermore, traditional cognitive neuropsychology places a disproportionate emphasis on representational (competence) deficits, with processing (performance) deficits being relatively neglected. Methods for distinguishing these two kinds of impairment are discussed, as well as other approaches for elucidating the underlying nature of developmental disorders.  相似文献   
3.
4.
OBJECTIVE: To test a theoretical model of how ethnic pride and self-control are related to risk and protective factors. DESIGN: A community sample of 670 African American youth (mean age = 11.2 years) were interviewed in households. MAIN OUTCOME MEASURES: Measures of cigarette smoking, alcohol use, and sexual behavior (lifetime to past month). RESULTS: Structural modeling analyses indicated parenting was related to self-control and self-esteem, and racial socialization was related to ethnic pride. Self-control and self-esteem variables were related to levels of deviance-prone attitudes and to perceptions of engagers in, or abstainers from, substance use and sexual behavior. The proximal factors (behavioral willingness, resistance efficacy, and peer behavior) had substantial relations to the criterion variables. Participant gender and parental education also had several paths in the model. Results were generally similar for the 2 outcome behaviors. CONCLUSIONS: In this population, self-esteem and self-control are related to parenting approaches and have pathways to attitudes and social perceptions that are significant factors for predisposing to, or protecting against, early involvement in substance use and sexual behavior.  相似文献   
5.
6.
Subjects in five experiments read nine-digit memory lists from a cathode ray tube for immediate recall. Reading aloud always produced a localized and reliable advantage for the last item, compared to reading silently. Two experiments on whispered and mouthed lists, with or without simultaneous broadband noise, falsified expectations derived from the theory of precategorical acoustic storage. Three additional experiments showed no enhancement of recency in the silent conditions when the digits were drawn or spelled gradually on the screen, a result that is inconsistent with the changing-state hypothesis. The classic auditory-visual modality effect is large and reliable, but still poorly understood.  相似文献   
7.
8.
OBJECTIVE: Compare the efficacy of a multicomponent social support intervention to standard-of-care counseling on medication adherence among HIV-infected patients initiating antiretroviral therapy. DESIGN: Randomized controlled trial. Generalized estimating equations tested for differences in the percentage of participants achieving 90% adherence. MAIN OUTCOME MEASURES: Pill-taking, electronically monitored over 6 consecutive months; plasma viral load (VL), assessed at 3 and 6 months following initiation of therapy. RESULTS: Of 226 participants who were randomized and began the trial, 87 (38%) were lost to the study by 6 months. The proportion of adherent participants declined steadily over time, with no time by group interaction. Sustained adherence was associated with increased odds of achieving an undetectable VL (OR=1.78; 95% CI=1.01, 3.13). In intention-to-treat analyses, a larger proportion of the intervention group than the control group was adherent (40.15% vs. 27.59%, p=.02) and achieved an undetectable VL p=.04). However, the majority of participants who remained on study experienced some reduction in VL (>or=1-log drop or undetectable), regardless of experimental condition. CONCLUSION: The multicomponent social support intervention significantly improved medication adherence over standard-of-care counseling; evidence for improved virologic outcomes was inconsistent. Early discontinuation of care and treatment may be a greater threat to the health of HIV patients than imperfect medication-taking.  相似文献   
9.
This study evaluated cardiovascular responses (CVR) to an active speech task with blatantly discriminatory (BRC) versus neutral (NRC) stimuli and an anger recall task in a sample of Black men (N = 73; age 18 to 47). Diastolic blood pressure scores were higher for NRC versus BRC stimuli during anger recall (p = .05). Moreover, persons in the NRC group who perceived high levels of racism (vs. no racism or BRC group) during active speech showed larger increases in blood pressure across postspeech rest, anger recall, and subsequent rest (p = .03). The notable elevation in CVR in response to an ambiguous event extends current models of racism suggesting that subtle racism is a psychosocial stressor that erodes health through chronically elevated CVR.  相似文献   
10.
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