全文获取类型
收费全文 | 53454篇 |
免费 | 2045篇 |
国内免费 | 17篇 |
专业分类
55516篇 |
出版年
2020年 | 501篇 |
2019年 | 630篇 |
2018年 | 865篇 |
2017年 | 944篇 |
2016年 | 945篇 |
2015年 | 638篇 |
2014年 | 836篇 |
2013年 | 3973篇 |
2012年 | 1542篇 |
2011年 | 1666篇 |
2010年 | 991篇 |
2009年 | 973篇 |
2008年 | 1437篇 |
2007年 | 1395篇 |
2006年 | 1296篇 |
2005年 | 1176篇 |
2004年 | 1154篇 |
2003年 | 1043篇 |
2002年 | 1136篇 |
2001年 | 1640篇 |
2000年 | 1580篇 |
1999年 | 1177篇 |
1998年 | 622篇 |
1997年 | 513篇 |
1992年 | 961篇 |
1991年 | 902篇 |
1990年 | 928篇 |
1989年 | 909篇 |
1988年 | 874篇 |
1987年 | 853篇 |
1986年 | 877篇 |
1985年 | 955篇 |
1984年 | 768篇 |
1983年 | 698篇 |
1982年 | 578篇 |
1981年 | 533篇 |
1979年 | 876篇 |
1978年 | 639篇 |
1977年 | 555篇 |
1976年 | 561篇 |
1975年 | 748篇 |
1974年 | 822篇 |
1973年 | 825篇 |
1972年 | 703篇 |
1971年 | 640篇 |
1970年 | 618篇 |
1969年 | 695篇 |
1968年 | 817篇 |
1967年 | 718篇 |
1966年 | 717篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Lewis E. Gilbert 《Knowledge, Technology, and Policy》1998,11(1-2):4-15
As the complexity of the challenges presented by our interactions with our planet continues to grow, we must develop new modes
of knowledge production. In these modes, distinctions between multidisciplinary and inter-disciplinary activities and processes
have renewed importance. There are at least two distinct types of interdisciplinary activities distinguished by the disciplinary
breadth they attempt to bridge. In the narrow case, reductionist processes reveal a common underlying principle or process
which can serve as a Rosetta stone. In the broad case, no such common arbiter exists. Investigators must develop integrating
vocabulary in the context of the full breadth of their work.
His primary activities are the fostering of university-wide interdisciplinary research and curriculum programs focused on
global change with the goal of developing Columbia into a world leader in issues related to global stewardship. 相似文献
12.
Thomas A Wills Velma McBride Murry Gene H Brody Frederick X Gibbons Meg Gerrard Carmella Walker Michael G Ainette 《Health psychology》2007,26(1):50-59
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
13.
Relationship of anxiety and depression to age and sex in an acute psychiatric population 总被引:1,自引:0,他引:1
R E Correll 《Psychological reports》1984,55(3):979-986
14.
15.
16.
Brain mapping studies using dynamic imaging methods demonstrate areas regional cerebral blood flow (rCBF) decreases, as well as areas where increases, during performance of various experimental tasks. Task holds for both sets of cerebral blood flow changes (CBF), providing the opportunity to investigate areas that become and “activated” in the experimental condition relative to control state. Such data yield the intriguing observation that in areas in emotional processing, such as the amygdala, the posteromedial cortex, and the ventral anterior cingulate cortex, although flow as expected during specific emotion-related tasks, flow decreases performance of some attentionally demanding, cognitive tasks. Conversely, in some of the areas that appear to subserve cognitive functions, as the dorsal anterior cingulate and the dorsolateral prefrontal cortices, increases while performing attentionally demanding cognitive tasks, but during some experimentally induced and pathological emotional Although the specific nature of such reciprocal patterns of regional remains unclear, they may reflect an important cross-modal interaction during mental operations. The possibility that neural activity is less in areas required in emotional processing during some higher cognitive processes holds implications for the mechanisms underlying interactions cognition and emotion. Furthermore, the possibility that neural in some cognitive-processing areas is suppressed during intense states suggests mechanisms by which extreme fear or severe may interfere with cognitive performance. 相似文献
17.
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
18.
Intention is theorized as the proximal determinant of behavior in some theories of motivation, but the need to understand predictors of action control (i.e., translating an intention into behavior) is warranted to tailor physical activity intervention efforts. The purpose of this study was to examine constructs of the transtheoretical model of behavior change (TTM) as predictors of physical activity intention-behavior profiles across 6 months in a large Canadian sample (N = 1,192). Results showed that 5 of the 8 possible intention-behavior profiles had a substantial number of participants: nonintenders, unsuccessful adopters, successful adopters, unsuccessful maintainers, and successful maintainers. Constructs of the TTM distinguished (p < .01) intention-behavior profiles. Self-efficacy and the behavioral processes of change were particularly good predictors of action control (p < .01), but disaggregated beliefs and processes identified specific intervention targets for successful physical activity adoption and maintenance. The results validate that both action planning and action control are important when understanding physical activity behavior. 相似文献
19.
Marcellus M Merritt Gary G Bennett Redford B Williams Christopher L Edwards John J Sollers 《Health psychology》2006,25(3):364-369
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
20.