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   51754篇
  免费   2142篇
  国内免费   19篇
  53915篇
  2020年   533篇
  2019年   641篇
  2018年   917篇
  2017年   905篇
  2016年   925篇
  2015年   634篇
  2014年   845篇
  2013年   3792篇
  2012年   1514篇
  2011年   1639篇
  2010年   933篇
  2009年   1004篇
  2008年   1422篇
  2007年   1412篇
  2006年   1323篇
  2005年   1156篇
  2004年   1143篇
  2003年   1062篇
  2002年   1068篇
  2001年   1679篇
  2000年   1592篇
  1999年   1222篇
  1998年   597篇
  1997年   507篇
  1992年   974篇
  1991年   909篇
  1990年   942篇
  1989年   891篇
  1988年   867篇
  1987年   810篇
  1986年   850篇
  1985年   944篇
  1984年   750篇
  1983年   683篇
  1982年   549篇
  1981年   512篇
  1979年   798篇
  1978年   599篇
  1977年   492篇
  1976年   525篇
  1975年   696篇
  1974年   792篇
  1973年   821篇
  1972年   646篇
  1971年   590篇
  1970年   561篇
  1969年   599篇
  1968年   740篇
  1967年   643篇
  1966年   656篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
982.
Why 2 + 2 = 5 looks so wrong: On the odd-even rule in sum verification   总被引:1,自引:0,他引:1  
The odd-even status of a sum depends on the odd-even status of its addends. A sum must be odd if an odd number of its addends are odd; else it must be even. A proposed sum that violates the required odd-even status of the sum—that is, deviates from the correct sum, whether odd or even, by an odd value (e.g., splits of ±1, ±3, ±5)—can be rejected immediately as false. Subjects in the present study did indeed use the odd-even rule in sum verification, because they were as fast and accurate in rejecting a split of ±1 as one of ±2, and a split of ±3 as one of ±4, even though a larger split generally is easier to reject (symbolic distance effect), and splits of ±3 and ±4 were rejected faster and more accurately than those of ±1 and ±2. Performance on separate odd-even tasks indicated that the odd-even properties of numbers and sums are readily available for use by adults, and that persons who do well on such tasks are especially likely to use the odd-even rule in sum verification.  相似文献   
983.
African Americans are at significantly greater risk of hypertension and worse cardiovascular outcomes than other racialized groups, yet hypertension intervention effects remain limited. Thus, it is necessary to understand the potential mechanisms whereby interventions may be more effectively targeted to improve health. Supported by prior research evidence and guided by the Biobehavioral Family Model, this study examined associations between family relationship quality, psychological wellbeing, and self-management behaviors for African Americans with hypertension. Data were pooled from three Midlife Development in the U.S. projects, resulting in a sample of 317 African Americans (63.4% female, Mage = 53.32) with self-reported high blood pressure in the past 12 months. We tested four cross-sectional multiple mediator models, with depressed mood and environmental mastery mediating associations between family strain and exercise, smoking, problematic alcohol use, and stress-eating. Environmental mastery mediated the association between greater family strain and decreased odds of achieving recommended exercise levels; greater odds of reporting problematic alcohol use; and greater stress-eating. Though family strain was associated with depressed mood in each model, this variable did not serve as an indirect pathway to self-management behaviors. Family strain, and the potential pathway identified via environmental mastery, may be a meaningful predictor of disease self-management for African Americans with hypertension. Longitudinal studies are needed to examine directionality and to support intervention trials for improving self-management and hypertension outcomes.  相似文献   
984.
Christians are notably underrepresented in science in part due to long-standing public perceptions of science-religion incompatibility and antireligious bias in science. This research explores whether undergraduates at a Christian university perceive and impose anti-Christian cultural stigma in science. Survey results from 126 biology students revealed that though students generally perceived the culture of science to be anti-Christian, they perceived Christians to have equal opportunities for scientific achievement. Results from a quasi-experimental audit study, in which students evaluated one of two profiles for mock prospective Ph.D. applicants (Christian or undisclosed faith) showed that students did not project anti-Christian stereotypes in terms of competence, hireability, or likeability, but showed some evidence of pro-Christian favorability. Together, this study suggests that the affirmational community of a Christian University may alleviate some negative impacts of anti-Christian stereotypes in academic biology, even as students perceive discrimination against Christians in science and atheists as more scientifically competent.  相似文献   
985.
986.
The other-race effect (ORE) is a longstanding phenomenon in experimental psychology, where recognition for same-race faces is superior than for other-race faces. The present research pits two competing theories of perceptual expertise and social motivation against each other to see which is the more robust predictor of the ORE. In Study 1, we measured Black and White participants' prior contact with individuals from the other-race (i.e. expertise) as well as their expected level of future interaction with other-race individuals (i.e. motivation). Of the two theories, anticipated interaction (i.e. motivation) emerged as a significant predictor of the ORE. Study 2 followed the same design, measuring motivation with a self-report assessment of how much participants are willing to have cross-race friendships. Here, neither experience nor motivation predicted the ORE, though an ORE was established. Differences in measures that assess motivation and the experience versus motivation debate are discussed.  相似文献   
987.
988.
Previous research has evaluated the effects of prompt rates on the rate of communicative behavior. More recent research has suggested that dense prompting can result in communicative behavior that is more resistant to change. However, existing research has not considered the impact that higher response rates had on reinforcement rate, a variable known to impact response persistence. The current study systematically replicated previous research by evaluating communicative responding in contexts associated with dense- and lean-prompt schedules and extended existing research by (a) holding reinforcement rates similar across the two prompting schedules (lean and dense), and (b) evaluating the persistence of communicative responding in the contexts associated with each prompting schedule. The results for Experiment 1 clearly replicated and extended previous research. The results for Experiment 2 were equivocal and suggested that previous reinforcement history and response class size impacted outcomes.  相似文献   
989.
Residents in juvenile residential treatment facilities (JRTFs) often display various emotional, behavioral, and educational needs. Researchers have recently developed behavioral interventions to increase residents' appropriate behavior such as cooperation with facility staff instructions, accepting feedback from facility staff, and tolerating unpleasant events. However, there is not a generally accepted tool for assessing the operant function of residents' problem behavior in JRTFs. For various logistical reasons, indirect functional assessments may be more appropriate in a JRTF than manipulating either antecedent or consequent events. This study obtained scores on the Questions About Behavior Function (QABF) assessment for 17 residents from two dormitory staff members for each resident. To increase the number of respondents, each resident completed a QABF for their own behavior. Results revealed moderate to high correspondence (i.e., agreement) for highest and lowest potential operant function of problem behavior between combinations of JRTF staff and residents. These preliminary findings suggest additional research with the QABF in JRTFs is warranted.  相似文献   
990.
In this study, we evaluated several components of a pedometer-based intervention with children in an elementary-school-aged classroom, across 24-h sessions. The intervention included combinations of self-monitoring, goal setting, feedback, and reinforcement, and data were analyzed at both the classroom level (i.e., average daily step totals) and the individual level (i.e., daily step totals), across phases. The highest levels of physical activity were observed when components of self-monitoring, public posting, goal setting, and feedback with reward were applied concurrently.  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