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   34658篇
  免费   655篇
  国内免费   3篇
  35316篇
  2020年   181篇
  2019年   210篇
  2018年   3767篇
  2017年   3061篇
  2016年   2535篇
  2015年   440篇
  2014年   353篇
  2013年   1232篇
  2012年   1042篇
  2011年   2892篇
  2010年   2826篇
  2009年   1768篇
  2008年   2149篇
  2007年   2616篇
  2006年   421篇
  2005年   544篇
  2004年   483篇
  2003年   419篇
  2002年   394篇
  2001年   514篇
  2000年   488篇
  1999年   353篇
  1998年   185篇
  1997年   149篇
  1996年   162篇
  1995年   136篇
  1993年   131篇
  1992年   263篇
  1991年   261篇
  1990年   260篇
  1989年   239篇
  1988年   237篇
  1987年   219篇
  1986年   209篇
  1985年   209篇
  1984年   209篇
  1983年   153篇
  1982年   164篇
  1981年   128篇
  1979年   181篇
  1975年   153篇
  1974年   180篇
  1973年   198篇
  1972年   162篇
  1971年   144篇
  1970年   125篇
  1969年   142篇
  1968年   180篇
  1967年   135篇
  1966年   145篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
851.
There are over 3,000 sleep related infant deaths each year in the United States. Attempts to teach medical personnel and parents safe infant sleep practices in the infant sleep training literature have demonstrated mixed results. Thus, strategies to teach arrangements of safe infant sleep environments warrant further investigation. Behavioral skills training (BST) is an evidence-based teaching strategy shown to successfully teach various safety skills to children and adults. The current study evaluated the effectiveness of behavioral skills training to teach safe infant sleep practices to typically developing adults. Specifically, differential responding was assessed across multiple environmental arrangements typical of contexts parents may be exposed to when putting an infant to sleep. BST significantly improved appropriate arrangement of a safe sleep environment for infants for all 8 participants.  相似文献   
852.
Studies have shown that the multiple-stimulus without replacement (MSWO) preference assessment is an effective assessment format for identifying preferred items. However, it is possible that factors other than reinforcer quality might influence selections by some individuals when the MSWO array consists of edible items. The validity of the MSWO results was evaluated by comparing items identified as most and least preferred by the MSWO assessment in a concurrent-schedule (CS) format. Varying edible items were used in each study. The MSWO format accurately identified the higher quality edible item for most participants across studies (76%); however, the MSWO format did not predict the highest quality edible item in the CS assessment for 20% to 30% of participants in each study.  相似文献   
853.
Individuals with fibromyalgia are at greater risk for depressive symptoms than the general population, and this may be partially attributable to physical symptoms that impair day-to-day functioning. However, individual-level protective characteristics may buffer risk for psychopathology. For instance, the ability to perceive a “silver lining” in one’s illness may be related to better mental and physical health. We examined perceived silver lining as a potential moderator of the relation between fibromyalgia impact and depressive symptoms. Our sample of persons with fibromyalgia (N = 401) completed self-report measures including the Fibromyalgia Impact Questionnaire-Revised, Depression Anxiety Stress Scales, and the Silver Lining Questionnaire. Moderation analyses covaried age, sex, and ethnicity. Supporting hypotheses, increasing impact of disease was related to greater depressive symptoms, and perceptions of a silver lining attenuated that association. Despite the linkage between impairment and depressive symptoms, identifying positive aspects or outcomes of illness may reduce risk for psychopathology. Therapeutically promoting perception of a silver lining, perhaps via signature strengths exercises or a blessings journal, and encouraging cognitive reframing of the illness experience, perhaps via Motivational Interviewing or Cognitive Behavioral Therapy, may reduce depressive symptoms in persons with fibromyalgia.  相似文献   
854.
855.
Male rats were either handled daily or left undisturbed (nonhandled) during the first 21 days of life. At weaning (Day 22) animals in each early treatment condition were assigned to two housing conditions, isolated or grouped, creating four early/late treatment conditions: Handled-Grouped (HG), Handled-Isolated (HI), Nonhandled-Grouped (NHG), and Nonhandled-Isolated (NHI). At maturity, all animals were tested in the latent inhibition (LI, Experiment 1) and the partial reinforcement extinction effect (PREE, Experiment 2) paradigms. In LI, animals receiving prior nonreinforced preexposure to a stimulus (PE) show subsequently retarded conditioning to that stimulus as compared to nonpreexposed (NPE) controls. In the PREE, partially reinforced (PRF) animals exhibit higher resistance to extinction as compared to continuously reinforced (CRF) controls. LI and PREE were obtained in the HG condition, but were impaired in NHG and HI animals. The pattern of impairment was different in the two conditions. The absence of LI in NHG males was due to increased suppression in the PE group, whereas in HI males, was due to decreased suppression in the NPE group. Likewise, the attenuation of the PREE in NHG males stemmed primarily from decreased resistance to extinction in the PRF group, whereas in HI males, it resulted from increased resistance to extinction in the CRF group. The combination of nonhandling and isolation led to the reinstatement of both LI and PREE: normal LI and PREE were obtained in the NHI animals. These results demonstrate that early rearing experience interacts with later experience differentially depending upon the later experience.  相似文献   
856.
Social diffusion theory has recently been recognized as a promising approach for large-scale disease prevention and health promotion efforts. This paper describes how principles and tactics from social cognitive theory, operant psychology, social psychology, social marketing, and the overarching stages of change model can be used to further develop the conceptual and strategic (technological) bases of social diffusion theory. Within an integrative framework, we discuss in detail more effective ways to train peer mediators of behavior change as one example of how social diffusion theory can benefit from this conceptual and strategic reformulation. We then further illustrate the use of peer mediators of change in human immunodeficiency virus (HIV) and cancer prevention intervention studies with both interventions training peer mediators to diffuse information, norms, and risk reduction strategies. Although the results of these studies showed reductions in high-risk behaviors across population segments, more closely following the framework discussed in this article should further increase the behavior change potential of future interventions based on social diffusion theory.  相似文献   
857.
Subjects had their initial frames of reference concerning a decision problem (Asian Disease problem; Tversky & Kahneman, 1981, Science,211, 453–458) manipulated in order to compose four-person groups containing members with different frames of reference. Three different group compositions (number of members with "gain-oriented" vs "loss-oriented" frames) were used: three gain-oriented and one loss oriented (3–1), two gain-oriented and two loss-oriented (2–2), and one gain-oriented and three loss-oriented (1–3). Results indicated a postgroup discussion choice shift toward the risk alternative in the 2–2 and the 1–3 composition conditions. However, changes in members′ frames of reference were unrelated to preference changes. Group composition also affected group decision processes. Implications for future theory and research in small group decision-making are discussed.  相似文献   
858.
859.
Rats with cannulas aimed at the posteroventral (PV) or ventrolateral (VL) areas of the caudate nucleus were trained on a conditioned emotional response (CER) task. Post-training microinjections of the indirect catecholamine agonist, d-amphetamine (5 micrograms), or of the dopamine D2 receptor agonist, LY171555 (1 microgram), into the PV area improved retention of a CER with a visual CS, but had no effect on a CER with an olfactory CS. Post-training injections of the same two drugs into the VL area improved retention of a CER with an olfactory CS, but had no effect on a CER with a visual CS. Post-training injections of the dopamine D1 receptor agonist, SKF38393 (0.5, 1.0, 2.0 micrograms), into either site had no effects on either CER. These findings suggest that different areas of the caudate nucleus mediate acquisition of CERs with different CSs, possibly implicating the topographically organized corticostriatal innervation in the acquisition of certain types of memories in the caudate nucleus. The findings also suggest that dopamine D2 receptors in the caudate nucleus are involved in the acquisition of these CERs.  相似文献   
860.
Domain experts regularly teach novice students how to perform a task. This often requires them to adjust their behavior to the less knowledgeable audience and, hence, to behave in a more didactic manner. Eye movement modeling examples (EMMEs) are a contemporary educational tool for displaying experts’ (natural or didactic) problem-solving behavior as well as their eye movements to learners. While research on expert-novice communication mainly focused on experts’ changes in explicit, verbal communication behavior, it is as yet unclear whether and how exactly experts adjust their nonverbal behavior. This study first investigated whether and how experts change their eye movements and mouse clicks (that are displayed in EMMEs) when they perform a task naturally versus teach a task didactically. Programming experts and novices initially debugged short computer codes in a natural manner. We first characterized experts’ natural problem-solving behavior by contrasting it with that of novices. Then, we explored the changes in experts’ behavior when being subsequently instructed to model their task solution didactically. Experts became more similar to novices on measures associated with experts’ automatized processes (i.e., shorter fixation durations, fewer transitions between code and output per click on the run button when behaving didactically). This adaptation might make it easier for novices to follow or imitate the expert behavior. In contrast, experts became less similar to novices for measures associated with more strategic behavior (i.e., code reading linearity, clicks on run button) when behaving didactically.  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