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   18561篇
  免费   1588篇
  国内免费   43篇
耳鼻咽喉   183篇
儿科学   612篇
妇产科学   483篇
基础医学   2587篇
口腔科学   210篇
临床医学   2186篇
内科学   3605篇
皮肤病学   279篇
神经病学   2119篇
特种医学   384篇
外科学   1952篇
综合类   165篇
一般理论   19篇
预防医学   2603篇
眼科学   254篇
药学   1164篇
中国医学   9篇
肿瘤学   1378篇
  2024年   40篇
  2023年   337篇
  2022年   581篇
  2021年   1199篇
  2020年   711篇
  2019年   989篇
  2018年   1060篇
  2017年   708篇
  2016年   715篇
  2015年   781篇
  2014年   1003篇
  2013年   1243篇
  2012年   1802篇
  2011年   1747篇
  2010年   830篇
  2009年   689篇
  2008年   1108篇
  2007年   962篇
  2006年   827篇
  2005年   662篇
  2004年   540篇
  2003年   455篇
  2002年   377篇
  2001年   80篇
  2000年   74篇
  1999年   63篇
  1998年   55篇
  1997年   39篇
  1996年   24篇
  1995年   29篇
  1994年   20篇
  1993年   16篇
  1992年   41篇
  1991年   38篇
  1990年   34篇
  1989年   32篇
  1988年   30篇
  1987年   21篇
  1986年   26篇
  1985年   29篇
  1984年   22篇
  1982年   13篇
  1981年   12篇
  1980年   14篇
  1979年   25篇
  1978年   11篇
  1977年   15篇
  1976年   11篇
  1973年   8篇
  1972年   9篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Despite the recent proliferation of mental health apps, few have directly focused on the prevention of self-harm. The available apps are described and the limited, although encouraging, outcome data are summarised. The design, content and initial outcome of the only app developed specifically for adolescents, BlueIce, is presented.  相似文献   
992.
International Journal of Mental Health and Addiction - Video game use becomes problematic when it disrupts the ability to fulfill social and personal responsibilities. It has also been associated...  相似文献   
993.
994.
995.
The crayfish claw opener neuromuscular junction is a biological model for studying presynaptic neuromodulation by serotonin (5HT) and synaptic vesicle recycling. It has been hypothesized that 5HT enhances release by recruiting a population of either previously nonrecycling or “reluctant” vesicles to increase the readily releasable pool. To determine if 5HT activates a distinct population of synaptic vesicles, recycling membranes were labeled with the membrane dye, FM1-43. Unloading (destaining) protocols could not resolve a population of vesicles that were only releasable in the presence of 5HT. Instead, we conclude synaptic vesicles change behavior in axon terminals independent of 5HT, becoming less likely to exocytose and unload dye over periods of >1 hr after recycling. We hypothesized this to be due to the slow conversion of a portion of recycled vesicles to a difficult to release state. The possibility that vesicles in these pools were spatially separated within the terminal was tested using photoconversion of FM1-43 and transmission electron microscopy. The location of FM1-43-labeled vesicles fixed 2 min following 3 min of 20-Hz stimulation did not reveal preferential localization of recycling vesicles specifically near release sites and the distribution of labeled vesicles was not significantly different between early (2 min) and late (180 min) time points. Terminals fixed 30 s following stimulation contained a significant proportion of vesicular structures equivalent in diameter to 2–5 regular vesicles, with multivesicular bodies and calveoli rarely seen, suggesting that endocytosis during sustained release at crayfish terminals occurs via multiple routes, most commonly through large “vesicle” intermediates.  相似文献   
996.
During multiple sclerosis (MS), an inflammatory and neurodegenerative disease of the central nervous system (CNS), symptoms, and outcomes are determined by the location of inflammatory lesions. While we and others have shown that T cell cytokines differentially regulate leukocyte entry into perivascular spaces and regional parenchymal localization in murine models of MS, the molecular mechanisms of this latter process are poorly understood. Here, we demonstrate that astrocytes exhibit region-specific responses to T cell cytokines that promote hindbrain versus spinal cord neuroinflammation. Analysis of cytokine receptor expression in human astrocytes showed region-specific responsiveness to Th1 and Th17 inflammatory cytokines. Consistent with this, human and murine astrocytes treated with these cytokines exhibit differential expression of the T cell localizing molecules VCAM-1 and CXCR7 that is both cytokine and CNS region-specific. Using in vivo models of spinal cord versus brain stem trafficking of myelin-specific T cells and astrocyte-specific deletion strategies, we confirmed that Th1 and Th17 cytokines differentially regulate astrocyte expression of VCAM-1 and CXCR7 in these locations. Finally, stereotaxic injection of individual cytokines into the hindbrain or spinal cord revealed region- and cytokine-specific modulation of localizing cue expression by astrocytes. These findings identify a role for inflammatory cytokines in mediating local astrocyte-dependent mechanisms of immune cell trafficking within the CNS during neuroinflammation.  相似文献   
997.
Social Psychiatry and Psychiatric Epidemiology - Early life adversity (ELA) is a significant risk factor for mental health disorders. One hypothesised mechanism by which this occurs is via an...  相似文献   
998.
Edward Zigler transformed the science and humanity of the work with persons with intellectual disability. The developmental approach is Ed's great contribution to the field of intellectual disability as it both led to more conceptually compelling and methodologically rigorous science and provided an alternative to the Zeitgeist of segregation, defect, and pathology that had prevailed for decades. In an entirely unique way, the developmental approach allowed a seamless integration of increasingly precise science with concern for the “whole child” and their family. Thus, Ed's legacy led to a discipline in which scholarship and compassion prevail hand in hand as the integrity of science and of the person are mutually informative and interdependent.  相似文献   
999.

The study aimed to explore associations between socioeconomic position (SEP) indicators, early child stimulation (ECS) and attention-related executive functions (EF) at age 11. Children born in Pelotas, Brazil, in 2004, were recruited to a birth cohort (n = 4231, non-response rate at recruitment < 1%) and followed from birth to age 11. SEP variables were family income and maternal schooling. At the 24 and 48-month follow-ups, five markers of cognitive stimulation and social interaction were recorded and positive answers were summed to a score ranging from 0 to 5. At age 11, attentional-switching and control, and selective-attention were assessed using the adapted Test-of-Everyday-Attention-for-Children (TEA-Ch). We used multivariable logistic regression models and mediation analysis to investigate potential mediator role of ECS in the association between SEP and EF. 3106 children were included in the analyses. Less than 7% of the more stimulated individuals showed low performance in attention-related EFs at age 11 compared with almost 20% in the bottom groups of stimulation. Higher child stimulation scores were associated with fewer impairments in attentional-control (OR adj 0.84; CI 95% 0.72–0.98) and attentional-switching (OR adj 0.85; CI 95% 0.73–0.99). Mediation analysis suggested that for attentional-switching, ECS mediated almost 20% of the total protective effect of maternal schooling for impaired EF. Assuming causal relationships, if maximum stimulation was provided to all children, the advantageous effect of maternal schooling on EF would be reduced by 47%. ECS may represent a protective factor for cognitive impairments in childhood and can be easily implemented at relatively low cost.

  相似文献   
1000.
Sleep and stress independently enhance emotional memory consolidation. In particular, theta oscillations (4–7 Hz) during rapid eye movement (REM) sleep increase coherence in an emotional memory network (i.e., hippocampus, amygdala, and prefrontal cortex) and enhance emotional memory. However, little is known about how stress during learning might interact with subsequent REM theta activity to affect emotional memory. In the current study, we examined whether the relationship between REM theta activity and emotional memory differs as a function of pre‐encoding stress exposure and reactivity. Participants underwent a psychosocial stressor (the Trier Social Stress Task; n = 32) or a comparable control task (n = 32) prior to encoding. Task‐evoked cortisol reactivity was assessed by salivary cortisol rise from pre‐ to post‐stressor, and participants in the stress condition were additionally categorized as high or low cortisol responders via a median split. During incidental encoding, participants studied 150 line drawings of negative, neutral, and positive images, followed by the complete color photo. All participants then slept overnight in the lab with polysomnographic recording. The next day, they were given a surprise recognition memory task. Results showed that memory was better for emotional relative to neutral information. Critically, these findings were observed only in the stress condition. No emotional memory benefit was observed in the control condition. In stressed participants, REM theta power significantly predicted memory for emotional information, specifically for positive items. This relationship was observed only in high cortisol responders. For low responders and controls, there was no relationship between REM theta and memory of any valence. These findings provide evidence that elevated stress at encoding, and accompanying changes in neuromodulators such as cortisol, may interact with theta activity during REM sleep to promote selective consolidation of emotional information.  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