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   39712篇
  免费   3756篇
  国内免费   480篇
耳鼻咽喉   377篇
儿科学   2286篇
妇产科学   384篇
基础医学   4749篇
口腔科学   551篇
临床医学   3408篇
内科学   2747篇
皮肤病学   221篇
神经病学   16484篇
特种医学   413篇
外科学   1357篇
综合类   2948篇
现状与发展   2篇
一般理论   1篇
预防医学   3220篇
眼科学   335篇
药学   3167篇
  12篇
中国医学   1055篇
肿瘤学   231篇
  2024年   182篇
  2023年   921篇
  2022年   1407篇
  2021年   2025篇
  2020年   1907篇
  2019年   1787篇
  2018年   1652篇
  2017年   1718篇
  2016年   1780篇
  2015年   1575篇
  2014年   2589篇
  2013年   3609篇
  2012年   2023篇
  2011年   2532篇
  2010年   1945篇
  2009年   1942篇
  2008年   1989篇
  2007年   1877篇
  2006年   1573篇
  2005年   1312篇
  2004年   1062篇
  2003年   943篇
  2002年   842篇
  2001年   598篇
  2000年   491篇
  1999年   419篇
  1998年   466篇
  1997年   373篇
  1996年   292篇
  1995年   256篇
  1994年   215篇
  1993年   195篇
  1992年   188篇
  1991年   179篇
  1990年   151篇
  1989年   136篇
  1988年   130篇
  1987年   103篇
  1986年   67篇
  1985年   106篇
  1984年   73篇
  1983年   52篇
  1982年   76篇
  1981年   42篇
  1980年   37篇
  1979年   25篇
  1978年   19篇
  1977年   26篇
  1976年   13篇
  1974年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.
BACKGROUND: Facial emotions are central to human interaction. Identifying pathophysiology in affect processing circuitry that supports the ability to assess facial emotions might facilitate understanding of affect regulation in pediatric bipolar disorder. METHODS: Ten euthymic, unmedicated pediatric bipolar patients and 10 healthy control subjects matched for age, gender, race, socioeconomic status, and IQ were scanned with functional magnetic resonance imaging. Angry, happy, and neutral faces were presented in 30-sec blocks, with a 20-sec rest period between blocks. Subjects were asked to press a button when each face appeared, to ensure that attention was maintained on-task. RESULTS: In bipolar patients, in response to both angry and happy faces relative to neutral faces, we observed reduced activation of right rostral ventrolateral prefrontal cortex together with increased activity in right pregenual anterior cingulate, amygdala, and paralimbic cortex. Bipolar patients also showed reduced activation of visual areas in occipital cortex together with greater activation in higher-order visual perceptual areas, including superior temporal sulcus and fusiform gyrus with angry faces and posterior parietal cortex with happy faces. CONCLUSIONS: Findings document a disturbance in affective neurocircuitry in pediatric bipolar disorder. Reduced activation in ventrolateral prefrontal cortex might reflect diminished top-down control that leads to the observed exaggerated activation in amygdala and paralimbic areas. Changes in occipital areas might represent an effort to gate sensory input when affective responses to the faces could not be successfully modulated. Disturbances in affect processing circuitry could contribute to emotional dysregulation and social cognitive difficulties in bipolar youth.  相似文献   
75.
We report a 51-year-old patient with severe haemophilia A developing a severe life-threatening anaphylactic reaction to recombinant factor VIII (rFVIII). Anaphylactic reactions are a rare but well-known side effect of FVIII products. The nature of these reactions could not be clarified as previous studies failed to demonstrate a specific IgE response. Here, we could prove a grade 3 anaphlyactic reaction as an IgE-mediated response to rFVIII for the first time by Western blotting.  相似文献   
76.
烧伤后机体应激导致代谢紊乱,表现为严重高分解代谢,机体损耗和抵抗力下降,严重影响患者预后。临床上主要采用生理营养指标、实验室诊断指标和能量消耗测定3类检测指标对机体代谢状况进行诊断评估,继而通过药物治疗结合非药物治疗手段加以调理支持,促进烧伤修复。目前,仍有多种诊断治疗方法尚未普及或有待完善。  相似文献   
77.
Administration of cholinotoxin etylcholine aziridinium (AF64A) into the brain selectively induces nonrever-sible cholinergic deficit. Wistar rats were injected intracerebroventricularly bilaterally with AF64A at doses of 1–3 nmol/ventricle. 28 days later the number of neurons survived was counted in dorsolateral, intermediate and medial groups of cells of the medial septum. AF64A induced a decrease in neuronal density and expression of cholineacetyl transferase at all doses used as well as in all regions studied. Brain sections were also stained for NADPH-diaphorase representing neuronal NO-synthase. Effects of AF64A on NADPH-diaphorase expression depended on the region studied. The number of NADPH-diaphorase-positive cells increased in the medial cellular group where more cholineacetly transferase-positive cells survived. In contrast, decrease in NADPH-diaphorase expression in the dorsolateral group of cells coincided with low level of cholineacetyltransferase-po-sitive neurons. The data presented suggest that in the AF64A-dependent model of neurodegeneration NO may play a neuroprotective function.  相似文献   
78.
79.
Nocturnal Sleep‐Related Eating Disorder (NSRED) is a well‐documented sleeping disorder where the person is reported to experience bizarre eating behavior during sleep. Although various causes are implicated in this disorder, role of drugs cannot be ruled out. Here we narrate an interesting rare case report of a drug‐induced new onset NSRED, where a 45‐year‐old man on zolipdem performed an unexpected and bizarre eating behavior during somnambulistic state, type of which has not been reported earlier in the literature. The case falls under even rarer category as such behavior in sleep is reported mainly in woman. © 2008 by Wiley Periodicals, Inc. Int J Eat Disord 2009  相似文献   
80.
BACKGROUND: The HOXA1 gene plays a major role in brainstem and cranial morphogenesis. The G allele of the HOXA1 A218G polymorphism has been previously found associated with autism. METHODS: We performed case-control and family-based association analyses, contrasting 127 autistic patients with 174 ethnically matched controls, and assessing for allelic transmission disequilibrium in 189 complete trios. RESULTS: A, and not G, alleles were associated with autism using both case-control (chi(2) = 8.96 and 5.71, 1 df, p <.005 and <.025 for genotypes and alleles, respectively), and family-based (transmission/disequilibrium test chi(2) = 8.80, 1 df, p <.005) association analyses. The head circumference of 31 patients carrying one or two copies of the G allele displayed significantly larger median values (95.0th vs. 82.5th percentile, p <.05) and dramatically reduced interindividual variability (p <.0001), compared with 166 patients carrying the A/A genotype. CONCLUSIONS: The HOXA1 A218G polymorphism explains approximately 5% of the variance in the head circumference of autistic patients and represents to our knowledge the first known gene variant providing sizable contributions to cranial morphology. The disease specificity of this finding is currently being investigated. Nonreplications in genetic linkage/association studies could partly stem from the dyshomogeneous distribution of an endophenotype morphologically defined by cranial circumference.  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