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   704篇
  免费   44篇
  国内免费   8篇
耳鼻咽喉   17篇
儿科学   22篇
妇产科学   5篇
基础医学   90篇
口腔科学   40篇
临床医学   43篇
内科学   68篇
皮肤病学   5篇
神经病学   175篇
特种医学   62篇
外科学   53篇
综合类   8篇
一般理论   1篇
预防医学   63篇
眼科学   8篇
药学   56篇
中国医学   4篇
肿瘤学   36篇
  2023年   6篇
  2022年   4篇
  2021年   13篇
  2020年   13篇
  2019年   12篇
  2018年   22篇
  2017年   14篇
  2016年   22篇
  2015年   27篇
  2014年   30篇
  2013年   40篇
  2012年   49篇
  2011年   55篇
  2010年   27篇
  2009年   37篇
  2008年   44篇
  2007年   53篇
  2006年   49篇
  2005年   39篇
  2004年   25篇
  2003年   25篇
  2002年   16篇
  2001年   9篇
  2000年   2篇
  1999年   6篇
  1998年   18篇
  1997年   17篇
  1996年   10篇
  1995年   7篇
  1994年   10篇
  1993年   8篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   6篇
  1987年   5篇
  1986年   5篇
  1985年   5篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   7篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   2篇
排序方式: 共有756条查询结果,搜索用时 15 毫秒
741.
Darier disease is an uncommon genodermatosis reflecting defective desmosomal structure and function. The present report details the oral features of a patient with well-characterized Darier disease and reviews current knowledge of the genetic basis of this genodermatosis that can often affect the craniofacial tissues.  相似文献   
742.
  • 1 The transition to extra‐uterine life at birth is critically dependent on airway liquid clearance to allow the entry of air and the onset of gaseous ventilation. We have used phase contrast X‐ray imaging to identify factors that regulate lung aeration at birth in spontaneously breathing term and mechanically ventilated preterm rabbit pups.
  • 2 Phase contrast X‐ray imaging exploits the difference in refractive index between air and water to enhance image contrast, enabling the smallest air‐filled structures of the lung (alveoli; < 100 µm) to be resolved. Using this technique, the lungs become visible as they aerate, allowing the air–liquid interface to be observed as it moves distally during lung aeration.
  • 3 Spontaneously breathing term rabbit pups rapidly aerate their lungs, with most fully recruiting their functional residual capacity (FRC) within the first few breaths. The increase in FRC occurs mainly during individual breaths, demonstrating that airway liquid clearance and lung aeration is closely associated with inspiration. We suggest that transpulmonary pressures generated by inspiration provide a hydrostatic pressure gradient for the movement of water out of the airways and into the surrounding lung tissue after birth.
  • 4 In mechanically ventilated preterm pups, lung aeration is closely associated with lung inflation and a positive end‐expiratory pressure is required to generate and maintain FRC after birth.
  • 5 In summary, phase contrast X‐ray imaging can image the air‐filled lung with high temporal and spatial resolution and is ideal for identifying factors that regulate lung aeration at birth in both spontaneously breathing term and mechanically ventilated preterm neonates.
  相似文献   
743.
Child maltreatment has been associated with different psychiatric disorders. Studies on both animals and humans have suggested that some brain areas would be directly affected by severe psychological trauma. The pathophsysiology of post-traumatic stress disorder (PTSD) appears to be related to a complex interaction involving genetic and environmental factors. Advanced neuroimaging techniques have been used to investigate neurofunctional and neurostructural abnormalities in children, adolescents, and adults with PTSD. This review examined structural brain imaging studies that were performed in abused and traumatized children, and discusses the possible biological mechanisms involved in the pathophysiology of PTSD, the implications and future directions for magnetic resonance imaging (MRI) studies. Published reports in refereed journals were reviewed by searching Medline and examining references of the articles related to structural neuroimaging of PTSD. Structural MRI studies have been performed in adults and children to evaluate the volumetric brain alterations in the PTSD population. In contrast with studies involving adults, in which hippocampus volumetric reduction was the most consistent finding, studies involving children and adolescents with PTSD have demonstrated smaller medial and posterior portions of the corpus callosum.  相似文献   
744.
745.
Disturbances in reward processing have been implicated in bulimia nervosa (BN). Abnormalities in processing reward-related stimuli might be linked to dysfunctions of the catecholaminergic neurotransmitter system, but findings have been inconclusive. A powerful way to investigate the relationship between catecholaminergic function and behavior is to examine behavioral changes in response to experimental catecholamine depletion (CD). The purpose of this study was to uncover putative catecholaminergic dysfunction in remitted subjects with BN who performed a reinforcement-learning task after CD. CD was achieved by oral alpha-methyl-para-tyrosine (AMPT) in 19 unmedicated female subjects with remitted BN (rBN) and 28 demographically matched healthy female controls (HC). Sham depletion administered identical capsules containing diphenhydramine. The study design consisted of a randomized, double-blind, placebo-controlled crossover, single-site experimental trial. The main outcome measures were reward learning in a probabilistic reward task analyzed using signal-detection theory. Secondary outcome measures included self-report assessments, including the Eating Disorder Examination-Questionnaire. Relative to healthy controls, rBN subjects were characterized by blunted reward learning in the AMPT--but not in placebo--condition. Highlighting the specificity of these findings, groups did not differ in their ability to perceptually distinguish between stimuli. Increased CD-induced anhedonic (but not eating disorder) symptoms were associated with a reduced response bias toward a more frequently rewarded stimulus. In conclusion, under CD, rBN subjects showed reduced reward learning compared with healthy control subjects. These deficits uncover disturbance of the central reward processing systems in rBN related to altered brain catecholamine levels, which might reflect a trait-like deficit increasing vulnerability to BN.  相似文献   
746.
We evaluated whether traumatic events are associated with a distinctive pattern of socio-demographic and clinical features of obsessive-compulsive disorder (OCD). We compared socio-demographic and clinical features of 106 patients developing OCD after post-traumatic stress disorder (PTSD; termed post-traumatic OCD), 41 patients developing OCD before PTSD (pre-traumatic OCD), and 810 OCD patients without any history of PTSD (non-traumatic OCD) using multinomial logistic regression analysis. A later age at onset of OCD, self-mutilation disorder, history of suicide plans, panic disorder with agoraphobia, and compulsive buying disorder were independently related to post-traumatic OCD. In contrast, earlier age at OCD onset, alcohol-related disorders, contamination-washing symptoms, and self-mutilation disorder were all independently associated with pre-traumatic OCD. In addition, patients with post-traumatic OCD without a previous history of obsessive-compulsive symptoms (OCS) showed lower educational levels, greater rates of contamination-washing symptoms, and more severe miscellaneous symptoms as compared to post-traumatic OCD patients with a history of OCS.  相似文献   
747.

BACKGROUND:

Recent studies have demonstrated high rates of psychopathology in the offspring of parents with bipolar disorder. The aim of this study was to identify psychiatric diagnoses in a sample of children of bipolar parents.

METHOD:

This case series comprised 35 children and adolescents aged 6 to 17 years, with a mean age of 12.5±2.9 years (20 males and 15 females), who had at least one parent with bipolar disorder type I. The subjects were assessed using the Schedule for Affective Disorders and Schizophrenia for School-Age Children – Present and Lifetime version (K-SADS-PL). Family psychiatric history and demographics were also evaluated.

RESULTS:

Of the offspring studied, 71.4% had a lifetime diagnosis of at least one psychiatric disorder (28.6% with a mood disorder, 40% with a disruptive behavior disorder and 20% with an anxiety disorder). Pure mood disorders (11.4%) occurred less frequently than mood disorders comorbid with attention deficit hyperactivity disorder (17.1%). Psychopathology was commonly reported in second-degree relatives of the offspring of parents with bipolar disorder (71.4%).

CONCLUSIONS:

Our results support previous findings of an increased risk for developing psychopathology, predominantly mood and disruptive disorders, in the offspring of bipolar individuals. Prospective studies with larger samples are needed to confirm and expand these results.  相似文献   
748.
Up to 50% of bipolar disorder (BD) patients present a lifetime diagnosis of alcohol use disorders (AUD). BD patients with comorbid AUD, even when in remission from the AUD, have a poorer outcome and functional impairment than patients with BD alone. The neurobiological abnormalities that potentially characterize this severe subgroup of BD patients are unknown. Our goal was to investigate gray matter (GM) volume abnormalities in BD I patients with comorbid AUD. Twenty-one BD-AUD patients, 21 BD-nonAUD BD patients, and 25 healthy controls (HC), matched by age, gender, and handedness were studied. The BD-AUD patients were in remission from AUD on average for 6.8 years. 3D SPGR MRIs (TR = 25 ms, TE = 5 ms, slice thickness = 1.5 mm) were acquired from all subjects using a 1.5 T GE Signa Imaging System. We used an optimized voxel-based morphometry protocol to compare GM volumes among the groups. BD-AUD patients presented smaller GM volumes in the left medial frontal and the right anterior cingulate gyri compared to BD-nonAUD patients. BDnon-AUD patients did not present GM volume differences compared to HC. These findings provide evidence for an effect of comorbid AUD on regional brain structure of BD I patients and warrant further research on neurobiological aspects of this prevalent and severe comorbidity.  相似文献   
749.
OBJECTIVE: The striatum, including the putamen and caudate, plays an important role in executive and emotional processing and may be involved in the pathophysiology of mood disorders. Few studies have examined structural abnormalities of the striatum in pediatric major depressive disorder (MDD) patients. We report striatal volume abnormalities in medication-na?ve pediatric MDD compared to healthy comparison subjects. METHOD: Twenty seven medication-na?ve pediatric Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) MDD and 26 healthy comparison subjects underwent volumetric magnetic resonance imaging (MRI). The putamen and caudate volumes were traced manually by a blinded rater, and the patient and control groups were compared using analysis of covariance adjusting for age, sex, intelligence quotient, and total brain volumes. RESULTS: MDD patients had significantly smaller right striatum (6.0% smaller) and right caudate volumes (7.4% smaller) compared to the healthy subjects. Left caudate volumes were inversely correlated with severity of depression in MDD subjects. Age was inversely correlated with left and right putamen volumes in MDD patients but not in the healthy subjects. CONCLUSIONS: These findings provide fresh evidence for abnormalities in the striatum of medication-na?ve pediatric MDD patients and suggest the possible involvement of the striatum in the pathophysiology of MDD.  相似文献   
750.
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