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   6622篇
  免费   508篇
  国内免费   64篇
耳鼻咽喉   46篇
儿科学   170篇
妇产科学   202篇
基础医学   942篇
口腔科学   100篇
临床医学   568篇
内科学   1691篇
皮肤病学   177篇
神经病学   840篇
特种医学   248篇
外科学   556篇
综合类   10篇
预防医学   403篇
眼科学   51篇
药学   481篇
中国医学   15篇
肿瘤学   694篇
  2024年   10篇
  2023年   112篇
  2022年   80篇
  2021年   354篇
  2020年   233篇
  2019年   294篇
  2018年   300篇
  2017年   245篇
  2016年   289篇
  2015年   330篇
  2014年   383篇
  2013年   472篇
  2012年   698篇
  2011年   686篇
  2010年   365篇
  2009年   280篇
  2008年   396篇
  2007年   362篇
  2006年   340篇
  2005年   275篇
  2004年   219篇
  2003年   186篇
  2002年   136篇
  2001年   13篇
  2000年   10篇
  1999年   12篇
  1998年   25篇
  1997年   11篇
  1996年   10篇
  1995年   9篇
  1994年   4篇
  1993年   7篇
  1992年   8篇
  1991年   2篇
  1990年   3篇
  1989年   7篇
  1988年   3篇
  1987年   3篇
  1986年   2篇
  1984年   3篇
  1979年   2篇
  1976年   1篇
  1974年   1篇
  1973年   1篇
  1969年   2篇
  1965年   1篇
  1947年   1篇
  1943年   1篇
  1942年   1篇
  1941年   1篇
排序方式: 共有7194条查询结果,搜索用时 453 毫秒
991.
PurposeTo examine fever as a precipitating factor for focal seizures in patients with Panayiotopoulos syndrome (PS) and evaluate the role of SCN1A in PS patients with seizures triggered by fever.MethodsFrom January 2000 to June 2008, we identified patients referred for seizures who fulfilled the criteria of PS. Patients were divided into two groups, according to the presence (group A) or the absence (group B) of seizures triggered by fever. Electroclinical features of the two groups were compared. In addition, an analysis of SCN1A in patients of group A was performed.ResultsThirty patients fulfilled the inclusion criteria. Eleven patients (36%) had at least one focal autonomic seizure triggered by fever (group A). In group A, 7/11 patients (63.5%) had the first focal autonomic seizure during a febrile illness. Two of these 7 patients were misdiagnosed at the onset of PS. The median age at the onset of PS was slightly lower in group A than in group B (p = .050). Moreover, patients in group A more frequently had a positive familial history of febrile seizures (FS) (p = .047). No mutations of SCN1A were found in any of the 10 patients screened.ConclusionFever is a common trigger for focal autonomic seizures in PS. Knowing that an autonomic manifestation during fever can be an epileptic seizure could facilitate diagnosis and prevent unnecessary investigations and erroneous treatments. Moreover, our data show that SCN1A gene does not contribute significantly to susceptibility to autonomic seizures during fever in patients with PS.  相似文献   
992.
Previous imaging studies assessing the relationship between white matter (WM) damage and matter (GM) atrophy have raised the concern that Multiple Sclerosis (MS) WM lesions may affect measures of GM volume by inducing voxel misclassification during intensity‐based tissue segmentation. Here, we quantified this misclassification error in simulated and real MS brains using a lesion‐filling method. Using this method, we also corrected GM measures in patients before comparing them with controls in order to assess the impact of this lesion‐induced misclassification error in clinical studies. We found that higher WM lesion volumes artificially reduced total GM volumes. In patients, this effect was about 72% of that predicted by simulation. Misclassified voxels were located at the GM/WM border and could be distant from lesions. Volume of individual deep gray matter (DGM) structures generally decreased with higher lesion volumes, consistent with results from total GM. While preserving differences in GM volumes between patients and controls, lesion‐filling correction revealed more lateralised DGM shape changes in patients, which were not evident with the original images. Our results confirm that WM lesions can influence MRI measures of GM volume and shape in MS patients through their effect on intensity‐based GM segmentation. The greater effect of lesions at increasing levels of damage supports the use of lesion‐filling to correct for this problem and improve the interpretability of the results. Volumetric or morphometric imaging studies, where lesion amount and characteristics may vary between groups of patients or change over time, may especially benefit from this correction. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.  相似文献   
993.
994.
Cytokines/chemokines are involved in the immune response of infections, including HIV-1. We defined the profile of 48 cytokines/chemokines in cerebrospinal fluid from 18 cART patients with chronic HIV-1 infection by Luminex technology. Nine patients were affected with leukoencephalopathies: five with John Cunningham virus (JCV) + progressive multifocal leukoencephalopathy (PML) and four with JCV-not determined leukoencephalopathy (NDLE). In addition, nine HIV-1-positive patients with no neurological signs (NND) and five HIV-1-negative patients affected with acute disseminated encephalomyelitis (ADEM) were enrolled. Ten cytokines (IL-15, IL-3, IL-16, IL-18, CTACK, GRO1, SCF, MCP-1, MIF, SDF) were highly expressed in HIV-1-positive patients while IL-1Ra and IL-17 were present at a lower level. In addition, the levels of IL-17, IL-9, FGF-basic, MIP-1??, and MCP-1 were significantly higher (p?<?0.05) in patients with neurological diseases (PML, NDLE, ADEM) with respect to NND. Focusing the attention to the cytokine profile in JCV + PML patients with respect to JCV-NDLE patients, only TNF-?? was significantly downregulated (p?<?0.05) in JCV + PML patients. This pilot study emphasized the role of immunoregulation in HIV-1-related neurological disorders during cART treatment.  相似文献   
995.
Studies reporting an inverse association between Alzheimer's disease (AD) and cancer are scant. Available data are mostly based on ancillary findings of mortality data or obtained from studies evaluating frequency of neoplasms in AD patients independently if they occurred before or after AD. Moreover, some studies estimated frequencies of neoplasms in demented individuals, who were not necessarily AD patients. We estimated frequency of tumors preceding the onset of AD in AD patients and compared it to that of age- and gender-matched AD-free individuals. Occurrence of tumors preceding AD onset was assessed through a semi-structured questionnaire. Tumors were categorized as benign, malignant, or of uncertain classification and as endocrine-related or not. Odds ratios (OR), used as measure of the association between the two diseases, were adjusted for tumor categories and known risk factors for AD and tumors. We included 126 AD patients and 252 matched controls. Tumor frequency before AD onset was 18.2% among cases and 24.2% among controls. There was a suggestive trend of an overall inverse association between the two diseases (adjusted OR 0.6; 95% CI 0.4-1.1; p = 0.11). Risk for neoplasms was significantly reduced only for women (adjusted OR, 0.5; 95% CI 0.3-0.9; p = 0.03) and for endocrine related tumors (adjusted OR, 0.5; 95% CI 0.2-1; p = 0.04). Our study confirms the inverse association reported in previous epidemiological studies. Though our findings might be explained by processes playing an opposite role in tumors development and neurodegeneration, they are also suggestive for a possible role of estrogen.  相似文献   
996.
ABSTRACT: BACKGROUND: This is an update of a previous meta-analysis published in 2005. METHODS: It includes the data published up to march 2010 for a total of 247 papers and 18,300 cases. Cognitive deficits are examined in 5 different domains: Memory functioning (128 studies), Global cognitive functioning (131 studies), Language (70 studies), Executive function (67 studies), Attention (76 studies). Only controlled studies were included: patients vs. normal subjects. RESULTS: Results evidence that in all domains and in all different analyses performed within each domain, patients show a significant reduction of cognitive efficiency with respect to normal subjects. The between studies heterogeneity is very high in almost all domains. There are various sources of this heterogeneity (age, sex, sample size, type of patients, and type of measurement) which contribute to the high degree of not-overlapping information offered by the single studies. CONCLUSIONS: Our results, based on the current scientific evidence, confirm the previous findings that there is a generalized impairment of various cognitive functions in patients with schizophrenia when compared to normal cases. The modalities with which these results are obtained have not changed over the years and the more recent studies do not modify the high heterogeneity previously found between the studies. This reduces the methodological quality of the results. In order to improve the methodological quality of the studies performed in the field of cognitive deficits of patients with schizophrenia, various factors should be taken into account and better managed in designing future studies.  相似文献   
997.
Objective. To assess the efficacy and safety of palmitoylethanolamide (PEA), an endogenous fatty acid amide belonging to the N-acylethanolamines family, in reducing pain severity in patients with pain associated to different pathological conditions. Methods. This was an observational study conducted on 610 patients who were unable to effectively control chronic pain with standard therapies. PEA (600?mg) was administered twice daily for 3 weeks followed by single daily dosing for 4 weeks, in addition to standard analgesic therapies or as single therapy. The primary outcome measure was the mean score pain severity evaluated by the numeric rating scale. Safety was also evaluated. Results. PEA treatment significantly decreased the mean score pain intensity evaluated in all patients who completed the study. The PEA effect was independent of the pain associated pathological condition. PEA-induced decrease of pain intensity was present also in patients without concomitant analgesic therapy. Importantly, PEA showed no adverse effects. Conclusions. In this study, PEA was effective and safe in the management of chronic pain in different pathological conditions.  相似文献   
998.
999.

Purpose  

The aim of this study is to report on a collective of 20 children from Belarus who had developed papillary thyroid carcinoma with pulmonary metastases after the Chernobyl disaster. In all children fractionated radioiodine therapy (RIT) was ceased before achieving complete remission due to a lack of further effects of 131I therapy and an increased risk of pulmonary fibrosis.  相似文献   
1000.
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