全文获取类型
收费全文 | 18371篇 |
免费 | 1647篇 |
国内免费 | 1288篇 |
专业分类
耳鼻咽喉 | 48篇 |
儿科学 | 134篇 |
妇产科学 | 294篇 |
基础医学 | 3375篇 |
口腔科学 | 423篇 |
临床医学 | 1302篇 |
内科学 | 2017篇 |
皮肤病学 | 202篇 |
神经病学 | 1325篇 |
特种医学 | 616篇 |
外国民族医学 | 6篇 |
外科学 | 947篇 |
综合类 | 4425篇 |
现状与发展 | 5篇 |
一般理论 | 1篇 |
预防医学 | 1123篇 |
眼科学 | 96篇 |
药学 | 1968篇 |
43篇 | |
中国医学 | 1422篇 |
肿瘤学 | 1534篇 |
出版年
2024年 | 45篇 |
2023年 | 735篇 |
2022年 | 1141篇 |
2021年 | 1167篇 |
2020年 | 1220篇 |
2019年 | 775篇 |
2018年 | 610篇 |
2017年 | 708篇 |
2016年 | 819篇 |
2015年 | 1054篇 |
2014年 | 1484篇 |
2013年 | 1285篇 |
2012年 | 1483篇 |
2011年 | 1489篇 |
2010年 | 1259篇 |
2009年 | 1034篇 |
2008年 | 651篇 |
2007年 | 887篇 |
2006年 | 689篇 |
2005年 | 441篇 |
2004年 | 357篇 |
2003年 | 296篇 |
2002年 | 221篇 |
2001年 | 153篇 |
2000年 | 130篇 |
1999年 | 127篇 |
1998年 | 144篇 |
1997年 | 106篇 |
1996年 | 94篇 |
1995年 | 90篇 |
1994年 | 69篇 |
1993年 | 60篇 |
1992年 | 45篇 |
1991年 | 30篇 |
1990年 | 56篇 |
1989年 | 27篇 |
1988年 | 32篇 |
1987年 | 37篇 |
1986年 | 40篇 |
1985年 | 28篇 |
1984年 | 35篇 |
1983年 | 14篇 |
1982年 | 24篇 |
1981年 | 39篇 |
1980年 | 21篇 |
1979年 | 6篇 |
1978年 | 13篇 |
1977年 | 10篇 |
1976年 | 5篇 |
1975年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
重庆地区驾驶员血液中乙醇浓度与驾驶能力的关系 总被引:5,自引:0,他引:5
目的 探讨重庆地区驾驶员血液中乙醇浓度 (BAC)和驾驶能力的关系 ,为交通安全立法提供科学依据。 方法 随机选择重庆地区 59名驾驶员志愿者 ,建立饮酒后驾车模型、科学的BAC测定以及驾驶能力评价体系 ,对不同BAC下驾驶能力进行测评。 结果 受试者出现驾驶能力损害时的BAC均数为 685.9mg/L ,最小值 190 .0mg/L ,最大值 152 0 .0mg/L ,总体均数 95%可信区间为 60 2 .4~ 70 9.5mg/L。汉族和土家族间、汉族男性和女性间、2 3~ 3 5岁和 3 6~ 56岁年龄组间差异无显著性意义 (P >0 .0 5) ,而既往饮酒量不同的三个组别间差异有显著性意义 (P <0 .0 5)。随着BAC增高 ,驾驶能力受损人数增加。在 2 0 0 .0mg/L有 3 % (2 / 59)的受试者驾驶能力降低 ,80 0 .0mg/L则达到 68% (40 / 59)。 结论 随着BAC增高 ,重庆地区驾驶员驾驶能力受损人数比例增加 ,出现驾驶能力明显损害时BAC为 60 2 .4~ 70 9.5mg/L ,既往酒量较大人群中该值较高 相似文献
992.
J.W. Lindsey U. Khan W. Ansari T. Powell Y.H. Wang M.S. Guirguis 《Journal of neuroimmunology》2013,254(1-2):146-153
Infection with Epstein–Barr virus (EBV) is associated with multiple sclerosis (MS), and patients with MS have an increased antibody response to some EBV antigens. The major antigens of EBV are only partly defined. Our hypothesis is that the antibody response to EBV is altered in MS. With ELISA, we found that antibodies to EB virions were increased in both serum and CSF of MS patients. Western blots demonstrated that there are multiple different antigens recognized. The antibody response was generally higher in MS to all EBV antigens, with particularly significant increases for certain antigens. We conclude that the antibody response to EBV in MS is generally increased with altered specificity. 相似文献
993.
Li Li Huizhen Chen Fangfang Chen Feng Li Meng Wang Li Wang Yunqing Li Dianshuai Gao 《Journal of neural transmission (Vienna, Austria : 1996)》2013,120(11):1511-1523
Parkinson’s disease (PD) is the second most prevalent, progressive neurodegenerative disease and is characterized by the irreversible and selective loss of nigrostriatal dopaminergic (DA) neurons. Glial cell line-derived neurotrophic factor (GDNF), which is a potent protective factor for DA neurons, is considered a promising neuroprotective candidate for PD. microRNAs (miRNAs) have been shown to be involved in a number of neurodegenerative diseases. Both miRNAs and GDNF affect DA neuronal processes, but the molecular crosstalk between these molecules remains unclear. The present study aimed to evaluate whether GDNF modulates miRNA expression. We used microarray analysis and real-time polymerase chain reaction (RT-PCR) to investigate miRNAs expression in 6-hydroxydopamine (6-OHDA)-injured MN9D cells treated with GDNF for 30 min, 1 h, or 3 h. Our results showed that GDNF treatment led to differential expression of 143 miRNAs. To further identify mechanisms by which GDNF exerts its effects, we compared miRNAs and mRNAs microarray data at the 1-h time point. We found that various biological processes and pathways were regulated at the miRNA level following GDNF treatment. Collectively, these results provide evidence of the capacity of GDNF to influence miRNAs expression, suggesting a new mechanism of GDNF action. 相似文献
994.
目的回顾性分析与总结颈深部多间隙脓肿的临床诊治经验,以提高临床医生对本病的认识与诊疗水平。方法选取2008年3月~2018年3月于陆军军医大学第一附属医院就诊的颈深部多间隙脓肿182例患者,对其临床特点、相关检查、治疗及随访情况进行回顾性分析。结果182例患者中,男女患者数之比为1.98∶1,27例合并有全身系统性疾病,其中25例为糖尿病,1例高血压3级,1例慢性肾病2期。最常见的临床症状为颈部包块和颈部疼痛。下颌下间隙是最常累及的间隙,其次是咽旁间隙,牙源性和上呼吸道感染是最常见的致病原因。对所有患者的脓液进行细菌学培养,其中45例(24.7%)培养阳性,阳性结果中最常见的致病菌为链球菌属(43.6%)。在糖尿病患者中,4例细菌培养阳性,全为肺炎克雷伯杆菌。所有患者选用敏感抗生素治疗,其中152例患者行脓肿切开引流术;最常见并发症为气道阻塞,其中33例(18.1%)行气管切开术;有合并症患者给予对症处理。住院治疗2~43 d,151例患者获治愈,31例患者缓解,没有死亡病例。出院后随访1个月情况良好,感染无复发。结论颈深部多间隙脓肿男性患病率较女性高,起病急,进展迅速,脓肿切开引流和联合应用敏感抗生素仍然是本病的主要治疗方法。脓液细菌培养呈现出大量的阴性结果,因此细菌学培养仅仅作为使用抗生素的参考,气管切开仍然是保障术后安全的必要条件,对于减少并发症及改善预后起到了重要作用。治疗中要特别关注合并全身系统性疾病和老年患者并发症的处理。 相似文献
995.
骨创伤修复基础研究的若干新进展 总被引:1,自引:1,他引:1
付小兵 《中华创伤骨科杂志》2004,6(1):46-50
分子生物学技术的迅猛发展给骨创伤后组织修复的基础研究和临床治疗提供了新的思路和手段。本文概述近年来在生长因子、基因治疗以及组织工程三方面进展对骨创伤后组织修复基础研究和临床治疗的促进作用。转化生长因子(TGF-β)、骨形成蛋白(BMP)、成纤维细胞生长因子(FGF)、血小板源性生长因子(PDGF)和胰岛素样生长因子(IGF)在骨修复中起重要作用,基因治疗将在软组织修复、骨形成和神经再生方面发挥作用。组织工程化骨与软骨、皮肤、血管等研究也将对骨科创伤修复产生积做影响。 相似文献
996.
目的:探讨地衣芽胞杆菌C01在模型小鼠体内对大肠杆菌、沙门氏菌抑制作用以及对乳杆菌等有益菌的促进作用。方法:用地衣芽胞杆菌C01灌胃肠道感染模型小鼠,采用体外活菌培养,分析粪便菌群数量的变化。结果:C01灌胃治疗组(EPEC C01)中乳杆菌的数量显著高于EPEC灌胃模型组(EPEC N)(P<0.01),肠杆菌数量下降极显著(P<0.01),而(EPEC N)组肠杆菌数显著高于正常对照组(NS)(P<0.05);肠炎沙门氏菌处理后C01灌胃治疗组(SL C01)和处理后肠炎沙门氏模型组(SL N)比较,乳杆菌、肠球菌和总厌氧菌的变化不明显,但肠杆菌数量下降极显著(P<0.01);形态病理学观察结果显示,C01芽胞杆菌灌胃治疗组肠粘膜病变明显减轻,肠粘膜及绒毛高度明显增加,绒毛轻度水肿,绒毛排列整齐、致密。结论:地衣芽胞杆菌C01在体内对肠炎沙门氏菌和致病性大肠杆菌有较强的抑制作用,能促进乳杆菌等生理性有益菌的增殖,可保护肠粘膜结构的完整性免受病原菌的侵袭。 相似文献
997.
《Alzheimer's & dementia》2014,10(6):704-712
BackgroundThis study examined the predictive value of different classes of markers in the progression from mild cognitive impairment (MCI) to Alzheimer's disease (AD) over an extended 4-year follow-up in the Alzheimer's Disease Neuroimaging Initiative (ADNI) database.MethodsMCI patients were assessed for clinical, cognitive, magnetic resonance imaging (MRI), positron emission tomography–fluorodeoxyglucose (PET-FDG), and cerebrospinal fluid (CSF) markers at baseline and were followed on a yearly basis for 4 years to ascertain progression to AD. Logistic regression models were fitted in clusters, including demographics, APOE genotype, cognitive markers, and biomarkers (morphometric, PET-FDG, CSF, amyloid-β, and tau).ResultsThe predictive model at 4 years revealed that two cognitive measures, an episodic memory measure and a Clock Drawing screening test, were the best predictors of conversion (area under the curve = 0.78).ConclusionsThis model of prediction is consistent with the previous model at 2 years, thus highlighting the importance of cognitive measures in progression from MCI to AD. Cognitive markers were more robust predictors than biomarkers. 相似文献
998.
《Parkinsonism & related disorders》2014,20(11):1203-1208
BackgroundLongitudinal neuroimaging studies could provide insights into pathophysiology of cognitive impairment in PD. We examined the role of hippocampal atrophy and cerebral white matter disease as risk factors for mild cognitive impairment and dementia in PD.MethodsProspective longitudinal study of patients with mild PD in a tertiary neurology center. All subjects underwent baseline MRI brain and had baseline and 6 monthly cognitive evaluations. Cognitive impairment was diagnosed based on the Movement Disorder Society Criteria. The predictive role of hippocampal volume and white matter hyperintensity at baseline on progression of cognitive impairment was studied.Results97 subjects with mean age 65.3 years, mean education of 10.3 years and mean Hoehn & Yahr of 1.9 were studied. Over 2 years, 16 subjects developed mild cognitive impairment and 8 subjects with mild cognitive impairment progressed to dementia. After adjusting for age and vascular risk factors, hippocampal volume was a significant predictor for mild cognitive impairment (OR 7.05, CI 1.5–34.1; p = 0.015) and dementia (OR 7.03, CI 2.39–25.2; p = 0.001). With Cox regression, hippocampal volume was a significant predictor for “time to cognitive impairment” (HR 7.67; CI 3.47–16.95, p < 0.001). Difference between survival curves based on volume of white matter hyperintensity in predicting “time to mild cognitive impairment” was significant (p = 0.0295).ConclusionsHippocampal volume is a major factor predicting the development of mild cognitive impairment and dementia in PD. White matter hyperintensity also contributes to the longitudinal cognitive status in PD. 相似文献
999.
1000.
Disturbances in neurocognitive performance are a core feature of the acute sickness response to infection; however the underlying mechanisms remain unclear. The current study used a computerised battery to assess neurocognitive functioning in subjects enrolled in the Dubbo Infection Outcomes Study (n = 107) – a prospective cohort of subjects followed from documented acute infection with Epstein Barr virus, Ross River virus, or Coxiella burnetii until recovery. Subjects were assessed when ill, and a subset again after complete recovery. Associations between sickness-related cognitive disturbances and single nucleotide polymorphisms (SNPs) in cytokine (interleukin [IL]-6, IL-10, tumor necrosis factor-α and interferon-γ) and neurobehavioral genes (serotonin transporter and catechol-O-methyltransferase) were explored.During acute infection, subjects exhibited slower matching-to-sample responses (p = 0.03), poorer working memory capacity (p = 0.014), mental planning (p = 0.045), and dual attention task performance (p = 0.02), and required longer to complete discordant Stroop trials (p = 0.01) compared to recovery. Objective impairments correlated significantly with self-reported symptoms (p < 0.05) as well as levels of the inflammation marker, C-reactive protein (p = 0.001). Linear regression analysis identified an association between neurocognitive disturbance during acute illness and functional polymorphisms in inflammatory cytokine genes. Specifically, the high cytokine producing G allele of the IL-6-174G/C SNP was associated with poorer neurocognitive performance when subjects were ill (p = 0.027).These findings confirm that acute infection impacts on neurocognitive performance, manifesting as slowed responses and impaired performance on complex tasks requiring higher-order functioning which has important real-world implications. The data provide the first preliminary evidence for a role of a genetic predisposition to more intense inflammatory responses in objective neurocognitive disturbances during acute infections. These associations require replication in a larger sample size. 相似文献