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   271508篇
  免费   23222篇
  国内免费   7042篇
耳鼻咽喉   2048篇
儿科学   4056篇
妇产科学   4136篇
基础医学   41466篇
口腔科学   5963篇
临床医学   18203篇
内科学   37686篇
皮肤病学   3878篇
神经病学   22181篇
特种医学   8943篇
外国民族医学   28篇
外科学   22282篇
综合类   33288篇
现状与发展   32篇
一般理论   8篇
预防医学   18502篇
眼科学   3267篇
药学   38218篇
  85篇
中国医学   15525篇
肿瘤学   21977篇
  2024年   562篇
  2023年   3797篇
  2022年   9070篇
  2021年   11867篇
  2020年   9734篇
  2019年   9868篇
  2018年   9770篇
  2017年   10386篇
  2016年   10219篇
  2015年   10291篇
  2014年   12783篇
  2013年   16745篇
  2012年   13949篇
  2011年   16801篇
  2010年   11643篇
  2009年   11806篇
  2008年   13202篇
  2007年   13447篇
  2006年   12382篇
  2005年   11393篇
  2004年   9730篇
  2003年   8655篇
  2002年   6726篇
  2001年   5998篇
  2000年   5018篇
  1999年   4373篇
  1998年   3641篇
  1997年   3686篇
  1996年   3373篇
  1995年   2990篇
  1994年   2865篇
  1993年   2499篇
  1992年   2184篇
  1991年   2003篇
  1990年   1740篇
  1989年   1418篇
  1988年   1372篇
  1987年   1246篇
  1986年   1265篇
  1985年   1817篇
  1984年   1587篇
  1983年   1219篇
  1982年   1258篇
  1981年   1046篇
  1980年   958篇
  1979年   795篇
  1978年   496篇
  1977年   423篇
  1976年   413篇
  1975年   290篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
BackgroundDual antiplatelet therapy (DAPT) is the cornerstone treatment of acute myocardial infarction (AMI).ObjectiveThe present study aimed to investigate the efficacy and safety of triple antiplatelet therapy (TAPT) in elderly female patients with diabetes and ST segment elevation myocardial infarction (STEMI), who had undergone percutaneous coronary intervention (PCI).MethodsWe designed a randomized, single-blind study. Control group A (97 elderly male patients with diabetes and STEMI, whose CRUSADE scores were < 30) received aspirin, ticagrelor, and tirofiban. A total of 162 elderly female patients with diabetes and STEMI were randomly divided into two groups according to CRUSADE score. Group B (69 patients with CRUSADE score > 31) received aspirin and ticagrelor. Group C (93 patients with CRUSADE score < 30) received aspirin, ticagrelor and tirofiban. P values < 0.05 were considered statistically significant.ResultsCompared to the findings in group A, post-PCI Thrombolysis in Myocardial Infarction (TIMI) grade 3 blood flow and TIMI myocardial perfusion grade 3 were significantly less prevalent in group B (p < 0.05). When compared to groups A and C, the incidence of major adverse complications was significantly higher in group B (p < 0.05).ConclusionTAPT could effectively reduce the incidence of major complications in elderly female patients with diabetes and STEMI. However, close attention should be paid to hemorrhage in patients receiving TAPT. (Arq Bras Cardiol. 2020; [online].ahead print, PP.0-0)  相似文献   
43.
44.
Context: Treatment of primary spinal syringomyelia is still controversial. Among others, shunting syrinx fluid to the subarachnoid, peritoneal or pleural space has been utilized with varying success. Shunt obstruction, migration, and infection represent the most common complications of these procedures.

Findings: The authors present the case of an 81-year-old woman who developed an unusual neurological deterioration resembling a subacute posttraumatic ascending myelopathy (SPAM) after the insertion of a syringosubarachnoid shunt for the treatment of slow-growing D10 syringomyelia.

Conclusion/Clinical Relevance: To date, no cases of SPAM secondary to the insertion of a syringosubarachnoid shunt for the treatment of syringomyelia have been reported. The potential pathogenesis related to this phenomenon is discussed.  相似文献   
45.
《Clinical neurophysiology》2020,131(7):1444-1452
ObjectiveTo investigate cognitive functions in non-demented patients with early-onset Parkinson's disease (PD), and to compare PARK2 gene mutation carriers and non-carriers by means of event-related brain potentials (ERPs).MethodsThe participants comprised patients with early-onset PD (EOPD) and healthy controls (HC). Patients with EOPD were divided into two groups as carriers of known pathogenic variants of PARK2 gene (EOPD-PC) and non-carriers of genes involved in familial PD (EOPD-NC). ERP data were collected during auditory oddball and visual continuous performance test (CPT).ResultsBoth EOPD groups (EOPD-PC and EOPD-NC) displayed reduced and delayed P3 in response to oddball target and CPT NoGo. CPT Go P3 was reduced in EOPD-NC but not in EOPD-PC. Oddball target N1 was reduced and P2 was enhanced in both EOPD-PC and EOPD-NC. In both cognitive tasks, RTs were prolonged and accuracy was lower in EOPD-PC and EOPD-NC.ConclusionsWe found several EOPD-related neurophysiologic changes, implying impairments in cognitive functions. Pairwise comparisons between EOPD-PC and EOPD-NC revealed no significant ERP marker.SignificanceIn this study, the confounding effect of normative aging was somewhat excluded compared with many previous studies. In contrast with the many oddball studies in non-demented PD, we clearly observed reduced and prolonged P3 in early-onset PD. Our NoGo P3 findings also contribute to the limited ERP research concerning response inhibition.  相似文献   
46.
目的探讨改良内固定融合术治疗成人Ⅱ型痛性足副舟骨(painful accessory navicular,PAN)的疗效。方法2016 年 1 月—2017 年 12 月,采用改良内固定融合术治疗 29 例(37 足)Ⅱ型 PAN。其中男 12 例,女 17 例;年龄 18~50 岁,平均 41.4 岁。扭伤 24 例,无明显诱因 5 例。患者均行 6 个月以上保守治疗,症状无明显改善。术前及末次随访时采用美国矫形足踝协会(AOFAS)中足评分评估临床疗效;X 线片测量跟骨倾斜角、距骨第 1 跖骨角、距舟关节包容角、距骨第 2 跖骨角。结果术后 1 例出现切口浅表感染,经加强换药后愈合;其余患者切口均Ⅰ期愈合,无深部感染或骨髓炎发生。29 例均获随访,随访时间 12~33 个月,平均 25.1 个月。X 线片示关节面均于术后 2~5 个月愈合,平均 3.4 个月。随访期间未见内固定物松动或断裂。末次随访时,AOFAS 疼痛、功能、力线评分及总分以及距舟关节包容角、距骨第 1 跖骨角和距骨第 2 跖骨角均较术前显著改善,差异有统计学意义(P<0.05);跟骨倾斜角手术前后差异无统计学意义(t=1.097,P=0.276)。 结论采用改良内固定融合术治疗成人Ⅱ型 PAN 可有效缓解症状,患足功能恢复良好,并发症少。  相似文献   
47.
Background: Extracellular matrix molecular components, previously linked to multisystem syndromes include collagens, fibrillins and laminins. Recently, we described a novel multisystem syndrome caused by the c.9418G>A p.(V3140M) mutation in the laminin alpha-5 (LAMA5) gene, which affects connective tissues of all organs and apparatus in a three generation family. In the same family, we have also reported a myopic trait, which, however, was linked to the Prolyl 4-hydroxylase subunit alpha-2 (P4HA2) gene. Results of investigation on vitreous changes and their pathogenesis are reported in the present study.Materials and Methods: Nineteen family individuals underwent complete ophthalmic examination including best-corrected visual acuity (BCVA), fundus examination, fundus photography, intraocular pressure measurement, axial length measurement using ocular biometry, Goldmann visual field examination, standard electroretinogram, SD-OCT. Segregation analysis of LAMA5 and P4HA2 mutations was performed in enrolled members.Results: The vitreous alterations fully segregated with LAMA5 mutation in both young and adult family members. Slight reduction of retinal thickness and peripheral retinal degeneration in only two patients were reported.Conclusions: In this work we showed that PVD is a common trait of LAMA5 multisystem syndrome, therefore occurring as an age-unrelated trait. We hypothesize that the p.(V3140M) mutation results in a reduction of retinal inner limiting membrane (ILM) stability, leading to a derangement in the macromolecular structure of the vitreous gel, and PVD. Further investigations will be necessary to elucidate the role of wild type and mutated LAMA5 in the pathogenesis of PVD.  相似文献   
48.
49.
50.
Objective Interferon-induced transmembrane protein 3(IFITM3) is an important member of the IFITM family. However, the molecular mechanisms underlying its antiviral action have not been completely elucidated. Recent studies on IFITM3, particularly those focused on innate antiviral defense mechanisms, have shown that IFITM3 affects the body's adaptive immune response. The aim of this study was to determine the contribution of IFITM3 proteins to immune control of influenza infection in vivo.Methods We performed proteomics, flow cytometry, and immunohistochemistry analysis and used bioinformatics tools to systematically compare and analyze the differences in natural killer(NK) cell numbers, their activation, and their immune function in the lungs of Ifitm3-/-and wild-type mice.Results Ifitm3-/-mice developed more severe inflammation and apoptotic responses compared to wild-type mice. Moreover, the NK cell activation was higher in the lungs of Ifitm3-/-mice during acute influenza infection.Conclusions Based on our results, we speculate that the NK cells are more readily activated in the absence of IFITM3, increasing mortality in Ifitm3-/-mice.  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