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   2847篇
  免费   189篇
  国内免费   61篇
耳鼻咽喉   66篇
儿科学   35篇
妇产科学   28篇
基础医学   320篇
口腔科学   54篇
临床医学   265篇
内科学   571篇
皮肤病学   100篇
神经病学   270篇
特种医学   94篇
外科学   621篇
综合类   328篇
预防医学   73篇
眼科学   36篇
药学   127篇
  3篇
中国医学   70篇
肿瘤学   36篇
  2024年   6篇
  2023年   41篇
  2022年   104篇
  2021年   115篇
  2020年   87篇
  2019年   73篇
  2018年   72篇
  2017年   83篇
  2016年   114篇
  2015年   126篇
  2014年   226篇
  2013年   184篇
  2012年   171篇
  2011年   189篇
  2010年   129篇
  2009年   130篇
  2008年   145篇
  2007年   126篇
  2006年   121篇
  2005年   109篇
  2004年   70篇
  2003年   70篇
  2002年   67篇
  2001年   45篇
  2000年   34篇
  1999年   47篇
  1998年   38篇
  1997年   32篇
  1996年   22篇
  1995年   38篇
  1994年   20篇
  1993年   25篇
  1992年   21篇
  1991年   25篇
  1990年   19篇
  1989年   17篇
  1988年   15篇
  1987年   15篇
  1986年   9篇
  1985年   25篇
  1984年   21篇
  1983年   8篇
  1982年   11篇
  1981年   6篇
  1980年   13篇
  1979年   9篇
  1978年   4篇
  1977年   4篇
  1975年   4篇
  1973年   4篇
排序方式: 共有3097条查询结果,搜索用时 15 毫秒
101.
Endoscopic detection of early upper GI cancers   总被引:3,自引:0,他引:3  
The detection of early-stage neoplastic lesions in the upper GI tract is associated with improved survival and the potential for complete endoscopic resection that is minimally invasive and less morbid than surgery. Despite technological advances in standard white-light endoscopy, the ability of the endoscopist to reliably detect dysplastic and early cancerous changes in the upper GI tract remains limited. In conditions such as Barrett's oesophagus, practice guidelines recommend periodic endoscopic surveillance with multiple biopsies, a methodology that is hindered by random sampling error, inconsistent histopathological interpretation, and delay in diagnosis. Early detection may be enhanced by several promising diagnostic modalities such as chromoendoscopy, magnification endoscopy, and optical spectroscopic/imaging techniques, as these modalities offer the potential to identify in real-time lesions that are inconspicuous under conventional endoscopy. The combination of novel diagnostic techniques and local endoscopic therapies will provide the endoscopist with much needed tools that can considerably enhance the detection and management of early stage lesions in the upper GI tract.  相似文献   
102.
Cathepsin is a typical and well-characterized lysosomal cysteine protease that, under pathological conditions, is involved in tissue destruction. A recent immunocytochemical study demonstrated that cathepsins B (CAB) and L (CAL) were localized in the periodontal ligament (PDL) of the rat molar, and they were expressed in compressed sites during experimental tooth movement. Further, we demonstrated previously that the levels of CAB and CAL in gingival crevicular fluid increased during orthodontic tooth movement. Therefore, CAB and CAL may play important roles in the process of collagen degradation during orthodontic tooth movement, and our in vitro study examined the secretion of CAB and CAL in PDL cells following mechanical stress. PDL cells were subjected to 0.5, 1.0, 2.0, or 3.0 g/cm2 of compression force or an increase in surface area by tension force of 0.28%, 0.95%, 1.72%, or 2.50% for 24 hr. For detection of CAB and CAL in conditioned medium, commercially available ELISA kits were used. We found compression and tension significantly increased the secretions of both CAB and CAL in PDL cells, which were exhibited in a time- and force magnitude-dependent manner. The compression-stimulated secretion of CAB was increased approximately 3-fold and that of CAL 4-fold, as compared with the control. Further, tension-stimulated secretion of CAB was increased by 1.5-fold and that of CAL 2-fold compared with the control. When analyzed using a semiquantitative polymerase chain reaction assay, CAB and CAL mRNA were increased in response to both compression and tension forces. These findings demonstrated that mechanical stress (compression and tension forces) causes an increase in secretion of CAB and CAL in PDL cells in vitro.  相似文献   
103.
《Clinical neurophysiology》2021,132(9):2152-2162
ObjectiveChildren diagnosed with auditory processing disorder (APD) show deficits in processing complex sounds that are associated with difficulties in higher-order language, learning, cognitive, and communicative functions. Amblyaudia (AMB) is a subcategory of APD characterized by abnormally large ear asymmetries in dichotic listening tasks.MethodsHere, we examined frequency-specific neural oscillations and functional connectivity via high-density electroencephalography (EEG) in children with and without AMB during passive listening of nonspeech stimuli.ResultsTime-frequency maps of these “brain rhythms” revealed stronger phase-locked beta-gamma (~35 Hz) oscillations in AMB participants within bilateral auditory cortex for sounds presented to the right ear, suggesting a hypersynchronization and imbalance of auditory neural activity. Brain-behavior correlations revealed neural asymmetries in cortical responses predicted the larger than normal right-ear advantage seen in participants with AMB. Additionally, we found weaker functional connectivity in the AMB group from right to left auditory cortex, despite their stronger neural responses overall.ConclusionOur results reveal abnormally large auditory sensory encoding and an imbalance in communication between cerebral hemispheres (ipsi- to -contralateral signaling) in AMB.SignificanceThese neurophysiological changes might lead to the functionally poorer behavioral capacity to integrate information between the two ears in children with AMB.  相似文献   
104.
The juncturae tendinum and sagittal bands transmit precise forces through the dorsum of the hand. Both structures are integral in the mechanics of normal digital extension and in stabilization of the metacarpophalangeal (MCP) joints. Extensor tendon injury, or rupture/attenuation of sagittal bands and/or juncturae tendinum, may disrupt the kinematic chain and lead to a number of abnormal hand postures and motions. Early treatment of extensor tendon and/or sagittal band injury is dependent upon proper recognition of primary pathology. Proper evaluation and the use of special clinical tests should be implemented to rule out other pathologies. Once diagnosed, treatment may consist of relative motion splinting and standard pain/edema control measures to increase joint motion, tendon excursion, and functional use of the hand.  相似文献   
105.
Based on quantitative analysis of red cell membrane proteins, hereditary spherocytosis (HS) can be divided into two main groups including isolated or ankyrin combined spectrin deficiency and band 3 reduction. Protein methyl esterification catalysed by protein carboxyl methyltransferase (PCMT type II; EC 2.1.1.77) is a post-biosynthetic modification which is involved in the metabolism of damaged membrane proteins. We utilized the evaluation of erythrocyte membrane protein methyl esterification as a marker of cytoskeletal disarray in seven HS subjects with spectrin reduction and in seven patients with HS due to band 3 deficiency. Our results support the notion that band 3 deficient erythrocytes are not affected by an extensive cytoskeletal derangement. On the contrary, we found a remarkable increase of membrane methylation in the unsplenectomized, spectrin-deficient, HS patients, suggesting a striking membrane skeleton disarray. This phenomenon was not observed in the spectrin-deficient red cells of splenectomized patients. Therefore in spectrin deficient erythrocytes the induction of cytoskeletal damage, specifically recognized by PCMT type II, could be one of the splenic steps producing conditioned spherocytes.  相似文献   
106.
107.
108.
<正>2010年1月~2013年12月,我科采用空心钉张力带固定治疗43例髌骨骨折患者,取得良好疗效,报道如下。1材料与方法1.1病例资料本组43例,男31例,女12例,年龄20~65岁。均为闭合横形髌骨骨折。1.2手术方法腰麻或硬膜外麻醉。髌骨前方纵行切口,复位髌骨,用布巾钳临时固定,在髌骨中内、中外1/3处分别钻入2枚克氏针,距关节面约3 mm,C  相似文献   
109.
目的观察自制自制踝足矫形带对痉挛型偏瘫脑瘫足下垂患儿下肢运动功能的疗效。方法 24例痉挛型偏瘫脑瘫足下垂患儿随机分为观察组和对照组各12例。两组患儿均行常规康复训练,对照组行步态训练,观察组佩戴自制踝足矫形带行步态训练,共12周。治疗前后分别采用腓肠肌改良Ashworth量表(MAS)、踝关节主动背屈活动度(ROM)和粗大运动功能测量(GMFM-88)D区(站立)、E区(走跑跳)进行评定。结果治疗后,两组MAS评分明显降低(P0.01),观察组低于对照组(P0.05);两组ROM、GMFM-88的D区和E区评分均明显高于治疗前(P0.01),观察组高于对照组(P0.05)。结论佩戴自制踝足矫形带行步态训练能进一步降低痉挛型偏瘫脑瘫患儿患侧的腓肠肌张力,增加踝关节活动度,提高下肢运动功能。  相似文献   
110.
目的 探讨医用钛缆张力带在髌骨骨折中的应用价值.方法 2009年10月至2012年12月102例髌骨骨折,均遵循张力带原则,行环扎加"8"字张力带内固定术治疗,根据内固定材料分成医用钛缆组和带针钢丝组.比较两组术后首次锻炼时间、住院时间、医疗费用、并发症及远期膝关节功能情况.结果 102例患者术后随访10周~8个月,末次随访时骨折均达骨性愈合标准.两组患者在术后首次锻炼时间、住院时间方面无明显差异.医用钛缆组费用较高.医用钛缆组在并发症及远期膝关节功能上优于带针钢丝组.结论 医用钛缆在行张力带内固定治疗髌骨骨折具有内固定坚强、便于术后早期功能锻炼,弥补带针钢丝内固定强度不足的缺点.  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