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   8524篇
  免费   472篇
  国内免费   255篇
耳鼻咽喉   47篇
儿科学   16篇
妇产科学   102篇
基础医学   1020篇
口腔科学   1449篇
临床医学   712篇
内科学   130篇
皮肤病学   3篇
神经病学   105篇
特种医学   1219篇
外科学   3192篇
综合类   812篇
预防医学   94篇
眼科学   37篇
药学   189篇
  3篇
中国医学   71篇
肿瘤学   50篇
  2024年   18篇
  2023年   143篇
  2022年   324篇
  2021年   430篇
  2020年   358篇
  2019年   285篇
  2018年   360篇
  2017年   359篇
  2016年   334篇
  2015年   275篇
  2014年   540篇
  2013年   621篇
  2012年   495篇
  2011年   527篇
  2010年   395篇
  2009年   490篇
  2008年   525篇
  2007年   459篇
  2006年   355篇
  2005年   267篇
  2004年   241篇
  2003年   222篇
  2002年   158篇
  2001年   149篇
  2000年   115篇
  1999年   131篇
  1998年   117篇
  1997年   90篇
  1996年   92篇
  1995年   57篇
  1994年   46篇
  1993年   35篇
  1992年   55篇
  1991年   27篇
  1990年   18篇
  1989年   17篇
  1988年   12篇
  1987年   9篇
  1986年   18篇
  1985年   17篇
  1984年   13篇
  1983年   9篇
  1982年   13篇
  1981年   8篇
  1980年   7篇
  1979年   3篇
  1977年   2篇
  1976年   2篇
  1975年   4篇
  1974年   2篇
排序方式: 共有9251条查询结果,搜索用时 390 毫秒
111.
目的探讨内侧髌股韧带重建治疗复发性髌骨脱位的临床效果。方法回顾性分析湖北省荆州市中心医院2017年1月至2019年6月通过关节镜辅助下内侧髌股韧带双束重建治疗的29例复发性髌骨脱位患者的临床资料。其中,男10例,女19例,年龄14.0~29.5岁,平均19.4岁。测量TT-TG距离、髌骨倾斜角,计算Caton指数。术前、术后通过Kujala、Lysholm评分评价膝关节功能。结果所有患者均获得随访,随访时间12~36个月,术前TT-TG距离均小于20 mm、髌骨倾斜角小于20°,Caton指数0.9~1.1。所有患者术后均未见脱位复发,术前术后Kujala评分分别为(51.32±5.52)分、(82.45±3.38)分;术前、术后Lysholm评分分别为(53.25±5.85)分、(89.65±4.75)分;术前、术后髌骨倾斜角为13.15°±1.67°,6.94°±1.47°。差异均具有统计学意义(P<0.05)。结论关节镜辅助下内侧髌股韧带双束重建治疗无严重骨性异常的复发性髌骨脱位,操作简单,疗效确切,并发症少,近期随访无复发,可以显著提高膝关节功能。  相似文献   
112.
下胫腓联合分离内固定术式的生物力学研究   总被引:2,自引:0,他引:2  
目的 探讨下胫腓联合分离采用新型内固定术式———下胫腓钩板固定器 (Hook -platefixation ,HPF)的生物力学特性 ,与螺钉、钢板和带钩固定器三种内固定方式比较 ,为临床提供科学依据。方法 采用新鲜成人尸体足标本 6具 ,运用生物力学实验应力分析方法和压敏片技术 ,测量不同内固定术式的远端胫腓骨强度、应变、负重面积、接触应力和足弓承载能力及踝关节稳定性的变化。结果 新型下胫腓钩板固定器内固定术式无论在胫腓骨强度和刚度、负重面积、接触压力、足弓的变形、移位强度和刚度、承载能力以及踝关节的稳定性方面均优于其它三种内固定术式 ,具有显著性差异 (P <0 .0 1)。结论 实验结果表明 ,采用下胫腓钩板固定器 (HPF) ,既有利于提高生物力学性能 ,又有利于改善踝关节的稳定性 ,与传统手术方式相比可减少一次手术 ,避免了断钉等并发症 ,且能有效地提高足部承载能力 ,是下胫腓联合分离内固定的一种优良术式  相似文献   
113.
正常踝关节内、外侧韧带的解剖及其影像学表现   总被引:1,自引:0,他引:1  
目的:探讨正常踝关节内、外侧韧带的解剖形态及其MRI和CT表现。方法:6例正常人踝关节新鲜标本MRI扫描,解剖显示内、外侧韧带后,CT断层扫描与MRI对照观察踝关节内、外侧韧带的影像学表现;在30例正常志愿者踝关节的MRI上测量内、外韧带的宽度及厚度。结果:MRI横断面及冠状面可充分显示踝关节内、外侧韧带及其周围组织的解剖结构;踝关节内、外侧韧带在冠状面及横断面上所测的宽、厚度,男女间存在一定的差异。结论:MRI能清晰地显示踝关节的解剖结构,所测量的正常踝关节内、外侧韧带的宽、厚度数据,为临床诊断踝关节内、外侧韧带的病变提供了形态学依据。  相似文献   
114.
Though a number of studies have reported the presence of synapses on neurons in the trigeminal mesencephalic nucleus (Vmes), there have been no quantitative studies of either the density of innervation, or the ultrastructure, of the synapses on single, physiologically identified neurons in this nucleus. In this study we recorded from single neurons in the Vmes, identified them as being either muscle spindle afferents (MS) or periodontal ligament mechanoreceptor afferents (PL), and then labeled the neurons by intra-axonal injection of horseradish peroxidase (HRP). The material was first processed to reveal the HRP activity, following which ultrathin sections through the labeled somata were cut and examined under the electron microscope. Complete serial reconstructions were made through the soma of one MS neuron and one PL neuron, and the contacts on the neurons reconstructed. Boutons were found on the soma, spines, appendages and the axon hillock and the initial segment of the axon. The numbers of boutons terminating on the two neurons were 198 (PL) and 424 (MS), giving a packing density of 4.4 and 10.7 boutons respectively (i.e., number of boutons/100 micron 2 of the postsynaptic membrane). Boutons could be separated into two types on the basis of their vesicles: those containing clear, round vesicles (i.e., S-type) and those containing a mixture of round, oval and flattened vesicles (P-type). Ninety-five (PL neuron) and 99% (MS neuron) of terminals on the two neurons were P-type. All the S-type boutons and 80% of the P-type boutons formed asymmetric synaptic contacts while 10% of the P-type boutons made symmetric contacts. Quantitative measurements of the P-type boutons on the labeled neurons, in which the data of MS and PL neurons were pooled, revealed that bouton volume was highly correlated with bouton surface area, active zone number, total active zone area, vesicle number, and mitochondrial volume. However, comparing the quantitative measurements of the P-type boutons with those of previously reported vibrissa afferent terminals and their associated axon terminals revealed that all the parameters were smaller for the P-type boutons (on Vmes neurons) than those of the vibrissa afferent terminals but similar to those of axon terminals presynaptic to the vibrissa afferents. Taken together, our results emphasize the wide scope for synaptic interactions in the Vmes and suggest that it may be more fruitful to view the Vmes as an integrating center.  相似文献   
115.
掌指关节的三维解剖及形态分析   总被引:2,自引:0,他引:2  
目的:观测掌指关节关节面的几何形态,为人工关节的设计和应用提供解剖学依据。方法:10只成人手标本,解剖掌指关节,测量侧副韧带起点距掌骨头关节面的直线距离,三维数据检测仪获得关节面三维坐标数据,应用SPSS软件进行统计分析和成像。结果:掌骨头有双髁结构,桡侧髁略大,第1掌骨头形态特殊;各掌骨头高度的比较无显著差异;其掌侧关节面大于背侧,第2、3掌骨头关节面面积明显较大。近节指骨底在形态、高度和面积方面各序列相似;各序列侧副韧带起点桡侧较尺侧距离掌骨头关节面远。结论:手指人工关节的设计应符合解剖形态,并根据各序列形态的差异进行个体化设计,尤其拇指更应区别对待;手指人工关节的设计和应用中应注意软组织保护,关节的切除范围应注意保留侧副韧带的起止点。  相似文献   
116.
Summary Integrated surface electromyograms of the three superficial parts of the quadriceps and isokinetic knee extensor maximum torque and power production were recorded simultaneously and at different angular velocities in both legs in 11 male subjects with unilateral tear of the anterior cruciate ligament. The cross-sectional area (CSA) of the thigh and its muscular components were measured by computerized tomography. The principal findings were a small but significant decrease in quadriceps CSA on the affected side; a decreased active, but not passive, range of movement; decreased mechanical output, whether or not corrected for differences in CSA; and decreased electrornyographic activity — particularly in rectus femoris. These findings suggest that the reason for the decreased maximum and total knee extensor performance seen in these patients is a change in knee joint receptor afferent inflow.  相似文献   
117.
The anatomy of the suprascapular nerve is important to surgeons when focal nerve lesions necessitate surgical repair. Recent experience with a patient who had a complete suprascapular nerve lesion in the retroclavicular region (combined with axillary and musculocutaneous nerve lesions) is presented to illustrate that successful direct nerve repair is possible despite resection of a neuroma. Specifically, we found that neurolysis and mobilization of the suprascapular nerve and release of the superior transverse scapular ligament provided the necessary nerve length to achieve direct nerve repair after the neuroma was removed. A combined supraclavicular and infraclavicular approach to the suprascapular nerve provided excellent visualization, especially in the retroclavicular region. Postoperatively, the patient recovered complete shoulder abduction and external rotation with the direct repair, an outcome uncommonly achieved with interpositional grafting. Based on our operative experience, we set out to quantify the length that the suprascapular nerve could be mobilized with neurolysis. Mobilization of the nerve and release of the superior transverse scapular ligament generated an average of 1.6 cm and 0.7 cm of extra nerve length respectively, totaling 2.3 cm of additional usable nerve length overall. The ability to expose the suprascapular nerve in the retroclavicular/infraclavicular region and to mobilize the suprascapular nerve for possible direct repair has not been previously emphasized and is clinically important. This surgical approach and technique permits direct nerve repair after resection of a focal neuroma in the retroclavicular or infraclavicular region, thus avoiding interpositional grafting, and improving outcomes.  相似文献   
118.
基于美国BRG公司的运动及动力学仿真分析软件LifeMOD,建立包括股骨、胫骨、腓骨、4条主要韧带及肌肉在内的较完整的膝关节动力学模型,并用该模型模拟了人体下肢在平地行走时膝关节的动力学行为以及前交叉韧带缺损对膝关节接触力大小的影响。通过动力学分析,得到人体在平地行走时,胫股关节之间最大的接触力值为2645N,最大韧带张力为590N,发生在内侧副韧带上;当胫股关节之间的滑动受到限制时,最大的韧带张力发生在前交叉韧带上,为560N,研究结果与文献较接近。通过动力学模拟,可以得出结论:胫股关节之间的滑动对韧带张力有较大影响;前交叉韧带缺损使得胫股关节之间的接触力变小。  相似文献   
119.

Background

Several investigations have studied gait variability of individuals with anterior cruciate ligament (ACL) deficiency; however, the effect of dual-tasking on the gait variability of these individuals remained unclear. The aim of the present study was to determine the effect of gait speed and dual-tasking on knee flexion–extension variability in subjects with and without ACL deficiency.

Methods

The knee flexion–extension Lyapunov exponent (LyE) was measured in 22 ACL-deficient (Mean±SD) (25.95?±?4.69?years) and 22 healthy subjects (24.18?±?3.32?years). They walked at three levels of gait speed in isolation or concurrently with a cognitive task.

Results

Repeated-measure analyses of variance (ANOVAs) demonstrated that the interaction of group by gait speed was statistically significant. As the gait speed increased from low to high, the knee flexion–extension LyE significantly decreased for the subjects with ACL deficiency (effect size: 0.57, P?=?0.01). The interaction of group by cognitive load was not statistically significant (P?=?0.07). In addition, the ACL-deficient subjects had statistically slower reaction times than healthy subjects during the dual-task compared with the single-task condition.

Conclusions

The ACL-deficient and healthy individuals had a tendency to maintain safe gait. It seems that the ACL-deficient subjects sacrificed the cognitive task more than the healthy individuals to pay more attention toward gait. Additionally, it seems that the gait speed was more challenging than cognitive load on the stride-to-stride variability in the individuals with ACL deficiency.  相似文献   
120.
目的:探讨颈前路椎体次全切治疗颈椎后纵韧带骨化的手术减压范围。方法:采用前路椎体次全切植骨融合术治疗颈椎后纵韧带骨化56例,其中完全切除骨化者47例,用“漂浮法”处理者9例,并针对不同个体及病变特点采用不同的减压范围。结果:54例获得3个月-6a随访,平均28个月。植骨均于术后3-5个月内获得骨性融合。JOA评分由术前8.5分提高到术后14.1,平均改善率74%,优良率80.2%。结论:行椎体次全切术治疗颈椎后纵韧带骨化时应针对不同个体及病变特点采用不同的足够的减压范围,可以减少并发症,并获得较佳的疗效。  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