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   21455篇
  免费   1298篇
  国内免费   974篇
耳鼻咽喉   447篇
儿科学   554篇
妇产科学   65篇
基础医学   1024篇
口腔科学   24篇
临床医学   2397篇
内科学   4429篇
皮肤病学   19篇
神经病学   1298篇
特种医学   1646篇
外科学   6317篇
综合类   2987篇
现状与发展   2篇
预防医学   396篇
眼科学   104篇
药学   851篇
  12篇
中国医学   927篇
肿瘤学   228篇
  2024年   62篇
  2023年   413篇
  2022年   591篇
  2021年   920篇
  2020年   903篇
  2019年   758篇
  2018年   830篇
  2017年   662篇
  2016年   733篇
  2015年   806篇
  2014年   1657篇
  2013年   1507篇
  2012年   1295篇
  2011年   1363篇
  2010年   1220篇
  2009年   1040篇
  2008年   958篇
  2007年   974篇
  2006年   921篇
  2005年   762篇
  2004年   667篇
  2003年   613篇
  2002年   483篇
  2001年   410篇
  2000年   353篇
  1999年   349篇
  1998年   290篇
  1997年   259篇
  1996年   228篇
  1995年   225篇
  1994年   192篇
  1993年   188篇
  1992年   159篇
  1991年   119篇
  1990年   93篇
  1989年   98篇
  1988年   84篇
  1987年   72篇
  1986年   65篇
  1985年   65篇
  1984年   59篇
  1983年   23篇
  1982年   66篇
  1981年   43篇
  1980年   39篇
  1979年   35篇
  1978年   21篇
  1977年   14篇
  1976年   13篇
  1973年   8篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Summary The prevalence of smoking, hypertension and diabetes mellitus was assessed in 221 patients suffering from internal carotid stenosis and compared with the prevalences in two sex- and age-matched control groups composed of subjects having normal Doppler findings and from non-neurological outpatients. Of the subjects with carotid stenosis 27.6% were hypertensive smokers in comparison with 9.5% and 17.2% in the two control groups. The difference of the stenosis cohort from the two control groups was significant (P<0.01 and P=0.016 respectively). There was no statistically significant differences between the occurrence of diabetes and hypertension in non-smokers and patients who smoked. In 394 investigated patients suffering from carotid stenosis or occlusion an obstruction index, based on the Doppler shift frequency, was calculated. This index was lowest in the normotentive non-smokers. It was only insignificantly higher in the hypertensive non-smokers but significantly so in the normotensive smokers. The index was highest in the hypertensive non-smokers. It was concluded that cigarette smoking, especially if associated with hypertension, is a determinant risk factor for carotid stenosis and occlusion.  相似文献   
42.
经皮穿刺髓核成形术治疗腰椎间盘突出症初步临床报道   总被引:36,自引:2,他引:34  
目的 寻求一种简单、安全、有效、微创的椎间盘突出症治疗方法。方法 对 1 6例腰椎间盘突出症采用经皮穿刺髓核成形术 (Nucleoplasty)治疗 ,并对其疗效进行观察分析。 结果 全部患者经二周至一个月短期随访 ,症状均有不同程度改善 ,疗效优良率为 93 8% ,有效率为 1 0 0 %。未发现明显并发症。结论 髓核成形术是一种先进、安全、有效的椎间盘突出微创手术 ,具有操作简单、安全、微创、疗效佳、恢复快、无需住院等优点。  相似文献   
43.
BACKGROUND CONTEXT: There is limited information describing the correlation between the initial quantitative measurements on magnetic resonance imaging (MRI) scans of disc herniation area, canal cross-section areas, percent canal compromise, and disc herniation location to the need for surgery. PURPOSE: Our aim is to determine if the size of disc herniation area, canal cross-section area, percent canal compromise, and disc herniation location taken from MRI images of patients with symptomatic single-level lumbar herniated intervertebral discs upon initial presentation to a spine surgeon, were predictive of the need for surgical treatment. STUDY DESIGN/SETTING: This is a retrospective case matched study of patient MRI images in the senior author's private practice. PATIENT SAMPLE: From a pool of 332 patients with sciatica caused by lumbar intervertebral disc herniations at our institution, 65 patients had surgery, of which MRI images were available and analyzed on 44 patients. Forty-four additional patients were randomly selected from the remaining 267 original group as nonoperative controls. METHODS: The axial MRI image showing the largest canal compromise by the herniated disc was selected for measurements. Using T1- and T2-weighted images, the areas of interest were digitally scanned at high resolution. The canal area and disc herniation area measurement were calculated from the total number of pixels per cross-sectional area, multiplied by a scan correction factor, mm(2) /pixel. Disc herniation locations were classified into either central or paracentral. The percent canal compromise was obtained by disc herniation area divided by canal cross-section area and multiplied by 100. RESULTS: The surgical group's overall mean herniated disc area was 219.6 square millimeter (mm(2)), 179.8 at L4-5, and 267.4 at L5-S1. The nonoperative group's overall mean herniated disc area was 178.4 mm(2), 135.1 at L2-3, 160.3 at L4-5, and 207.4 at L5-S1. The surgical group's overall mean canal cross-sectional area was 471.8 mm(2), 418.6 at L4-5, and 535.6 at L5-S1. The nonoperative group's overall mean canal cross-sectional area was 541.3 mm(2), 518.1 at L2-3, 446.8 at L4-5, and 669.9 at L5-S1. The overall percent canal compromise ratio in the surgery group was 46.7%, 44.1% at L4-5, and 49.8% at L5-S1. The overall percent canal compromise in the nonoperative group was 34.2%, 34.1% at L2-3, 36.1% at L4-5, and 31.8% at L5-S1. The percent canal compromise in central herniations at L4-5 level was 53.0% in the surgical group, and 32.8% in the nonoperative group; at the L5-S1 level surgical group percent canal compromise was 64.1% and in the nonoperative group canal compromise was 27%. L4-L5 level paracentral herniations canal compromise was 36.7% in the surgical group compared with 42.5% canal compromise in the nonoperative group. At the L5-S1 level the canal compromise was 45% in the surgical group and 34.8% in the nonoperative group. CONCLUSIONS: Our findings show a trend for patients treated with surgery to have larger disc herniation areas and smaller canal cross-section areas, corresponding to larger percent canal compromise than the nonoperative group. Centrally located herniations followed this trend closely at all levels studied. However, the paracentral herniation at the L4-5 level does not follow this trend, possibly because paracentral disc herniation clinical course is determined more by herniation location rather than the overall herniation size.  相似文献   
44.
45.
168例食管烧伤后瘢痕狭窄的预防和治疗   总被引:2,自引:0,他引:2  
目的 总结食管烧伤后瘢痕狭窄预防和治疗的经马命。方法 168例中158例进行了172次外科治疗,11例进行了2次以上手术。早期人院Ⅱ度期以上34例采用改良食管腔内置管预防食管烧伤后瘢痕,末切除瘢痕狭窄结肠重建77例,切除狭窄食管胃重建27例,颈阔肌皮瓣修复颈部食管狭窄22例,其他类型手术12例。结果 29例拔出支撑管后治愈(85%);5例再狭窄,其中1例扩张治愈。77例结肠重建术后5例死亡,颈部吻合口瘘14例,吻合口狭窄4例,腹部切口裂开2例。27例胃重建中,吻合口狭窄2例。脓胸1。颈阔肌皮瓣修复颈段狭窄22例中,3例发生颈部瘘。其他手术12例中,1例术后死于肠梗阻。所有生存出院患者均能进普食。 结论 管腔内置管能有效预防食管烧伤后瘢痕形成,根据瘢痕狭窄部位确定食管重建时是否切除狭窄食管。颈阔肌皮瓣是修复颈段食管狭窄或吻合口狭窄的优良方法。  相似文献   
46.
目的:观察喉罩全麻下行颈动脉狭窄的造影诊断及介入治疗术的临床效果。方法:择期DSA下颈动脉狭窄患者23例,年龄42-78岁,无明显肺部疾患及喉罩禁忌症患者,异丙酚(Pmpofol)泵入静脉全麻下插入喉罩完成手术,观察其不同时段的BP(MAP)、SpO2、HR、ECG(ST-Ⅱ)。结果:各时段的BP(MAP)、Sp02、HR、ECG(ST-Ⅱ)比较无显著性差异。结论:喉罩全麻在行颈动脉狭窄的造影诊断及介入治疗术的临床效果是肯定的。喉罩全麻颈动脉狭窄造影介入治疗  相似文献   
47.
高金亮 《实用骨科杂志》2007,13(9):528-529,576
目的探讨经后路椎间盘镜手术治疗合并腰椎管狭窄症的椎间盘突出症的临床应用。方法采用后路椎间盘镜进行单侧开窗减压术。通过术前标记腰椎正侧位片定位,于定位棘突间隙后正中偏患侧作长约1.5 cm小切口,逐级扩张后置入工作通道管,钻除部分椎板,置入内窥镜,于电视监视器下显露椎板、增生内聚的关节突、肥厚的黄韧带及突出的椎间盘髓核组织,彻底解除其对硬脊膜、神经根的压迫。结果本组共治疗合并腰椎管狭窄症的腰椎间盘突出症23例,平均随访7个月,按Prolo标准评定,治愈20例,有效2例,无效1例。结论本术式在严格掌握适应证前提下对合并腰椎管狭窄症的腰椎间盘突出症患者效果明显。  相似文献   
48.
64排螺旋CT冠状动脉造影与DSA的对照研究   总被引:1,自引:0,他引:1  
目的:通过和冠脉造影对比,评价64排螺旋CT冠状动脉成像在冠状动脉狭窄中的临床应用价值。方法:28例患者同时行64排螺旋CT冠状动脉成像和有创性冠脉造影检查,依据AHA17段分段法,评价所有有效节段,并将两者进行对比。结果:冠脉造影显示阴性病例占7.1%(2例),单只病变占21.4%(6例),多支病变占71.4%(20例)。按节段分析,CT检出冠脉狭窄的敏感度,特异度,阳性预测值和阴性预测值分别为91.1%,94.6%,90.0和95.3%。结论:64排螺旋CT冠状动脉成像和传统的冠脉造影检查对检出正常冠脉节段以及狭窄节段具有很好的一致性。  相似文献   
49.
腰椎后路非融合固定系统的临床应用   总被引:11,自引:1,他引:10  
郑应  谭明生 《中国骨伤》2007,20(4):283-285
复习腰椎后路非融合固定系统的设计原理、临床应用及治疗效果等相关文献,与传统的脊柱融合术相比,应用非融合系统可获得很好的疗效,并可以减少邻近节段退变的发生率。  相似文献   
50.
A prospective longitudinal study was performed to evaluate the vertebral body replacement system Synex associated with posterior fixation in unstable burst fractures of the lumbar and thoracic spine. Within 24 months, we treated 28 patients (average age, 41 years; range, 22–64 years; 14 women, 14 men) with acute unstable burst fractures without osteoporosis of the thoracolumbar region (n=16) and the thoracic (n=3) as well as the lumbar (n=9) spine in two stages (primary dorsal transpedicular stabilization and secondary vertebral body replacement). The complications were analyzed and the postoperative follow-up result was evaluated regarding stability, bone fusion, correction loss, pain and neurological status. One patient showed a transient irritation of the lumbosacral plexus and one patient had a superficial wound infection (complication rate, 7.1%). At the follow-up examination (mean follow-up, 13 months) only in two cases a minimal loss of correction (<5°) was measured. Radiologically, 27 patients showed secure bone fusions and all patients had stability of the osteosynthesis. Most of the patients stated no or just slight pain at follow-up. Only two patients with pain to a medium degree had to take painkillers. The vertebral body replacement system Synex seems to be a good alternative for vertebral body replacement in unstable burst fractures of the thoracic and lumbar spine since at present follow-up it shows a high rate of bone fusion and minimal loss of correction.  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