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   11393篇
  免费   672篇
  国内免费   690篇
耳鼻咽喉   54篇
儿科学   78篇
妇产科学   32篇
基础医学   640篇
口腔科学   16篇
临床医学   1501篇
内科学   339篇
皮肤病学   13篇
神经病学   486篇
特种医学   740篇
外科学   4525篇
综合类   2047篇
预防医学   377篇
眼科学   31篇
药学   703篇
  16篇
中国医学   986篇
肿瘤学   171篇
  2024年   76篇
  2023年   247篇
  2022年   359篇
  2021年   450篇
  2020年   451篇
  2019年   303篇
  2018年   320篇
  2017年   377篇
  2016年   403篇
  2015年   437篇
  2014年   964篇
  2013年   850篇
  2012年   879篇
  2011年   818篇
  2010年   788篇
  2009年   631篇
  2008年   526篇
  2007年   545篇
  2006年   489篇
  2005年   407篇
  2004年   379篇
  2003年   362篇
  2002年   252篇
  2001年   230篇
  2000年   148篇
  1999年   178篇
  1998年   120篇
  1997年   105篇
  1996年   91篇
  1995年   98篇
  1994年   85篇
  1993年   76篇
  1992年   47篇
  1991年   32篇
  1990年   21篇
  1989年   35篇
  1988年   26篇
  1987年   27篇
  1986年   30篇
  1985年   19篇
  1984年   11篇
  1983年   4篇
  1982年   14篇
  1981年   5篇
  1980年   9篇
  1979年   12篇
  1978年   4篇
  1977年   6篇
  1976年   3篇
  1971年   3篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
BACKGROUNDGuillain-Barré syndrome (GBS) is a rare disorder that typically presents with ascending weakness, pain, paraesthesias, and numbness, which mimic the findings in lumbar spinal stenosis. Here, we report a case of severe lumbar spinal stenosis combined with GBS.CASE SUMMARYA 70-year-old man with a history of lumbar spinal stenosis presented to our emergency department with severe lower back pain and lower extremity numbness. Magnetic resonance imaging confirmed the diagnosis of severe lumbar spinal stenosis. However, his symptoms did not improve postoperatively and he developed dysphagia and upper extremity numbness. An electromyogram was performed. Based on his symptoms, physical examination, and electromyogram, he was diagnosed with GBS. After 5 d of intravenous immunoglobulin (0.4 g/kg/d for 5 d) therapy, he gained 4/5 of strength in his upper and lower extremities and denied paraesthesias. He had regained 5/5 of strength in his extremities when he was discharged and had no symptoms during follow-up.CONCLUSIONGBS should be considered in the differential diagnosis of spinal disorder, even though magnetic resonance imaging shows severe lumbar spinal stenosis. This case highlights the importance of a careful diagnosis when a patient has a history of a disease and comes to the hospital with the same or similar symptoms.  相似文献   
2.
BackgroundOur meta-analysis from 2013 showed that inserting a catheter intrathecally after an observed accidental dural puncture can reduce the need for epidural blood patch in labouring women requesting epidural analgesia. We updated our conventional meta-analysis and added a trial-sequential analysis (TSA).MethodsA systematic literature search was conducted to identify studies that compared inserting the catheter intrathecally with an epidural catheter re-site or with no intervention. The extracted data were pooled and the risk ratio (RR) and 95% confidence interval (95%CI) for the incidence of post-dural puncture headache (PDPH) was calculated, using the random effects model. A contour-enhanced funnel plot was constructed. A TSA was performed and the cumulative Z score, monitoring and futility boundaries were constructed.ResultsOur search identified 13 studies, reporting on 1653 patients, with a low risk of bias. The RR for the incidence of PDPH was 0.82 (95%CI 0.71 to 0.95) and the RR for the need for epidural blood patch was 0.62 (95%CI 0.49 to 0.79); heterogeneity of both analyses was high. The TSA showed that the monitoring or futility boundaries were not crossed, indicating insufficient data to exclude a type I error of statistical analysis. Contour-enhanced funnel plots were symmetric, suggesting no publication bias.ConclusionsConventional meta-analyses showed for the first time that intrathecal catheterisation can reduce the incidence of PDPH. However, TSA did not corroborate this finding. Despite increasing use in clinical practice there is no firm evidence on which to base a definite conclusion.  相似文献   
3.
4.
5.

Background Context

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

Purpose

The present study aimed to evaluate the longitudinal revision rates following dynamic pedicle screw stabilization in the lumbar spine and to determine specific risk factors predictive for ASD, SL, and overall reoperation in a large cohort with considerable follow-up.

Design

We carried out a post hoc analysis of a prospectively collected database in a level I spine center.

Patients Example

The patient sample comprised 283 (151 female/132 male) consecutive patients suffering from painful degenerative lumbar segmental instability with or without spinal stenosis who underwent DS of the lumbar spine (Ulrich Cosmic, Ulrich Medical, Ulm, Germany) between January 2008 and December 2011.

Outcome Measures

Longitudinal reoperation rate and risk factors predictive for revision surgery were evaluated.

Methods

We analyzed the longitudinal reoperation rate due to ASD and SL and overall reoperation. Risk factors such as age, gender, body mass index, lumbar lordosis (LL), number of segments, and number of previous surgeries were taken into account. Regular and mixed model logistic regressions were performed to determine risk factors for revision surgery on a patient and on a screw level.

Results

The mean age was 65.7±10.2 years (range 31–88). One hundred thirty-two patients were stabilized in 1 segment, 134 in 2 segments, 15 in 3 segments, and 2 patients in 4 segments. Reoperation rate for ASD and SL after 1 year was 7.4 %, after 2 years was 15.0%, and after a mean follow-up of 51.4±15 months was 22.6%. Reasons for revision were SL in 19 cases (6.6%), ASD in 39 cases (13.7%), SL and ASD in 6 cases, hematoma in 2 cases (0.7%), cerebrospinal fluid fistulae in 3 cases (1.1%), infection in 6 cases (2.1%), and implant failure in 1 case (0.4%). The patients' age, the number of stabilized segments, and the number of previous surgeries and postoperative LL had a significant influence on the probability for revision surgery.

Conclusions

Reoperation rates after DS of the lumbar spine are comparable with rigid fixations. The younger the patient and the more segments are involved, the lower the LL and the more previous surgeries were found, the higher was the risk of revision. Risk of revision was almost twice as high in men compared with women. We therefore conclude that for clear clinical indication and careful evaluation of preoperative imaging data, DS using the Cosmic system seems to be a possible option. The presented data will help to further tailor indication and patient selection.  相似文献   
6.
7.
Ewing sarcoma (ES) is a rare primary neoplasm in the lumbar adult spine and may mimic a benign tumor. In this case, after a patient's three-month history of lower back pain and rapidly progressing leg numbness and weakness, magnetic resonance imaging (MRI) showed a mass in the third lumbar vertebra. At a two-month follow-up, imaging showed a fracture, compression and lesion enlargement. Decompression and fixation confirmed ES, and the patient began combined radiotherapy and chemotherapy. Two months postoperatively, residual ES was suspected on MRI. The patient underwent a second surgery, and histopathology confirmed necrosis. A six-month follow-up after the first surgery showed no tumor recurrence. This case supports the inclusion of ES in the differential diagnosis of pathologic spinal fracture. Early decompression and spinal fixation are critical for preserving neurologic and spinal functions in ES complicated by a compression fracture. Combined adjuvant radiotherapy and chemotherapy remain the standard therapeutic strategy.  相似文献   
8.
IntroductionDural puncture epidural (DPE) analgesia is a modification of conventional epidural analgesia that involves the intentional puncture of the dura with a spinal needle through the needle placed in the epidural space, without a medication being injected intrathecally. There have been contradictory findings regarding better analgesia and better block quality.MethodsA systematic literature search was done to identify randomized controlled trials (RCT) comparing DPE with epidural analgesia. The risk of bias was assessed with the Cochrane tool. Risk ratio and 95% confidence intervals were calculated.ResultsFive RCTs including 581 patients were identified. One RCT on caesarean section was excluded. Single studies suggested slightly better analgesia by finding a median time to achieve sufficient analgesia of two minutes less in the DPE group, a higher number of women having a pain score <10/100 at 20 min, a reduction in the number of epidural top-ups and better sacral spread. The studies did not show a difference between DPE and epidural analgesia for catheter replacement or manipulation rates, the incidence of intravascular placement or unilateral block.ConclusionThere is a lack of clear evidence on either the benefits or the risks of the DPE technique, such that a recommendation for or against its routine use is premature. Two of the three studies showing a beneficial effect of DPE came from the same institution and replication of the findings by other groups is warranted.  相似文献   
9.
目的:分析针刀与针灸配合应用于腰椎间盘突出症患者中的临床治疗效果。方法:在我院针灸康复科2017年12月-2018年12月治疗的腰椎间盘突出症患者中选取64例,并严格按照系统随机分配原则分为对照组和观察组,各32例。其中对照组采用针灸进行治疗,观察组采用针刀与针灸配合治疗,观察对比两组患者治疗后临床效果和治疗前后运动功能评分(Fugl-Meyer)、腰椎日本骨科学会(Japanese Orthopaedic Association,JOA)评分、视觉模拟评分法(Visual Analogue Scale,VAS)评分以及临床症状改善情况。结果:两组患者治疗前Fugl-Meyer、VAS、JOA评分差异无统计学意义(P>0.05),治疗后对照组VAS评分高于观察组,Fugl-Meyer、JOA评分低于观察组,且对照组总有效率低于观察组,对照组腰骶疼痛评分和腿疼痛评分均低于观察组,直腿抬高度高于观察组,差异具有统计学意义(P<0.05)。结论:予以腰椎间盘突出症患者针刀与针灸配合治疗效果显著,效果优于单一使用针灸治疗,可有效缓解患者疼痛感,改善临床症状,值得推广。  相似文献   
10.
目的:探讨椎管扩大成形术治疗腰椎管狭窄的效果。方法:椎板减压后复位,用棘突或髂骨植于一侧开槽处扩大椎管,并进行椎板及关节突关节植骨,对54例随访病人的手术前后临床表现及X线和CT进行比较。结果:随访6—39个月,临床优良率为81.1%。随访X线片显示椎板明显后移,CT测量与术前对比显示椎管内径扩大明显。结论:椎管扩大成形术操作简单,效果满意,术后并发症少,是治疗腰椎管狭窄的又一选择。  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