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   8465篇
  免费   453篇
  国内免费   55篇
耳鼻咽喉   90篇
儿科学   193篇
妇产科学   136篇
基础医学   1103篇
口腔科学   145篇
临床医学   576篇
内科学   2357篇
皮肤病学   133篇
神经病学   577篇
特种医学   444篇
外科学   1356篇
综合类   19篇
预防医学   289篇
眼科学   145篇
药学   566篇
中国医学   8篇
肿瘤学   836篇
  2023年   88篇
  2022年   168篇
  2021年   289篇
  2020年   139篇
  2019年   176篇
  2018年   233篇
  2017年   158篇
  2016年   196篇
  2015年   184篇
  2014年   244篇
  2013年   299篇
  2012年   461篇
  2011年   444篇
  2010年   230篇
  2009年   228篇
  2008年   412篇
  2007年   413篇
  2006年   363篇
  2005年   385篇
  2004年   351篇
  2003年   309篇
  2002年   269篇
  2001年   279篇
  2000年   271篇
  1999年   235篇
  1998年   93篇
  1997年   68篇
  1996年   77篇
  1995年   58篇
  1994年   53篇
  1993年   39篇
  1992年   151篇
  1991年   157篇
  1990年   155篇
  1989年   154篇
  1988年   126篇
  1987年   119篇
  1986年   131篇
  1985年   94篇
  1984年   95篇
  1983年   72篇
  1982年   36篇
  1981年   29篇
  1979年   48篇
  1978年   32篇
  1977年   35篇
  1974年   33篇
  1971年   31篇
  1970年   40篇
  1969年   29篇
排序方式: 共有8973条查询结果,搜索用时 14 毫秒
111.

Background Context

For patients diagnosed with lumbar central canal stenosis with asymptomatic foraminal stenosis (FS), surgeons occasionally only decompress central stenosis and preserve asymptomatic FS. These surgeries have the potential risk of converting preoperative asymptomatic FS into symptomatic FS postoperatively by accelerating spinal degeneration, which requires reoperation. However, little is known about delayed-onset symptomatic FS postoperatively.

Purpose

This study aimed to evaluate the rate of reoperation for delayed-onset symptomatic FS after lumbar central canal decompression in patients with preoperative asymptomatic FS, and determine the predictive risk factors of those reoperations.

Study Design

This study is a retrospective cohort study.

Patient Sample

Two hundred eight consecutive patients undergoing posterior central decompression for lumbar canal stenosis between January 2009 and June 2014 were included in this study.

Outcome Measures

The number of patients who had preoperative FS and the reoperation rate for delayed-onset symptomatic FS at the index levels were the outcome measures.

Methods

Patients were divided into two groups with and without preoperative asymptomatic FS at the decompressed levels. The baseline characteristics and revision rates for delayed-onset symptomatic FS were compared between the two groups. Predictive risk factors for such reoperations were determined using multivariate logistic regression and receiver operating characteristics analyses.

Results

Preoperatively, 118 patients (56.7%) had asymptomatic FS. Of those, 18 patients (15.3%) underwent reoperation for delayed-onset symptomatic FS at a mean of 1.9 years after the initial surgery. Posterior slip in neutral position and posterior extension-neutral translation were significant risk factors for reoperation due to FS. The optimal cutoff values of posterior slip in neutral position and posterior extension-neutral translation for predicting the occurrence of such reoperations were both 1?mm; 66.7% of patients who met both of these cutoff values had undergone reoperation.

Conclusions

This study demonstrated that 15.3% of patients with preoperative asymptomatic FS underwent reoperation for delayed-onset symptomatic FS at the index levels at a mean of 1.9 years after central decompression, and preoperative retrolisthesis was a predictive risk factor for such a reoperation. These findings are valuable for establishing standards of appropriate treatment strategies in patients with lumbar central canal stenosis with asymptomatic FS.  相似文献   
112.
This prospective randomized study was done to examine whether any difference in presentation of condyler lift-off exists between posterior cruciate-retaining and posterior-stabilized total knee arthroplasties. Fluoroscopic analysis of flexion kinematics under weightbearing condition was done for 18 patients who had bilateral paired total knee arthroplasties. The posterior cruciate-retaining and posterior-stabilized prostheses were from the same total knee arthroplasty series with comparable surface geometries and were implanted by one surgeon. At evaluation, five of 18 patients (28%) with posterior cruciate-retaining total knee arthroplasties had condylar lift-off, compared with 12 of 18 patients (67%) with posterior-stabilized total knee arthroplasties. Consequently, a significant difference in its incidence was seen between the groups. Condylar lift-off in posterior-stabilized knees was observed at various flexion angles, and one knee in this group had lift-off laterally and medially at different flexion angles. These findings raise concern that the higher incidence of condylar lift-off in posterior-stabilized total knee arthroplasty may lead to an increased wear rate of polyethylene associated with long-term prosthetic loosening.  相似文献   
113.
An in vivo comparison of flexion kinematics for posterior cruciate-retaining (PCR) and posterior stabilized (PS) total knee arthroplasty (TKA) was performed. Twenty patients who underwent bilateral paired TKAs were included in this prospective study. Both PCR and PS prostheses were from the same TKA series with comparable surface geometries, and all were implanted by a single surgeon. Of these 20 patients, 3-dimensional kinematics during flexion could be analyzed using a computer model fitting technique in 18 patients. The follow-up period ranged from 18 to 53 months. In the PCR TKA, an anterior femoral translation from 30 degrees to 60 degrees of flexion was observed in the weight-bearing condition. In contrast, flexion kinematics for the PS TKA was characterized by the maintenance of a constant contact position under weight-bearing conditions and posterior femoral rollback in passive flexion.  相似文献   
114.

Background

Postoperative hepatic insufficiency is a critical complication after extended hepatic resection in patients with biliary tract malignancies, the majority of whom suffer from obstructive jaundice. The aim of this study was to assess clinical parameters linked to this type of liver dysfunction.

Methods

A total of 111 patients were retrospectively reviewed. Patient background, pre- and intraoperative parameters, and a ratio of remnant liver volume/entire liver volume (RLV/ELV) as a volumetric parameter were compared between patients with and without postoperative hyperbilirubinemia and subsequent fatal outcome.

Results

Logistic regression indicated that only RLV/ELV ratio was an independent factor influencing postoperative hyperbilirubinemia, and RLV/ELV ratio and indocyanine green retention rate at 15 minutes (ICG-R15) were factors affecting survival. Patients with RLV/ELV less than 40% had 7.6 times the risk of postoperative hyperbilirubinemia, while no patients with RLV/ELV greater than 40% and ICG-R15 less than 25% died of liver failure.

Conclusions

The RLV/ELV ratio was the factor with the greatest impact on liver dysfunction after extended hepatectomy in patients with biliary tract malignancies.  相似文献   
115.
116.
Background  The purpose of this study was to evaluate surgical outcomes of arthroscopic débridement for lateral epicondylitis using a validated, patient-assessed scoring system as well as conventional outcome measures. We also wanted to identify potential predictive factors that may be associated with the outcomes. Methods  A total of 20 elbows in 18 patients with chronic lateral epicondylitis who underwent arthroscopic surgery were included. There were nine men and nine women with a mean age of 54 years (range 42–71 years). Operative treatment consisted of débridement of the extensor carpi radialis brevis (ECRB) origin and resection of the radiocapitellar synovial plica interposed in the joint. Outcomes were assessed using a patient rating, visual analogue scale (VAS) pain score, the Japanese Orthopaedic Association (JOA) elbow score, and the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire. The average length of follow-up was 28 months (range 24–40 months). Results  After surgery, according to the patients’ reports, 14 of 20 elbows were much better, and 6 elbows were better. A mean preoperative VAS pain score at rest of 3.9 points improved to 0.3 points (P < 0.0001), and that during activity improved from 7.8 points to 0.9 points (P < 0.0001). The mean preoperative JOA elbow score of 29 points was improved to 90 points (P < 0.0001). The mean postoperative DASH score was 10.6 (range 0–50). Absent of T2-weighted high signal focus of the ECRB origin on preoperative magnetic resonance imaging (MRI) (P = 0.02) and receiving public assistance (P = 0.01) were significantly associated with worse DASH scores. Conclusions  Arthroscopic release was a satisfactory procedure for chronic lateral epicondylitis. Preoperative MRI of the ECRB origin and socioeconomic factors were significantly associated with postoperative residual symptoms evaluated with the DASH score.  相似文献   
117.
118.
119.
BACKGROUND: A randomized, controlled clinical trial was conducted in 1991 to compare an intravenous megadose of methylprednisolone with a control drug (mecobalamin) for treating acute idiopathic optic neuritis. CASES: Sixty-six cases from 22 clinical centers throughout Japan were examined to evaluate the treatment on visual function parameters, such as visual acuity, visual field, color vision, contrast sensitivity, and critical flicker frequency. OBSERVATIONS: The methylprednisolone pulse treatment group showed faster recovery of visual function, particularly the visual acuity at 1 week (P<.05), Humphrey field analyzer mean deviation at 3 weeks (P<.05), and color vision at 1 week (P<.05). Recovery of contrast sensitivity at several different spatial frequencies was significant in the pulse treatment group at 1 (P<.01), 2 (P<.05), and 4 weeks (P<.05) after the start of treatment. Visual function test results at 12 weeks and 1 year were essentially the same in the two treatment groups. Side effects appeared more frequently in the pulse treatment group than in the control (P<.05). CONCLUSIONS: Pulse treatment does not appear effective for idiopathic optic neuritis even though visual function in the pulse treatment group of this trial recovered more quickly during the initial phase compared to the controls. More effective and specific treatment should be established for optic neuritis.  相似文献   
120.
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