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   2561篇
  免费   79篇
  国内免费   19篇
耳鼻咽喉   133篇
儿科学   124篇
妇产科学   99篇
基础医学   175篇
口腔科学   180篇
临床医学   185篇
内科学   502篇
皮肤病学   21篇
神经病学   174篇
特种医学   111篇
外科学   512篇
综合类   36篇
一般理论   1篇
预防医学   61篇
眼科学   119篇
药学   106篇
中国医学   30篇
肿瘤学   90篇
  2024年   1篇
  2023年   21篇
  2022年   29篇
  2021年   44篇
  2020年   39篇
  2019年   41篇
  2018年   57篇
  2017年   43篇
  2016年   56篇
  2015年   71篇
  2014年   77篇
  2013年   125篇
  2012年   199篇
  2011年   197篇
  2010年   131篇
  2009年   120篇
  2008年   187篇
  2007年   185篇
  2006年   192篇
  2005年   178篇
  2004年   185篇
  2003年   181篇
  2002年   115篇
  2001年   44篇
  2000年   28篇
  1999年   15篇
  1998年   14篇
  1997年   12篇
  1996年   13篇
  1995年   9篇
  1994年   8篇
  1993年   6篇
  1992年   4篇
  1991年   4篇
  1990年   7篇
  1989年   2篇
  1985年   2篇
  1984年   3篇
  1983年   3篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1974年   1篇
  1962年   1篇
  1961年   1篇
  1959年   1篇
排序方式: 共有2659条查询结果,搜索用时 15 毫秒
11.

Background/Purpose

Development of indirect inguinal hernia and hydrocele in childhood is readily explained by the persistence of smooth muscle component around the processus vaginalis (PV) after the descent of the testis into the scrotum. The aim of this study was to investigate the expression of smooth muscle myosin heavy chain (SM MHC) isoforms as the markers of smooth muscle cell (SMC) differentiation in childhood inguinal hernia and hydrocele and in age-matched controls.

Methods

The authors analyzed sacs from patients with inguinal hernia (male, 10; female, 10) and hydrocele (n = 10) immunohistochemically using monoclonal antibodies against α-smooth muscle actin, SM1, SM2 and SMemb. Peritoneal samples (male, 5; female, 5) obtained from age-matched patients served as controls. Immunostaining was evaluated with semiquantitative scoring and χ2 test.

Results

The expression pattern of SM MHC isoforms did not differ among sacs obtained from female inguinal hernia when compared with that of controls. However, strong expression of SMemb within the sac walls of male inguinal hernia and SM1 in hydrocele groups were observed.

Conclusions

Our results indicate that SMC differentiation may play an important role in the obliteration of processus vaginalis in male inguinal hernia and hydrocele after the descent of the testis.  相似文献   
12.
INTRODUCTIONSymtomatic lumbar ligamantum flavum calcification is quite rare in the young age group.PRESENTATION OF CASEThe authors report a case of young adult with diagnosis of lumbar spinal stenosis, presenting with leg pain and neurological deficits. Computerized tomography (CT) scan and magnetic resonance (MR) imaging studies revealed ossification of the ligamantum flavum as the causative factor of the disease and the patient recovered completely after the decompressive operation.DISCUSSIONIt is emphasized that attention should be given to this rare etiological factor of lumbar spinal stenosis.CONCLUSIONComplete relief can be achieved with early and adequate surgery.  相似文献   
13.
14.
Salvage total hip arthroplasty (THA) presents a viable solution for failed open reduction internal fixation. This study compares salvage THA in patients with prior femoral neck fractures vs patients with prior intertrochanteric fractures. One hundred fifty-four hips in 152 patients underwent conversion from open reduction internal fixation to THA. Eighty-three patients had previous femoral neck fractures, and 69 patients (71 hips) had prior intertrochanteric fractures. Salvage THA in patients with prior intertrochanteric fractures presented a more technically demanding procedure with longer operative times and larger amounts of blood loss. Although conversion THA presents a technically challenging procedure, it is safe and yields relatively few orthopedic complications.  相似文献   
15.
16.

Background

Although recent studies have shown the feasibility and safety of robotic adrenalectomy, an advantage over the laparoscopic approach has not been demonstrated. Our hypothesis was that the use of the robot would facilitate minimally invasive resection of large adrenal tumors.

Methods

Adrenal tumors ??5?cm resected robotically were compared with those removed laparoscopically from a prospective institutional review board-approved adrenal database. Clinical and perioperative parameters were analyzed using t and chi-square tests. All data are expressed as mean?±?standard error of mean.

Results

There were 24 patients with 25 tumors in the robotic group and 38 patients with 38 tumors in the laparoscopic group. Tumor size was similar in both groups (6.5?±?0.4 [robotic] vs 6.2?±?0.3?cm [laparoscopic], P?=?.661). Operative time was shorter for the robotic versus laparoscopic group (159.4?±?13.4 vs 187.2?±?8.3 min, respectively, P?=?.043), while estimated blood loss was similar (P?=?.147). The conversion to open rate was less in the robotic (4%) versus the laparoscopic (11%) group; P?=?.043. Hospital stay was shorter for the robotic group (1.4?±?0.2 vs 1.9?±?0.1?days, respectively, P?=?.009). The 30-day morbidity was 0 in robotic and 2.7% in laparoscopic group. Pathology was similar between groups.

Conclusions

Our study shows that the use of the robot could shorten operative time and decrease the rate of conversion to open for adrenal tumors larger than 5?cm. Based on our favorable experience, robotic adrenalectomy has become our preferred minimally invasive surgical approach for removing large adrenal tumors.  相似文献   
17.
Pigmented villonodular synovitis (PVNS) is a benign tumor that affects synovial lined joints, tendon sheaths and bursae. It is most commonly seen in one knee joint. The recommended treatment is total synovectomy, while radiotherapy can be used as adjuvant therapy for patients at risk for recurrence. The aim of our study was to show that the devastating effects of inactive diffuse PVNS may not be recognized for years and to evaluate the efficiency of aggressive total synovectomy on patients with PVNS during a follow-up period of 5 years. In the present study, 5 knees of four patients who had been previously followed due to gonarthrosis and diagnosed with PVNS during total knee arthroplasty (TKA) were followed and evaluated for a mean duration of 68 months. Mean age of the patients was 61.2 (52–66). All patients were women. One patient had right knee involvement, two had left knee involvement, and one had both knees involved. All patients had diffuse PVNS. Total synovectomy was performed in all patients in addition to TKA. During the follow-up, recurrence was not seen in any of the patients and prosthesis loosening was not detected. The aim of the present study was to evaluate the effectiveness of total synovectomy over the 5 years following the operation and to show that the devastating effects of inactive PVNS may sometimes be overlooked for years before being recognized during the treatment of the gonarthrosis that develops due to the disease. Although the disease is generally monoarticular, the study also presents a patient with bilateral PVNS.  相似文献   
18.
OBJECTIVES: The purpose of this study was to investigate the effects of PEEP on oxygenation and airway pressures during PCV-OLV. DESIGN: Randomized, crossover, clinical study. SETTING: University hospital. PARTICIPANTS: Twenty-five patients undergoing thoracotomy. INTERVENTIONS: During the first 5 minutes of OLV, all patients were ventilated with VCV (PEEP: 0) (VCV-ZEEP). Afterward, ventilation was changed to PCV with PEEP: 0 (PCV-ZEEP) or PEEP: 4 cmH2O (PCV-PEEP) for 20 minutes. In the following 20 minutes, PCV-PEEP and PCV-ZEEP were applied in reverse sequence. MEASUREMENTS AND MAIN RESULTS: At the end of VCV-ZEEP airway pressures (peak airway pressure, plateau airway pressure, mean airway pressure, and pause airway pressure) were recorded. At the end of PCV-PEEP and PCV-ZEEP airway pressures, PaO2 and Qs/Qt were recorded. Ppeak and Pplat were significantly lower with PCV-PEEP compared with VCV-ZEEP (eg, Ppeak: 33.4+/-4.2, 28.3+/-4.1, and 28.9+/-3.7 cmH2O in VCV-ZEEP, PCV-ZEEP, and PCV-PEEP, respectively; p<0.05 for PCV-ZEEP v VCV-ZEEP and PCV-PEEP v VCV-ZEEP). PCV-PEEP was associated with an increased PaO2 (230.3+/-69.8 v 189.0+/-54.8 mmHg, p<0.05) and decreased Qs/Qt (33.4%+/-7.3% v 38.4%+/-5.7%, p<0.05) compared with PCV-ZEEP (mean+/-SD). Eighty-eight percent of the patients have benefited from PEEP. CONCLUSION: During OLV, PCV with a low level of PEEP leads to improved oxygenation with lower airway pressures.  相似文献   
19.
PURPOSE: To evaluate erectile dysfunction, penile color Doppler ultrasound is currently considered the best method. But intracavernous injection is invasive and has adverse effects, such as prolonged erection and risk of priapism. In our study we want to evaluate whether vardenafil can be used instead of papaverine in penile Doppler ultrasonography. MATERIALS AND METHODS: A total of 24 patients with erectile dysfunction underwent color Doppler ultrasound before and after intracavernous injection of 60 mg papaverine with genital and audiovisual sexual stimulation. Peak flow and end diastolic velocity were measured in the recorded waveforms obtained 0, 1, 5, 10 and 20 min after injection. The patients also underwent color Doppler ultrasound after a 10-mg oral dose of vardenafil with genital and audiovisual sexual stimulation and at least 5 days after the prior examination. The same parameters were measured at 30, 45, 60, 75 and 90 min after the drug administration. We compared the results with the values obtained after papaverine injection. RESULTS: After oral vardenafil mean peak flow velocity significantly increased starting at 30 min and achieving a maximum value at 60 min. There were no significant differences in the 2 methods in mean peak velocity 1, 5, 10 and 20 min after papaverine injection, and 30, 45, 60, 75 and 90 min after oral vardenafil administration. Although papaverine injection is the gold standard for penile color Doppler ultrasound, it has severe adverse effects such as prolonged erection which we observed in 3 patients (12.5%) and required pharmacological detumescence. After vardenafil no severe adverse effects were observed. CONCLUSIONS: Vardenafil administration achieved increased peak flow velocity comparable to that after intracavernous papaverine injection. With no prolonged erection vardenafil is a safer alternative compared to more invasive intracavernous injection and is also an alternative for patients who fear injections.  相似文献   
20.

Objectives:

This study assessed the influence of different voxel resolutions of two different CBCT units on the in vitro detection of periodontal defects.

Methods:

The study used 12 dry skulls with a maxilla and a mandible. Artificial defects (dehiscence, tunnel, fenestration) were separately created on the anterior, premolar and molar teeth using burrs. A total of 14 dehiscences, 13 fenestrations, 8 tunnels and 16 non-defect controls were used in the study. Images were obtained from two different CBCT units in six voxel sizes (voxel size: 0.080, 0.100, 0.125, 0.150, 0.160 and 0.200 mm3). Kappa coefficients were calculated to assess both intra- and interobserver agreements for each image set.

Results:

Overall intraobserver kappa coefficients ranged between 0.978 and 0.973 for the 0.080-mm3 images and between 0.751 and 0.737 for the 0.160-mm3 images, suggesting notably high intraobserver agreement for detecting periodontal defects. CBCT performed significantly better at detecting fenestrations (p < 0.05) than tunnel and dehiscence defects. No statistically significant difference was found between the detection of dehiscence and tunnel defects (p > 0.05).

Conclusions:

A voxel size of 0.150 mm3 was identified as the cut-off point for overall detection of periodontal defects. CBCT should be considered the most reliable imaging modality for the diagnosis of periodontal defects.  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