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   2328篇
  免费   115篇
  国内免费   44篇
耳鼻咽喉   3篇
儿科学   55篇
妇产科学   51篇
基础医学   95篇
口腔科学   5篇
临床医学   400篇
内科学   157篇
皮肤病学   13篇
神经病学   26篇
特种医学   250篇
外国民族医学   1篇
外科学   421篇
综合类   499篇
预防医学   128篇
眼科学   9篇
药学   144篇
  4篇
中国医学   160篇
肿瘤学   66篇
  2024年   2篇
  2023年   37篇
  2022年   71篇
  2021年   85篇
  2020年   82篇
  2019年   83篇
  2018年   58篇
  2017年   55篇
  2016年   80篇
  2015年   68篇
  2014年   148篇
  2013年   162篇
  2012年   139篇
  2011年   155篇
  2010年   128篇
  2009年   111篇
  2008年   124篇
  2007年   118篇
  2006年   105篇
  2005年   109篇
  2004年   88篇
  2003年   63篇
  2002年   55篇
  2001年   44篇
  2000年   37篇
  1999年   39篇
  1998年   33篇
  1997年   28篇
  1996年   24篇
  1995年   18篇
  1994年   16篇
  1993年   10篇
  1992年   16篇
  1991年   8篇
  1990年   7篇
  1989年   10篇
  1988年   9篇
  1987年   6篇
  1986年   6篇
  1985年   6篇
  1984年   8篇
  1983年   2篇
  1982年   11篇
  1981年   5篇
  1980年   5篇
  1979年   5篇
  1978年   4篇
  1976年   1篇
  1975年   1篇
  1973年   1篇
排序方式: 共有2487条查询结果,搜索用时 15 毫秒
1.

Background

Persistent iatrogenic atrial septal defect (iASD) is a common but poorly characterized complication after cryoballoon (CB) pulmonary vein isolation (PVI) procedures. We therefore investigate its prevalence, evolution, risk factors, and clinical outcomes in a prospective longitudinal study.

Methods

A total of 108 patients (41 women, mean age 57 ± 11.3) underwent CB PVI for AF. Serial transesophageal echocardiography (TEE) was performed 9 months and then annually until 6 years after the procedure to study the characteristics of persistent iASD.

Results

Persistent iASD occurred in 33 (30.6%) patients 9 months after CB PVI. Spontaneous closure of iASD was found in 6 (22.2%) and 3 (15.8%) patients 2 and 3 years after the procedures, respectively. No spontaneous closure was observed on 4, 5, and 6-year TEE follow-up. The projected long-term persistence rate of iASD after CB PVI was therefore 20% (30.6% × 0.778 × 0.842). Using multivariate logistic regression, a higher number of cryoapplications (≥ 2 minutes) was the only independent predictor of persistent iASD 9 months after CB PVI (odds ratio [OR] 1.207; 95% confidence interval [CI], 1.033-1.411, P = 0.018). Two (1.9%) patients with significantly larger iASD size than the others (long diameter 12.6 ± 0.8 vs 3.7 ± 1.5 mm, P < 0.001; short diameter 10.9 ± 0.2 vs 3 ± 1.1 mm, P < 0.001) required percutaneous closure because of exertional dyspnea and right ventricular enlargement. Over 129.7 patient-years follow-up, during which iASD persisted, there was no occurrence of neurologic events.

Conclusions

Approximately one fifth of patients undergoing CB PVI will have permanently persistent iASD. Patients with defect sizes of greater than 10 mm may need percutaneous closure due to significant left-to-right shunting.  相似文献   
2.
几丁糖预防术后腹腔粘连的实验研究   总被引:1,自引:1,他引:0  
目的探讨几丁糖对术后腹腔粘连的预防作用.方法将45只大鼠随机分为A、B、C 3组,于腹腔内浆膜损伤部位分别注入1%乳酸液、32%右旋糖酐-70液和2%几丁糖乳酸液各2 ml,术后14 d处死动物,观察各组腹腔粘连状况.结果 3组粘连分级比较有显著性差异(P<0.01),C组粘连发生率与另2组有显著差异(P<0.05).光镜下C组炎症反应轻微,纤维增生不明显;电镜下C组纤维细胞分泌胶原能力弱,间皮细胞增生活跃.结论几丁糖可有效降低大鼠术后腹腔粘连的发生和粘连程度,其作用优于右旋糖酐-70,且不影响切口的愈合.  相似文献   
3.
目的:探讨PHILIPSGyroscanIntera1.5TMRI成像仪正常腹部实质脏器表观弥散系数(ADC)值范围并研究适合本扫描仪腹部弥散加权成像的最佳b值。材料和方法:对30例健康志愿者行磁共振弥散加权成像。在ADC图上直接测量ADC值。结果:所有检查均一次成功得到弥散加权成像(DWI)和ADC图。正常肝脏、胰腺、肾脏、脾脏在b值分别为300、1000、1500s/mm2时的ADC值分别为(10-3mm2/s)1.520±0.169、1.937±0.370、2.632±0.258、1.163±0.188,1.200±0.132、1.484±0.272、2.016±0.178、0.840±0.117,1.068±0.118、1.321±0.149、1.659±0.169、0.747±0.102。不同b值时同一脏器ADC值有统计学差异;四种实质性脏器在同一b值时ADC值有统计学差异。结论:正常腹部不同脏器的ADC值有明显差异。腹部弥散加权成像的b值为300s/mm2和1000s/mm2时,DWI和ADC图像可以互相补充。  相似文献   
4.
腹部术后胃瘫综合征的诊治体会   总被引:4,自引:3,他引:1  
目的探讨腹部术后胃瘫的诊断及治疗.方法总结16例腹部术后胃瘫患者的临床资料进行回顾性分析.结果该组病例中男11例,女5例;年龄36~85岁,平均(60.50±15.76)岁.术前长期流出道梗阻、恶性肿瘤、胆道疾病、胰十二指肠切除术后,胃大部切除术后的病人发病率高.胃镜、X线口服造影及核素胃排空试验对术后胃瘫的诊断有价值,经保守治疗后胃肠动力一般在术后4周内恢复.结论该病是一种功能性疾病,一旦诊断成立,采取促动力药物在内的保守治疗是治疗的有效方法,不宜盲目手术.  相似文献   
5.
Thirty patients with malignant tumours in the upper abdomen underwent surgery and intraoperalive radiation (IORT), using electron beam, to: the surgical bed, residual or unresected tumour. The technical aspects and results of this treatment are described. Renal, adrenal, bile duct and gastrointestinal tumours were treated. along with several other lesions. The surgical procedure consisted in 10 cases simply of exposure of the tumour for IORT and in 20 the tumour was resected. The TORT dose ranged from 10 to: 20 Gv. In 13 patients, external beam radiation was also given to: residual tumour or to: areas of high risk for recurrence. Chemotherapy was given to: 10 patients. Tolerance to: the combined treatment was acceptable; with few complications related to: IORT.The median follow-up and survival time 23 months (range 4-more than 70 months). Local tumour control rate (or tumour stabilisation) is 90%. Distant metastases developed in 19 patients (63%). The actuarial survival rate for the group projected at 70 months (maximum follow-up) is 37%. IORT in useful in the management of tumours arising in the upper abdominal organs, for palliation surgery or when resectability of the tumour is in doubt. Indications for IORT include patients with uncommon tumours of the upper abdomen who are not be candidates for standardised cancer treatment.Presented at the European Congress of Radiology, Vienna, September 15–20,1991  相似文献   
6.
张小曼  吴戴红 《河北医学》2003,9(8):686-687
目的:探讨成人急腹症超声诊断价值。方法:回顾分析ll0例经临床及手术证实的成人急腹症的超声诊断。结果:临床诊断准确率为97.3%,在成人腹腔脓肿,肝破裂,急性胰腺炎,胰腺外伤等病的诊断准确率分别为91.3%,93.5%,92.7%。结论:超声诊断在成人急腹症具有重要的诊断价值。在大部分病例是首选的诊断手段。  相似文献   
7.
Rectus sheath haematoma is a well‐documented but unusual cause of acute abdomen. Combination of clinical features and appropriate radiological investigations can make for a prompt diagnosis. Most authors advocate conservative management and it has been reported that patients were directly discharged from the emergency department. We report a case of rectus sheath haematoma which progressed with clinical deterioration and necessitated surgical intervention for clot evacuation. Causes, physical signs, radiological features and classification of rectus sheath haematoma are discussed. It may be necessary to continue close clinical monitoring after diagnosis of rectus sheath haematoma.  相似文献   
8.
腹部平滑肌肉瘤CT诊断及鉴别诊断   总被引:1,自引:0,他引:1  
目的探讨CT在腹部平滑肌肉瘤诊断中的作用。方法分析9例经手术病理证实的腹部平滑肌肉瘤的CT表现。结果9例平滑肌肉瘤发生于腹膜3例,胃3例,直肠、结肠及子宫各1例。肿瘤密度不均,中心有大片坏死,周围实质呈破絮状或环状,其中1例可见液平面。增强后为延迟边缘强化。结论CT检查对平滑肌肉瘤可做出较准确的诊断。  相似文献   
9.
Background: One hypothesis for the pathogenesis of keratoconus includes teenage allergy, ocular itch and associated eye‐rubbing. Methods: This study examined the prevalence of these factors for teenage and adult patients. The results for a sample of 53 subjects with bilateral keratoconus were compared with those for a control sample of non‐keratoconus subjects, who also routinely wore RGP contact lenses. The strongest dominant hand and the eye with more advanced keratoconus were also determined, to examine for a relationship between them. Results: The keratoconic sample reported significantly higher levels of allergy, itch and rubbing as teenagers and as adults. However, all distributions were bimodal, consistent with the hypothesis that allergy, itch and rubbing are relevant in the pathogenesis of keratoconus only when the highest levels of these factors are present. For example, a significant relationship between the stronger dominant hand and the more advanced eye was evident only in subjects who reported the most severe rubbing. Conclusions: This finding adds weight to the circumstantial evidence that rubbing contributes to the pathogenesis of keratoconus. Low levels of teenage rubbing by some keratoconic subjects suggest a non‐rubbing pathogenesis and that emphasis on rubbing management is not warranted in these cases. However, high levels of adult rubbing reported by many keratoconic subjects indicate that the standard advice to avoid vigorous and prolonged rubbing is often not effective, even when repeated. There appears to be an indication for the need to improve the management of eye‐rubbing for some patients with keratoconus or at risk of developing this disease.  相似文献   
10.
腹腔镜治疗妇科急症593例临床分析   总被引:1,自引:0,他引:1  
目的:探讨腹腔镜治疗妇科急症的可行性、安全性及治疗效果。方法:回顾分析2003年7月至2007年10月我院用腹腔镜治疗593例妇科急症患者的临床资料。结果:593例患者均用腹腔镜完成手术,其中异位妊娠512例,手术时间18~75min,平均32min,术中出血10~70ml,平均25ml;盆腔炎、盆腔脓肿47例,手术时间35~90min,平均49min,术中出血45~130ml,平均84ml;黄体破裂、卵巢内膜囊肿破裂、卵巢囊肿蒂扭转34例,手术时间35~80min,平均52min,术中出血20~85ml,平均65ml;术后住院3~7d,平均4.5d,随访12~36个月无复发。结论:腹腔镜手术治疗妇科急症安全可行,且具有良好的效果。  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