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   10916篇
  免费   886篇
  国内免费   273篇
耳鼻咽喉   1559篇
儿科学   173篇
妇产科学   47篇
基础医学   908篇
口腔科学   1671篇
临床医学   1164篇
内科学   1718篇
皮肤病学   56篇
神经病学   794篇
特种医学   514篇
外科学   1008篇
综合类   1379篇
预防医学   118篇
眼科学   177篇
药学   370篇
  6篇
中国医学   105篇
肿瘤学   308篇
  2024年   19篇
  2023年   174篇
  2022年   267篇
  2021年   401篇
  2020年   383篇
  2019年   376篇
  2018年   369篇
  2017年   381篇
  2016年   434篇
  2015年   421篇
  2014年   703篇
  2013年   650篇
  2012年   597篇
  2011年   645篇
  2010年   514篇
  2009年   526篇
  2008年   507篇
  2007年   547篇
  2006年   505篇
  2005年   465篇
  2004年   404篇
  2003年   315篇
  2002年   263篇
  2001年   241篇
  2000年   217篇
  1999年   192篇
  1998年   155篇
  1997年   158篇
  1996年   116篇
  1995年   126篇
  1994年   102篇
  1993年   98篇
  1992年   89篇
  1991年   75篇
  1990年   69篇
  1989年   78篇
  1988年   66篇
  1987年   60篇
  1986年   57篇
  1985年   61篇
  1984年   48篇
  1983年   36篇
  1982年   44篇
  1981年   36篇
  1980年   25篇
  1979年   19篇
  1978年   10篇
  1977年   11篇
  1976年   8篇
  1972年   5篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
目的:分析左主干起源于右冠状动脉窦的临床特征,提高对左主干起源于右冠状动脉窦的认识和诊断.方法:回顾分析2例左主干起源于右冠状动脉窦的临床病例并对文献进行回顾分析.结果:左主干起源于右冠状动脉窦是一种罕见的先天性冠脉畸形,这种畸形可分为良性或恶性,主要根据异常左冠状动脉与主动脉和肺动脉之间的关系.对于可能引起猝死或严重心肌缺血患者,应进行冠状动脉旁路移植术.2例患者左主干起源于右冠状动脉窦,其中1例左主干走行于主动脉与肺动脉之间,1例走行于主动脉前方,这2例未进行预防性外科手术,目前预后良好.结论:左主干起源于右冠状动脉窦是罕见的冠脉畸形,应注意鉴别是良性或是恶性,确定下一步治疗方案.  相似文献   
42.
Synchronized coronary venous retroperfusion of autologous arterial blood was offered to patients referred for medically refractory unstable angina or evolving myocardial infarction with contraindications to thrombolytic therapy. Primary endpoints of angina, ST segment deviation, and two-dimensional echocardiographic systolic wall motion were followed to determine the efficacy of retroperfusion in patients prior to and then during angioplasty, surgical intervention, or pharmacological management, as the clinical picture warranted. Over a 12 month period, 21 patients were referred and 15 received retroperfusion. All experienced full relief of angina (p = 0·008). ST segment deviations and systolic wall motion of ischemic zones were observed to improve (p = 0·06 ST changes; p = 0·0001 wall motion changes) with synchronized retrograde perfusion. During attempts to remove patients from retroperfusion, statistically significant (p < 0·01) reproducible changes in these same endpoints were documented. Retroperfusion appears to improve acute myocardial ischemia. This technique functions well in the intensive care unit environment with only fluoroscopy as technical imaging support.  相似文献   
43.
Endoscopically controlled sinus floor augmentation. A preliminary report.   总被引:1,自引:0,他引:1  
Sinus augmentation has been advocated to be a surgical technique with predictable results in peri‐implant surgery. Endoscopic surgery of the maxillary sinus so far has been used as diagnostic procedure. In this paper, the use of endoscopy is described as a low invasive adjunctive technique in sinus floor augmentation. After preparation of the mucoperiosteum, bone grafts can be placed under endoscopic control between sinus floor and mucoperiosteum. A laterobasal approach via a small osteotomy and a transalveolar approach are possible for mucosal elevation and graft placement. First clinical results are reported. Endoscopic sinus lift may contribute to a reduction of perioperative morbidity, reduction of oroantal fistulae and control of graft position. The less invasive technique may allow to extend the indication for sinus augmentation.  相似文献   
44.
《Headache》1993,33(2):98-104
SYNOPSIS
Respiratory sinus arrhythmia is regarded as indicative of cardiac vagal integrity. A ratio of the longest R-R interval to the shortest R-R interval during deep breathing test (E:I ratio) was calculated in controls (n=49), cluster headache (n=33) and CPH (n=4) patients, E:I ratio decreased with age but was not dependent upon sex or upon smoking habits. Furthermore, there were no significant differences as regards E:I ratio between cluster headache patients in and outside a bout, or between patients with right-sided and left-sided headache. However, the E:I ratio was found to be significantly lower in the cluster headache group as such, when compared with controls, but the number of patients disclosing pathological or borderline results was small, 2 and 2, respectively. This may indicate that a putative vagal dysfunction in cluster headache is usually less marked than in patients with e.g. diabetic autonomic neuropathy. Significant attack-related change in the E:I ratio were detected in all individual patients though these changes were not of a uniform nature from individual to individual. E:I ratios were rather high in 3 out of 4 CPH patients examined. However, the number of patients in this group is too small to allow definite statements about the difference between CPH end cluster headache with regard to E:I ratios. There was no significant difference between E:I ratios outside and during a mild, short, mechanically precipitated attack in a single CPH patient.  相似文献   
45.
Summary Cavernous sinus thrombosis (CST) is rarely seen clinically as a complication of infectious processes since the discovery of penicillin. At the present time, dental abscess is an uncommon cause of CST. We now report our experiences with a 60-year-old diabetic male, who developed CST 38 days after extraction of an infected upper third molar tooth. The importance of eradicating regional cervicofacial foci of infection is stressed.  相似文献   
46.
47.
Limited randomized clinical trial data favor the use of anticoagulation in patients with cerebral venous thrombosis. We present a patient with deep cerebral venous thrombosis in whom anticoagulation was withheld because of coexistent intraventricular hemorrhage. She had a benign clinical course without anticoagulation, suggesting that close observation may be a management option in these patients.  相似文献   
48.
Introduction There have been many surgical techniques described for the treatment of pilonidal sinuses. Recurrent disease causes significant morbidity particularly with time from work. Aim To assess the rhomboid flap's role in promoting one‐stage primary healing in pilonidal disease and to evaluate the morbidity and recurrence. Methods Fifty‐three patients were prospectively recruited of which 27 had previous multiple abscess formation requiring surgical drainage from their pilonidal disease, although none had acute disease at the time of surgery. By using the transposition flap, we were able to obliterate the natal cleft and therefore the rolling action of the buttocks between the cleft in these patients and thereby remove one of the factors involved in pilonidal disease. Hospital stay, healing time, wound infection, wound breakdown and recurrence were noted. Results There were 47 males and 6 females with a median age of 28 years (range 16–64 years). Median follow‐up was 24 months (range 3–36 months). Post‐operative morbidity involved superficial wound infection in 7 (13%) which settled with out‐patient dressings. There were four recurrences (7%), two occurred between the flap and the anal canal, and the other two in the flap margin needing intervention. All the patients healed their wounds and the median healing time was 14 days. Conclusion As this condition affects a predominantly young population causing significant time off from work, we feel that the Rhomboid Flap is useful for difficult cases in that it allows early return to full activity and does not necessitate prolonged postoperative care.  相似文献   
49.
While a dural sinus thrombosis (DST), is a well-known consequence of the use of oral contraceptives, the role of hormone replacement therapy (HRT) in DST was not previously evaluated. We report two postmenopausal women, presenting with DST under HRT. Antiphospholipid antibodies in one case and borderline protein S deficiency in another were diagnosed. Only five cases of DST under HRT were previously reported and in two of them additional prothrombotic risk factors were found. According to these and previous cases, HRT is not an independent risk factor for DST.  相似文献   
50.
扩大经蝶入路进入海绵窦内侧腔的应用显微解剖   总被引:1,自引:0,他引:1  
目的为临床开展扩大经蝶入路进入海绵窦内侧腔手术提供解剖学依据。方法用50例成人头颅标本.在显微镜下对蝶窦外侧壁、蝶鞍、海绵窦及周围结构进行解剖学观察并测量。模拟扩大经蝶入路磨除海绵窦腹侧骨质,切开海绵窦内侧壁,显露海绵窦内侧腔。结果颈内动脉(ICA)明显隆起于蝶窦侧壁的占58%,蝶窦内隆起呈管型占3%。鞍底硬膜分为2层,海绵窦内侧壁的上部南垂体硬膜构成,无骨性结构支撑;下部由骨周硬膜构成,有蝶窦侧壁骨质支撑。两侧海绵窦内侧壁的距离为(14.8±2.7)mm。海绵窦内侧腔位于C4段ICA与垂体之间,腔内为丰富的静脉丛,最宽可达7mm,但常因ICA扭曲而闭塞。无颅神经穿越海绵窦内侧腔,ICA是扩大经蝶入路探查海绵窦遇到的第一个主要结构。结论扩大经蝶入路进入海绵窦内侧腔是安全可行的。  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