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   8149篇
  免费   547篇
  国内免费   50篇
耳鼻咽喉   136篇
儿科学   195篇
妇产科学   132篇
基础医学   977篇
口腔科学   274篇
临床医学   687篇
内科学   1725篇
皮肤病学   165篇
神经病学   520篇
特种医学   316篇
外国民族医学   2篇
外科学   1280篇
综合类   138篇
一般理论   5篇
预防医学   552篇
眼科学   363篇
药学   748篇
中国医学   73篇
肿瘤学   458篇
  2024年   10篇
  2023年   100篇
  2022年   202篇
  2021年   382篇
  2020年   251篇
  2019年   325篇
  2018年   406篇
  2017年   270篇
  2016年   334篇
  2015年   325篇
  2014年   479篇
  2013年   576篇
  2012年   806篇
  2011年   799篇
  2010年   466篇
  2009年   326篇
  2008年   525篇
  2007年   476篇
  2006年   368篇
  2005年   304篇
  2004年   237篇
  2003年   235篇
  2002年   182篇
  2001年   41篇
  2000年   25篇
  1999年   34篇
  1998年   26篇
  1997年   13篇
  1996年   17篇
  1995年   15篇
  1994年   12篇
  1993年   12篇
  1992年   5篇
  1991年   13篇
  1990年   8篇
  1989年   13篇
  1988年   11篇
  1987年   8篇
  1985年   5篇
  1984年   5篇
  1982年   9篇
  1981年   5篇
  1980年   6篇
  1979年   12篇
  1978年   12篇
  1977年   14篇
  1976年   9篇
  1975年   13篇
  1974年   7篇
  1972年   3篇
排序方式: 共有8746条查询结果,搜索用时 15 毫秒
1.
2.
Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital condition. It responds well to early diagnosis and treatment, but otherwise the prognosis is poor. We present our case series of 12 patients (mean age, 2 ± 2.58 yr; age range, 2 mo–8 yr), emphasizing the diagnostic process and discussing our surgical results. The diagnosis of ALCAPA should be suspected in infants who have dilated cardiomyopathy with electrocardiographic changes that suggest ischemia, and in older children who have isolated mitral regurgitation. When clinical suspicion is high, the results of 2-dimensional echocardiography combined with color-flow Doppler studies in expert hands can establish the diagnosis, thus avoiding angiography in critically ill infants. The treatment of choice in our patients was transfer and reimplantation of the left coronary artery onto the ascending aorta. There were 2 deaths: both were infants in extremis who underwent emergency surgery. An older child with severe ventricular dysfunction was given mechanical ventricular assistance and then heart transplantation. As of this report, all 10 survivors remained well and asymptomatic.  相似文献   
3.
The floating metacarpal bone is a result of simultaneous fracture-dislocation of both carpometacarpal and metacarpophalangeal joints. This rare entity may be associated with other hand injuries. Here we present a floating index metacarpal with concomitant 3rd–5th carpometacarpal fracture-dislocations. Excellent functional short-term result was achieved after open metacarpopha langeal reduction and closed carpometacarpal reduction and percutaneous pinning.  相似文献   
4.
Several regulatory bodies have agreed that low-dose radiation used in medical imaging is a weak carcinogen that follows a linear, non-threshold model of cancer risk. While avoiding radiation is the best course of action to mitigate risk, computed tomography (CT) scans are often critical for diagnosis. In addition to the as low as reasonably achievable principle, a more concrete method of dose reduction for common CT imaging exams is the use of a diagnostic reference level (DRL). This paper examines Canada's national DRL values from the recent CT survey and compares it to published provincial DRLs as well as the DRLs in the United Kingdom and the United States of America for the 3 most common CT exams: head, chest, and abdomen/pelvis. Canada compares well on the international scale, but it should consider using more electronic dose monitoring solutions to create a culture of dose optimization.  相似文献   
5.
6.
Experimental autoimmune encephalomyelitis (EAE) is a mouse model for multiple sclerosis (MS), in which an inflammatory demyelination and axonal damage occurs. Kombucha tea is a fermented beverage made from kombucha mushroom, brewed tea, and sugar. In recent years kombucha tea has attracted interest due to its pharmacological properties like antioxidant effects. The aim of the present research was to test the therapeutic effect of kombucha tea in EAE. We induced EAE model in 18 female C57BL/6 mice by inoculation of myelin oligodendrocyte glycoprotein-35-55 (MOG35-55) in complete Freund’s adjuvant emulsion. Then, in order to ameliorate EAE symptoms, we used kombucha tea. During the course of study clinical evaluation was assessed, and on the day 21 post-immunization, for evaluation of nitric oxide (NO), total antioxidants capacity and tumor necrosis factor-alpha (TNF-α), blood samples were taken from the heart of mice. The mice were sacrificed and brains and cerebellums of mice were removed for histological analysis. Our findings demonstrated that kombucha tea had beneficial effects on EAE by lower incidence, attenuation in the severity, and also a delay in the onset of disease. Histological analysis showed that inflammatory criteria including the number of infiltrated immune cells and plaques as well as demyelination in kombucha tea dosed mice were significantly lower than the control group. Also, in comparison with control mice, the serum levels of NO and TNF-α in kombucha tea-treated mice were significantly decreased. Kombucha tea with its potential therapeutic effects and immunomodulatory properties might be proposed, after additional necessary tests and trials, for treatment of MS.  相似文献   
7.
PATIENTS AND METHOD: The aim of the present study was to contribute to a more accurate indication and better integration of developing third molar transplantation into orthodontic space management, using the results gleaned from the authors' own pool of patients. For this purpose, a clinical and radiographic examination of 61 transplanted developing molars in 57 patients was carried out after an average of 3.3 years. RESULTS: The overall success rate was 85%. Failure was due in 10% of cases to impaired periodontal healing (inflammatory root resorption, ankylosis, or increased pocket probing depths) and in 5% of cases to insufficient or arrested postoperative root development accompanied by increased transplant mobility. The incidence of postoperative cessation of further root development was significantly higher (p = 0.011) in transplants at early developmental stages, which also had a negative impact on the final root length, the crown-root ratio and the mobility values of these transplants. CONCLUSIONS: The transplantation of developing third molars should be given stronger consideration in treatment plans for orthodontic space management although it represents a real alternative to orthodontic space closure only in exceptional cases. However, unlike implantological or prosthodontic treatment, it offers an opportunity to replace a missing or non-retainable tooth with a patient's own vital and fully functional tooth, provided the appropriate transplant is selected.  相似文献   
8.
9.
10.
BACKGROUND: To ascertain survival of ischemic advanced heart failure patients by treatment allocation, we examined the outcome of transplant assessment patients allocated to medical therapy, high-risk conventional surgery, or transplantation. METHODS: Patients were identified from the Papworth transplant database and excluded if primary etiology was not ischemic. Grouping was undertaken according to treatment allocation at initial assessment, and analysis was performed by intention to treat. Survival was computed from the time of assessment and Cox regression used to stratify patients according risk with the Heart Failure Survival Score. RESULTS: From May 1993 to September 2001, a total of 755 patients were admitted for transplant assessment, with 348 (46.1%) identified as having heart failure of ischemic origin. Variables required for calculation of the Heart Failure Survival Score was available in 273 patients (78.4%), and 20 patients (7.3%) were lost to follow-up. Of the remaining 253 patients, 89 (35.2%) were allocated to medical therapy, 32 (12.6%) to surgery, and 132 (52.2%) to transplantation. The relative risk (95% confidence limit) of death compared with medical therapy was 0.62 (0.28, 1.40) for surgery and 0.38 (0.24, 0.61) for transplantation in medium- to high-risk patients. For low-risk patients, the relative risks for death compared with medical therapy were 1.87 (0.63, 5.60) for surgery and 1.97 (0.79, 4.96) for transplantation. CONCLUSIONS: Transplantation improved survival of medium- and high-risk patients compared with medical therapy. In the low-risk group, this was not evident. However, repeated assessment of risk is required because the hazard for death rises steadily after the third year in these patients.  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