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   2404篇
  免费   103篇
  国内免费   21篇
耳鼻咽喉   18篇
儿科学   66篇
妇产科学   10篇
基础医学   234篇
口腔科学   37篇
临床医学   148篇
内科学   631篇
皮肤病学   29篇
神经病学   186篇
特种医学   120篇
外科学   566篇
综合类   27篇
预防医学   50篇
眼科学   56篇
药学   86篇
中国医学   4篇
肿瘤学   260篇
  2023年   15篇
  2022年   24篇
  2021年   55篇
  2020年   30篇
  2019年   41篇
  2018年   58篇
  2017年   43篇
  2016年   45篇
  2015年   51篇
  2014年   61篇
  2013年   87篇
  2012年   153篇
  2011年   160篇
  2010年   96篇
  2009年   104篇
  2008年   129篇
  2007年   125篇
  2006年   140篇
  2005年   161篇
  2004年   162篇
  2003年   154篇
  2002年   159篇
  2001年   26篇
  2000年   32篇
  1999年   26篇
  1998年   43篇
  1997年   22篇
  1996年   29篇
  1995年   25篇
  1994年   23篇
  1993年   28篇
  1992年   24篇
  1991年   20篇
  1990年   13篇
  1989年   15篇
  1988年   12篇
  1987年   14篇
  1986年   8篇
  1985年   8篇
  1984年   5篇
  1983年   6篇
  1982年   5篇
  1981年   9篇
  1980年   14篇
  1979年   8篇
  1977年   7篇
  1975年   7篇
  1973年   6篇
  1970年   5篇
  1969年   5篇
排序方式: 共有2528条查询结果,搜索用时 15 毫秒
41.
42.
Summary We report a case of a papillary fibroelastoma originating from the left ventricular endocardium in the outflow tract which was discovered by echocardiography in an asymptomatic patient. Two echocardiographic features were observed: (1) the tumor surface was smooth, and characteristic papillary formation was not detected; and (2) the outline of the mass was clearly defined as a dense echo, with the central, radiolucent, portion surrounded by a highly refractive linear echo at the level of the maximum diameter of the mass. The excised tumor was covered with a gelatinous substance that masked multiple papillae on the surface, but its echolucent center could not be explained by the pathology of the tumor which was solid centrally. Our case indicates that a papillary fibroelastoma may sometimes show echocardiographic findings similar to those of a myxoma, although other investigators have not noted the smooth surface and the echolucent center makes it indistinguishable from a myxoma. Thus, in some cases, it is difficult to distinguish papillary fibroelastoma from myxoma by echocardiography.  相似文献   
43.
A patient with pure red cell aplasia (PRCA) and autoimmune haemolytic anaemia (AIHA), associated with a thymoma which had already been removed, was studied in order to investigate the pathogenesis of PRCA and AIHA. The autoantibody eluted from the surface of the patient's red blood cells (RBC) reacted with the large E antigen of the Rh complex. Immunoglobulin-G (IgG) purified from the patient's serum suppressed CFU-E and BFU-E but not CFU-GM colony formation in the presence of complement. This antibody was not adsorbed with large E antigen. T-lymphocytes in the bone marrow suppressing autologous CFU-E and BFU-E colonies were demonstrated. Thus, three distinct immunological disorders on erythropoiesis were present in this patient with PRCA and AIHA associated with thymoma in a thymectomized state.  相似文献   
44.
Introduction: Although successful ablation of ventricular tachycardia (VT) is feasible in arrhythmogenic right ventricular cardiomyopathy (ARVC), long-term recurrence is common. The aim of this study was to assess the usefulness of a change in the isolated delayed component (IDC) as an endpoint of the catheter ablation in ARVC.
Methods and Results: Eighteen patients (48 ± 11 years) with ARVC were studied. Detailed endocardial mapping of the right ventricle (RV) was performed during sinus rhythm. IDCs were recorded in 16 patients and the latest IDCs were related to the VT circuit. Catheter ablation was carried out in the areas with the IDCs. At the end of the session, the IDC was electrically dissociated in one, disappeared in five, exhibited second-degree block in one, was significantly delayed (≥50 ms) in three, and remained unchanged in six. The change in the IDC was correlated with the change in the type II/III late potentials in the signal-averaged electrocardiography (ECG) and the inducibility of the clinical VT after the ablation. During a follow-up of 61 ± 38 months, VT recurred in six. The patients with a changed IDC had a significantly lower VT recurrence than those with no IDC or an unchanged IDC (P < 0.02).
Conclusion: In patients with ARVC, (1) the IDCs during sinus rhythm are related to the clinical VT and can be a target for the ablation, (2) a change in the IDC can be used as an endpoint, and (3) qualitative analyses of the serial signal-averaged ECGs may be useful for the long-term follow-up.  相似文献   
45.
46.
Solitary mediastinal lymph node metastasis of hepatocellular carcinoma (HCC) is rare. We report a case of metachronically solitary mediastinal metastases of HCC treated by video‐assisted thoracic surgery (VATS) twice. A 66‐year‐old man underwent repeated laparoscopic radiofrequency ablation or trans‐arterial catheter chemo‐embolization against HCC for more than 10 years. The level of alpha fetoprotein protein was elevated, and radiological modalities including FDG‐PET revealed solitary mediastinal tumor metachronically. VATS was performed bilaterally twice. The postoperative course was uneventful and there had no recurrence of extra‐hepatic metastases and tumor markers are within normal limits at 18 months after second VATS. VATS is a minimally invasive and useful procedure for solitary mediastinal lymph node metastasis of HCC. If primary HCC was controlled and lymph node metastasis was solitary, mediastinum lymphadenectomy using VATS might give good short and long term results.  相似文献   
47.

Background and Purpose

Post-operative ileus (POI) is induced by intestinal inflammation. Here, we aimed to clarify the effects of 5-HT3 receptor antagonists against POI.

Experimental Approach

We administered three 5-HT3 receptor antagonists, ondansetron, tropisetron and palonosetron, to a mouse model of POI induced by surgical intestinal manipulation (IM). Immunohistochemistry, intestinal transit, inflammatory mediator mRNA expression and 5-HT content were measured. In some experiments, 5-HT3A receptor null mice were used.

Key Results

Three 5-HT3 receptor antagonists reduced IM-induced infiltration of inflammatory CD68-positive macrophages and myeloperoxidase-stained neutrophils. Ondansetron exhibited no anti-inflammatory actions in 5-HT3A receptor null mice. Ondansetron inhibited expression of the chemokine CCL2, IL-1β, IL-6, TNF-α and iNOS mRNAs up-regulated by IM, and also ameliorated the delayed gastrointestinal transit. Peritoneal macrophages, but not most infiltrating monocyte-derived macrophages, expressed 5-HT3 receptors. IM stimulation increased the 5-HT content of peritoneal lavage fluid, which up-regulated mRNA expression of proinflammatory cytokines in peritoneal macrophages. Immunohistochemical localization of 5-HT3 receptors suggests that ondansetron suppressed expression of these mRNAs in activated peritoneal macrophages, adhering to the serosal region of the inflamed intestinal wall.

Conclusion and Implications

5-HT3 receptor antagonists were anti-inflammatory, mainly targeting peritoneal macrophages expressing these receptors. They also restored the delayed gastrointestinal transit by IM. 5-HT3 receptor antagonists should be therapeutically useful agents against POI.  相似文献   
48.
Journal of Gastroenterology - In clinical practice, rectal cancer (RC) is classified according to tumor location. However, RC’s genetic characteristics according to tumor location remain...  相似文献   
49.
BACKGROUNDRecent improvements in the prognosis of patients with esophageal cancer have led to the increased occurrence of gastric tube cancer (GTC) in the reconstructed gastric tube. However, there are few reports on the treatment results of endoscopic submucosal dissection (ESD) for GTC.AIMTo evaluate the efficacy and safety of ESD for GTC after esophagectomy in a multicenter trial.METHODSWe retrospectively investigated 48 GTC lesions in 38 consecutive patients with GTC in the reconstructed gastric tube after esophagectomy who had undergone ESD between January 2005 and December 2019 at 8 institutions participating in the Okayama Gut Study group. The clinical indications of ESD for early gastric cancer were similarly applied for GTC after esophagectomy. ESD specimens were evaluated in 2-mm slices according to the Japanese Classification of Gastric Carcinoma with curability assessments divided into curative and non-curative resection based on the Gastric Cancer Treatment Guidelines. Patient characteristics, treatment results, clinical course, and treatment outcomes were analyzed.RESULTSThe median age of patients was 71.5 years (range, 57-84years), and there were 34 men and 4 women. The median observation period after ESD was 884 d (range, 8-4040 d). The median procedure time was 81 min (range, 29-334 min), the en bloc resection rate was 91.7% (44/48), and the curative resection rate was 79% (38/48). Complications during ESD were seen in 4% (2/48) of case, and those after ESD were seen in 10% (5/48) of case. The survival rate at 5 years was 59.5%. During the observation period after ESD, 10 patients died of other diseases. Although there were differences in the procedure time between institutions, a multivariate analysis showed that tumor size was the only factor associated with prolonged procedure time.CONCLUSIONESD for GTC after esophagectomy was shown to be safe and effective.  相似文献   
50.
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