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   31347篇
  免费   1497篇
  国内免费   166篇
耳鼻咽喉   372篇
儿科学   557篇
妇产科学   301篇
基础医学   4007篇
口腔科学   885篇
临床医学   2239篇
内科学   7682篇
皮肤病学   527篇
神经病学   2451篇
特种医学   1199篇
外科学   4995篇
综合类   199篇
预防医学   1162篇
眼科学   469篇
药学   2695篇
中国医学   67篇
肿瘤学   3203篇
  2023年   154篇
  2022年   303篇
  2021年   544篇
  2020年   254篇
  2019年   387篇
  2018年   502篇
  2017年   409篇
  2016年   482篇
  2015年   517篇
  2014年   689篇
  2013年   871篇
  2012年   1268篇
  2011年   1366篇
  2010年   788篇
  2009年   687篇
  2008年   1201篇
  2007年   1253篇
  2006年   1284篇
  2005年   1390篇
  2004年   1303篇
  2003年   1281篇
  2002年   1334篇
  2001年   1223篇
  2000年   1363篇
  1999年   1187篇
  1998年   406篇
  1997年   302篇
  1996年   307篇
  1995年   264篇
  1994年   253篇
  1993年   246篇
  1992年   800篇
  1991年   717篇
  1990年   731篇
  1989年   776篇
  1988年   708篇
  1987年   637篇
  1986年   608篇
  1985年   570篇
  1984年   442篇
  1983年   331篇
  1982年   188篇
  1980年   159篇
  1979年   284篇
  1978年   223篇
  1977年   172篇
  1974年   165篇
  1973年   152篇
  1971年   153篇
  1969年   171篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
A 56-year-old man was admitted to our hospital with right chest pain. Chest X-ray, CT scan and MRI revealed a chest wall tumor and enlarged mediastinal lymph nodes. Percutaneous lung biopsy was performed, and the pathological diagnosis of pleomorphic rhabdomyosarcoma was obtained. The only significant abnormal laboratory finding was elevation of serum NSE (24.5 ng/ml). Although chemotherapy (VAC-ADM) and radiation therapy were performed, the patient died about 7 months after admission. To our knowledge, only 17 cases of chest wall rhabdomyosarcoma have been reported in Japan.  相似文献   
42.
43.
To apply Nd:YAG laser irradiation through a new sapphire tip contact laser method to catheter ablation in treatment of tachy-arrhythmias, effects of laser irradiation on ventricular myocardium were investigated in 10 mongrel dogs. Nd:YAG lase (1064nm) discharges were delivered to different sites on the endomyocardium at power of 5, 10, 15, 20 or 25w with duration of 3, 5, or 10 seconds (sec.) respectively in closed beating hearts. Histopathologically, the lesion irradiated was clearly demarcated from the normal myocardium by the construction band necrosis zone. The depth of injured myocardium was less than 2mm with 3 sec. irradiations, with 5 sec. from 1 mm to 4 mm in proportion to power increase, with 10 sec. from 3mm to 8 mm in proportion to the power from 5w to 15w and could not be measured in cases of more than 20w irradiations. Although with every irradiation duration, the depth of injury increased in proportion to the power increase. With the same total energy, a longer time of irradiation produced deeper injury than a shorter time. This method makes it easier to keep the laser positioned to target than bare laser, and is suitable for use in catheter ablation.  相似文献   
44.
A 74-year-old man with combined valvular disease with a recent cerebral infarction was admitted. While undergoing thorough examination for valvular disease, absent right superior vena cava (RSVC) and persistent left superior vena cava (PLSVC) were recognized. Chest X-ray film suggested a right arch protrusion, and CT and venogram confirmed the diagnosis. During surgery, replacement of the mitral and aortic valves and annuloplasty of the tricuspid valve were performed. A blood draining cannula was inserted in retrograde fashion from the coronary sinus into the PLSVC, without any difficulties in the tricuspid valve repair. Due to bradycardic atrial fibrillation, we believed that it would be difficult to insert an endocardial electrode postoperatively, hence myocardial electrode was placed in the right ventricular wall. Absent RSVC combined with PLSVC is very rare, and a patient who underwent combined valve surgery with this rare anatomical abnormality is herein presented.  相似文献   
45.
Based on the findings that expression of endogenous tumor necrosis factor (enTNF), which is not present in TNF-susceptible cells, was generally observed in TNF-resistant cells and that TNF gene transfection gives rise to TNF resistance, the assumption was made that enTNF may be a protective protein against the cytotoxicity of exogenous TNF. However, it remains unknown whether the protection by enTNF is exerted in an intracellular or extracellular (autocrine) manner. We therefore transfected a nonsecretory human TNF gene (pTNF delta pro) into highly TNF-sensitive mouse tumorigenic fibroblasts (L-M cells) and investigated their TNF susceptibility. The transfectants expressed enTNF which was not secreted into the medium and acquired an appreciable degree of resistance to exogenous TNF. A significant increase in the manganous superoxide dismutase level was also noted in the transfectants. These findings suggest that enTNF exerts its protective function intracellularly by inducing manganous superoxide dismutase production.  相似文献   
46.
47.
The preoperative diagnosis of diffuse heterotopic submucosal cystic malformation of the stomach is very difficult to make with upper gastrointestinal (GI) series or endoscopy. We report a case of submucosal cysts associated with an early gastric carcinoma in which ultrasonography (US) and endoscopic ultrasonography (EUS) were very useful in the preoperative diagnosis.  相似文献   
48.
Lesions in the thalamus or basal ganglia have rarely been reported in acute disseminated encephalomyelitis (ADEM). We experienced 2 cases of ADEM, in which MRI showed lesions in the thalamus or basal ganglia. Case 1, a 4-year-old boy, had gait disturbance, hyperesthesia and hyperreflexia. MRI (T2 weighted image) showed multiple high intensity areas in the right frontal lobe, bilateral parietal lobes and bilateral thalami. Case 2, a 4-year-old girl, complained of gait disturbance following a febrile episode, and displayed hyperreflexia. Several days later, she had visual disturbance of the left eye. MRI (T2 weighted image) revealed multiple high intensity areas in the dentate nucleus of left cerebellum, left occipital lobe, bilateral caudate nuclei, and the anterior part of bilateral lenticular nuclei. In both cases, CT could not demonstrate these lesions. Both of them were treated with corticosteroid and recovered rapidly. They had no recurrence. MRI is useful in diagnosis and follow-up of ADEM and may reveal lesions other than cerebral or cerebellar white matters.  相似文献   
49.
We describe the case of a 61-year-old woman diagnosed with primary Sj?gren's syndrome (SS) after an 8-year history of IgA nephropathy and a 3-year history of recurrent purpuric rashes. Her two daughters had previously been diagnosed with other autoimmune diseases. One daughter had Graves' disease and the other had Hashimoto's disease and systemic lupus erythematosus. The diagnosis of SS was made based on dryness of mucous membranes, Shirmer test, and parotid sialography. Thrombocytopenia, high platelet-aggregated IgG (PA-IgG) level, and normal megakaryocytes count in bone marrow suggested that her recurrent purpuric rashes were due to idiopathic thrombocytopenic purpura (ITP). Patients with SS may develop other autoimmune diseases. This case aids understanding of the immune pathogenesis and genetic background of SS.  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