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   735423篇
  免费   50255篇
  国内免费   1433篇
耳鼻咽喉   9405篇
儿科学   23747篇
妇产科学   17979篇
基础医学   114430篇
口腔科学   20842篇
临床医学   65796篇
内科学   141747篇
皮肤病学   16855篇
神经病学   51576篇
特种医学   26799篇
外国民族医学   76篇
外科学   109168篇
综合类   14944篇
现状与发展   2篇
一般理论   161篇
预防医学   52461篇
眼科学   16890篇
药学   55963篇
  3篇
中国医学   2414篇
肿瘤学   45853篇
  2021年   5997篇
  2019年   5812篇
  2018年   8369篇
  2017年   6508篇
  2016年   7308篇
  2015年   8029篇
  2014年   10919篇
  2013年   16195篇
  2012年   21788篇
  2011年   22971篇
  2010年   13500篇
  2009年   12658篇
  2008年   21278篇
  2007年   22904篇
  2006年   23339篇
  2005年   21871篇
  2004年   21320篇
  2003年   20350篇
  2002年   19911篇
  2001年   37386篇
  2000年   37961篇
  1999年   31315篇
  1998年   8283篇
  1997年   6961篇
  1996年   7230篇
  1995年   6866篇
  1994年   6307篇
  1992年   23670篇
  1991年   23552篇
  1990年   22888篇
  1989年   22666篇
  1988年   20574篇
  1987年   19956篇
  1986年   18946篇
  1985年   17758篇
  1984年   12995篇
  1983年   10993篇
  1982年   6057篇
  1979年   11723篇
  1978年   8285篇
  1977年   6961篇
  1976年   6700篇
  1975年   7389篇
  1974年   8627篇
  1973年   8286篇
  1972年   7789篇
  1971年   7248篇
  1970年   7003篇
  1969年   6434篇
  1968年   5903篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
There is increasing evidence that the assessment of eosinophilic airway inflammation using induced sputum and measurement of airway hyperresponsiveness provides additional, clinically important information concerning asthma control. The aim of this study was to directly compare the effects of different treatments on these markers in patients with asthma and persistent symptoms, despite the use of low-dose inhaled corticosteroids. A double-blind four-way crossover study was performed, which compared a 1-month treatment with budesonide 400 mug b.i.d., additional formoterol, additional montelukast and placebo in 49 patients with uncontrolled asthma despite budesonide 100 mug b.i.d., with each treatment separated by a 4-week washout period. The change in sputum eosinophil count with formoterol (2.4 to 3.8% change, 0.6-fold reduction, 95% confidence interval (CI) 0.5-0.9) differed significantly from placebo (2.8 to 2.5% change, 1.1-fold reduction, 95% CI 0.7-1.6) and high-dose budesonide (2.7 to 1.6% change, 1.6-fold reduction, 95% CI 1.2-2.2). The effects of montelukast did not differ from placebo. The changes in methacholine airway responsiveness were small and did not differ between treatments. High-dose budesonide had the broadest range of beneficial effects on other outcomes, including symptom scores, morning peak expiratory flow and forced expiratory volume in one second. In conclusion, treatment given in addition to low-dose inhaled corticosteroids results in modest benefits. Formoterol and high-dose budesonide have contrasting effects on eosinophilic airway inflammation.  相似文献   
32.
33.
34.
35.
36.
BACKGROUND: The incidence of malignant melanoma of the skin has risen in every part of the world where reliable cancer registration data are found. OBJECTIVE: Our study aims to describe the changing incidence of and survival from invasive cutaneous malignant melanoma in Malta, by analysing the data from the 211 cases that were registered at the Malta National Cancer Registry between 1993 and 2002. RESULTS: The age standardized incidence rates for invasive cutaneous malignant melanoma rose from 3.7 per 100,000 population per year for males and 5.1 for females in the first 5-year period, to 8.0 per 100,000 population per year for males and 5.9 for females in the second 5-year period. In both sexes, numbers of thin (< or = 1.0 mm) invasive melanomas increased significantly between 1993 and 2002; males also registered a significant increase in intermediate-thickness (1.01-4.0 mm) melanomas. The increase in numbers of thin and intermediate-thickness melanomas between the two 5-year periods was greatest in patients aged 60 years and over. The overall absolute 5-year survival rate for the first period was 74% and for the second period 92%. CONCLUSION: Numbers of reported cases of invasive cutaneous malignant melanoma in Malta have more than doubled during the 10-year study period. This is mostly due to a marked rise in the diagnosis of thin melanomas in both sexes, occurring mainly in patients aged 60 years and over. As thin melanomas are of low metastasizing potential, this has resulted in an increase in survival between the two 5-year study periods.  相似文献   
37.
38.
Volume and profile of alcohol consumption among students and classmates as predictors of aggression and victimization: a multilevel analysis among Swiss adolescents

Objective:  

To test the effects of the volume of alcohol consumption and drinking patterns on alcohol-related aggression and victimization, both at the individual and class levels.  相似文献   
39.
Complex regional pain syndrome (CRPS) was formerly known as “Sudeck’s atrophy”. The disease belongs to the group of neuropathic pain syndromes and is differentiated into three types. Type I is characterized by a lack of nerve lesions, type II by the presence of nerve lesions, and type III by the presence of other entities such as fibromyalgia. The exact pathogenic factors leading to the disease are still unknown and are currently the subject of investigation in various studies. These studies suggest a contribution of the central nervous system to the development and maintenance of CRPS. However, the clinical symptoms are well documented and include pain, autonomic changes and impaired motor function of the affected extremity. Diagnosis is based clinically on signs and symptoms. However, in a few cases radiography and scintiscanning may be useful to finalize the diagnosis. The treatment options are centred on the symptoms of pain, autonomic changes and functional impairment. A multidisciplinary treatment strategy is recommended, with surgeons, anaesthesiologists, physiotherapists and psychotherapists working together. Surgical intervention in this disease is only required in rare cases of neurological and bone pain, and the indications for such intervention are narrow and should be strictly observed.  相似文献   
40.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  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