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   1696877篇
  免费   123818篇
  国内免费   3802篇
耳鼻咽喉   21740篇
儿科学   55681篇
妇产科学   46170篇
基础医学   241414篇
口腔科学   48765篇
临床医学   151424篇
内科学   333919篇
皮肤病学   38686篇
神经病学   131283篇
特种医学   64058篇
外国民族医学   242篇
外科学   257586篇
综合类   38953篇
现状与发展   4篇
一般理论   531篇
预防医学   124282篇
眼科学   40233篇
药学   123667篇
  7篇
中国医学   4487篇
肿瘤学   101365篇
  2021年   12819篇
  2019年   13551篇
  2018年   19996篇
  2017年   15249篇
  2016年   16663篇
  2015年   19018篇
  2014年   26278篇
  2013年   38011篇
  2012年   52844篇
  2011年   55537篇
  2010年   32852篇
  2009年   30759篇
  2008年   51615篇
  2007年   54889篇
  2006年   55366篇
  2005年   52612篇
  2004年   50824篇
  2003年   48226篇
  2002年   46427篇
  2001年   91808篇
  2000年   93631篇
  1999年   76995篇
  1998年   19734篇
  1997年   17281篇
  1996年   17411篇
  1995年   16755篇
  1994年   15300篇
  1993年   14080篇
  1992年   57402篇
  1991年   55276篇
  1990年   52989篇
  1989年   50756篇
  1988年   46143篇
  1987年   44947篇
  1986年   42237篇
  1985年   39997篇
  1984年   29358篇
  1983年   24912篇
  1982年   13904篇
  1979年   25535篇
  1978年   17578篇
  1977年   14910篇
  1976年   13878篇
  1975年   14564篇
  1974年   17637篇
  1973年   16954篇
  1972年   15682篇
  1971年   14458篇
  1970年   13437篇
  1969年   12524篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
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   
62.
63.
64.
Group A streptococcal meningitis is less common than other forms of meningitis; however, the occurrence of this infection is associated with high mortality and morbidity. Early recognition and a prompt treatment are therefore essential. We review one case of an Asian women admitted with group A streptococcal meningitis as a complication of otitis media.  相似文献   
65.
Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision.  相似文献   
66.
The authors discuss techniques for Monte Carlo (MC) cohort simulations that reduce the number of simulation replications required to achieve a given degree of precision for various output measures. Known as variance reduction techniques, they are often used in industrial engineering and operations research models, but they are seldom used in medical models. However, most MC cohort simulations are well suited to the implementation of these techniques. The authors discuss the cost of implementation versus the benefit of reduced replications.  相似文献   
67.
French asthma patients may be supervised by general practitioners (GPs) and/or specialists. Therefore, this study examined asthma management in patients exclusively supervised by specialists (SPE), GPs, (GP) and both (GP+SPE group), and compared the findings. Asthma patients were consecutively recruited in 348 pharmacies. Each patient completed a questionnaire providing data on personal characteristics, asthma management, perception of disease and asthma supervision. Asthma control was measured using the Asthma Control Test. Questionnaires were linked to computerised records of medications which had been dispensed before inclusion in the study. From the 1,256 patients (mean age = 36.1 yrs, 54.3% females), 11.4, 36.6, and 52.0% were placed in the SPE, GP, and GP+SPE groups, respectively. During the previous 4 weeks, most patients in the SPE group were properly controlled (52.2 versus 26.4 and 21.5% in GP and GP+SPE groups, respectively). The SPE group made more use of fixed combinations of long-acting beta agonist and inhaled corticosteroid, while receiving less short-acting beta agonists, antitussives and antibiotics. Striking differences in symptoms and asthma management were observed according to the type of asthma supervision. The current results strongly support the need to improve the management of asthma in primary care, and the coordination of care between general practitioners and specialists.  相似文献   
68.
69.
70.
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