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   1697640篇
  免费   123839篇
  国内免费   3788篇
耳鼻咽喉   21756篇
儿科学   55713篇
妇产科学   46183篇
基础医学   241602篇
口腔科学   48778篇
临床医学   151503篇
内科学   334019篇
皮肤病学   38684篇
神经病学   131353篇
特种医学   64113篇
外国民族医学   244篇
外科学   257559篇
综合类   38953篇
现状与发展   4篇
一般理论   532篇
预防医学   124354篇
眼科学   40241篇
药学   123767篇
  7篇
中国医学   4477篇
肿瘤学   101425篇
  2021年   12829篇
  2019年   13551篇
  2018年   19981篇
  2017年   15241篇
  2016年   16652篇
  2015年   19004篇
  2014年   26280篇
  2013年   38022篇
  2012年   52848篇
  2011年   55527篇
  2010年   32851篇
  2009年   30776篇
  2008年   51616篇
  2007年   54938篇
  2006年   55360篇
  2005年   52651篇
  2004年   50839篇
  2003年   48250篇
  2002年   46483篇
  2001年   91843篇
  2000年   93671篇
  1999年   77019篇
  1998年   19761篇
  1997年   17291篇
  1996年   17405篇
  1995年   16751篇
  1994年   15309篇
  1993年   14086篇
  1992年   57416篇
  1991年   55306篇
  1990年   53017篇
  1989年   50795篇
  1988年   46168篇
  1987年   44966篇
  1986年   42255篇
  1985年   40023篇
  1984年   29374篇
  1983年   24926篇
  1982年   13913篇
  1979年   25556篇
  1978年   17591篇
  1977年   14919篇
  1976年   13882篇
  1975年   14578篇
  1974年   17642篇
  1973年   16960篇
  1972年   15689篇
  1971年   14463篇
  1970年   13440篇
  1969年   12522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