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   2739239篇
  免费   204878篇
  国内免费   6051篇
耳鼻咽喉   36216篇
儿科学   90630篇
妇产科学   75747篇
基础医学   388297篇
口腔科学   77838篇
临床医学   248335篇
内科学   537124篇
皮肤病学   62887篇
神经病学   218049篇
特种医学   103313篇
外国民族医学   696篇
外科学   412240篇
综合类   64007篇
现状与发展   7篇
一般理论   950篇
预防医学   209900篇
眼科学   64197篇
药学   197400篇
  7篇
中国医学   6600篇
肿瘤学   155728篇
  2021年   20852篇
  2019年   22035篇
  2018年   31577篇
  2017年   23924篇
  2016年   26663篇
  2015年   30013篇
  2014年   42107篇
  2013年   62497篇
  2012年   85645篇
  2011年   90744篇
  2010年   53506篇
  2009年   50446篇
  2008年   83921篇
  2007年   89127篇
  2006年   89984篇
  2005年   86597篇
  2004年   83297篇
  2003年   79417篇
  2002年   76550篇
  2001年   138772篇
  2000年   142280篇
  1999年   117826篇
  1998年   32406篇
  1997年   28575篇
  1996年   28646篇
  1995年   27396篇
  1994年   25015篇
  1993年   23282篇
  1992年   89809篇
  1991年   86180篇
  1990年   82925篇
  1989年   79622篇
  1988年   72874篇
  1987年   71216篇
  1986年   66715篇
  1985年   63528篇
  1984年   47454篇
  1983年   40141篇
  1982年   23408篇
  1979年   41848篇
  1978年   29129篇
  1977年   24513篇
  1976年   23055篇
  1975年   23981篇
  1974年   29037篇
  1973年   28009篇
  1972年   26076篇
  1971年   23936篇
  1970年   22562篇
  1969年   21031篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
The aim of the present study was to explore differences in the clinical expression, clinical diagnoses and management of airway diseases in a primary-care setting. Patients aged >or=35 yrs who had ever smoked were enrolled when they presented for any reason to one of eight rural primary-care practices. Respiratory symptom questionnaires and spirometry were administered. In total, 1,034 patients had acceptable and reproducible spirometry, of whom 550 (53%) were males and 484 (47%) were females. Males smoked more than females (41.2 versus 29.2 pack-yrs) respectively, and were more likely to have a pre-bronchodilator forced expiratory volume in one second/forced vital capacity <0.70 at 22.4 versus 11.8%, respectively. However, more females than males reported breathlessness (51.0 versus 42.8%, respectively), a prior diagnosis compatible with airflow obstruction and taking respiratory medications (23.4 versus 14.9%, respectively). In conclusion, the current results suggest that females are more likely than males to report breathlessness and be prescribed respiratory medications independent of differences in the severity of airflow obstruction.  相似文献   
92.
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   
93.
94.
95.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  相似文献   
96.
97.
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   
98.
99.
100.
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   
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