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   2088778篇
  免费   148401篇
  国内免费   4365篇
耳鼻咽喉   27390篇
儿科学   68540篇
妇产科学   56552篇
基础医学   304605篇
口腔科学   60691篇
临床医学   185248篇
内科学   404957篇
皮肤病学   48136篇
神经病学   159191篇
特种医学   77912篇
外国民族医学   302篇
外科学   315953篇
综合类   45524篇
现状与发展   4篇
一般理论   624篇
预防医学   154963篇
眼科学   49717篇
药学   154178篇
  7篇
中国医学   5137篇
肿瘤学   121913篇
  2019年   16225篇
  2018年   23703篇
  2017年   17976篇
  2016年   19767篇
  2015年   22433篇
  2014年   30923篇
  2013年   45353篇
  2012年   62742篇
  2011年   66613篇
  2010年   39266篇
  2009年   36754篇
  2008年   62142篇
  2007年   66228篇
  2006年   66956篇
  2005年   63890篇
  2004年   61893篇
  2003年   58778篇
  2002年   56939篇
  2001年   107617篇
  2000年   110177篇
  1999年   91111篇
  1998年   23869篇
  1997年   20854篇
  1996年   21188篇
  1995年   20187篇
  1994年   18548篇
  1993年   17189篇
  1992年   68718篇
  1991年   67043篇
  1990年   64772篇
  1989年   62349篇
  1988年   56900篇
  1987年   55717篇
  1986年   52322篇
  1985年   49713篇
  1984年   36551篇
  1983年   31148篇
  1982年   17419篇
  1979年   32830篇
  1978年   23016篇
  1977年   19503篇
  1976年   18333篇
  1975年   19729篇
  1974年   23817篇
  1973年   22769篇
  1972年   21334篇
  1971年   19932篇
  1970年   18531篇
  1969年   17441篇
  1968年   16322篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
121.
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   
122.
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   
123.
124.
125.
We report a case of cervical necrotizing fasciitis (CNF) in a female having uncontrolled type II diabetes mellitus. The patient was presented to us after 20 days of preliminary symptoms. The aetiology of microbial inoculation in subdermal tissue was not known. The isolate was Staphylococcus aureus. In spite of the delay in presentation, the patient was successfully treated with combined antimicrobial and surgical intervention.  相似文献   
126.
127.
128.
Priori  A.  Cogiamanian  F.  Mrakic-Sposta  S. 《Neurological sciences》2006,27(4):s307-s309
Neurological Sciences - Spasticity arises from lesions involving the corticoreticulospinal system in the brain, brainstem or spinal cord. Abnormal suprasegmental influences lead to increased spinal...  相似文献   
129.
Abstract Chorea is a rare complication of polycythaemia vera. Polycythaemic chorea occurs predominantly in females and usually in generalised form. We present a 66-year-old woman with acute onset hemichorea-ballism with no vascular pathology in the basal ganglia region. A clear relationship was observed between the onset of chorea and worsening of haematological parameters in the patient. After repeated phlebotomies the patient's clinical status was improved. Polycythaemic chorea must be considered, especially in the elderly, as early diagnosis leads to effective treatment and prevention of complications.  相似文献   
130.
OBJECTIVE: This study aimed to describe the use of the P300 event-related potential as a control signal in a brain computer interface (BCI) for healthy and paralysed participants. METHODS: The experimental device used the P300 wave to control the movement of an object on a graphical interface. Visual stimuli, consisting of four arrows (up, right, down, left) were randomly presented in peripheral positions on the screen. Participants were instructed to recognize only the arrow indicating a specific direction for an object to move. P300 epochs, synchronized with the stimulus, were analyzed on-line via Independent Component Analysis (ICA) with subsequent feature extraction and classification by using a neural network. RESULTS: We tested the reliability and the performance of the system in real-time. The system needed a short training period to allow task completion and reached good performance. Nonetheless, severely impaired patients had lower performance than healthy participants. CONCLUSIONS: The proposed system is effective for use with healthy participants, whereas further research is needed before it can be used with locked-in syndrome patients. SIGNIFICANCE: The P300-based BCI described can reliably control, in 'real time', the motion of a cursor on a graphical interface, and no time-consuming training is needed in order to test possible applications for motor-impaired patients.  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