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   3371434篇
  免费   242567篇
  国内免费   8563篇
耳鼻咽喉   46496篇
儿科学   112625篇
妇产科学   93437篇
基础医学   473835篇
口腔科学   92630篇
临床医学   306406篇
内科学   662126篇
皮肤病学   78659篇
神经病学   273957篇
特种医学   130529篇
外国民族医学   1282篇
外科学   506722篇
综合类   70049篇
现状与发展   6篇
一般理论   1235篇
预防医学   258567篇
眼科学   76002篇
药学   248155篇
  9篇
中国医学   6794篇
肿瘤学   183043篇
  2019年   26064篇
  2018年   36800篇
  2017年   28185篇
  2016年   32335篇
  2015年   36438篇
  2014年   50268篇
  2013年   75944篇
  2012年   101568篇
  2011年   107637篇
  2010年   64905篇
  2009年   62047篇
  2008年   101047篇
  2007年   107540篇
  2006年   109053篇
  2005年   104974篇
  2004年   101593篇
  2003年   98126篇
  2002年   94975篇
  2001年   161465篇
  2000年   165901篇
  1999年   140417篇
  1998年   40332篇
  1997年   35863篇
  1996年   36077篇
  1995年   34786篇
  1994年   32234篇
  1993年   30214篇
  1992年   110266篇
  1991年   106484篇
  1990年   103454篇
  1989年   99882篇
  1988年   91678篇
  1987年   89988篇
  1986年   84187篇
  1985年   80467篇
  1984年   60171篇
  1983年   50961篇
  1982年   29972篇
  1981年   27080篇
  1979年   53429篇
  1978年   37581篇
  1977年   32043篇
  1976年   29704篇
  1975年   31740篇
  1974年   37401篇
  1973年   35652篇
  1972年   33333篇
  1971年   30742篇
  1970年   28621篇
  1969年   26984篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
OBJECTIVE: To explore the presence and grade of denervation in three mimic muscles in facial nerve palsy. METHODS: The frontalis, orbicularis oculi (OO), and mentalis muscles were explored in 54 patients with Bell's palsy, after 30 days from the beginning of symptoms. Concentric needle electromyography, including fibrillation detection, was performed in the three muscles on the affected side. Compound muscle action potentials (CMAP) were recorded on both sides and a CMAP ratio was calculated from each muscle. The House-Brackman scale was used to assess the initial clinical evaluation and the follow-up until recovery. RESULTS: Fibrillation was recorded in 32 patients on the 30th day after the onset and was present in 100% of mentalis and in 90% of frontalis, but in only 34% of OO, a statistically significant difference. The grade of fibrillation in OO was also statistically lower from those in the other two muscles. The 32 patients were grouped according to the presence (A) or not (B) of fibrillation in OO. In group A, CMAP ratios (affected/normal side) did not differ significantly among the three muscles. However, in group B they were significantly greater in OO and frontalis than in mentalis. In between-group comparison, group B muscles had significantly higher CMAP ratios, lower degree of fibrillation, and better functional recovery. CONCLUSION: In facial palsy, the presence and grade of fibrillation in OO are lower than in frontalis and mentalis muscles and prognosis is more favorable for the non-fibrillating OO group of patients.  相似文献   
82.
83.
OBJECTIVES: To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS: We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS: In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS: While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE: Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning.  相似文献   
84.
85.
A 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in Indonesia. Physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. All blood cultures yielded growth of Salmonella enterica serovar Typhi, and typhoid fever was diagnosed. Subsequently, the patient developed septic shock and pulmonary edema.In this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with special emphasis on criteria for severe typhoid fever, which is treated with additional glucocorticoids.  相似文献   
86.
87.
OBJECTIVE: Spinal reflexes from hand to wrist muscles were investigated in writer's cramp. METHODS: Stimulus-triggered rectified EMG averages after ulnar nerve and cutaneous stimulation, in wrist flexors and extensors during tonic contraction, were compared in 18 controls and 19 patients. RESULTS: On the patient dystonic side, ulnar-induced EMG suppression was decreased in wrist extensors, and facilitation in wrist flexors modified dependent on the dystonic wrist posture during writing. No change was found on the patient non-dystonic side. Cutaneous stimulation increased wrist flexor EMG on both sides of the patients with normal wrist posture during writing, but had no effect in controls and patients with abnormal wrist posture. CONCLUSIONS: Comparison between cutaneous and mixed nerve stimuli suggests that spindle afferents from intrinsic hand muscles may mediate patients' ulnar-induced EMG modulations. Abnormal proprioceptive control was only observed on dystonic side, while bilateral unusual cutaneous control was found in patients. Changes in spinal transmission were partly related to the dystonic wrist posture, suggesting that systems involved in sensory processing can be differentially altered in writer's cramp. SIGNIFICANCE: Changes in spinal transmission, probably related to peripheral and/or cortical inputs, might either take part in primary or adaptive mechanisms underlying writer's cramp.  相似文献   
88.
89.
Vitiligo and psoriasis are both common skin disorders. However, psoriasis strictly confined to pre-existing vitiligo areas is rare and suggests a causal relationship. We report here on two patients with a strict anatomical colocalization of vitiligo and psoriasis. The histopathological examinations showed typical changes for both diseases together with a dense infiltrate of CD4+ and CD8+ T cells. By immunohistochemistry, intracytoplasmatic granzyme B and tumour necrosis factor alpha (TNF-alpha) were detected within the T-cell population, suggesting the functional activity of these cells and the creation of a local T helper 1 (Th1)-cytokine milieu. Additionally, in one patient we could identify anti-melanocytic T cells by tetramer staining and enzyme-linked immunospot (ELISPOT) analysis. These skin-infiltrating lymphocytes might trigger, by the local production of Th-1 cytokines such as TNF-alpha and interferon-gamma (IFN-gamma), the eruption of psoriatic plaques in patients with a genetic predisposition for psoriasis.  相似文献   
90.
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