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   8028篇
  免费   492篇
  国内免费   39篇
耳鼻咽喉   147篇
儿科学   234篇
妇产科学   71篇
基础医学   981篇
口腔科学   93篇
临床医学   667篇
内科学   2216篇
皮肤病学   223篇
神经病学   773篇
特种医学   307篇
外国民族医学   7篇
外科学   1328篇
综合类   49篇
预防医学   431篇
眼科学   98篇
药学   455篇
中国医学   6篇
肿瘤学   473篇
  2023年   39篇
  2022年   39篇
  2021年   139篇
  2020年   79篇
  2019年   144篇
  2018年   186篇
  2017年   126篇
  2016年   142篇
  2015年   180篇
  2014年   227篇
  2013年   309篇
  2012年   461篇
  2011年   463篇
  2010年   265篇
  2009年   246篇
  2008年   401篇
  2007年   417篇
  2006年   467篇
  2005年   430篇
  2004年   375篇
  2003年   395篇
  2002年   361篇
  2001年   174篇
  2000年   189篇
  1999年   176篇
  1998年   94篇
  1997年   67篇
  1996年   80篇
  1995年   58篇
  1994年   54篇
  1993年   51篇
  1992年   155篇
  1991年   129篇
  1990年   96篇
  1989年   111篇
  1988年   99篇
  1987年   117篇
  1986年   102篇
  1985年   112篇
  1984年   69篇
  1983年   64篇
  1982年   41篇
  1981年   37篇
  1979年   62篇
  1978年   37篇
  1976年   37篇
  1974年   37篇
  1973年   44篇
  1972年   42篇
  1971年   47篇
排序方式: 共有8559条查询结果,搜索用时 31 毫秒
21.
22.
A new case of pseudo-diastrophic dysplasia in a boy born to consanguineous parents is reported. The patient developed neurologic (hydrocephalus) and respiratory anomalies and died at the age of 11 months of an unknown cause. Features that distinguish this chondrodysplasia from diastrophic dysplasia include decreased height of vertebral bodies and anomalies of the pelvis with short iliac wings and a horizontal orientation of the internal spine of the acetabular roof.  相似文献   
23.
背景:以往对面部肉芽肿(GF)的研究仅局限于病例报道或小样本研究。目标:通过对GF的大样本研究,描述其临床病理特征。方法:对66例患者和73份皮肤组织标本进行回顾性分析。结果:GF通常发生在中年人,表现为淡红色斑块或结节,1/3患者有多个皮损,5例患者有面部以外皮损。只有10例患者临床诊断为GF;其主要鉴别诊断包括:肉样瘤病、淋巴瘤、狼疮及基底细胞癌。GF最常见的组织病理学特征为一条grenz带、中性粒细胞浸润及毛细血管扩张。尽管坏死性血管炎罕见,但血管改变常见。通常皮损同时存在急性和慢性炎症,提示GF为急性复发的慢性过程,而不是一个明显连续的急性和慢性阶段。  相似文献   
24.
Cavernous angiomas of the spinal cord   总被引:7,自引:0,他引:7  
Five cases of histologically verified cavernous angiomas of the spinal cord are reported. Acute lower-extremity sensory disturbance was the initial symptom in four patients, and one presented with weakness of the hand. Progressive neurological deficit occurred in all patients, but the clinical course and outcome were extremely variable. Myelography revealed an intramedullary lesion in two cases but was completely normal in three; magnetic resonance imaging was diagnostic in these patients. Subtotal removal was accomplished in two cases, and myelotomy and biopsy were carried out in three. Four of the cavernous angiomas were located in the cervicothoracic region, whereas one was found in the thoracolumbar cord. All of the patients exhibited characteristic gross and microscopic features as well as hemosiderin-laden macrophages indicating remote hemorrhage. The diagnostic, therapeutic, and prognostic implications of this rare condition are discussed.  相似文献   
25.
The aim of the present study was to determine whether the Ity gene, which controls the resistance to S. typhimurium infection in mice, also governs the resistance to S. abortusovis, a serotype specific for goat and sheep. During either i.v. or i.p. infection, BALB/c mice (Itys) were not able to control the growth of S. abortusovis and eventually died from infection. In contrast CBA (Ityr) or (C.CB)F1 (Ityr/s) mice were able to control the growth of these bacteria. Using congenic C.D2 Ityr mice, we found that the gene controlling resistance to S. abortusovis was tightly linked to the Ity gene on chromosome 1. Furthermore, in the spleen and the liver of backcross BALB/c x (CBA x BALB/c) mice, the S. abortusovis resistance phenotype cosegregated with the two alleles of the Len-1 gene, a gene tightly linked to the Ity gene. By contrast, in these backcross mice, the level of infection of the peritoneal cavity, the site of inoculation, did not correlated with the Len-1 phenotype of the animal. These results provide evidence that after i.p. inoculation the control of S. abortusovis growth in the spleen and the liver is controlled by the Ity gene, but also suggest that additional gene(s) regulate the number of bacteria at the site of inoculation.  相似文献   
26.
The occurrence of hyperplastic pacinian corpuscles in the hand is rare, with only 13 cases reported in the literature. We describe such a case in a 70-year-old male who had worked as a locksmith for many years. A grape-like cluster of firm, rice-sized nodules was discovered in the subcutaneous tissue of the finger following a glass-induced injury. Histopathological findings revealed pacinian corpuscles to be increased in size and number. Individual corpuscles consisted of a central nerve fiber surrounded by 35 to 60 concentric lamellae (normal controls from other specimens: 13–15 lamellae). The external corpuscular diameter ranged from 1.8 to 3.2 mm (normal controls from other specimens: 1.6 mm). Immunohistochemistry showed positive staining with Leu 7 antibody and anti-glial fibrillary acidic protein in the small nerves situated in the vicinity of the pacinian corpuscles, but not in the corpuscles themselves. The lesion reported here clearly differed from both neurofibroma with occasional pacinian differentiation and the so-called pacinian neurofibroma. There was no evidence of neurofibromatosis.  相似文献   
27.
28.
Of 552 patients undergoing percutaneous transluminal coronary angioplasty 102 had coronary artery spasm superimposed on atherosclerotic narrowing. Coronary angioplasty was successful in 97 (95%). The patients were discharged on a regimen of nifedipine (40-60 mg/day). Seventy six patients were symptom free 6-8 months after the procedure. Restenosis was detected in 35% of patients. Coronary artery spasm was provoked in 38 (44%) of the 87 patients who underwent an ergometrine maleate test. Twenty seven of the 34 patients with restenosis had a provocation test and coronary artery spasm was superimposed on restenosis in 22 (81.5%). Coronary angioplasty is feasible in patients with coronary artery spasm superimposed on atherosclerotic narrowing but the rate of restenosis is high and coronary artery spasm could have a role in the pathogenesis of restenosis.  相似文献   
29.
The effect of intravenous streptokinase therapy on the time course of functional recovery was investigated in a controlled study of 64 patients randomized within 3 hours after the onset of acute myocardial infarction (AMI). Contrast ventriculography was performed 1 to 4 days after AMI and repeated 5 weeks later. Wall motion was analyzed by the centerline method in the central infarct, peripheral infarct and noninfarct regions. In patients with ventriculographic data at the early catheterization, streptokinase-treated patients had less severe hypokinesia in the central infarct region than control patients (-2.9 +/- 0.9 [n = 29] vs -3.4 +/- 0.7 standard deviations below normal [n = 21], p less than 0.05). The benefit of streptokinase was more marked in the peripheral infarct region (-1.5 +/- 0.7 vs -2.1 +/- 0.6, p less than 0.001). As a result, the ejection fraction was slightly higher in treated versus control groups (46 +/- 10 vs 43 +/- 7%, respectively; difference not significant). At 5 weeks, function in the streptokinase and control groups had diverged further because of continued improvement in the streptokinase-treated patients. This study shows that streptokinase benefits left ventricular (LV) function by 1 to 4 days after AMI, earlier than previously reported. The benefit was not limited to the peripheral infarct region, where ischemia might have been less severe, but was also seen in the central infarct region. The implication is that thrombolytic therapy can improve LV function during the period of myocardial stunning, while myocardial function is still recovering.  相似文献   
30.
GOALS: To give an overview on the theoretical and practical applications of chemosensory event-related potentials. METHODS: Chemosensory event-related potentials (ERPs) may be elicited by brief and precisely defined odorous stimuli. Based on the principles of air-dilution olfactometry, a stimulator was developed in the late 1970s, which allows stimulation of the olfactory neuroepithelium and the nasal mucosa with no concomitant mechanical stimulation. Chemosensory ERPs were obtained after stimulation of the olfactory nerve (olfactory ERPs) or the trigeminal nerve (somatosensory or trigeminal ERPs). The characteristics of the stimulator for chemosensory research as well as the variables influencing the responses are discussed in this paper. RESULTS: Implementation and normative data from our department are reported with different clinical examples from otorhinolaryngologic clinic. The bulk of the evoked response consists of a large negative component (often referred to as N1), which occurs between 320 and 450 ms after stimulus onset. This component is followed by a large positive component, often referred to as P2, occurring between 530 and 800 ms after stimulus onset. Absence of olfactory ERPs and presence (even with subtle changes) of somatosensory ERPs is a strong indicator of the presence of an olfactory dysfunction. CONCLUSIONS: This review examines and discusses the methods of chemosensory stimulation as well as the electrophysiological correlates elicited by such stimuli. The clinical applications of chemosensory ERPs in neurology and otorhinolaryngology are outlined.  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