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   55938篇
  免费   4424篇
  国内免费   1265篇
耳鼻咽喉   825篇
儿科学   500篇
妇产科学   160篇
基础医学   2056篇
口腔科学   2243篇
临床医学   8801篇
内科学   6331篇
皮肤病学   191篇
神经病学   2953篇
特种医学   17900篇
外国民族医学   27篇
外科学   4911篇
综合类   6170篇
现状与发展   4篇
预防医学   860篇
眼科学   3190篇
药学   1402篇
  9篇
中国医学   156篇
肿瘤学   2938篇
  2024年   175篇
  2023年   1136篇
  2022年   2004篇
  2021年   2621篇
  2020年   2069篇
  2019年   1830篇
  2018年   1882篇
  2017年   1773篇
  2016年   1884篇
  2015年   1899篇
  2014年   3736篇
  2013年   2986篇
  2012年   3298篇
  2011年   3530篇
  2010年   3101篇
  2009年   3211篇
  2008年   3131篇
  2007年   3153篇
  2006年   2816篇
  2005年   2397篇
  2004年   1945篇
  2003年   1614篇
  2002年   1321篇
  2001年   1189篇
  2000年   936篇
  1999年   803篇
  1998年   634篇
  1997年   651篇
  1996年   509篇
  1995年   468篇
  1994年   417篇
  1993年   304篇
  1992年   245篇
  1991年   207篇
  1990年   195篇
  1989年   190篇
  1988年   164篇
  1987年   177篇
  1986年   125篇
  1985年   155篇
  1984年   161篇
  1983年   94篇
  1982年   140篇
  1981年   114篇
  1980年   78篇
  1979年   61篇
  1978年   34篇
  1977年   39篇
  1976年   23篇
  1974年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
对50例神经根型颈椎病的CT征象进行了分析,并与X线平片加以比较。认为CT不仅在神经根型颈椎病的诊断中具有独特作用,而且在确定手术方法和手术途径的选择上也很有意义。作者认为在CT机还没有普及的情况下,摄一张良好的钩椎关节放大斜位片或椎间孔断层片对诊断神经根型颈椎病应是首选的。CT和X线平片相结合,综合分析,更有价值。  相似文献   
22.
Cranial computed tomography (CCT) findings for 37 patients with cycloid psychosis and 19 patients with DSM-III-R schizophrenia were compared with findings for age- and sex-matched controls. Schizophrenic patients showed enlarged ventricles compared both to controls and to patients suffering from cycloid psychosis. In patients with cycloid psychosis, neither at the first episode nor after many years (mean 16.6 years) of disease were significant differences found compared to control subjects. Over the course of the illness, patients with cycloid psychosis showed ventricular enlargement which was correlated with age but not with the duration of illness. The morphological differences provide further evidence for the proposed nosological distinction between cycloid psychosis and schizophrenia.  相似文献   
23.
Individual skull model fabrication was introduced into preoperative diagnostics in maxillofacial surgery in the mid-1980s. The aim of the present study was to collect information on the reproducibility of a skull model milled from hardened polyurethane foam. This model was based on the CT data of a real skull. Twenty comparative studies were carried out on both the model and the original skull, the model showing an average inaccuracy of 1.6 mm. The deviations ranged between 0.0 and 3.6 mm; the general trend favouring enlargements. The total deviation of the model as compared to the original skull was 1.8%. A convincing aspect of the model, which cannot be obtained by any other method, is its plasticity and the possibility of 3 D orientation on a lifesize model. This new method is already used in preoperative planning of corrections of post-traumatic defects and craniofacial deformities as well as in tumour surgery. Correspondence to: P. Solar  相似文献   
24.
Summary Obturator hernias comprise a rare group of abdominal hernias. They are often diagnosed when the small bowel has become obstructed and the patients are operated on without the causes of the obstruction being known. Although many techniques for closure of the defect are available, there is no agreement at the present time as to which is the procedure of choice.  相似文献   
25.
A 36-year-old man was brought to the emergency department after being assaulted. A mandible series showed a nondisplaced fracture through the angle of the mandible extending through the left third molar tooth. Axial slices from a nonhelical computed tomographic (CT) examination of the head as well as a helical CT examination of the mandible failed to demonstrate the fracture. The fracture was well shown, however, on sagittal CT reformations. Although CT is generally regarded as more sensitive than plain radiography for the detection of fractures, fractures may be overlooked by CT if examination in only one plane is performed.  相似文献   
26.
This article reviews a focused helical appendiceal computed tomographic technique and discusses an approach to appendiceal computed tomographic interpretation.  相似文献   
27.
28.
鼻咽癌增强CT扫描的影像表现及价值(附102例报告)   总被引:7,自引:0,他引:7  
目的 探讨鼻咽癌 (NPC)增强CT表现和价值。方法 对 10 2例NPC放化疗前病人行平扫加增强扫描 ,观察癌灶密度变化、鼻咽表面线样强化层和癌灶周界情况。结果 平扫癌灶密度与同层面鼻咽肌相近的有 89例 (87% ) ,其余与翼外肌相近(13 % )。平扫难以明确癌灶的大小和范围 ,所能显示的仅是有无占位。增强扫描癌灶密度差异明显的占 44% ,单靠密度差异能使其周界全部或大部清楚的仅占 40 %。根据癌灶强化和线样强化层的表现 ,综合判断癌灶周界全部或大部清楚的达到 76%。结论 增强扫描对准确判断NPC癌灶的大小、范围以及对发现小的癌灶和鉴别诊断有重要作用。在主要针对鼻咽部本身的检查 ,增强也应列为常规扫描  相似文献   
29.
BACKGROUND: Elevated cortisol levels might account for the reduction in central serotonin 1A (5-hydroxytryptamine [5-HT](1A)) receptor binding and function observed in patients with major depression. We tested this hypothesis by studying the effect of acute administration of hydrocortisone on 5-HT(1A) receptor binding potential (BP) in subjects recovered from depression. METHODS: We studied 14 subjects (8 male, 6 female) who had recovered from at least two episodes of major depression and had been euthymic and drug free for at least 6 months. Serotonin 1A receptor BP was measured by [(11)C]WAY-100635 in conjunction with positron emission tomography. Subjects were tested on two occasions in a double-blind, random-order, crossover design after administration of either hydrocortisone (100 mg orally) or placebo 12 hours previously. Positron emission tomography scans were analyzed with a region of interest analysis. RESULTS: Hydrocortisone treatment did not decrease 5-HT(1A) receptor BP either in the hippocampus, which was our a priori hypothesis, or in other cortical 5-HT(1A) regions; however, female subjects had a higher 5-HT(1A) receptor BP in certain brain areas compared with male subjects. CONCLUSIONS: These data are consistent with an earlier study in healthy volunteers and do not support the proposal that decreased 5-HT(1A) receptor BP in patients with acute major depression is a consequence of cortisol hypersecretion.  相似文献   
30.
This report describes a technique in which deep-seated CNS neoplasms, the volume and shape of which had been determined and stereotactically localized by computer reconstruction of CT data, were vaporized with a carbon dioxide laser attached to a stereotactic frame. The clinical results with 6 patients treated by this technique are presented.  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