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   1328篇
  免费   79篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   14篇
妇产科学   8篇
基础医学   182篇
口腔科学   149篇
临床医学   114篇
内科学   393篇
皮肤病学   25篇
神经病学   47篇
特种医学   39篇
外科学   153篇
综合类   4篇
预防医学   119篇
眼科学   9篇
药学   94篇
中国医学   2篇
肿瘤学   52篇
  2023年   9篇
  2022年   20篇
  2021年   57篇
  2020年   22篇
  2019年   61篇
  2018年   42篇
  2017年   35篇
  2016年   42篇
  2015年   39篇
  2014年   77篇
  2013年   74篇
  2012年   121篇
  2011年   117篇
  2010年   69篇
  2009年   61篇
  2008年   83篇
  2007年   97篇
  2006年   91篇
  2005年   58篇
  2004年   44篇
  2003年   32篇
  2002年   25篇
  2001年   10篇
  2000年   9篇
  1999年   20篇
  1998年   9篇
  1997年   7篇
  1996年   2篇
  1995年   6篇
  1993年   2篇
  1992年   5篇
  1991年   3篇
  1990年   5篇
  1989年   4篇
  1988年   4篇
  1986年   4篇
  1979年   2篇
  1975年   2篇
  1974年   3篇
  1972年   5篇
  1970年   2篇
  1969年   3篇
  1968年   4篇
  1967年   4篇
  1966年   3篇
  1965年   2篇
  1964年   3篇
  1963年   1篇
  1962年   1篇
  1961年   1篇
排序方式: 共有1409条查询结果,搜索用时 15 毫秒
1.
We report the case of a 49-year-old patient, with recent onset of fatigue, who was diagnosed with atrial fibrillation, which was cardioverted electrically. A diagnosis of right atrial aneurysm, with no other cardiac pathology, was made. An aneurysmectomy was performed. Both surgery and postoperative recovery were uneventful.  相似文献   
2.
This paper presents a full reconstruction process of magnetic resonance images. The first step is to bring the acquired data from the frequency domain, using a Fast Fourier Transform algorithm. A Tomographic Image Interpolation is then used to transform a sequence of tomographic slices in an isotropic volume data set, a process also called 3D Reconstruction. This work describes an automatic method whose interpolation stage is based on a previous matching stage using Delaunay Triangulation. The reconstruction approach uses an extrapolation procedure that permits appropriate treatment of the boundaries of the object under analysis.  相似文献   
3.
Medullary sponge kidney and congenital hemi-hypertrophy   总被引:2,自引:0,他引:2  
  相似文献   
4.
5.
6.
The cerebrovascular coupling under neuronal nitric oxide synthase (nNOS) inhibition was investigated in alpha-chloralose anesthetized rats. Cerebral blood flow (CBF), cerebral blood volume (CBV), and blood oxygenation level dependent (BOLD) responses to electrical stimulation of the forepaw were measured before and after an intraperitoneal bolus of 7-nitroindazole (7-NI), an in vivo inhibitor of the neuronal isoform of nitric oxide synthase. Neuronal activity was measured by recording somatosensory-evoked potentials (SEPs) via intracranial electrodes. 7-Nitroindazole produced a significant attenuation of the activation-elicited CBF (P<10(-6)), CBV (P<10(-6)), and BOLD responses (P<10(-6)), without affecting the baseline perfusion level. The average DeltaCBF was nulled, while DeltaBOLD and DeltaCBV decreased to approximately 30% of their respective amplitudes before 7-NI administration. The average SEP amplitude decreased (P<10(-5)) to approximately 60% of its pretreatment value. These data describe a pharmacologically induced uncoupling between neuronal and hemodynamic responses to functional activation, and provide further support for the critical role of neuronally produced NO in the cerebrovascular coupling.  相似文献   
7.
In this report, we describe an investigation of the effects of Lutzomyia longipalpis sand fly salivary gland homogenates (SGH) on cytokine production and expression of costimulatory molecules on human monocytes, macrophages (Ms), and dendritic cells (DCs). SGH of L. longipalpis induced an increase in interleukin-6 (IL-6), IL-8 and IL-12p40 production but a decrease in tumor necrosis factor alpha and IL-10 production by lipopolysaccharida (LPS)-stimulated monocytes. We also examined the expression of costimulatory molecules on the surface of monocytes, Ms, and DCs. Whereas SGH affected the expression of these molecules on monocytes and Ms, it had little effect on these molecules on DCs. However, when DCs were generated from human monocytes in the presence of SGH, SGH inhibited the expression of costimulatory molecules. In addition, a decrease in the maturation of DCs induced by CD40L was observed in the presence of SGH. Finally, preincubating SGH with human sera containing anti-SGH-specific antibodies abolished the effects of SGH on cytokine production by LPS-stimulated monocytes.  相似文献   
8.
9.
The difficulty in studying dengue virus (DENV) infection in humans and in developing a virus vaccine is the absence of a suitable animal model which develops the full spectra of the Dengue haemorrhagic fever (DHF) and Dengue shock syndrome (DSS). Despite the fact that viruses have been found in various animal tissues, we isolated DENV from tissues of adult BALB/c mice, inoculated with DENV serotype 2 (DENV-2) obtained from human serum. Viruses were ultrastructurally identified and immunolocalized by immunofluorescence techniques in C6/36 mosquito cell cultures, inoculated with tissues (liver, lung, kidney and cerebellum) macerate supernatant from mice, 48 h post-infection (p.i.). These organs, collected at the same stage of infection, were examined histologically. The histopathological analysis revealed focal alterations in all tissues examined. Liver contained focal ballooned hepatocytes, but without modifying the average diameter of the majority of hepatocytes. Sinusoidal lumen was significantly diminished at this stage but portal and centrolobular veins became congested. Lungs exhibited hemorrhagic foci in the alveolar space, vascular congestion and focal alveolitis. Cerebellar tissue showed rare foci of neuronal compactation (Purkinje cells) and perivascular oedema. In kidneys it was observed an increase in glomerular volume with augmented endocapillary and mesangial cellularity, with reactivity to anti-IgM in all glomeruli of infected mice. In conclusion, DENV-2 was found in all tissues examined early in the evolution of infection. Presence of viruses in tissues has mainly led to hemodynamic alterations with generalized vascular congestion and increased permeability, and mast cell recruitment in lungs. The latter could participate in the vascular modifications in tissues.  相似文献   
10.
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