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   1424篇
  免费   73篇
  国内免费   5篇
耳鼻咽喉   2篇
儿科学   24篇
妇产科学   18篇
基础医学   180篇
口腔科学   18篇
临床医学   71篇
内科学   260篇
皮肤病学   44篇
神经病学   193篇
特种医学   59篇
外科学   125篇
综合类   4篇
预防医学   43篇
眼科学   25篇
药学   60篇
中国医学   3篇
肿瘤学   373篇
  2023年   4篇
  2022年   9篇
  2021年   27篇
  2020年   16篇
  2019年   23篇
  2018年   40篇
  2017年   27篇
  2016年   24篇
  2015年   18篇
  2014年   43篇
  2013年   55篇
  2012年   110篇
  2011年   90篇
  2010年   48篇
  2009年   54篇
  2008年   68篇
  2007年   96篇
  2006年   87篇
  2005年   90篇
  2004年   78篇
  2003年   86篇
  2002年   75篇
  2001年   18篇
  2000年   24篇
  1999年   29篇
  1998年   23篇
  1997年   17篇
  1996年   14篇
  1995年   8篇
  1994年   10篇
  1993年   14篇
  1992年   17篇
  1991年   12篇
  1990年   17篇
  1989年   9篇
  1988年   18篇
  1987年   16篇
  1986年   8篇
  1985年   11篇
  1984年   8篇
  1983年   9篇
  1981年   5篇
  1980年   9篇
  1979年   5篇
  1978年   6篇
  1976年   4篇
  1974年   3篇
  1972年   3篇
  1970年   3篇
  1969年   3篇
排序方式: 共有1502条查询结果,搜索用时 140 毫秒
41.
42.
We describe a case of serum amyloid A (SAA) and C‐reactive protein (CRP) positive nodule detected by immunohistochemical analysis in a 37‐year‐old woman with alcohol‐related cirrhosis. Imaging studies at first admission pointed to hepatocellular carcinoma (HCC), a dysplastic nodule, an inflammatory pseudotumor or focal nodular hyperplasia (FNH). Ultrasonography‐guided biopsy in Segment 2 showed minimal atypical changes, except for a slight increase in cell density and micronodular cirrhosis in the non‐nodular portion. gadolinium‐ethoxybenzyl‐diethylenetriamine pentaacetic acid‐enhanced magnetic resonance imaging carried out after a year and a half revealed hypervascularity in the arterial phase and isointensity in the hepatobiliary phase. Three years thereafter, however, the imaging displayed a change from isointensity to a defect in the hepatobiliary phase, and the nodule demonstrated minimal histological atypia. Immunohistochemical staining of the nodule was positive for SAA, CRP, liver fatty acid‐binding protein and glutamine synthetase, but negative for β‐catenin, heat shock protein 70 and Glypican 3. Organic anion transporter (OATP)8 staining was weaker in the nodule than in the non‐nodular portion of the alcohol‐related micronodular cirrhosis. The nodule was diagnosed as an SAA and CRP positive nodule, and HCC was ruled out. Despite the change from isointensity to a defect in the hepatobiliary phase, no evidence of HCC was found in the biopsy specimen. The change may be explained more by the weak OATP8 staining compared with that of alcohol‐related liver cirrhosis than by malignant transformation into HCC.  相似文献   
43.
44.
45.
46.
BackgroundThe utilities of magnetic cervical motor root stimulation are well known for lesions in the lower part of the brachial plexus, but not for lesions in the other parts.ObjectiveThe aim of paper is to show the utilities of magnetic cervical motor root stimulation for lesions in the upper part of the brachial plexus.MethodsWe analyzed the brachial plexus using both electrical stimulation at Erb's point and magnetic cervical motor root stimulation in a patient with brachial plexopathy caused by tumor invasion.ResultsOn the fourth day after onset, magnetic cervical motor root stimulation revealed abnormal findings in the upper part of the brachial plexus. Two weeks after onset, needle electromyography supported the existence of the focal lesion.ConclusionMagnetic cervical motor root stimulation is useful in detecting abnormal findings in the upper part of the brachial plexus, even at the acute phase.  相似文献   
47.
Aim: In elderly patients with dementia, disturbed eating behavior is understood to be a core symptom or a behavioral and psychological symptom of dementia (BPSD). The purpose of the present study was to investigate the factors affecting self‐feeding in elderly patients with Alzheimer's disease (AD). Methods: A total of 150 AD patients who were hospitalized in dementia wards, or were residents of institutions or group homes were enrolled. The patients underwent an eating behavior examination, cognitive assessment, neurological examination and vital function tests. The eating behavior examination consisted of observation of the patients at mealtime. Items assessing eating behavior included the number of feeding cycles, stopping of eating or agitation and dysfunction. Results: Logistic regression analysis carried out to identify factors with a significant effect on decreased independence in eating were difficulty in beginning a meal (OR = 14.498, CI = 2.067–101.690), presence of dysphagia signs (OR = 5.214, CI = 1.031–26.377) and the severity of dementia (OR = 4.538, CI = 1.154–17.843). Conclusion: The present study is the first to generate objective data showing that difficulty in beginning a meal is a factor that hinders independence in eating in AD, in addition to the presence of dysphagia signs and the severity of dementia. Assisting AD patients in maintaining eating independence might be effectively achieved by eliminating environmental factors that interfere with beginning a meal, and by providing assistance that will promote beginning a meal. The present results show the necessity of developing effective methods for assisting elderly patients with AD. Geriatr Gerontol Int 2012; 12: 481–490.  相似文献   
48.
This report describes a 60-year-old female patient with Krabbe disease who presented with slowly progressive gait disturbance due to mild spastic paraplegia. Brain magnetic resonance imaging showed high-intensity lesions along the upper parts of the bilateral pyramidal tracts in fluid-attenuated inversion recovery images. Central motor conduction time was prolonged both in the upper and the lower extremities, while central sensory conduction time was normal. The reduced lymphocyte galactocerebrosidase (GALC) activity and two novel mutations in the GALC gene, p.G496S and p.G569S, proved the diagnosis of Krabbe disease. Our findings show that adult-onset Krabbe disease is characterized by isolated pyramidal tract impairment in the central nervous system, both neurophysiologically and radiologically.  相似文献   
49.

Objective

To clarify the details of homogeneously enhancing lesions on contrast-enhanced ultrasonography (CEUS) and also to elucidate whether their differential diagnosis is possible.

Methods

Seventy-three homogeneously enhancing lesions on CEUS were retrospectively selected. Two radiologists first assessed conventional US findings alone in consensus to differentiate malignant vs. benign lesions. Then, qualitative and quantitative CEUS findings were analyzed to determine the useful findings for the differential diagnosis. Determined CEUS findings were applied to the indeterminate lesions based on conventional US findings to see whether CEUS can improve the diagnostic performance.

Results

There were 42 cancers (58 %) out of 73. Sensitivity and specificity using conventional US findings alone were 91 and 55 %, respectively. Among the CEUS findings tested, multivariate analysis revealed only the type 3 enhancement pattern, which indicates a larger enhancing area than the precontrast hypoechoic lesion, was related to malignancy (p < 0.05). By adding this information, however, no improvement was achieved in the diagnostic performance as determined by conventional US findings.

Conclusions

Approximately half of the homogeneously enhancing lesions on CEUS are malignant, and differentiation of malignant from benign lesions may be possible, at least to some extent, by meticulous assessment of the conventional US rather than CEUS findings.
  相似文献   
50.
Dutch-belted and New Zealand White rabbits were passively immunized with AVP-21D9, a human monoclonal antibody to protective antigen (PA), at the time of Bacillus anthracis spore challenge using either nasal instillation or aerosol challenge techniques. AVP-21D9 (10 mg/kg) completely protected both rabbit strains against lethal infection with Bacillus anthracis Ames spores, regardless of the inoculation method. Further, all but one of the passively immunized animals (23/24) were completely resistant to rechallenge with spores by either respiratory challenge method at 5 weeks after primary challenge. Analysis of the sera at 5 weeks after primary challenge showed that residual human anti-PA levels decreased by 85 to 95%, but low titers of rabbit-specific anti-PA titers were also measured. Both sources of anti-PA could have contributed to protection from rechallenge. In a subsequent study, bacteriological and histopathology analyses revealed that B. anthracis disseminated to the bloodstream in some na?ve animals as early as 24 h postchallenge and increased in frequency with time. AVP-21D9 significantly reduced the dissemination of the bacteria to the bloodstream and to various organs following infection. Examination of tissue sections from infected control animals, stained with hematoxylin-eosin and the Gram stain, showed edema and/or hemorrhage in the lungs and the presence of bacteria in mediastinal lymph nodes, with necrosis and inflammation. Tissue sections from infected rabbits dosed with AVP-21D9 appeared comparable to corresponding tissues from uninfected animals despite lethal challenge with B. anthracis Ames spores. Concomitant treatment with AVP-21D9 at the time of challenge conferred complete protection in the rabbit inhalation anthrax model. Early treatment increased the efficacy progressively and in a dose-dependent manner. Thus, AVP-21D9 could offer an adjunct or alternative clinical treatment regimen against inhalation anthrax.  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