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   876篇
  免费   70篇
  国内免费   5篇
耳鼻咽喉   5篇
儿科学   58篇
妇产科学   17篇
基础医学   92篇
口腔科学   12篇
临床医学   138篇
内科学   210篇
皮肤病学   13篇
神经病学   170篇
特种医学   11篇
外科学   133篇
综合类   10篇
预防医学   12篇
眼科学   1篇
药学   26篇
中国医学   5篇
肿瘤学   38篇
  2023年   3篇
  2022年   6篇
  2021年   12篇
  2020年   11篇
  2019年   19篇
  2018年   20篇
  2017年   25篇
  2016年   28篇
  2015年   28篇
  2014年   23篇
  2013年   49篇
  2012年   65篇
  2011年   77篇
  2010年   40篇
  2009年   40篇
  2008年   42篇
  2007年   57篇
  2006年   54篇
  2005年   45篇
  2004年   44篇
  2003年   33篇
  2002年   42篇
  2001年   27篇
  2000年   18篇
  1999年   24篇
  1998年   7篇
  1997年   8篇
  1996年   7篇
  1995年   6篇
  1994年   4篇
  1993年   7篇
  1992年   7篇
  1991年   7篇
  1990年   6篇
  1989年   2篇
  1988年   6篇
  1987年   3篇
  1986年   8篇
  1985年   7篇
  1984年   4篇
  1983年   6篇
  1982年   2篇
  1977年   2篇
  1976年   3篇
  1974年   4篇
  1940年   1篇
  1939年   1篇
  1934年   1篇
  1932年   1篇
  1931年   1篇
排序方式: 共有951条查询结果,搜索用时 15 毫秒
1.
2.
Hashimoto's thyroiditis, autoimmune adrenalitis, pernicious anaemia, and diabetes mellitus are all recognised associations with Down's syndrome. In addition chronic active hepatitis (CAH) resulting from chronic hepatitis B antigenaemia is known to occur in these patients, but an association of autoimmune CAH and Down's syndrome has not previously been described. We report a case in which Down's syndrome was associated with autoimmune CAH, Hashimoto's thyroiditis, and alopecia areata.  相似文献   
3.
The Rotalex test, a commercial latex agglutination test for rotavirus, was compared with direct electron microscopy (EM) and the Rotazyme test I, a commercial enzyme immunoassay, for detection of rotavirus in stools of children and neonates. For initial stool specimens from 265 children (less than 3 years old) with diarrhea, the Rotalex test had a sensitivity of 81.7% and specificity of 99.5% compared with EM results. Positive and negative predictive values were 98 and 94.9%, respectively. The Rotalex test was slightly more sensitive and specific than the Rotazyme test. When daily stool specimens from patients with rotavirus gastroenteritis were examined, the sensitivity of the Rotalex test varied depending on the time of stool collection relative to the onset of symptoms. Sensitivity was 100 (20/20), 96 (23/24), and 54% (7/13) during 1 to 4, 5 to 7, and 8 to 18 days, respectively, after the onset of symptoms. The sensitivity of the Rotazyme test varied similarly with days from onset. We also examined 214 EM-negative stool specimens from asymptomatic newborns. False positivity by the Rotalex test was only 3.3% (7/214) compared with 4.2% (9/215) for the Rotazyme test. The Rotalex test was as sensitive and specific as EM for detection of rotavirus during the acute stage of illness and much faster and cheaper than EM or the Rotazyme test. The test appears to be suitable for routine use in small hospitals, emergency wards, or even the physician's office for rapid diagnosis of rotavirus gastroenteritis.  相似文献   
4.
OBJECTIVE: To determine the validity of a clinical diagnosis of probable or possible dementia with Lewy bodies (DLB) made using International Consensus criteria. BACKGROUND: Validation studies based on retrospective chart reviews of autopsy-confirmed cases have suggested that diagnostic specificity for DLB is acceptable but case detection rates as low as 0.22 have been suggested. METHODS: We evaluated the first 50 cases reaching neuropathologic autopsy in a cohort to which Consensus clinical diagnostic criteria for DLB, National Institute for Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for AD, and National Institute of Neurological Disorders and Stroke-Association Internationale pour la Recherche et l'Enseignement en Neurosciences criteria for vascular dementia (VaD) had been prospectively applied. RESULTS: Twenty-six clinical diagnoses of DLB, 19 of AD, and 5 of VaD were made. At autopsy, 29 DLB cases, 15 AD, 5 VaD, and 1 progressive supranuclear palsy were identified. The sensitivity and specificity of a clinical diagnosis of probable DLB in this sample were 0.83 and 0.95. Of the five cases receiving a false-negative diagnosis of DLB, significant fluctuation was present in four but visual hallucinations and spontaneous motor features of parkinsonism were generally absent. Thirty-one percent of the DLB cases had additional vascular pathology and in two cases this contributed to a misdiagnosis of VaD. No correlations were found between the distribution of Lewy bodies and clinical features. CONCLUSION: The Consensus criteria for DLB performed as well in this prospective study as those for AD and VaD, with a diagnostic sensitivity substantially higher than that reported by previous retrospective studies. DLB occurs in the absence of extrapyramidal features and in the presence of comorbid cerebrovascular disease. Fluctuation is an important diagnostic indicator, reliable measures of which need to be developed further.  相似文献   
5.
One year follow-up of parkinsonism in dementia with Lewy bodies   总被引:1,自引:0,他引:1  
The progression of parkinsonism over 1 year was evaluated in a prospective cohort of patients (n = 338), suffering from dementia with Lewy bodies (DLB), Alzheimer's disease (AD) or vascular dementia (VaD). Parkinsonism was assessed using the modified Unified Parkinson's Disease Rating Scale. Significant parkinsonism was significantly commoner in DLB sufferers (71%) than amongst patients with AD (7%) or VaD (10%). DLB patients with established parkinsonism had an annual increase in severity of 9%, but progression was more rapid (49% in 1 year) in patients with early parkinsonism. Parkinsonism was frequent at all severities in DLB patients, but usually only present in other dementias when MMSE <10.  相似文献   
6.
The neuropathological substrates of dementia and depression were evaluated in 30 patients with cerebrovascular disease and significant cognitive impairment (VaD), with a particular focus on patients with small infarct volumes (<15 ml). VaD patients with small infarct volumes had a similar degree of cognitive impairment to those with larger infarct volumes (>15 ml) but were significantly more likely to be depressed and to have areas of microinfarction. A review of individual cases with small infarct volumes suggested that the combination of microinfarction, diffuse white matter disease and perivascular changes, or the overlap of neurodegenerative pathologies and microvascular changes were particularly important. Microinfarction was also significantly associated with major depression.  相似文献   
7.
Mesenchymal stromal cells (MSCs) have a multilineage differentiation potential and provide immunosuppressive and antimicrobial functions. Murine as well as human MSCs restrict the proliferation of T cells. However, species-specific differences in the underlying molecular mechanisms have been described. Here, we analyzed the antiparasitic effector mechanisms active in murine MSCs. Murine MSCs, in contrast to human MSCs, could not restrict the growth of a highly virulent strain of Toxoplasma gondii (BK) after stimulation with IFN-γ. However, the growth of a type II strain of T. gondii (ME49) was strongly inhibited by IFN-γ-activated murine MSCs. Immunity-related GTPases (IRGs) as well as guanylate-binding proteins (GBPs) contributed to this antiparasitic effect. Further analysis showed that IFN-γ-activated mMSCs also inhibit the growth of Neospora caninum, a parasite belonging to the apicomplexan group as well. Detailed studies with murine IFN-γ-activated MSC indicated an involvement in IRGs like Irga6, Irgb6 and Irgd in the inhibition of N. caninum. Additional data showed that, furthermore, GBPs like mGBP1 and mGBP2 could have played a role in the anti-N. caninum effect of murine MSCs. These data underline that MSCs, in addition to their regenerative and immunosuppressive activity, function as antiparasitic effector cells as well. However, IRGs are not present in the human genome, indicating a species-specific difference in anti-T. gondii and anti-N. caninum effect between human and murine MSCs.  相似文献   
8.
9.
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