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   732篇
  免费   42篇
  国内免费   2篇
耳鼻咽喉   18篇
儿科学   7篇
妇产科学   3篇
基础医学   129篇
口腔科学   9篇
临床医学   74篇
内科学   131篇
皮肤病学   29篇
神经病学   126篇
特种医学   35篇
外国民族医学   1篇
外科学   98篇
综合类   4篇
预防医学   29篇
眼科学   9篇
药学   54篇
中国医学   2篇
肿瘤学   18篇
  2023年   5篇
  2022年   13篇
  2021年   49篇
  2020年   19篇
  2019年   37篇
  2018年   24篇
  2017年   16篇
  2016年   22篇
  2015年   25篇
  2014年   25篇
  2013年   26篇
  2012年   47篇
  2011年   47篇
  2010年   50篇
  2009年   25篇
  2008年   32篇
  2007年   30篇
  2006年   21篇
  2005年   25篇
  2004年   20篇
  2003年   15篇
  2002年   11篇
  2001年   13篇
  2000年   7篇
  1999年   14篇
  1998年   4篇
  1995年   5篇
  1994年   3篇
  1992年   12篇
  1991年   3篇
  1990年   7篇
  1989年   8篇
  1988年   4篇
  1987年   4篇
  1986年   4篇
  1985年   4篇
  1983年   9篇
  1979年   8篇
  1978年   3篇
  1977年   5篇
  1976年   5篇
  1975年   5篇
  1973年   4篇
  1972年   8篇
  1971年   7篇
  1970年   12篇
  1969年   6篇
  1967年   5篇
  1966年   2篇
  1965年   4篇
排序方式: 共有776条查询结果,搜索用时 515 毫秒
1.
It is well recognized that the world population is ageing rapidly. Therefore, it is important to understand ageing processes at the cellular and molecular levels to predict the onset of age‐related diseases and prevent them. Recent research has focused on the identification of ageing biomarkers, including those associated with the properties of the Golgi apparatus. In this context, Golgi‐mediated glycosylation of proteins has been well characterized. Additionally, other studies show that the secretion of many compounds, including pro‐inflammatory cytokines and extracellular matrix–degrading enzymes, is modified during ageing, resulting in physical and functional skin degradation. Since the Golgi apparatus is a central organelle of the secretory pathway, we investigated its structural organization in senescent primary human dermal fibroblasts using confocal and electron microscopy. In addition, we monitored the expression of Golgi‐related genes in the same cells. Our data showed a marked alteration in the Golgi morphology during replicative senescence. In contrast to its small and compact structure in non‐senescent cells, the Golgi apparatus exhibited a large and expanded morphology in senescent fibroblasts. Our data also demonstrated that the expression of many genes related to Golgi structural integrity and function was significantly modified in senescent cells, suggesting a relationship between Golgi apparatus function and ageing.  相似文献   
2.
Dry skin (xerosis) is a common dermatosis affecting people of varying skin types and ages and various areas of the body. It is associated with both skin thickening and skin thinning and is triggered by both exogenous (e.g. climate, environment, lifestyle) and endogenous (e.g. medication, hormone fluctuations, organ diseases) factors. Skin requires a water content of 10–15% to remain supple and intact. This water is either ‘static’ (i.e. bound) or ‘dynamic’. The predominance of hydrophobic substances in intercellular constituents is a means of regulating the humidity of the skin. Emollients, highly effective treatment adjuncts in the management of all dry skin disorders, help to restore damaged intercorneocyte lipid structures and increase the water content of the skin, helping to reduce scaling and improving its barrier function.  相似文献   
3.
Exogenous glucocorticoid hormones are widely used as therapeutical agents, whereas endogenous glucocorticoids may act as physiological immunosuppressants involved in the control of immune and inflammatory responses. The optimal activation of T lymphocytes requires two distinct signals: the major histocompatibility complex-restricted presentation of the antigen and an additional co-stimulatory signal provided by the antigen-presenting cells. There is ample evidence that, among the cells able to present the antigen, the dendritic cells (DC) have the unique property to activate antigen-specific, naive T cells in vitro and in vivo, and are therefore required for the induction of primary immune responses. In this work, we tested whether glucocorticoids affected the capacity of DC to sensitize naive T cells. Our data show that, in vitro, the steroid hormone analog dexamethasone (Dex) affects the viability of DC, selectively downregulates the expression of co-stimulatory molecules on viable DC, and strongly reduces their immunostimulatory properties. In vivo, a single injection of Dex results in impaired antigen presenting function, a finding which correlates with reduced numbers of splenic DC. These results show that glucocorticoids regulate DC maturation and immune function in vitro and in vivo and suggest that this mechanism may play a role in preventing overstimulation of the immune system.  相似文献   
4.
Burn survivors experience myriad associated symptoms such as pain, pruritus, fatigue, impaired motor strength, post-traumatic stress, depression, anxiety, and sleep disturbance. Many of these symptoms are common and remain chronic, despite current standard of care. One potential novel intervention to target these post burn symptoms is transcranial direct current stimulation (tDCS). tDCS is a non-invasive brain stimulation (NIBS) technique that modulates neural excitability of a specific target or neural network. The aim of this work is to review the neural circuits of the aforementioned clinical sequelae associated with burn injuries and to provide a scientific rationale for specific NIBS targets that can potentially treat these conditions. We ran a systematic review, following the PRISMA statement, of tDCS effects on burn symptoms. Only three studies matched our criteria. One was a feasibility study assessing cortical plasticity in chronic neuropathic pain following burn injury, one looked at the effects of tDCS to reduce pain anxiety during burn wound care, and one assessed the effects of tDCS to manage pain and pruritus in burn survivors. Current literature on NIBS in burn remains limited, only a few trials have been conducted. Based on our review and results in other populations suffering from similar symptoms as patients with burn injuries, three main areas were selected: the prefrontal region, the parietal area and the motor cortex. Based on the importance of the prefrontal cortex in the emotional component of pain and its implication in various psychosocial symptoms, targeting this region may represent the most promising target. Our review of the neural circuitry involved in post burn symptoms and suggested targeted areas for stimulation provide a spring board for future study initiatives.  相似文献   
5.
ObjectivesMeasures on conventional radiography are used to detect, especially in rheumatoid arthritis, upper cervical spine instabilities (CSIs) with the anterior and posterior atlanto-dental intervals (AADI and PADI) measurements. Our objective was to evaluate the diagnostic performance and reliability of AADIs and PADIs extrapolated based on ratios in assessing anterior atlanto-axial subluxation (aAAS) when plain radiographs do not allow the measures.MethodsRadiographies of 119 patients were randomly selected. Two blinded observers performed two measurements of the odontoid sagittal diameter (O), axis body base sagittal diameter (C2), AADI, PADI, Clark station and Ranawat index, and the AADI/O, AADI/C2, PADI/O and PADI/C2 ratios were calculated. The diagnostic value of AADI and PADI extrapolated from the AADI/O, AADI/C2, PADI/O and PADI/C2 ratios was evaluated using ROC curves, with AADI > 2.9 mm used as the gold standard.ResultsAmong the 119 patients, 12 patients had aAAS (AADI > 2.9 mm), 6 of them had severe aAAS (AADI > 8.9 mm and/or a PADI < 14 mm), and 6 patients had vertical AAS (Clarks station = 2 or 3 and/or Ranawat index < 13 mm). The AADI extrapolated from the AADI/O and AADI/C2 ratios has excellent intra- and inter-observer reproducibility. The diagnostic value of the extrapolated AADI was high for aAAS (sensitivity 92%; specificity of 100%) and severe aAAS (sensitivity75%; specificity 100%). The diagnostic value of the extrapolated PADI was good but lower than the diagnostic value of the extrapolated AADI.ConclusionExtrapolated AADI can be used instead AADI to detect aAAS and severe aAAS.  相似文献   
6.
The present study aimed to determine whether current commercial immunoassays are adequate for detecting anti-Omicron antibodies. We analyzed the anti-SARS-CoV-2 antibody response of 23 unvaccinated individuals 1–2 months after an Omicron infection. All blood samples were tested with a live virus neutralization assay using a clinical Omicron BA.1 strain and four commercial SARS-CoV-2 immunoassays. We assessed three anti-Spike immunoassays (SARS-CoV-2 IgG II Quant [Abbott S], Wantaï anti-SARS-CoV-2 antibody ELISA [Wantaï], Elecsys Anti-SARS-CoV-2 S assay [Roche]) and one anti-Nucleocapsid immunoassay (Abbott SARS-CoV-2 IgG assay [Abbott N]). Omicron neutralizing antibodies were detected in all samples with the live virus neutralization assay. The detection rate of the Abbott S, Wantai, Roche, and Abbott N immunoassays were 65.2%, 69.6%, 86.9%, and 91.3%, respectively. The sensitivities of Abbott S and Wantai immunoassays were significantly lower than that of the live virus neutralization assay (p = 0.004, p = 0.009; Fisher's exact test). Antibody concentrations obtained with anti-S immunoassays were correlated with Omicron neutralizing antibody concentrations. These data provide clinical evidence of the loss of performance of some commercial immunoassays to detect antibodies elicited by Omicron infections. It highlights the need to optimize these assays by adapting antigens to the circulating SARS-CoV-2 strains.  相似文献   
7.
BACKGROUND: The implementation of organized breast cancer screening in Flanders was prepared by means of pilot projects within a multicenter study. In the semi-rural district of Kontich (Province of Antwerp, Flanders) a pilot project was performed using a mobile screening unit. Compared to international standards, the attendance rate for this pilot project (i.e. 34%) was low. Non-organized screening, which already exists in Flanders, at least partly explains this low attendance rate for the organized screening. The main purpose of our study was to investigate the experience of the pilot target group with respect to the organized breast cancer screening in the district of Kontich, in order to maximize the conditions for a high attendance rate in the organized breast cancer screening programme throughout Flanders. METHODS: With a random numbers procedure, performed by the computer, 500 women were selected among those who were invited to the first screening round of the breast cancer screening programme in the district of Kontich (n = 6,897). These 500 randomly selected women were asked to cooperate with a face-to-face interview. The questionnaire used dealt with the different aspects of the organized mammographic screening which were expected to influence the decision to attend. RESULTS: There were 348 women who responded to the questionnaire (69.6%): 138 of them were attenders and 210 were non-attenders at the organized breast cancer screening. Attenders and non-attenders at the organized breast cancer screening in the district of Kontich had different views about various aspects of the screening programme. The percentages of those who thought that an item was important or very important to them, were for the 138 attenders and the 210 non-attenders respectively: "to receive a personal invitation letter": 90.6 vs. 48.1% (p < 0.05); "a preliminary visit to the GP": 9.4 vs. 34.3% (p < 0.05); "possibility of examination outside business hours": 15.9 vs. 30.0% (p < 0.05). CONCLUSIONS: Although the putting into action of a mobile unit in the semi-rural area of the district of Kontich was productive, the attendance rate was still too low compared to international standards. To increase the attendance rate, the following interventions should be considered: devising the personal invitation letter in a more attractive way, activating and stimulating the important motivational role of the GP in persuading women to attend the organized screening programme and offering the invited population the possibility to have a mammographic examination performed outside business hours. Appropriate measures are being explored.  相似文献   
8.
BRomocriptine (15-75 mg per day) alone or with L-dopa was studied during five to 29 months on 44 patients with Parkinson's disease. Used as sole therapeutic agent, it was found excellent in 12 patients who had never received regular L-dopa treatment either because it was never attempted or because of intolerance from the outset. Its anti-Parkinsonism activity was comparable with L-dopa. The gain was stable in the long term until this report. The side effects of L-dopa were not seen after bromocriptine. In cases where L-dopa had ceased to be active, bromocriptine produced a further improvement if mental deterioration was not associated. In very advanced forms of Parkinson's disease with associated dementia, bromocriptine did not produce durable results. Bromocriptine did not improve the "on-off" effects but reduced a number of the side effects of L-dopa, in particular cardiac, painful contractions, and dyskinesia without "on-off" effects.  相似文献   
9.
OBJECTIVE: Proton magnetic resonance spectroscopy (1H-MRS) was used to study medial prefrontal metabolic impairments in schizophrenic patients with the deficit syndrome. METHOD: The subjects were 22 schizophrenic patients categorized as deficit (N=5) or nondeficit (N=17) and 21 healthy subjects. (1)H-MRS was performed for the right and the left medial prefrontal cortex. RESULTS: The patients with the deficit syndrome had significantly lower ratios of N-acetylaspartate to creatine plus phosphocreatine than did the healthy subjects or nondeficit patients. CONCLUSIONS: As N-acetylaspartate levels could reflect neuronal density and/or viability, this finding suggests a neuronal loss in the medial prefrontal cortex of deficit patients.  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