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   630篇
  免费   36篇
耳鼻咽喉   9篇
儿科学   19篇
妇产科学   32篇
基础医学   86篇
口腔科学   32篇
临床医学   82篇
内科学   90篇
皮肤病学   10篇
神经病学   77篇
特种医学   27篇
外科学   39篇
综合类   6篇
一般理论   4篇
预防医学   66篇
眼科学   5篇
药学   61篇
中国医学   5篇
肿瘤学   16篇
  2023年   6篇
  2022年   9篇
  2021年   20篇
  2020年   13篇
  2019年   19篇
  2018年   19篇
  2017年   20篇
  2016年   20篇
  2015年   14篇
  2014年   28篇
  2013年   28篇
  2012年   38篇
  2011年   45篇
  2010年   26篇
  2009年   17篇
  2008年   36篇
  2007年   36篇
  2006年   21篇
  2005年   37篇
  2004年   31篇
  2003年   34篇
  2002年   14篇
  2001年   6篇
  1998年   3篇
  1996年   6篇
  1995年   5篇
  1994年   7篇
  1993年   5篇
  1991年   3篇
  1990年   3篇
  1989年   3篇
  1988年   5篇
  1986年   3篇
  1985年   4篇
  1984年   5篇
  1983年   4篇
  1982年   5篇
  1981年   5篇
  1980年   5篇
  1974年   5篇
  1971年   2篇
  1970年   2篇
  1966年   2篇
  1958年   2篇
  1955年   2篇
  1939年   2篇
  1937年   2篇
  1935年   3篇
  1934年   2篇
  1933年   3篇
排序方式: 共有666条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Rheumatoid arthritis as well as collagen-induced arthritis (CIA) is thought to involve T cell autoimmunity of the Th1 type and the Th2 cytokine IL-4 has been proposed to play a suppressive role. To exclude a possible skewing role of the mycobacteria used in the complete Freund's adjuvant (CFA) we induced CIA with type II collagen (CII) in incomplete Freund's adjuvant (IFA). Our results show that IL-4 deficiency leads to a lesser susceptibility to arthritis and lower B and T cell responses if induced with CII/IFA but not if induced with CII/CFA. In addition, IL-4-deficient mice were less susceptible to arthritis induced with monoclonal anti-CII antibodies. However, mice immunized with CII/IFA later developed a chronic relapsing disease, which was promoted by IL-4 deficiency. We conclude that IL-4 plays different roles depending on the type of adjuvant used and the phase (acute or chronic) of the clinical disease.  相似文献   
5.
6.
Summary The outflow of noradrenaline, 3,4-dihydroxyphenylglycol (DOPEG) and 3,4-dihydroxymandelic acid (DOMA) from rabbit perfused hearts was studied by chromatography on alumina followed by high pressure liquid chromatography with electrochemical detection. In the absence of drugs and without nerve stimulation, the outflow of endogenous noradrenaline over a period of 108 min averaged 0.17 pmol×g–1×min–1 and the outflow of DOPEG 2.1 pmol×g–1×min–1. The outflow of DOMA was below the detection limit (<0.13 pmol×g–1×min–1). The effect of perfusion with (–)-noradrenaline 0.1, 1 or 10 mol/l for 18 min was then investigated. As the concentration of noradrenaline increased so did the outflow of DOPEG. Moreover, DOMA was found in the venous effluent during and after perfusion with noradrenaline 1 or 10 mol/l. The increase in the outflow of DOPEG and DOMA was almost abolished when cocaine 10 mol/l was present during the perfusion with noradrenaline 1 mol/l. The release of endogenous noradrenaline by sympathetic nerve stimulation or tyramine 10 mol/l, but not the release evoked by nicotine 30 mol/l, was accompanied by an increase in the outflow of DOPEG; an outflow of DOMA was not observed.It is concluded that, in the rabbit perfused heart, DOPEG is an important metabolite of endogenous noradrenaline. DOMA is at best a minor product, either when the neurones are at rest or when noradrenaline is released by sympathetic nerve stimulation, nicotine or tyramine. DOMA is formed in detectable amounts when the tissue is exposed to a high concentration of exogenous noradrenaline. Like DOPEG, it is formed intraneuronally. The results confirm and extend those obtained previously on guinea-pig incubated atria. They make it unlikely that, in these tissues at least, DOMA formation is one of the physiological pathways of noradrenaline catabolism.  相似文献   
7.
PURPOSE Positron emission tomography (PET) has been used in grading of CNS tumors in adults, whereas studies of children have been limited. PATIENTS AND METHODS Nineteen boys and 19 girls (median age, 8 years) with primary CNS tumors were studied prospectively by fluorine-18 2-fluoro-2-deoxy-D-glucose (FDG) PET with (n = 16) or without (n = 22) H(2)(15)O-PET before therapy. Image processing included coregistration to magnetic resonance imaging (MRI) in all patients. The FDG uptake in tumors was semiquantitatively calculated by a region-of-interest-based tumor hotspot/brain index. Eight tumors without histologic confirmation were classified as WHO grade 1 based on location, MRI, and clinical course (22 to 42 months). Results Four grade 4 tumors had a mean index of 4.27 +/- 0.5, four grade 3 tumors had a mean index of 2.47 +/- 1.07, 10 grade 2 tumors had a mean index of 1.34 +/- 0.73, and eight of 12 grade 1 tumors had a mean index of -0.31 +/- 0.59. Eight patients with no histologic confirmation had a mean index of 1.04. For these 34 tumors, FDG uptake was positively correlated with malignancy grading (n = 34; r = 0.72; P < .01), as for the 26 histologically classified tumors (n = 26; r = 0.89; P < .01). The choroid plexus papilloma (n = 1) and the pilocytic astrocytomas (n = 3) had a mean index of 3.26 (n = 38; r = 0.57; P < .01). H(2)(15)O-uptake showed no correlation with malignancy. Digitally performed PET/MRI coregistration increased information on tumor characterization in 90% of cases. CONCLUSION FDG PET of the brain with MRI coregistration can be used to obtain a more specific diagnosis with respect to malignancy grading. Improved PET/MRI imaging of the benign hypermetabolic tumors is needed to optimize clinical use.  相似文献   
8.
Objective: Today’s health care system faces challenges in meeting the needs of older people with multimorbidity. To better cope with these needs, tailored primary health care with geriatric competence and person-centred care has been suggested. The aim of this study was to explore older patients’ experiences of a tailored primary health care unit.Design: This was a qualitative study using semi-structured individual interviews and qualitative content analysis.Setting and patients: Nineteen patients were recruited from a tailored PHC unit for people aged 75 years or older in a region in central Sweden.Methods: The interview data were analysed using inductive category development.Results: In the analysis, the theme In safe hands when in need of primary health care emerged. The interviewees expressed a desire to participate in their own care. Easy access, enough consultation time and a calm environment, along with the PHC professionals’ welcoming and attentive approach enhanced their feeling of being in safe hands. PHC professionals were perceived as having geriatric knowledge and taking responsibility for the care of older patients. Although the interviewees experienced that they received attention for their health conditions, a need for a more preventive approach to care emerged.Conclusion: Older patients highly appreciated their tailored PHC unit and they emphasised that it was an improvement compared to the ordinary PHC centre. This study provides insights into older patients’ experiences, which may be helpful in the ongoing process of improving care for older patients in PHC.

KEY POINTS

  • Older patients attending a tailored Primary health care (PHC) unit felt acknowledged, unlike in the ordinary PHC centre, which facilitated their participation in their care.
  • The calm environment, specialist geriatric competence and ample patient contact time enabled them to feel secure and taken care of.
  • Older patients expressed a need for an incorporation of social services and health promotion visits at the tailored PHC unit.
  相似文献   
9.
Illustrated by a clinical case supplemented by epidemiologic data, early reinfections with SARS-CoV-2 Omicron BA.1 after infection with Delta variant, and reinfection with Omicron BA.2 after Omicron BA.1 infection, can occur within 60 days, especially in young, unvaccinated persons. The case definition of reinfection, which influences retesting policies, should be reconsidered.  相似文献   
10.
A sulfated emodin glucoside, emodin 8-O-beta-D-glucopyranosyl-6-O-sulfate (1), was isolated from the roots of Rheum emodi in an investigation of the active constituents of this Nepalese medicinal plant, and its structure was determined by spectroscopic and chemical methods. Additionally, two rare auronols, carpusin (2) and maesopsin (3), besides other anthraquinones and phenolics, were isolated and identified. Compounds 2 and 3 showed significant antioxidant activity in the DPPH assay, while chrysophanol, physcion, and emodin and their 8-O-glucosides were found to be inactive.  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