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   548篇
  免费   23篇
耳鼻咽喉   8篇
儿科学   30篇
妇产科学   21篇
基础医学   63篇
口腔科学   15篇
临床医学   66篇
内科学   80篇
皮肤病学   22篇
神经病学   74篇
特种医学   4篇
外科学   51篇
综合类   3篇
预防医学   31篇
眼科学   7篇
药学   33篇
中国医学   3篇
肿瘤学   60篇
  2022年   2篇
  2021年   11篇
  2020年   4篇
  2019年   8篇
  2018年   7篇
  2017年   5篇
  2016年   1篇
  2015年   9篇
  2014年   12篇
  2013年   11篇
  2012年   52篇
  2011年   49篇
  2010年   12篇
  2009年   14篇
  2008年   54篇
  2007年   64篇
  2006年   46篇
  2005年   51篇
  2004年   45篇
  2003年   34篇
  2002年   31篇
  2001年   8篇
  2000年   2篇
  1999年   1篇
  1998年   1篇
  1997年   3篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   4篇
  1992年   4篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1988年   3篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1979年   3篇
  1976年   1篇
  1972年   2篇
  1971年   2篇
  1959年   1篇
排序方式: 共有571条查询结果,搜索用时 0 毫秒
471.
BACKGROUND: To examine the long-term child outcome after IVF until the age of 3 years in Northern Finland, we conducted a population-based cohort study. METHODS: First, a cohort of 299 IVF children born in 1990-1995 was compared with a cohort of 558 controls representing the general population in terms of a multiple birth rate of 1.2%, randomly chosen from the Finnish Medical Birth Register (FMBR) and matched for sex, year of birth, area of residence, parity, maternal age and social class (full sample analyses). Second, IVF singletons (n = 150) were compared with singleton controls (n = 280). Third, a plurality matched control cohort (n = 100) for IVF twins (n = 100) was randomly chosen, matched as above, from the FMBR and analysed separately. Infant mortality rate was compared with the national rate from the FMBR. RESULTS: Infant mortality in the IVF group was >2-fold higher compared to the national rate in the general population. The risk (OR, 95% CI) of low weight and height, below the lowest quartile, at 1 year of age (1.6, 1.1-2.2; 1.6, 1.1-2.4) and 2 years of age (1.5, 1.1-2.4; 1.7, 1.2-2.5) was significantly higher in the IVF group when compared with the general population control group. No statistically significant differences were found in the psychomotor development between the cohorts. Cumulative incidence of different diseases up to 3 years of age was significantly higher among IVF children in the full sample and singleton analyses (OR, 95% CI: 2.3, 1.7-3.2; 2.1, 1.3-3.3 respectively) especially regarding respiratory diseases (3.5, 1.9-6.5; 3.1, 1.0-9.4) and diarrhoea (3.7, 2.2-6.2; 5.7, 2.6-12.7), but not in twin comparisons. CONCLUSIONS: The growth of IVF children was behind that of control children during the first 3 years of life, but their psychomotor development was similar. Their postnatal health was worse, probably reflecting the problems in the neonatal period.  相似文献   
472.
The period of immune programming during early life presents a critical window of opportunity for the prevention of allergic diseases. There is mounting evidence that inappropriate immune programming may involve disruption of specific epigenetic modifications (switches) at immune-related genes. This novel area of research has great potential, as epigenetic changes are known to be sensitive to environmental factors and may therefore provide a mechanistic link for the observed association between specific environmental cues, faulty immune development, and the risk of allergic disease. In addition, the dynamic and potentially reversible nature of epigenetic modifications offers potentially novel targets for therapeutic and/or preventative interventions. We review the evidence that (1) failure to up-regulate the interferon gamma (IFNγ) response during infancy is an important determinant of the risk of allergic disease, (2) expression of the IFNγ gene in naïve T-cells is regulated by epigenetic mechanisms, and (3) failure to up-regulate IFNγ gene expression of naïve T-cells associated with low early life microbial exposure. Taken together, these lines of evidence suggest that low microbial exposure during early life increases the risk of allergic disease by reducing demethylation (activation) of the IFNγ gene of naive T-cells.  相似文献   
473.

Aim of the study

To offer routine information on smoking cessation and bedside counseling to smokers admitted in cardiac intensive care unit. The objective is to encourage cessation and/or use of smoking cessation services after discharge.

Population and methods

Thirty-three smokers were admitted in cardiac intensive care unit at the Georges Pompidou European hospital (HEGP) in Paris (France) from 1st March to June 30th 2010. Assessment of tobacco use and offer of counseling and follow-up visits during and after hospital stay. Evaluation of tobacco use by telephone at least six months after discharge.

Results

It was found that 30.3% of the patients stopped smoking, mostly without specialized help despite heavy smoking prior to hospitalization. They declared being impressed by their hospital stay. Motives for smoking among continuing smokers were mostly automatic smoking and stress relief. They had declined any smoking aid, despite subsequent hospital stays in cardiac intensive care. Three smokers with a severe profile had died at follow-up. Smokers followed-up at HEGP were in need of nicotine replacement therapy. More than six months after hospital discharge, nearly all smokers remembered being offered bedside counseling to stop smoking.

Conclusion

This experience reveals the importance of routine bedside counseling for smoking cessation in cardiac intensive care unit. Smokers in this unit often continue smoking even though smoking hinders cardiac rehabilitation.  相似文献   
474.
BACKGROUND AND PURPOSE: Radiation is a common treatment of cancer, but some patients show severe side effects when exposed to small doses of radiation. The aim of this study was to explore the underlying cause of radiation sensitivity in a group of radiation sensitive patients. MATERIALS AND METHODS: Lymphoblastoid cell lines from 5 normal individuals, 4 Ataxia Telangiectasia (AT), and 12 non-AT radiation sensitive (RS) patients were irradiated. RNA was isolated before and after radiation and hybridized to 15k cDNA microarrays and gene expression was recorded. RESULTS AND CONCLUSION: The RS cell lines showed an expression phenotype different from both the AT and normal cell lines. Six of the RS cell lines had a distinct expression profile before radiation. This implies that the RS patients are a heterogeneous group, but that six of the patients may have a common cause of radiation sensitivity.  相似文献   
475.
BACKGROUND: External auditory canal cholesteatoma (EACC) is a chronic inflammation of the bony ear meatus. Its etiology is not clearly understood. Other than surgical intervention, conservative methods are investigated for different cholesteatomas. Inducing apoptosis seems to be an appropriate strategy. Sulindac sulfone is a new class of targeted and pro-apoptotic drugs. It provokes apoptosis by inducing phosphorylation of beta-catenin, which is a multifunctional protein in the cell-cell adhesion complex. METHODS: EACC-cell cultures were incubated with different concentrations of sulindac sulfone (400 and 800 micromol). After 16, 24, and 48 h, beta-catenin concentrations were determined by ELISA, Western blot, and immunohistochemical analysis. RESULTS: After 48 h incubation with 400 micromol sulindac sulfone, the average level of beta-catenin showed a decrease of 46% (0.004337 microg/mL) from those determined at 16 h with the same concentration of sulindac sulfone. At 800 micromol sulindac sulfone, the treated cell culture showed a reduction of 66.2% (0.003443 microg/mL). Comparing total protein content and the fraction of beta-catenin at different points in time, the concentration of beta-catenin decreased in both EACC cell cultures, 400 micromol (minus 63%) and 800 micromol (minus 81%). CONCLUSIONS: The results presented in this paper are the first to demonstrate the chemopreventive effects of the agent sulindac sulfone on cholesteatomas. The greatest decrease of beta-catenin was observed between 16 and 24 h incubation. The inhibitory effect of sulindac sulfone as a local treatment seems to be a useful additional tool for nonsurgical approach to the therapy of EACCs.  相似文献   
476.
Benign cough headache is an uncommon primary headache disorder marked by short-lasting attacks of pain triggered by coughing. Magnetic resonance imaging of the brain is required to assure that the cough headache is truly benign. The aetiology of the pain is unclear, but is probably associated with the brief increased intracranial pressure that attends coughing. We have reviewed the clinical features, aetiology, differential diagnosis, management, and prognosis of benign cough headache.  相似文献   
477.
478.
OBJECTIVE: To study the association between body size from birth to adulthood and self-reported symptoms of polycystic ovary syndrome (PCOS), particularly hirsutism and menstrual disturbances. DESIGN: Longitudinal, population-based study of a cohort of women born in 1966 in northern Finland. The study population included 2007 women who were not pregnant and did not use hormonal contraception. Of these 528 (26%) had self-reported symptoms of PCOS. RESULTS: Weight at birth, gestational age, being small for gestational age or growth retardation at birth were not associated with PCOS symptoms at 31 y. An increased risk of PCOS symptoms was observed among women with abdominal obesity (waist/hip ratio >85th percentile) at 31 y who had normal weight in adolescence and were overweight (body mass index (BMI) 25.0-29.9 kg/m(2)) or obese (BMI>30.0 kg/m(2)) at 31 y (relative risk (RR) (95% CI) 1.44(1.10-1.89)), and among women with abdominal obesity who were overweight or obese at both 14 and 31 y (1.71 (1.30-2.24)). A total of 30% and 41% of the women with PCOS symptoms in these groups could be attributed, respectively, to overweight, obesity and abdominal obesity at 31 y. CONCLUSIONS: These results suggest that obesity in adolescence and in adulthood, and also weight gain after adolescence, particularly in the presence of abdominal obesity, are associated with self-reported PCOS symptoms in adulthood. Thus, based on the results from intervention studies treating PCOS and the results of this study, the prevention of obesity and abdominal obesity is important among young women.  相似文献   
479.
Recent evidence indicates that the abundance of recurring elementary interaction patterns in complex networks, often called subgraphs or motifs, carry significant information about their function and overall organization. Yet, the underlying reasons for the variable quantity of different subgraph types, their propensity to form clusters, and their relationship with the networks' global organization remain poorly understood. Here we show that a network's large-scale topological organization and its local subgraph structure mutually define and predict each other, as confirmed by direct measurements in five well studied cellular networks. We also demonstrate the inherent existence of two distinct classes of subgraphs, and show that, in contrast to the low-density type II subgraphs, the highly abundant type I subgraphs cannot exist in isolation but must naturally aggregate into subgraph clusters. The identified topological framework may have important implications for our understanding of the origin and function of subgraphs in all complex networks.  相似文献   
480.
One of the greatest technological advances in the history of medicine is the total joint replacement. Hip, knee, and shoulder replacements are routine throughout the world. They reduce pain in a cost-effective way and improve quality of life for millions of patients with end stage arthritis. Total hip replacement (THR) is considered a landmark surgery in modern medical history. The THR has developed with research and experimentation over the last 40–50 years with progressive improvement in materials used, fixation techniques, and peri-operative care. With improving life expectancy and increasing demand at a younger age, clinicians and scientists are always trying to find better performing implants to reduce the revision burden. This paper provides an up-to-date account of the relevant history of metal-on-metal (MoM) hips, problems associated with their use, current status, and guidance about how to continue surveillance of patients with MoM hip replacements.  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