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   11082篇
  免费   696篇
  国内免费   53篇
耳鼻咽喉   303篇
儿科学   277篇
妇产科学   301篇
基础医学   1566篇
口腔科学   420篇
临床医学   915篇
内科学   2582篇
皮肤病学   232篇
神经病学   1252篇
特种医学   220篇
外科学   1005篇
综合类   21篇
一般理论   5篇
预防医学   645篇
眼科学   132篇
药学   690篇
中国医学   36篇
肿瘤学   1229篇
  2024年   19篇
  2023年   116篇
  2022年   275篇
  2021年   424篇
  2020年   271篇
  2019年   316篇
  2018年   352篇
  2017年   288篇
  2016年   349篇
  2015年   371篇
  2014年   495篇
  2013年   603篇
  2012年   924篇
  2011年   1042篇
  2010年   517篇
  2009年   449篇
  2008年   784篇
  2007年   714篇
  2006年   640篇
  2005年   670篇
  2004年   602篇
  2003年   550篇
  2002年   482篇
  2001年   60篇
  2000年   38篇
  1999年   53篇
  1998年   87篇
  1997年   60篇
  1996年   45篇
  1995年   46篇
  1994年   34篇
  1993年   32篇
  1992年   20篇
  1991年   11篇
  1990年   10篇
  1989年   15篇
  1988年   7篇
  1987年   2篇
  1986年   13篇
  1985年   3篇
  1984年   6篇
  1983年   4篇
  1982年   5篇
  1981年   4篇
  1980年   6篇
  1979年   4篇
  1978年   3篇
  1976年   3篇
  1974年   2篇
  1973年   2篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
51.
52.

Objective

To verify whether a multidomain intervention lowers the risk of developing new chronic diseases in older adults.

Methods

Multicenter, double-blind randomized controlled trial started in October 2009, with 2-year follow-up. A total of 1260 people aged 60 to 77?years were enrolled in the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (FINGER). Participants were randomly assigned in a 1:1 ratio to a 2-year multidomain intervention (n?=?631) (nutritional guidance, exercise, cognitive training, and management of metabolic and vascular risk factors) or a control group (n?=?629) (general health advice). Data on most common chronic diseases were collected by a physician at baseline and 2?years later.

Results

At 2-year follow-up, the average number of new chronic diseases was 0.47 [standard deviation (SD) 0.7] in the intervention group and 0.58 (SD 0.8) in the control group (P?<?.01). The incidence rate per 100 person-years for developing 1+?new disease(s) was 17.4 [95% confidence interval (CI)?=?15.1-20.1] in the intervention group and 20.5 (95% CI?=?18.0-23.4) in the control group; for developing 2+?new diseases, 4.9 (95% CI?=?3.7-6.4) and 6.1 (95% CI?=?4.8-7.8); and for 3+?new diseases, 0.7 (95% CI?=?0.4-1.5) and 1.8 (95% CI?=?1.1-2.8), respectively. After adjustment for age, sex, education, current smoking, alcohol intake, and the number of chronic diseases at baseline, the intervention group had a hazard ratio ranging from 0.80 (0.66-0.98) for developing 1+?new chronic disease(s) to 0.38 (0.16-0.88) for developing 3+?new chronic diseases compared to the control group.

Conclusions

Findings from this randomized controlled trial suggest that a multidomain intervention could reduce the risk of developing new chronic diseases in older people.  相似文献   
53.
Lipopolysaccharide (LPS) may play an important role in chronic diseases through the activation of inflammatory responses. The type of diet consumed is of major concern for the prevention and treatment of these diseases. Evidence from animal and human studies has shown that LPS can diffuse from the gut to the circulatory system in response to the intake of high amounts of fat. The method by which LPS move into the circulatory system is either through direct diffusion due to intestinal paracellular permeability or through absorption by enterocytes during chylomicron secretion. Considering the impact of metabolic diseases on public health and the association between these diseases and the levels of LPS in the circulatory system, this review will mainly discuss the current knowledge about high-fat diets and subclinical inflammation. It will also describe the new evidence that correlates gut microbiota, intestinal permeability and alkaline phosphatase activity with increased blood LPS levels and the biological effects of this increase, such as insulin resistance. Although the majority of the studies published so far have assessed the effects of dietary fat, additional studies are necessary to deepen the understanding of how the amount, the quality and the structure of the fat may affect endotoxaemia. The potential of food combinations to reduce the negative effects of fat intake should also be considered in future studies. In these studies, the effects of flavonoids, prebiotics and probiotics on endotoxaemia should be investigated. Thus, it is essential to identify dietetic strategies capable of minimising endotoxaemia and its postprandial inflammatory effects.  相似文献   
54.
55.
56.
ObjectivesThe aim of this study was to assess the prevalence of delirium, using the Assessment Test for Delirium and Cognitive Impairment (4AT) in end-of-life palliative care patients.Subjects and MethodsThis retrospective cross-sectional study was conducted on end-of-life patients in a hospice or at home. All patients were evaluated with the 4AT for the presence of delirium.ResultsOf the 461 patients analyzed, 76 (16.5%) were inpatients and 83.5% (385) outpatients. The median age was 79.5 (72–86) years, and 51.0% were female. According to the 4AT score, 126 patients (27.3%) had delirium (A4T ≥4) at admission, 28 (36.8%) were inpatients, and 98 (25.5%) outpatients. Around 33.8% of the cancer inpatients had delirium, while 20.6% of the cancer outpatients had delirium. The prevalence of delirium varied according to the setting, clinical condition, and life expectancy. In addition, 55.0% (11) actively dying inpatients, within 3 days, had delirium, and 56.7% (17) outpatients had delirium; while among those with life expectancy longer than 4 days, 30.4% (17) inpatients and 22.8% (81) outpatients were with delirium.ConclusionsOur study confirms that delirium is common in cancer and noncancer palliative care patients. Further research on delirium in end-of-life palliative care patients should consider the complexity of palliative care of this population as well as of the characteristics of the settings.  相似文献   
57.
58.
Osteoscleroses are a heterogeneous group of bone remodeling disorders characterized by an increase in bone density. Here we report on a consanguineous Lebanese family in which two sisters, aged 39 and 36 years, exhibit a severe genu varum, a square‐face appearance, high forehead, slight proptosis of the eyes, symmetric enlargement of the jaw, protruding chin, and short stature. Bone X‐rays showed the presence of hyperostosis of the cranial base and vault with increased density of the orbits, hyperostosis of the bones, thickening of the cortices, diaphyseal modeling defects, cortical thickening of the medullary cavity, mild enlargement of the medullary cavity of the short long bones, short femoral necks, increased width of the ribs, and narrow interpedicular distances of the lower lumbar spine. Osteodensitometry showed values 200% to 300% above values for age. A cervical MRI revealed the presence of a diffuse osteosclerosis with calcification of the posterior vertebral ligament and a narrow canal between C2 and T2. Blood test results were unremarkable. Serum osteocalcin levels were in the normal range, whereas high values of serum C ‐ telopeptide were noted. A bone biopsy showed only the presence of compact bone and did not allow for histomorphometric analysis. Molecular studies excluded genes known to be involved in sclerosing bone dysplasias as the cause of this condition. In vitro analysis of osteoclast function indicated that contrary to most cases of autosomal recessive osteopetrosis, osteoclasts both formed and resorbed but exhibited a small decrease in resorptive activity compared with osteoclasts generated from normal control individuals. Differential diagnoses are discussed, and the possibility that this may be a novel clinical entity is raised. © 2010 American Society for Bone and Mineral Research.  相似文献   
59.
Gallates with eight or more carbon atoms in the lateral chain show potent anticancer activity against various cell lines. However, studies regarding the in vivo antimelanoma activity of tetradecyl gallate (C14) have not yet been reported. In this study an evaluation of the ability of C14 to inhibit metastasis, using lung metastases as a model, was carried out. The experimental mouse melanoma model was established by intravenous injection of metastatic B16F10 melanoma cells. The systemic toxicity of C14 was evaluated in vivo by monitoring the weight, survival, biochemical and hematological parameters, and through histological analysis. It was observed that C14 decreased lung metastasis in vivo by 80% and increased the survival rate of the animals without toxic effects. Additionally, C14 induced cytotoxic effects on B16F10 cells, inhibited the inter-cellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) expression, and significantly decreased cell adhesion. These results reveal that C14 has potent antimetastatic ability and is a good candidate for further study as a potential therapeutic agent for tumor metastases.  相似文献   
60.
Radial shock waves therapy (RSWT) differs from extracorporeal shock waves therapy (ESWT) in that it produces a non-focused wave that is dissipated radially at the skin. Few studies have yet explored the effects of RSWT on bone tissue. Osteoblasts in culture flasks were studied by polymerase chain reaction after treatment with RSW (500 impulses, 0.05?mJ/mm2). An inhibited osteoblastogenesis was observed, with a statistically significant reduction in type 1 collagen, osterix, bone sialoprotein and receptor activator NF kappa ligand expression at 24 and 48?h, of osteocalcin at 24, 48 and 72?h, and osteopontin at 48 and 72?h. These findings show that RSWT is not indicated for treatment of delayed fracture union, pseudoarthrosis, and complex regional pain syndrome. The observed reduction in the receptor activator of nuclear factor-kB ligand/osteoprotegerin ratio suggests that it has an inhibiting effect on osteoclastogenesis, which could make it a useful tool for applications in proliferative diseases.  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