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   1998篇
  免费   98篇
  国内免费   17篇
耳鼻咽喉   20篇
儿科学   120篇
妇产科学   129篇
基础医学   171篇
口腔科学   58篇
临床医学   198篇
内科学   470篇
皮肤病学   69篇
神经病学   131篇
特种医学   62篇
外科学   322篇
综合类   27篇
预防医学   68篇
眼科学   92篇
药学   112篇
  1篇
中国医学   1篇
肿瘤学   62篇
  2024年   2篇
  2023年   25篇
  2022年   35篇
  2021年   61篇
  2020年   34篇
  2019年   41篇
  2018年   72篇
  2017年   51篇
  2016年   74篇
  2015年   68篇
  2014年   86篇
  2013年   142篇
  2012年   152篇
  2011年   158篇
  2010年   84篇
  2009年   72篇
  2008年   158篇
  2007年   142篇
  2006年   135篇
  2005年   155篇
  2004年   131篇
  2003年   80篇
  2002年   84篇
  2001年   14篇
  2000年   11篇
  1999年   20篇
  1998年   8篇
  1997年   4篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1992年   1篇
  1991年   2篇
  1990年   2篇
  1989年   2篇
  1981年   1篇
排序方式: 共有2113条查询结果,搜索用时 31 毫秒
991.
AIMS: A restrictive transmitral filling (RF) pattern predicts increased mortality in heart failure (HF) with reduced left ventricular (LV) systolic function. We performed a combined evaluation of LV function and RF for prognosis in patients with HF with and without systolic dysfunction. METHODS AND RESULTS: Doppler echocardiography was performed in 972 patients with symptomatic HF. RF was considered present when deceleration time (DT) was 140 ms. A DT >240 ms was defined as delayed relaxation. During a median of 51 months the unadjusted all-cause mortality rates were significantly increased among patients with RF vs. the non-RF group (1- and 4-year mortality was 25% and 54% vs. 17% and 43%). In a multivariable model, RF was a significant predictor of all-cause mortality (hazard ratio (HR)=2.0, 95% confidence interval (CI):1.5-2.6) whereas delayed relaxation was without prognostic importance (HR=0.9, CI:0.5-1.6). Repeating the multivariable model in subgroups of wall motion index (WMI) showed that RF was a strong predictor of mortality independent of WMI. For patients with LVEF of at least 50%, HR for RF was 2.0 (CI:1.1-3.4; p=0.02) and interaction between LVEF and RF was not significant. CONCLUSION: In a heterogeneous population hospitalised for symptomatic HF a restrictive transmitral filling pattern, defined as shortened deceleration time, during hospitalisation is an ominous prognostic sign independent of LV systolic function.  相似文献   
992.
OBJECTIVE: Reperfusion treatment modalities used in the routine treatment protocols of acute myocardial infarction (AMI) were found to be ineffective in establishing the nutritional cellular reperfusion in the microvascular environment even they succeed to open the infarct related artery. Glucose-insulin-potassium (GIK) solution, which is presumed to stimulate the glycolytic pathway, is experimentally proven to be the most efficacious substrate for the preservation of energy production and therefore the myocardial viability, in the setting of acute ischemia. METHODS: We compared, 54 patients who suffered AMI and received GIK solution (300 g glucose+50 IU crystallized insulin+80 mEq potassium chloride in one liter solution) in addition to conventional treatment (GIK group) with 27 patients who were traditionally treated (control group) for in-hospital and early-term (1 month) cardiac morbidity. We also compared the two groups in terms of heart rate variability (HRV). RESULTS: Eight patients in the control group developed new-onset symptomatic congestive heart failure whereas only 5 patients in GIK group were found to have such a cardiac morbidity (p=0.01). Reduced HRV (<50 ms) was found in 3 patients of control group whereas no patient in GIK group had abnormal HRV (p=0.01). CONCLUSION: The GIK solution decreased the incidence of new-onset symptomatic congestive heart failure and low HRV after myocardial infarction. Larger multicenter trials need to resolve the questions on the efficiency of metabolic intervention with GIK solution in acute myocardial infarction.  相似文献   
993.
Nonenzymatic glycation of tissue and plasma proteins may stimulate the production of oxidant and carbonyl stress in diabetes. The aim of this study was to evaluate the effects of aminoguanidine (AG) on lipid peroxidation, protein oxidation and nitric oxide (NO) release in diabetic rat kidneys. After induction of diabetes with streptozotocin, female Wistar rats were divided into 2 groups. Group DAG (n=9) rats were given AG hydrogen carbonate (1 g/L) in drinking water and group D (n=8) was diabetic control rats given only tap water. Group H (n=8) was followed as healthy controls. At the end of an 8 week period, NO release, lipid and protein oxidation were determined in kidney tissues. NO release was significantly lower in diabetic rats compared with healthy controls (p<0.05). Lipid peroxidation was significantly high in group D (3.9 +/- 0.3 nmol MDA/g tissue) compared with the group DAG (2.6 0.1 nmol MDA/g tissue, p<0.01) and group H (2.4 +/- 0.2 nmol MDA/g tissue). Protein oxidation was significantly higher in diabetics than healthy controls (563.8 +/- 23.9, 655.8 +/- 7.2, 431.5 +/- 8.8 mmol carbonyl / g tissue for group DAG, D and H, respectively, p< 0.05). A positive correlation between albuminuria and thiobarbituric acid reactive substance (TBARS) levels (r= 0.54,p<0.005) and carbonyl content (r=0.70, p<0.0005) in kidney homogenate were observed. Although AG treatment had no effect on NO release, it significantly decreased lipid peroxidation in diabetic rat cortices. Consequently increased lipid peroxidation -as well as- protein oxidation could be involved in the pathogenesis of diabetic albuminuria.  相似文献   
994.
Gazel  Ummugulsum  Ayan  Gizem  Solmaz  Dilek  Bakirci  Sibel  Karsh  Jacob  Sampaio  Marcos  Jibri  Zaid  Aydin  Sibel Zehra 《Clinical rheumatology》2021,40(12):4909-4913
Clinical Rheumatology - To evaluate the added value of whole spine magnetic resonance imaging (MRI) for disease activity assessment in ankylosing spondylitis (AS) and psoriatic arthritis (PsA)....  相似文献   
995.
996.

Introduction and objectives

Atopic dermatitis is a chronic, relapsing, highly pruritic, inflammatory skin disease characterized by typical localization with increasing prevalence of 10–20% in children. Pruritus is one of the major diagnostic criteria of atopic dermatitis and also the main complaint altering quality-of-life of affected patients, inducing and aggravating inflammation. Although pruritus is the absolute symptom of AD, the etiology has not been fully explained yet and current antihistamine therapies are ineffective.The aim of the study was to assess the correlation between IL-31 level and disease severity in patients with atopic dermatitis through Severity SCORing of Atopic Dermatitis (SCORAD) index and the degree of itching assessed subjectively.

Material and methods

One hundred thirty-five children were enrolled in the study in total, 70 children with diagnosis of atopic dermatitis and 65 healthy children in control group. Data on demographic features (age, gender, family history of atopy) and laboratory values of serum eosinophil, total IgE, IgM, IgA, IgG levels and skin prick test results were collected through patient files. The disease severity was assessed by SCORAD index. IL-31 levels were measured with human IL-31 ELISA kit.

Results

The statistical analysis showed that IL-31 level was significantly higher in AD patients than in the control group (AD vs CG, p 0.0001). There was no significant difference in IL-31 levels between the three subgroups divided according to the SCORAD severity score (p:0.27).

Conclusion

IL-31 levels were significantly higher in AD patients compared to control group but irrelevant to the disease severity.  相似文献   
997.
In this study, the endothelin-1 (ET-1) and nitric oxide (NO) concentrations in slow coronary flow (SCF) patients were assessed before and at the peak of the exercise stress test and compared with the values from healthy controls. The study population was 25 patients who underwent coronary angiography and were diagnosed as SCF (11 females (44%), aged 56.7+/-9.8 years), and 20 normal subjects (9 females (45%), aged 54.3+/-9.2 years). Mean TIMI frame count in the patients was 54.1+/-13.4. Blood samples were drawn at rest and immediately at the end of exercise testing. The baseline ET-1 concentrations of the control subjects were lower than those of the patients (7.0+/-4.5 pg/ml vs 11.1+/-5.9 pg/ml p<0.0001) and this difference increased after exercise (6.2+/-4.3 pg/ml vs 20.1 +/-10.4 pg/ml, p<0.0001). Post-exercise ET-1 concentrations were significantly higher than baseline in patients with SCF (p<0.0001) and a reduction in the ET-1 concentrations was observed in control subjects (p<0.05). Baseline NO concentrations of the patients were lower than those of the control subjects (27 +/-5.1 micromol/L vs 31.2+/-4.9 micromol/L, p=0.0001). Although the NO concentrations in both groups were significantly increased after exercise (29.4 +/-5.9 micromol/L vs 33.3+/-5.6 micromol/L, p<0.05 for both), the difference was not significant. A significant negative correlation among post-exercise ET-1 concentrations and maximal heart rate, exercise duration and exercise rate - pressure product, and a significant positive correlation among post-exercise NO concentrations and maximal heart rate and exercise duration were observed in both groups. The results of this study show that endothelial function (assessed by ET-1 and NO concentrations) and its response to exercise were abnormal in SCF patients compared with healthy subjects, and this may play some pathophysiologic role.  相似文献   
998.
BACKGROUND/AIMS: Gastroesophageal reflux disease is one of the most common gastrointestinal diseases of adulthood. Hypersensitive esophagus is a new term which defines patients with reflux symptoms, negative endoscopic findings and normal acid contact time on 24 hour pH analysis, although there is a convincing relationship between symptoms and acid reflux episodes on pH analysis- positive symptom index. In this study, the frequency of hypersensitive esophagus among patients with heartburn was determined and demographic findings, symptoms, manometric and pHmetric findings were compared among hypersensitive esophagus, non-erosive reflux disease, erosive reflux disease and normals. METHODS: Patients admitted to hospital with heartburn and without any cardiac, severe gastric or duodenal pathologies (except minimal antral gastritis) and with no abnormal manometric findings suggestive of esophageal motility disorders were included in the study. All patients were questioned about age, height, weight, educational status and intestinal and extraintestinal reflux related symptoms. Upper endoscopy, esophageal manometry and 24 hour pH monitoring were performed respectively. RESULTS: Of the 44 patients (17 male, 27 female) included in the study, seven (16%) had hypersensitive esophagus, 15 (34%) had non-erosive reflux disease, seven (16%) had erosive reflux disease and 15 (34%) had normal findings. The female ratio in the hypersensitive esophagus and normal groups was higher while the male ratio was higher in erosive reflux disease. There was no significant difference among groups according to age, body mass index and symptoms. There was also no significant difference according to manometric findings. De Meester scores were significantly lower in hypersensitive esophagus and normal groups while symptom index was highest in the hypersensitive esophagus group. Reflux was observed especially in the upright position in all groups. CONCLUSION: The ratio of hypersensitive esophagus, gastroesophageal reflux disease and no pathology in patients with heartburn was 16%, 50% and 34% respectively. It would be appropriate to accept hypersensitive esophagus as a subgroup of reflux disease as it has both symptoms and some manometric and pHmetric changes.  相似文献   
999.
Immunologic response to acute hepatitis C is mainly a Th1 response, whereas fasciolopsiasis is associated with a diverse T-cell response. Interferon-alpha has immunomodulatory effects and enhances Th1 immune response. Fasciola infection could theoretically interfere with the Th1 immune response, even when acquired after an initial response to interferon-alpha treatment for acute hepatitis C virus (HCV) infection. We report here the case of a male patient who acquired Fasciola hepatica infection after an initial response to IFN-alpha therapy with a favorable outcome  相似文献   
1000.
Posterior leukoencephalopathy syndrome (PLES) is an acute neurological disorder. The most plausible hypothesis for the pathophysiology of PLES is the loss of autoregulation and consequent vasogenic edema. PLES is mostly attributed to severe or sudden elevations of arterial blood pressure. A number of reports, however, describe patients with PLES without severe hypertension. This report presents two patients with nephrotic syndrome who developed PLES without customarily severe hypertension. Proteinuria, low levels of serum albumin, or generalized increase in capillary permeability in nephrotic syndrome can initiate PLES with moderately high arterial blood pressure levels. PLES is increasingly recognized by neurologists, but it should also be remembered by internists when confronted with patients with nephrotic syndrome who present with neurological symptoms, whether or not they have severe hypertension.  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