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   604篇
  免费   9篇
  国内免费   1篇
耳鼻咽喉   5篇
儿科学   27篇
妇产科学   36篇
基础医学   71篇
口腔科学   21篇
临床医学   97篇
内科学   99篇
皮肤病学   10篇
神经病学   33篇
特种医学   27篇
外科学   72篇
综合类   17篇
一般理论   1篇
预防医学   35篇
眼科学   4篇
药学   22篇
  1篇
肿瘤学   36篇
  2024年   6篇
  2023年   12篇
  2022年   17篇
  2021年   31篇
  2020年   30篇
  2019年   29篇
  2018年   20篇
  2017年   12篇
  2016年   13篇
  2015年   17篇
  2014年   15篇
  2013年   35篇
  2012年   48篇
  2011年   57篇
  2010年   28篇
  2009年   26篇
  2008年   30篇
  2007年   37篇
  2006年   25篇
  2005年   22篇
  2004年   20篇
  2003年   19篇
  2002年   12篇
  2001年   6篇
  2000年   5篇
  1999年   3篇
  1997年   4篇
  1996年   1篇
  1995年   3篇
  1994年   2篇
  1992年   4篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1986年   3篇
  1985年   5篇
  1984年   1篇
  1981年   2篇
  1979年   1篇
  1976年   2篇
  1973年   1篇
  1972年   2篇
  1971年   1篇
排序方式: 共有614条查询结果,搜索用时 15 毫秒
51.
ABSTRACT: Low dose (<3 mSv) noncontrast CT (NCCT) is the imaging study of choice for accurate evaluation of patients with acute onset of flank pain and suspicion of stone disease (sensitivity 97%, specificity 95%). NCCT can reliably characterize the location and size of an offending ureteral calculus, identify complications, and diagnose alternative etiologies of abdominal pain such as appendicitis. By comparison, the sensitivity of radiographs (59%) and ultrasound (24-57%) for the detection of renal and ureteral calculi is relatively poor. Ultrasound can accurately diagnose pelvicaliectasis and ureterectasis, but it may take several hours for these findings to develop. In the pregnant patient, however, ultrasound is a first line test as it does not expose the fetus to ionizing radiation. MR is an accurate test for the diagnosis of pelvicaliectasis and ureterectasis, but is less sensitive than CT for the diagnosis of renal and ureteral calculi. For patients with known stone disease whose stones are visible on radiographs, radiographs are a good tool for post-treatment follow-up.The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every two years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances where evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.  相似文献   
52.
Thalassemias are the most common hereditary diseases in Iran, resulting from synthesis defects in one or more hemoglobin (Hb) subunits. The majority of patients suffer from beta-thalassemia (thal), but cases with microcytic hypochromic anemia and normal electrophoretic patterns are suspected to have alpha- or silent beta-thal. A family from the northern part of Iran, an area highly prevalent for thalassemias, was referred to us for prenatal diagnosis. The hematological data of the father indicated a pattern of beta-thal minor. Reverse hybridization analysis for the most common beta-globin mutations identified IVS-II-1 (G-->A) in the heterozygous state. The maternal laboratory data indicated a case more compatible with alpha-thal. Iron deficient anemia was ruled out, and common alpha-thal point mutations and deletions were investigated. As no mutation was detected, chain synthesis was performed and showed an alpha/beta chain ratio of 2.1, that was in the range of beta-thal minor. DNA sequencing of the entire beta-globin gene identified a heterozygous GTG-->GGG (Val-->Gly) mutation at codon 126, also known as Hb Dhonburi (Neapolis). Prenatal diagnosis of the fetal DNA showed the absence of the IVS-II-1 and codon 126 anomalies. This result demonstrates the importance of screening of individuals with mild microcytic hypochromic anemia for both alpha- and silent beta-thal mutations.  相似文献   
53.
BACKGROUND: Therapeutic plasma exchange (TPE) is an extracorporeal blood purification method for the treatment of diseases in which pathological proteins have to be eliminated. In the aim to demonstrate our single center activity, we analyzed our data since 2 years. METHODS: Between years 2002 and 2005, 104 TPE procedures were performed on 42 patients. Median age and male/female ratio were 32 (range, 17-56) and 24/18, respectively. Departments those referred the majority of the TPE were neurology (n=32), nephrology (n=5) and intensive care unit (n=5). The most common indications were: polyradiculoneuropathies (53%), myasthenia gravis (17%) and Guillain-Barré syndrome (12%). RESULTS: The median TPE procedure per patient was 2.3 (range, 1-10). In the majority of patients, vascular access was provided by puncture of two large, durable peripheral antecubital veins. The procedures were performed with the "Haemonetic Ultralight" discontinuous flow cell separator devices. Citrate solution was used as an anticoagulant in all cases. The substitution fluids most often used in our unit are Albumin 20% solution (92 times), Albumin 4% (10 times) and fresh frozen plasma (twice). Seventy five percent of the patients showed improvement, 7% remained the same and 18% worsened. Thirteen adverse reactions were recorded. CONCLUSION: The creation of a national registry by the local society is a vital move to improve TPE practice in our country.  相似文献   
54.
BACKGROUND AND AIMS: Few studies focused on nurses' career commitment and nurses' job performance. This research aimed at studying variables of nurses' career commitment and job performance, and assessing the relationship between the two concepts as well as their predictors. METHODS: A survey was used to collect data from a convenient sample of 640 Registered Nurses employed in 24 hospitals. RESULTS: Nurses 'agreed' to be committed to their careers and they were performing their jobs 'well'. As a part of career commitment, nurses were willing to be involved, in their own time, in projects that would benefit patient care. The highest and lowest means of nurses' job performance were reported for the following aspects: leadership, critical care, teaching/collaboration, planning/evaluation, interpersonal relations/communications and professional development. Correlating of total scores of nurses' career commitment and job performance revealed the presence of a significant and positive relationship between the two concepts. Stepwise regression models revealed that the explained variance in nurses' career commitment was 23.9% and that in nurses' job performance was 29.9%. IMPLICATIONS FOR NURSING MANAGEMENT: Nurse managers should promote nursing as a career and they should develop and implement various strategies to increase nurses' career commitment and nurses' job performance. These strategies should focus on nurse retention, staff development and quality of care. CONCLUSIONS: Nurses' career commitment and job performance are inter-related complex concepts that require further studies to understand, promote and maintain these positive factors in work environments.  相似文献   
55.
GH has been suggested to influence the function of the immune system in several species. Experimental autoimmune encephalomyelitis (EAE) (an animal model for multiple sclerosis) has been reported not to occur in GH-deficient (GHD) mice. The aim of this study was to elucidate the effects of GH and GHRH replacement on development of EAE in a mouse model of isolated GHD due to removal of the GHRH gene [GHRH knockout (GHRHKO)]. We studied two groups of adult female mice: 12 GH-sufficient animals (control) and 36 GHRHKO animals. All mice were immunized with myelin oligodendrocyte glycoprotein peptide, a peptide known to induce EAE. GHRHKO mice were left untreated or were treated for 4 wk with daily sc injections of recombinant GH or of a GHRH super agonist JI-38 (JI38-GHD). Evaluation of EAE symptoms was carried out daily, and T-proliferative assay and histopathological analysis of the spinal cord were performed. GHRHKO mice were less prone to develop EAE when compared with control mice. GH (but not JI-38) restored the original susceptibility of mice to the disease, despite lack of complete serum IGF-I normalization. GH treatment was also associated with a markedly increase in spleen size and T-cell proliferation specific to myelin oligodendrocyte glycoprotein peptide. GH (but not GHRH) plays an important role in the development of EAE.  相似文献   
56.
Outcome and complications of retrievable inferior vena cava filters   总被引:6,自引:0,他引:6  
The results and risks of retrievable inferior vena cava filters were reviewed. Systematic review identified 6 prospective case series with broad ranges of indications for filters. In these case series, 4 different types of retrievable filters were inserted in 284 patients. The longest reported duration of insertion was 134 days. Among patients in whom percutaneous removal of the filter was attempted, the filter was successfully removed in 144 of 159 (91%). Surgery was necessary to remove the filter from 1 patient (1%), and filters could not be removed because of large trapped thrombi in 14 patients (9%).  相似文献   
57.

Objective

There is a J-shaped relationship between body mass index (BMI) and cardiovascular outcomes in elderly patients (obesity paradox). Whether low BMI correlates with aortic calcification (AC) and whether this association is accounted for by bone demineralization is uncertain.

Methods

Presence of AC was evaluated in 687 community-dwelling individuals (49% male, mean age 67 ± 13 years) using CT images of the thoracic, upper and lower abdominal aorta, and scored from 0 to 3 according to number of sites that showed any calcification. Whole-body bone mineral density (BMD) was evaluated by dual-energy X-ray absorptiometry. Predictors of AC were assessed by logistic regression, and the role of BMD using mediation analysis.

Results

Age and cardiovascular risk factors were positively associated while both BMI (r = −0.11, p < 0.01) and BMD (r = −0.17, p < 0.0001) were negatively associated with AC severity. In multivariate models, lower BMI (OR 0.96, 95%CI 0.92–0.99, p = 0.01), older age, higher systolic blood pressure, use of lipid-lowering drugs and smoking were independent predictors of AC. A nonlinear relationship between BMI and AC was noticed (p = 0.03), with decreased AC severity among overweight participants. After adjusting for BMD, the coefficient relating BMI to AC was reduced by 14% and was no longer significant, whereas BMD remained negatively associated with AC (OR 0.82, 95%CI 0.069–0.96, p = 0.01), with a trend for a stronger relationship in older participants.

Conclusion

Low BMI is associated with increased AC, possibly through calcium mobilization from bone, resulting in low BMD. Prevention of weight loss and bone demineralization with aging may help reducing AC.  相似文献   
58.
AIM: To improve our understanding of Iranian regional variation in Helicobacter pylori (H. pylori ) antibiotic resistance rates to find the best antibiotic therapy for eradication of H. pylori infections.METHODS: A total of 266 patients undergoing endoscopy in Shiraz, Southern Iran, were included in this study. H. pylori strains were isolated from antral biopsies by culture and confirmed by the rapid urease-test and gram staining. Antibiotic susceptibility of H. pylori isolates was determined by E-test.RESULTS: A total of 121 H. pylori strains were isolated, 50 from male and 71 from female patients. Data showed that 44% (n = 53), 20% (n = 24), 5% (n = 6), and 3% (n = 4) of all strains were resistant to the antibiotics metronidazole, amoxicillin, clarithromycin, and tetracycline, respectively. When the antibiotics were considered together we found 11 sensitivity patterns for the strains. Resistance to metronidazole was significantly higher in female than in male patients (P < 0.05). In about 71% of the metronidazole-resistant isolates, the minimum inhibitory concentrations (MICs) exceeded 256 μg/mL.CONCLUSION: We found a moderate rate of primary resistance to metronidazole. However, a high MIC (> 256 mg/L) which was found in 71% of the isolates is considerable. In the case of amoxicillin, an increased resistance rate of 20% is worrying. Resistance to clarithromycin and tetracycline is also emerging among the H. pylori strains in our region.  相似文献   
59.
Inflammatory liver pseudotumor is a rare entity. Associations with several inflammatory conditions were reported but association with inflammatory bowel disease is unusual.We report the case of liver inflammatory pseudotumor occurring in the course of Crohn's disease in a 23-year-old woman and treated conservatively.  相似文献   
60.
ObjectiveThis study examines the prevalence and correlates of poor glycemic control in Mexican Americans aged 75 years and older with diabetes.MethodsData are from the 5th wave (2004-05) of the Hispanic Established Population for the Epidemiological Study of the Elderly (H-EPESE). A total of 2,069 Mexican Americans aged 75 and over were interviewed. Six hundred eighty nine subjects (33.5%) reported having been diagnosed with diabetes and 209 (30.3%) subjects agreed to a blood test of their HbA1c level.ResultsOf the 209 diabetic subjects with an HbA1c test, 73 (34.9%) had good glycemic control (HbA1c < 7%) and 136 (65.1%) had poor glycemic control (HbA1c > 7%). Bivariate analysis revealed that subjects with poor control had longer disease duration, had lower education, used the glucometer more frequently, and had more diabetes-complications when compared to those in the good glycemic control group. Multivariable logistic regression analysis found the following factors associated with poor glycemic control: < 8 years of education, foreign-born, smoking, obesity, longer disease duration, daily glucometer use, and having macro-complications.DiscussionPrevalence of poor glycemic control is very high in this population with very high and rising prevalence of diabetes. Further studies are needed to explore the effect of these and other characteristics on glycemic control among older Mexican Americans and to develop appropriate interventions to improve diabetes outcomes and increase life-expectancy.  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