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   446篇
  免费   27篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   17篇
妇产科学   7篇
基础医学   67篇
口腔科学   27篇
临床医学   32篇
内科学   126篇
皮肤病学   4篇
神经病学   11篇
特种医学   12篇
外科学   45篇
综合类   13篇
预防医学   42篇
眼科学   3篇
药学   50篇
中国医学   2篇
肿瘤学   18篇
  2023年   5篇
  2022年   10篇
  2021年   25篇
  2020年   13篇
  2019年   10篇
  2018年   23篇
  2017年   17篇
  2016年   15篇
  2015年   13篇
  2014年   16篇
  2013年   29篇
  2012年   35篇
  2011年   48篇
  2010年   18篇
  2009年   21篇
  2008年   23篇
  2007年   18篇
  2006年   27篇
  2005年   16篇
  2004年   24篇
  2003年   17篇
  2002年   22篇
  2001年   1篇
  1999年   1篇
  1998年   1篇
  1995年   2篇
  1993年   1篇
  1992年   1篇
  1990年   3篇
  1989年   2篇
  1984年   4篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1975年   1篇
  1973年   3篇
  1972年   1篇
  1971年   2篇
  1967年   1篇
  1966年   1篇
排序方式: 共有477条查询结果,搜索用时 739 毫秒
61.
62.
In the present case report, we present the unusual occurrence of traumatic rupture of a ureteropelvic junction hydronephrosis, and discuss the potential mechanisms producing such a rupture and the management options.  相似文献   
63.
This study was designed to characterize neutrophil chemotactic factors released by gastric tissue. Full-thickness rabbit stomach (organ culture) was prepared and incubated in Ringer's solution at 37°C. Culture supernatants were collected at 1, 2, 3, and 4 hr and assayed for neutrophil chemotactic activity in modified Boyden chambers. High levels of chemotactic activity were seen at 3 hr of incubation. Antral and fundic tissue were equally capable of producing neutrophil chemotactic activity. In addition, high levels of activity were seen from both the serosal and mucosal surfaces. Initial biochemical characterization of these gastricderived factors revealed that: (1) a majority of the activity (80–90%) exhibited molecular weight values of greater than 300 kDa, (2) the chemotactic activity was heat stable but was partially reduced by treatment with a protease, subtilisin (37% inhibition), and (3) 70–80% of the activity in the supernatants was extracted into organic solvent (ethyl acetate). These factors may prove to be important in recruitment of neutrophils to areas of gastric injury.Support by a Department of Surgery Research Grant.Presented in part at the annual meeting of the American Gastroenterological Association, May, 1988, New Orleans.  相似文献   
64.
65.
66.
67.

Purpose

This study was conducted to determine the magnetic resonance imaging (MRI) findings in cases of complications following anterior cruciate ligament (ACL) reconstructive surgery, and to correlate these complications with their possible etiological factors based on clinical and radiological criteria.

Methods

The study included 48 symptomatic patients (40 males and 8 females) after arthroscopic ACL reconstruction in the period between 2006 and 2008. Clinical evaluation of the patients was performed using the International Knee Documentation Committee scoring system (IKDC). MRI was performed using 1.5 T dedicated system and a standard imaging protocol. The scans were then reviewed by two senior radiologists for the assessment of integrity of the reconstructed ligament and the presence of related complications. The findings were then analyzed and correlated with the clinical evaluation.

Results

Tunnel widening was the most common MRI finding seen, as it was present in 42 patients (87.5%). The detected post reconstructive complications encountered in our patients included graft tear in 34 patients (70.83%), impingement in 12 patients (25%), osteoarthritis in six patients (12.5%), cystic degeneration in two patients (4.16%), and Cyclops lesion in two patients (4.16%).

Conclusions

MRI is a valuable imaging modality for assessment of post ACL reconstructive complications, as it is useful in demonstrating tunnel positioning, graft integrity and other soft tissue structures of the knee. It also helps in identifying possible underlying causes and predisposing factors for ACL graft failure.  相似文献   
68.
Iron deficiency anemia (IDA) is one of the most prevalent micronutrient deficiencies particularly in the developing countries. While there is evidence of an altered immune profile in iron deficiency, the exact immunoregulatory role of iron is not known. Knowledge particularly in children, who are vulnerable to iron deficiency and infection, is lacking. We aimed to study the effects of IDA and its treatment with oral iron supplementation on cell-mediated immunity. The levels of T-lymphocytes, their CD4+, CD8+ and CD1a+ subsets, transferrin receptor (CD71) and serum ferritin were evaluated in 40 iron-deficient and 40 healthy children. The impact of oral iron supplementation for three months on the same parameters was also noted in children with IDA. The level of mature T-lymphocytes (CD4+ and CD8+) was significantly lower (P<0.001) while that of the immature T-cells (CD1a+) was significantly higher (p<0.001) in IDA children compared to the control. The mature T-cell count was significantly improved after iron therapy. In spite of significant reduction in the immature T-cells (CD1a+) level after iron supplementation, it was significantly higher than the control. The present study demonstrated that T-lymphocytes maturation was defective in IDA and improved partially after 3 months of iron supplementation. Therefore, longer time of iron therapy may be required to induce complete maturation of T-lymphocytes.  相似文献   
69.
BackgroundBreast cancer (BC) is the leading cause of cancer death in women worldwide. Most BC studies on candidate microRNAs were tissue specimen based. Recently, there has been a focus on the study of cell‐free circulating miRNAs as promising biomarkers in (BC) diagnosis and prognosis. Therefore, we aimed to investigate the circulating levels of miR‐10b and its target soluble E‐ cadherin as potentially easily accessible biomarkers for breast cancer.MethodsSixty‐one breast cancer patients and forty‐eight age‐ and sex‐matched healthy volunteers serving as a control group were enrolled in the present study. Serum samples were used to assess miRNA10b expression by TaqMan miRNA assay technique. In addition, soluble E‐cadherin expression level in serum was determined using ELISA technique.ResultCirculating miR‐10b expression level and serum sE‐cadherin was significantly upregulated in patients with BC compared to controls. Moreover, serum miR‐10b displayed progressive up‐regulation in advanced stages with higher level in metastatic compared to non‐metastatic BC. Additionally, the combined use of both serum miR‐10b and sE‐cadherin revealed the highest sensitivity and specificity for detection of BC metastasis (92.9% and 97.9% respectively) with an area under curve (AUC) of 0.98, 95% CI (0.958–1.00).ConclusionOur data suggest that circulating miR‐10b could be utilized as a potential non‐invasive serum biomarker for diagnosis and prognosis of breast cancer with better performance to predict BC metastasis achieved on measuring it simultaneously with serum sE‐cadherin. Further studies with a large cohort of patients are warranted to validate the serum biomarker for breast cancer management.  相似文献   
70.
BACKGROUND: Angiogenesis is a prerequisite for airway remodeling in bronchial asthma. Several factors may play important roles in inflammation and angiogenesis through effects on inflammatory cell infiltration or neovascularization. OBJECTIVES: (1) To determine the levels of vascular endothelial growth factor (VEGF) and angiogenin in sputum supernatants of asthmatic children during the acute attack and 6 weeks after start of therapy; and (2) to correlate their levels with the degree of asthma severity. SUBJECTS AND METHODS: Twenty asthmatic children with acute attack (mean age, 9.6 +/- 3.5 years [+/- SD]) and 12 sex- and age-matched healthy control children were enrolled in the study. Sputum supernatants were collected for determination of VEGF and angiogenin levels. Serum samples were withdrawn for IgE measurement. The above tests were performed using an enzyme-linked immunosorbent assay. The FEV1 was measured using spirometry. VEGF, angiogenin, and FEV1 estimations were repeated for asthmatic children 6 weeks after start of therapy. RESULTS: During the acute attack, asthmatic children had significantly higher levels of VEGF and angiogenin than in healthy control children (p < 0.001). VEGF and angiogenin levels showed more elevation with increase in asthma severity (p < 0.001). A significant positive correlation existed between both angiogenic factors (r = 0.98, p < 0.001). A negative significant correlation was found between FEV1 percentage of predicted and both VEGF (r = -0.99, p < 0.001) and angiogenin (r = -0.97, p < 0.001). A nonsignificant correlation was found between serum IgE and sputum VEGF (r = 0.09, p > 0.05). Although there was a significant decrease in the levels of both VEGF and angiogenin after 6 weeks of treatment with corticosteroid inhalation therapy, the levels did not reach normal control levels (p < 0.001 and p < 0.05, respectively). CONCLUSIONS: Our results show that both VEGF and angiogenin levels were elevated in children with acute asthma. The study also suggests that increased severity of bronchial asthma in children is associated with the expression of both angiogenic factors, which are implicated in asthma pathogenesis. After 6 weeks of therapy, the levels of both angiogenic factors showed significant decrease.  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