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   357篇
  免费   11篇
  国内免费   4篇
耳鼻咽喉   2篇
儿科学   7篇
妇产科学   12篇
基础医学   50篇
口腔科学   2篇
临床医学   36篇
内科学   121篇
皮肤病学   7篇
神经病学   38篇
特种医学   7篇
外科学   23篇
综合类   1篇
预防医学   12篇
眼科学   4篇
药学   18篇
肿瘤学   32篇
  2024年   1篇
  2023年   9篇
  2022年   26篇
  2021年   27篇
  2020年   11篇
  2019年   9篇
  2018年   16篇
  2017年   4篇
  2016年   19篇
  2015年   11篇
  2014年   12篇
  2013年   22篇
  2012年   31篇
  2011年   33篇
  2010年   9篇
  2009年   5篇
  2008年   26篇
  2007年   23篇
  2006年   22篇
  2005年   21篇
  2004年   17篇
  2003年   5篇
  2002年   3篇
  2001年   1篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1996年   3篇
排序方式: 共有372条查询结果,搜索用时 15 毫秒
21.
22.
23.
BACKGROUND: Until the late 1970's occupational asthma (OA) was considered reversible once patients were removed from exposure. Unfortunately, respiratory symptoms and non-specific bronchial hyper-responsiveness (NSBH) persist in about two-thirds of patients for years after removal from the offending agent. OBJECTIVES AND METHODS: This review focuses on the role of airways inflammation and remodelling in persistent respiratory symptoms and NSBH after cessation of occupational exposure. RESULTS: Even though cessation of exposure does not always result in remission of OA, symptoms, airways calibre and NSBH do improve in many patients. Although improvements in FEV1 and NSBH tend to reach a plateau 1-2 years after workers leave exposure, reversing NSBH may take much longer and respiratory symptoms and NSBH can persist in subjects removed from exposurefor >10 yrs. Long-term treatment with inhaled corticosteroids (ICS) induces a small but significant improvement in respiratory symptoms and in quality of life and a decrease in NSBH. Prolonged exposure and respiratory symptoms, marked airway obstruction and NSBH, high total cell, eosinophil and neutrophil counts in bronchoalveolar lavage fluid, a strong reaction during specific inhalation challenge, and delayed treatment with ICS have been identified as prognostic factors of unfavourable outcome. If exposure persists, OA tends to deteriorate in many patients but regular long-term treatment with ICS and long-acting beta2-agonists seems to stabilize the outcome. Soon after the last exposure inflammatory cell infiltrates, including eosinophils, and increased thickness of sub-epithelial collagen have been observed. When time since removal from exposure was longer, persistence of respiratory symptoms and NSBH was associated with airway inflammation, remodelling and hypersensitivity to the offending agent. Thickness of sub-epithelial collagen and specific airway sensitivity were reduced after prolonged non-exposure to isocyanates, although NSBH and airway inflammation persisted. CONCLUSIONS: Pathologic features are similar in OA and non-occupational asthma. The main factors of favourable outcome are early removal from exposure and a mild airway obstruction and NSBH at diagnosis. Persistence of airway inflammation years after removal from exposure suggests this process may become independent of the offending agent. The role of remodelling on persistence of OA needs to be clarified further.  相似文献   
24.
BACKGROUND: To the authors' knowledge, little is known to date regarding the prognostic relevance of measuring serum levels of vascular endothelial growth factor (VEGF), a potent stimulator of angiogenesis, in patients with colon carcinoma who undergo surgery. METHODS: Preoperative and postoperative VEGF serum levels were determined by enzyme-linked immunoadsorbent assay in 81 patients with colon carcinoma who were undergoing surgery. Fifty healthy individuals served to define normal VEGF serum levels. RESULTS: Preoperative VEGF serum levels were significantly higher in the group of patients with colon carcinoma (mean, 504.1 pg/mL +/- 223 pg/mL; range, 285-1390 pg/mL; 95% confidence interval [95%CI], 49 pg/mL) compared with the control group (mean, 78.1 pg/mL +/- 22 pg/mL; range, 40-110 pg/mL; 95%CI, 4.3 pg/mL; P < 0.001). Multiple regression analysis demonstrated a significant correlation (r) between preoperative VEGF serum levels and age (r = - 0.275; P = 0.013), Dukes stage (r = 0.488; P < 0.001), and carcinoembryonic antigen (CEA) levels (r = 0.285; P < 0.018). No significant correlation was found between preoperative VEGF serum levels and disease site, patient gender, tumor size, tumor grade, or performance status. Moreover, preoperative VEGF serum levels were significantly lower in patients who underwent curative surgery compared with patients who underwent noncurative surgery (443 pg/mL +/- 117 pg/mL vs. 821 +/- 353 pg/mL, respectively; P < 0.0001). Logistic regression analysis selected preoperative VEGF and CEA serum levels as the only good prognostic indicators of curative and noncurative surgery (P < 0.001; relative risk, 2.98 and 2.03, respectively). Furthermore, VEGF serum levels dropped significantly after surgery, with a further downward trend until the 30th postoperative day (P < 0.001). Stepwise regression analysis selected preoperative VEGF serum level as the only variable associated significantly with the prediction of both disease-specific survival and disease-free survival (P = 0.001). CONCLUSIONS: Preoperative serum VEGF levels may be useful for predicting outcome in patients with colon carcinoma who undergo surgery.  相似文献   
25.
BACKGROUND: Cardiac abnormalities develop in patients with acromegaly as a consequence of effects of GH/IGF-I on the heart and related cardiovascular risk factors. OBJECTIVE: To evaluate the possible contribution of postoperative variations in blood pressure (BP), glucose tolerance and insulin sensitivity to the cardiac improvement reported in patients who have been cured of acromegaly. DESIGN: Thirty-one patients with acromegaly were studied before and 6 Months after successful transsphenoidal surgery, defined by normal age-related IGF-I concentrations and glucose-suppressed GH concentrations <1 microg/l. METHODS: Cardiovascular parameters were assessed by Doppler echocardiography and 24-h ambulatory blood pressure monitoring. Insulin sensitivity indexes were calculated on the basis of fasting and post-load glycaemia and insulinaemia and referred to as HOMA(ISI) and OGTT(ISI), respectively. RESULTS: Successful surgery was confirmed to improve left ventricular mass index (LVMI) and diastolic filling significantly. Mean 24-h systolic BP values decreased (P=0.009) and BP rhythm was restored in 12 of 15 patients with a blunted preoperative profile. Glucose tolerance normalized in patients with preoperative glucose intolerance (n=7) or diabetes mellitus (n=3). HOMA(ISI) and OGTT(ISI) increased (P=0.0001 for each parameter), indicating a marked improvement in insulin sensitivity. The postoperative reduction in LVMI correlated with increased insulin sensitivity (P<0.001 for both indexes), but not with other parameters. Improved diastolic filling correlated with the reduction in LVMI. CONCLUSIONS: Successful surgery in patients with acromegaly induces a significant improvement in haemodynamic and metabolic risk factors. This study suggests a direct link between insulin resistance and acromegalic cardiomyopathy.  相似文献   
26.
BACKGROUND: Interleukin-10 (IL-10) is a cytokine with immunosuppressive properties. In this study, the authors investigated the prognostic significance of IL-10 levels in the sera of 58 patients with advanced gastric or colorectal carcinoma. METHODS: IL-10 serum levels were measured before chemotherapy, on completion of chemotherapy, and at follow-up by means of a commercially available enzyme-linked immunoadsorbent assay kit. The results then were analyzed in comparison with other prognostic variables and a model predicting overall survival (OS) and time to disease progression (TTP) was generated. RESULTS: Elevated levels of serum IL-10 were found in carcinoma patients compared with healthy controls (19.6 +/- 6.8 pg/mL vs. 9.2 +/- 1.5 pg/mL; P < 0.0001), with those patients with metastatic disease showing significantly higher levels than patients with undisseminated disease (21.9 +/- 6. 7 pg/mL vs. 15.5 +/- 3.6 pg/mL; P = 0.0003). Retrospective analysis of prechemotherapy IL-10 serum levels showed a significant difference between responders and nonresponders (15.8 +/- 2.5 pg/mL vs. 21.6 +/- 7.6 pg/mL; P < 0.0001). Moreover, a further significant increase in IL-10 serum levels was observed in nonresponders at the end of therapy (21.6 +/- 7.6 pg/mL prechemotherapy vs. 31.3 +/- 11.6 pg/mL postchemotherapy; P < 0.0001) whereas no significant differences were observed in responders. Using univariate analysis, both OS and TTP were shown to be affected by the median pathologic levels of IL-10; multivariate analysis related to OS and TTP identified performance status and IL-10 serum level as the relevant prognostic factors, respectively. Finally, stepwise regression analysis identified IL-10 serum level and metastases as the prognostic factors related to both OS and TTP. CONCLUSIONS: The results of the current study show that measurement of pretreatment serum levels of IL-10 is of independent prognostic utility in patients with advanced gastrointestinal carcinoma and may be useful for the detection of disease progression.  相似文献   
27.
Diamond-Blackfan Anemia (DBA) is characterized by a defect of erythroid progenitors and, clinically, by anemia and malformations. DBA exhibits an autosomal dominant pattern of inheritance with incomplete penetrance. Currently nine genes, all encoding ribosomal proteins (RP), have been found mutated in approximately 50% of patients. Experimental evidence supports the hypothesis that DBA is primarily the result of defective ribosome synthesis. By means of a large collaboration among six centers, we report here a mutation update that includes nine genes and 220 distinct mutations, 56 of which are new. The DBA Mutation Database now includes data from 355 patients. Of those where inheritance has been examined, 125 patients carry a de novo mutation and 72 an inherited mutation. Mutagenesis may be ascribed to slippage in 65.5% of indels, whereas CpG dinucleotides are involved in 23% of transitions. Using bioinformatic tools we show that gene conversion mechanism is not common in RP genes mutagenesis, notwithstanding the abundance of RP pseudogenes. Genotype-phenotype analysis reveals that malformations are more frequently associated with mutations in RPL5 and RPL11 than in the other genes. All currently reported DBA mutations together with their functional and clinical data are included in the DBA Mutation Database.  相似文献   
28.
In the last few years,the advent of next generation sequencing(NGS) has revolutionized the approach to genetic studies,making whole-genome sequencing a possible way of obtaining global genomic information.NGS has very recently been shown to be successful in identifying novel causative mutations of rare or common Mendelian disorders.At the present time,it is expected that NGS will be increasingly important in the study of inherited and complex cardiovascular diseases(CVDs).However,the NGS approach to the genetics of CVDs represents a territory which has not been widely investigated.The identification of rare and frequent genetic variants can be very important in clinical practice to detect pathogenic mutations or to establish a profile of risk for the development of pathology.The purpose of this paper is to discuss the recent application of NGS in the study of several CVDs such as inherited cardiomyopathies,channelopathies,coronary artery disease and aortic aneurysm.We also discuss the future utility and challenges related to NGS in studying the genetic basis of CVDs in order to improve diagnosis,prevention,and treatment.  相似文献   
29.
30.
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