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   448篇
  免费   34篇
  国内免费   3篇
耳鼻咽喉   6篇
儿科学   33篇
妇产科学   18篇
基础医学   25篇
口腔科学   7篇
临床医学   37篇
内科学   143篇
皮肤病学   50篇
神经病学   33篇
特种医学   9篇
外科学   49篇
综合类   3篇
预防医学   10篇
眼科学   30篇
药学   17篇
肿瘤学   15篇
  2023年   5篇
  2022年   6篇
  2021年   19篇
  2020年   17篇
  2019年   17篇
  2018年   14篇
  2017年   13篇
  2016年   22篇
  2015年   16篇
  2014年   24篇
  2013年   25篇
  2012年   38篇
  2011年   45篇
  2010年   28篇
  2009年   18篇
  2008年   32篇
  2007年   39篇
  2006年   33篇
  2005年   25篇
  2004年   27篇
  2003年   7篇
  2002年   5篇
  2001年   5篇
  2000年   4篇
  1999年   1篇
排序方式: 共有485条查询结果,搜索用时 15 毫秒
61.
PURPOSE: We aimed to investigate the effects of methylene blue (MB) on NO production, myeloperoxidase (MPO) activity, antioxidant status and lipid peroxidation in lung injury during different stages of sepsis in rats. MATERIAL AND METHODS: Rats were randomly divided into 4 groups (n = 20): group C, sham operated; group CMB, sham operated and receiving MB (25 mg/kg, i.p.); group S, sepsis; group SMB, sepsis and receiving MB (25 mg/kg, i.p.). Sepsis was induced by cecal ligation and puncture (CLP). The MB dose was administered after CLP. Each group was subdivided into two subgroups (n = 10) which were sacrificed at 9 or 18 h after the surgical procedure. The levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) and MPO activity, total nitrite/nitrate and malondialdehyde (MDA) in the lung tissue were measured. Lung injury was graded from 1 (injury to 25% of the field) to 4 (diffuse injury) by the pathologist. RESULTS: In group SMB, while SOD and CAT increased in both early and late sepsis periods, GSH-PX increased significantly only in the early sepsis period when compared with group S. Increase in lung MPO activity after CLP-induced sepsis was prevented by MB administration. MB significantly decreased to nitrite/nitrate and MDA levels both in early and late sepsis periods when compared with group S (p < 0.05). Group S showed a marked increase in neutrophil infiltration into the interstitial space and thickening of the alveolar septa, whereas the alveolar damage score was lower in the SMB group (p < 0.05). CONCLUSION: MB reduced the MPO activity and lipid peroxidation by both decreasing oxidative stress and NO overproduction in the lungs, which resulted in the attenuation of lung injury after CLP-induced sepsis in rats.  相似文献   
62.
Synovial sarcoma usually arises in the extremities and in close proximity to large joints. Primary synovial sarcoma of the anterior abdominal wall is rare. A 17-year-old girl was admitted to the hospital with a palpable abdominal mass, and there was a 9.5 cm x 7.5 cm x 6-cm lobulated, cystic, and semisolid lesion of in the external oblique abdominal muscle shown on the abdominal magnetic resonance image. She was then operated and pathology was consistent with synovial sarcoma. The presence of synovial sarcoma in extraarticular sites such as the abdominal wall argues against an origin from arthrogenous mesenchyme.  相似文献   
63.
64.
Trace elements as a component of oxidative stress in COPD   总被引:5,自引:0,他引:5  
OBJECTIVE: The purpose of this study was to assess the serum concentrations of those trace elements that act as a component of oxidative stress in COPD patients. Clinically stable COPD outpatients (n = 26) and healthy controls (n = 24) were studied. METHODOLOGY: Serum concentrations of copper (Cu) and zinc (Zn) were determined using a Varian Spectra AA220 flame atomic absorption spectrophotometer. Serum concentration of iron (Fe) was measured by the ferene assay, using a commercially available kit (IL Test Iron) with the ILAb 900 autoanalyser. The lipid peroxidation product malondialdehyde (MDA) in serum samples was measured spectrophotometrically in terms of TBARS (thiobarbituric acid reactive substances). RESULTS: The serum MDA concentration in COPD patients was found to be similar to the control group (0.68 +/- 0.15 nmol/mL vs 0.62 +/- 0.13 nmol/mL, respectively; P= 0.163). The serum concentrations of the trace elements in both study groups were in the normal reference range. There was no difference in Fe concentration between COPD patients and the control group (0.81 +/- 0.38 micro g/mL vs 0.92 +/- 0.41 micro g/mL; P= 0.360). Copper concentrations were higher (1.06 +/- 0.26 microg/mL vs 0.92 +/- 0.19 microg/mL; P <0.040); while zinc was lower in the COPD group compared to the controls (0.83 +/- 0.25 microg/mL vs 1.03 +/- 0.23 microg/mL; P= 0.006). Serum Zn concentrations were lower in the severe COPD patients compared to mild-moderate COPD patients (P = 0.038). CONCLUSION: The results of this study indicate that there are alterations in serum concentrations of trace elements in COPD patients, suggesting that they may play a role in the pathophysiology of this disease by virtue of their role in oxidative stress. We recommend further studies on the role of trace elements in the pathophysiology of COPD, their association with markers of oxidant/antioxidant status and on the clinical significance of their deficiency.  相似文献   
65.
The aim of the current study is to investigate hearing function in patients with allergic rhinitis. Fifty-eight patients with positive skin prick test (Group 1) (116 ears) and 31 subjects with negative skin prick test (62 ears) as group 2 were included. Pure tone audiometry at 250, 500, 1000, 2000, 4000 and 8000 Hz and immittance measures, including tympanometry and acoustic reflex tests, were performed in both groups. There was statistically significant difference between pure-tone threshold of the group 1 and group 2 at 8000 Hz (p< 0.05). Based on our study, the patients with allergic rhinitis had better hearing than the control group at 8000 Hz.  相似文献   
66.
67.
Objectives: Subclinical cardiac involvement may occur in patients with Behçet's disease (BD). The purpose of our study was to assess the noninvasive parameters of biventricular function derived from Doppler tissue imaging (DTI) of the tricuspid and mitral annular motion in BD. Methods: Twenty‐one patients with BD and 20 control subjects were enrolled in this study. All subjects were selected to exclude those with cardiovascular risk factors. Standard echocardiography and pulsed DTI were obtained in every patient. Results: Peak systolic (13.71 ± 2.09 vs 20.01 ± 1.57, P < 0.001), peak early diastolic (11.26 ± 2.52 vs 15.35 ± 2.06, P < 0.001) tricuspid annular velocities were significantly lower in patients than controls. Peak systolic (8.68 ± 1.4 vs 12.25 ± 1.7, P < 0.001), peak early diastolic (7.89 ± 1.07 vs 9.94 ± 1.12, P < 0.001), and peak end diastolic (8.30 ± 1.32 vs 9.23 ± 0.91, P = 0.013) lateral mitral annular velocities were significantly lower in patients than controls. Conclusions: We demonstrated that myocardial velocities, were affected in patients with BD. Therefore, we conclude that right and left ventricular function is impaired in patients with BD.  相似文献   
68.
69.
Polymorphonuclear leukocytes play a central role in all stages of the atherothrombotic inflammatory process. The atherothrombotic activity of polymorphonuclear leukocytes is exerted by mediators such as myeloperoxidase (MPO). Although the role of MPO has been studied with respect to the development of adverse cardiac events in acute coronary syndromes (ACS), the association of this molecule with effectiveness of reperfusion in patients receiving thrombolysis is not yet known. The study population consisted of a total of 158 patients with acute coronary syndromes. Final diagnosis was ST-segment elevation myocardial infarction in 86 patients, 80 of whom received thrombolysis. Blood samples were drawn at presentation of the patients and serum myeloperoxidase levels were measured. Reperfusion was defined in terms of electrocardiographic ST-segment resolution. The serum levels of MPO were found to be correlated with rates of in-hospital adverse events including death (P < 0.001), reinfarction (P < 0.001), recurrent ischemia (P < 0.001), arrhythmias (P < 0.001), clinical heart failure (P < 0.001), and cardiogenic shock (P < 0.001). There was a significant difference in serum MPO levels between subjects with three-vessel disease and two- or one-vessel disease (P < 0.001). Pre-lytic serum high-sensitivity C-reactive protein levels in patients with successful reperfusion were lower than in patients with failed reperfusion (P < 0.001). Analysis of patients with ST segment elevation myocardial infarction receiving thrombolytic therapy revealed that pre-lytic serum MPO levels in patients with successful reperfusion were significantly lower than those of patients with failed reperfusion (P < 0.001). In the present study, serum MPO levels were found to be a strong predictor of response to thrombolytic treatment in patients with ST-segment elevation myocardial infarction. Therefore the level of inflammatory activity in acute coronary syndromes seems to influence the effectiveness of fibrinolysis.  相似文献   
70.
Certain occupational groups are known to be at particularly high risk of developing allergic diseases. The objective of the present study was to evaluate the prevalence of allergic diseases among working adolescents. The International Study of Asthma and Allergies in Childhood questionnaire was used. Four hundred and thirty six adolescents working in motor, lathe-finish, coiffure and textile and 366 high school students as control group were enrolled to the study. Mean age was 16.8 +/- 1.2 years and 82.9% of them were male. There was no significant difference among groups for ever and current wheezing while doctor diagnosed asthma was higher in lathe- finish group (p = 0.036). Family history of allergy, history of allergic rhinitis, and active smoking were found to be risk factors for asthma and related symptoms. Working in coiffure (p = 0.054), and textile (p = 0.003) were significant risk factors for ever allergic rhinitis. Working in lathe finish (p = 0.023), coiffure (p = .002), and textile (p < 0.001) were associated with a higher risk for current allergic rhinitis. Working in coiffure was a risk factor for ever eczema (p = 0.008) and doctor diagnosed eczema (p = 0.014). It was concluded that working in lathe-finish was associated with doctor diagnosed asthma and active smoking was a risk factor for asthma and related symptoms. Working in coiffure, textile and lathe- finish were risk factors for rhinitis, and working in coiffure was a risk factor for eczema. Preventive measures should be taken at the onset of employment in order to prevent or reduce the detrimental effects of exposures in these occupational groups.  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