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   351篇
  免费   23篇
  国内免费   1篇
耳鼻咽喉   5篇
儿科学   15篇
妇产科学   7篇
基础医学   18篇
口腔科学   62篇
临床医学   44篇
内科学   83篇
皮肤病学   8篇
神经病学   46篇
特种医学   3篇
外科学   31篇
综合类   3篇
预防医学   17篇
眼科学   7篇
药学   20篇
中国医学   2篇
肿瘤学   4篇
  2023年   2篇
  2022年   6篇
  2021年   12篇
  2020年   9篇
  2019年   9篇
  2018年   9篇
  2017年   12篇
  2016年   12篇
  2015年   16篇
  2014年   29篇
  2013年   23篇
  2012年   26篇
  2011年   29篇
  2010年   13篇
  2009年   10篇
  2008年   30篇
  2007年   26篇
  2006年   30篇
  2005年   35篇
  2004年   21篇
  2003年   7篇
  2002年   6篇
  1999年   1篇
  1997年   1篇
  1995年   1篇
排序方式: 共有375条查询结果,搜索用时 15 毫秒
21.
Although most childhood nephrotic syndromes respond to steroid treatment, steroid resistant nephrotic syndrome (SRNS) is also common and is particularly difficult to treat. This study investigated the role of glycosaminoglycans (GAG) in the pathogenesis and clinical course of nephrotic syndrome in children. Thirty-four children (21 males and 13 females, mean age 3.7±1.6 years) with steroid-sensitive nephrotic syndrome and 20 children with steroid-resistant nephrotic syndrome (12 males and 8 females, mean age 10.9±3.8 years; of the twenty, four had primary SRNS (FSGS) and the others had secondary SRNS) were included the study. Mean urine levels of GAG relative to creatinine (UGAG/UCr) in patients with SRNS (n=20, 113.01±78.46 mg g–1 Cr) and in patients experiencing the nephrotic period of steroid-sensitive nephrotic syndrome (n=34, 132.15±101.55 mg g–1 Cr) were both significantly higher than mean UGAG/UCr for control subjects (n=30, 51.83±47.66 mg g–1 Cr) (P<0.01 for both). Patients excreted significantly more GAG during the nephrotic period of steroid-sensitive nephrotic syndrome than during remission (132.15±101.55 vs 39.11±42.73 mg g–1 Cr, respectively; P<0.01). There was, however, no significant difference between UGAG/UCr for patients with steroid-resistant nephrotic syndrome and UGAG/UCr in the nephrotic period of steroid-sensitive nephrotic syndrome. Urine GAG excretion correlated significantly with the severity of proteinuria. The results suggest that GAG play a significant role in the pathogenesis of nephrotic syndrome but that GAG excretion is not a marker for response to steroid treatment in pediatric patients with this condition.  相似文献   
22.
Disturbances of coagulation and fibrinolysis have been reported in patients with chronic uremia. Studies of different coagulation and fibrinolysis parameters in regularly dialyzed patients have yielded conflicting results. Global fibrinolytic capacity (GFC) examines the function of the entire fibrinolytic system. This assay is a sensitive and reliable method for evaluating the fibrinolytic function of plasma in vitro. In this study, GFC was used as a screening test to investigate the effects of two different dialysis modalities on the fibrinolytic system on children on long-term dialysis. MATERIALS AND METHODS: The study included 12 children (age range, 11-20 years; mean age, 15.9+/-3.3 years) who were undergoing regular hemodialysis (HD) and 12 children (age range, 10-15 years; mean age, 13.1+/-1.7 years) who were undergoing continuous ambulatory peritoneal dialysis (CAPD). Thirteen healthy age- and sex-matched subjects served as controls. Each sample was investigated for complete blood count and serum levels of C-reactive protein, serum electrolytes, total cholesterol, triglyceride, fibrinogen, total protein and albumin. A GFC assay was also done in each case. RESULTS: The mean GFC in the CAPD group was lower than that in the HD and control groups (p<0.05). There was no significant difference between the mean GFC values of HD patients and controls. The mean serum albumin level was lower in CAPD patients than in HD patients (p<0.05), and there was also a positive correlation between serum albumin level and GFC in patient groups(r=0.52, p<0.05). Global fibrinolytic capacity was positively correlated with hemoglobin level and negatively correlated with weekly erythropoietin dose per kg body weight (r=0.56 and r=-0.49, respectively; p<0.05). CONCLUSION: The results suggest that CAPD patients have decreased fibrinolytic capacity compared to HD patients. Hypoalbuminemia and erythropoietin treatment may contribute to suppression of fibrinolytic function CAPD patients.  相似文献   
23.
The trace element selenium is discussed as a chemopreventive agent in colorectal carcinogenesis. Selenocysteine-containing proteins, so-called selenoproteins, represent potential molecular targets for nutritive selenium supplementation. Due to their antioxidative potential, the selenoproteins gastrointestinal glutathione peroxidase (GI-GPx) and selenoprotein P (SePP) are considered to provide protection against reactive oxygen species (ROS), thereby reducing DNA damage and preventing development of colon cancer. GI-GPx and SePP are abundantly expressed in normal colon mucosa. Recently, we demonstrated both reduced SePP expression and increased GI-GPx expression in colorectal adenomas. In this study, we investigated the expression of SePP and GI-GPx in colorectal cancers compared with corresponding normal mucosa. Further, the occurrence of genetic alterations within the SePP and GI-GPx genes was analyzed. We observed a significant reduction or loss of SePP mRNA expression in colon cancers, whereas GI-GPx mRNA and protein expression varied between different tumor samples. In addition, we identified novel polymorphisms within the SePP and GI-GPx genes with so far unknown relevance for protein function. Our results argue against a general decrease of selenoprotein expression in colorectal carcinogenesis but imply specific differential regulation of expression of individual selenoproteins.  相似文献   
24.
Secretory meningiomas   总被引:4,自引:0,他引:4  
Secretory meningiomas are a rare meningioma subtype. Among meningiomas, the frequency of secretory meningiomas is 1.6%. Unlike other meningioma types, most of the patients were female (ratio 3:1). No recurrence was reported during the 24–180 months follow-up period of our secretory meningiomas in which, a low level of 0.3% Ki-67 proliferative index was reported. In this meningioma subtype, the percentage of cases with positive progesterone receptor is 33%. With carcinoembryonic antigen, cytokeratin and epithelial membrane antigen, in all the cases positivity was observed in both, the inclusions and the cells surrounding them. With human milk fat globulin 2, a high ratio (92%) of positivity was observed. Majority of the cases were negative with CA125, only three of the cases had suspicious positivity. Distribution of inclusions was irregular and their positive reactions showed varying staining features. Positivity with alpha-1-antitripsin was seen not only in the inclusions but also in some meningothelial cells as well. Ubiquitin was positive in inclusions of the 83% of cases. Staining features of the inclusions pointed out the possibility of them being in a varying age and/or content. Secretory meningiomas are a different type compared to other meningiomas, not only with their histological features but also with their clinical features as well.  相似文献   
25.
Rathke's cleft cysts (RCCs) are considered to arise from the remnants of Rathke's pouch, an invagination of the stomodeum. They classically described as benign epithelium lined intrasellar cysts containing mucoid material, and also found in 2–33% of routine autopsy series. The most common presenting symptoms are visual impairment, hypothalamic dysfunction, hypopituitarism and headache. Diabetes insipidus has been described in patients with RCC. Very few cases presented with only diabetes insipidus in adults. To our knowledge, our patient is the first case of RCC presenting with only diabetes insipidus in childhood. A 9-year-old girl presented with diabetes insipidus. The physical, neurological and endocrinological examinations were normal, except for diabetes insipidus. Magnetic resonance imaging scan revealed a hyperintense lesion with supra sellar extension in the posterior pituitary both on T1 and T2 weighted images. Subtotal excision of RCC was performed via transsphenoidal surgery. However, diabetes insipidus persisted after the surgery.  相似文献   
26.
Background: Atrial septal defect (ASD) is a common form of congenital heart defect in adults, which affects all cardiac chambers. Atrial myocardial function in patients with ASD has not yet been clearly elucidated. The aim of this study was to investigate atrial myocardial deformation properties in patients with ASDs. Methods: The study involved 24 patients with a secundum type ASD, and 22 healthy subjects. Color Doppler myocardial imaging was used to measure left and right atrial myocardial systolic strain and strain rate values, together with peak systolic velocity, early velocity, and late diastolic velocity. Results: There was no significant difference between the two groups with regard to age, gender, body mass index, heart rate, blood pressure, left atrial diameter, and ventricular function. The peak systolic atrial myocardial strain and strain rate values in each of the atrial walls studied were lower in the ASD group compared to those of the control group, but the difference reached statistical significance only in the case of the right atrial wall (right atrial strain: 48.0 ± 32.7% vs 100.2 ± 46.6%, P = 0.006; right atrial strain rate: 2.6 ± 1.2/sec vs 3.8 ± 1.2/sec, P = 0.024). Conclusion: The left to right cardiac shunt that results from ASD leads to a reduction in the right atrial myocardial longitudinal lengthening that occurs during ventricular ejection. These findings demonstrate that the reservoir function of the atrium is impaired and atrial stiffness increases in patients with ASDs.  相似文献   
27.
Üçeyler  Nurcan 《Der Diabetologe》2019,15(7):647-652
Die Diabetologie - Diabetes mellitus ist eine Volkskrankheit mit rapide steigenden Zahlen. Ein gravierendes Hauptsymptom ist die diabetische Neuropathie, die in etwa der Hälfte der Fälle...  相似文献   
28.
It is aimed to investigate the central antinociceptive effect of protocatechuic acid and the involvement of stimulation of opioidergic, serotonin 5-HT2A/2C, α2-adrenergic and muscarinic receptors in protocatechuic acid-induced central analgesia in mice. Time-dependent antinociceptive effects of protocatechuic acid at the oral doses of 75, 150 and 300?mg/kg were tested in hot-plate (integrated supraspinal response) and tail-immersion (spinal reflex) tests in mice. To investigate the mechanisms of action; the mice administered 300?mg/kg protocatechuic acid (p.o.) were pre-treated with non-specific opioid antagonist naloxone (5?mg/kg, i.p.), serotonin 5-HT2A/2C receptor antagonist ketanserin (1?mg/kg, i.p.), α2-adrenoceptor antagonist yohimbine (1?mg/kg, i.p.) and non-specific muscarinic antagonist atropine (5?mg/kg, i.p.), respectively. The antinociceptive effect of protocatechuic acid was observed at the doses of 75, 150 and 300?mg/kg in tail-immersion test, at the doses of 150 and 300?mg/kg in hot-plate test at different time interval. The enhancement in the latency of protocatechuic acid-induced response to thermal stimuli was antagonized by yohimbine, naloxone and atropine in tail-immersion test, while it was antagonized only by yohimbine and naloxone pretreatments in hot-plate test. These results indicated that protocatechuic acid has the central antinociceptive action that is probably organized by spinal mediated cholinergic and opiodiergic, also spinal and supraspinal mediated noradrenergic modulation. However, further studies are required to understand how protocatechuic acid organizes the interactions of these modulatory systems. As a whole, these findings reinforce that protocatechuic acid is a potential agent that might be used for pain relief. Additionally, the clarification of the effect and mechanisms of action of protocatechuic acid will contribute to new therapeutic approaches and provide guidance for new drug development studies.  相似文献   
29.
BACKGROUND: Low muscle glutamine levels during sepsis are associated with reduced protein synthesis and elevated protein breakdown, in particular myofibrillar protein breakdown. Thus, in a cecal ligation and puncture (CLP)-induced sepsis model in the rat, we hypothesized that glutamine pretreatment would protect the diaphragm muscle function. METHODS: Eighty-four male Wistar rats weighing between 180 g and 200 g received standard amino acid solution 1.2 g kg(-1) per day intraperitoneally (IP) or standard amino acid solution 1.2 g kg(-1) per day plus alanyl-glutamine (GLN) 0.25 g kg(-1) per day (IP) during the first 6 days of the experiment. On the seventh day, CLP or sham procedures were applied. The sham and CLP groups were equally divided into 3 subgroups according to the termination of the experiment, which took place at either the 24th hour, 48th hour, or 72nd hour. After the compound muscle action potentials (CMAP) were recorded from the diaphragms of the rats at these selected times, they were decapitated under ketamine/xylazine anesthesia, and diaphragms were harvested for biochemical and histopathological examination. RESULTS: The mean area and amplitude of CMAP were significantly larger in sham+GLN groups when compared with CLP and CLP+GLN groups at all times (p < .05). Diaphragm Ca+2 -ATPase levels were found to be significantly decreased in CLP group at all times compared to sham groups (p < .05). Diaphragm reduced glutathione levels were significantly higher in sham+GLN groups when compared with CLP and CLP+GLN groups at all times (p < .05). In histopathologic assessment, moderate neutrophil infiltration, which was observed in CLP48, was significantly reduced with alanyl-glutamine supplementation in CLP+GLN48 group (p < .05). CONCLUSIONS: This study showed that glutamine pretreatment did not improve diaphragm muscle function, but prevented the biochemical and histopathological changes in diaphragmatic muscle in CLP-induced sepsis. However, further studies are needed to clarify whether a higher dose of glutamine supplementation might protect the diaphragmatic muscle functions.  相似文献   
30.
The aim of this study was to compare the biological activities of ethanolic propolis extracts of Apis mellifera caucasica obtained from Ardahan and Erzurum provinces of Turkey. Samples were tested for antioxidant, anticytotoxic, anticarcinogenic, antibacterial, and antifungal potentials using different techniques. Propolis samples from the two provinces had different mineral and organic compositions related to their geographical origin. The ferric reducing antioxidant power (FRAP) test showed superiority of Ardahan propolis over the Erzurum. Regardless of origin and the presence of mitomycin C in the culture medium, propolis enhanced human peripheral lymphocyte viability, which depended on the duration and propolis concentration. Antiperoxidative activity on MCF-7 breast cancer cells was concentration-dependent. Erzurum propolis showed the highest anticarcinogenic activity at the concentrations of 62.5 μg/mL and 125 μg/ mL, which dropped at higher concentrations. All propolis samples also showed antibacterial activity against the tested human pathogens similar to ampicillin and penicillin controls, except for Pseudomonas aeruginosa. However, they did not exert any antifungal activity against Candida albicans and Yarrowia lipolytica. In conclusion, propolis samples from both provinces showed promising biological activities, but further research should focus on finding the right concentrations for optimal effect and include the cell necrosis pathway to get a better idea of the anticarcinogenic effects.Key words: anticarcinogen, antimicrobial, biological activity, mineral, mitomycin C, organic composition  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