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   402篇
  免费   18篇
  国内免费   1篇
耳鼻咽喉   16篇
儿科学   20篇
妇产科学   42篇
基础医学   40篇
口腔科学   32篇
临床医学   24篇
内科学   87篇
皮肤病学   10篇
神经病学   15篇
特种医学   5篇
外科学   56篇
综合类   8篇
一般理论   1篇
预防医学   13篇
眼科学   9篇
药学   16篇
中国医学   2篇
肿瘤学   25篇
  2023年   6篇
  2022年   6篇
  2021年   17篇
  2020年   11篇
  2019年   9篇
  2018年   14篇
  2017年   12篇
  2016年   17篇
  2015年   17篇
  2014年   22篇
  2013年   31篇
  2012年   28篇
  2011年   28篇
  2010年   19篇
  2009年   23篇
  2008年   23篇
  2007年   32篇
  2006年   30篇
  2005年   29篇
  2004年   16篇
  2003年   14篇
  2002年   13篇
  2001年   3篇
  2000年   1篇
排序方式: 共有421条查询结果,搜索用时 15 毫秒
91.
92.
ObjectiveThis study aimed to compare 2 methods of ulnar variance (UV) measurement (the perpendicular method and the circular method) and to determine whether UV changed based on the demographic characteristics (sex and age).MethodsUV was measured on bilateral wrist radiographs of 124 patients (62 men, 62 women; mean age=48.5 years; range=18–79 years) who had no history of trauma, congenital wrist anomaly, previous wrist surgery, and wrist osteoarthritis by a single radiologist with 4 years of experience. All measurements were made on standardized radiographic images using 2 methods: the perpendicular method and the circular method. All the patients were then divided into groups based on sex and age, and the study population was determined by selecting a similar number of patients for each sex and age group.ResultsThe mean UV of the right and left wrists was measured as 0.33 (range=−4.3 to 5.7) mm by the perpendicular method and as 0.034 (range=−5 to 5.7) mm by the circular method. A significant difference was determined between the 2 measurement methods (p<0.001). There was a statistically significant difference between sex and UV values in the left wrist measurements by both methods (p<0.05). A significant correlation was found between the UV and age in both right and left side measurements, indicating a statistically significant difference between the methods (p<0.001).ConclusionThe results of our study demonstrated significant differences in the UV measurement between the 2 methods. Furthermore, UV measurement may change based on age and sex. These differences should be considered in the treatment planning of patients with wrist disorders.Level of EvidenceLevel IV, Therapeutic Study  相似文献   
93.
94.

Aim of the study

Seeds of Aesculus hippocastanum L. have long been used in European phytotherapy to treat inflammatory and vascular problems. In Turkish folk medicine, tea prepared from the crushed seeds was used to pass kidney stone and against stomach ache, while a fraction of seed was swallowed to alleviate hemorroids symptoms.In order to evaluate the in vivo effects of escin mixture from Aesculus hippocastanum seed on the blood and tissue antioxidant defense systems in standard pellet diet (SPD) and in high-fat diet (HFD) consumed male mice.

Materials and methods

Escin mixture was obtained from the ethanol extract of seeds. Escin mixture was administered orally to male mice fed either standard pellet diet (SPD) or high-fat diet (HFD) at 100 mg/kg doses daily for 5 weeks and the tissue (liver, kidney and heart) and blood samples were collected at the end of experimental period. The effect of escin mixture on the plasma antioxidant activity; blood and tissue malondialdehyde (MDA) and reduced glutathione (GSH) levels; erythrocyte and tissue superoxide dismutase (SOD) and catalase activity (CAT) in SPD and HFD consumed animals were experimentally studied.

Results

Escin mixture prohibited the adverse effects of oxidative stress and showed a protective effect on the liver architecture both in SPD and HFD consumed male mice. Escin mixture prohibited the adverse effects of oxidative stress and showed a protective effect on the liver architecture both in SPD and HFD consumed male mice. Combined administration of high-fat diet with escin mixture decreased blood (p < 0.01), liver (p < 0.01), kidney (p < 0.05), and heart (p < 0.05) of MDA, liver SOD (p < 0.01) and CAT (p < 0.05) levels and increased blood (p < 0.01) and liver GSH (p < 0.001) levels in mice.

Conclusion

The present results indicate that Aesculus hippocastanum increase the antioxidative defense system of the body and prevent HFD-induced lipid peroxidation in male mice.  相似文献   
95.
Objective:The synthesis of vitamin D is related to sun exposure, thus the restrictions during the Coronavirus disease-2019 (COVID-19) pandemic may have affected the levels of vitamin D in all age groups. The aim of this study was to evaluate vitamin D levels of healthy children and adolescents during the first year of the pandemic.Methods:The study group included healthy children and adolescents who were admitted for general check-ups and evaluated with 25(OH)D levels. Then, it was divided into two groups: Group 1 “pre-pandemic”, and Group 2 “pandemic”. Vitamin D levels were recorded from the hospital database and were compared according to age groups, gender, and the season, retrospectively.Results:The study group [mean age=90.29±59.45 median age=79 interquartile range (IQR): 102 months, male/female: 1409/1624] included 3033 children and adolescents (Group 1/Group 2 n=1864/1169). Although the mean 25(OH)D levels among preschool children did not differ between groups, the vitamin D levels of school-aged children and adolescents were significantly lower in the pandemic period than in the pre-pandemic period [Group 1 median=16.50 (IQR: 10.5) vs Group 2 median=15.9 (IQR: 11.3) in 6-12 age group (p=0.026); Group 1 median=13.30 (IQR: 10.2) vs Group 2 median=11.20 (IQR: 9.7) in 12-18 age group (p=0.003)]. Moreover, the 25(OH)D levels of adolescents showed seasonal variance with lower levels in winter, and unexpectedly, in summer.Conclusion:Pandemic-related restrictions have caused significant decreases in vitamin D levels of school-aged children and adolescents. We suggest that children and adolescents should be given vitamin D supplementation in order to maintain sufficient levels of vitamin D during the pandemic.  相似文献   
96.
BACKGROUND: Older age and axial location of Ewing's sarcoma have been reported as unfavorable prognostic factors. METHODS: The records of patients older than 15 years with the Ewing's family of tumors were reviewed retrospectively. After the induction chemotherapy consisting of alternating vincristine, adriablastin, cyclophosphamide (VAC) and etoposide, ifosfamide with mesna protection (IE), a local treatment modality was chosen based on tumor and patient characteristics. RESULTS: Twenty-five patients with a median age of 19 years were evaluated. Median follow-up was 26 months (range 4-58). Seventeen patients (68%) had died. In univariate analysis, factors predictive of shorter survival were the patients presenting with metastatic disease, with the primary tumor located at the pelvis, those who never achieved complete response to chemotherapy and those who had chemotherapy for <12 months. Only a negative link with pelvic location was observed in multivariate analysis [risk ratio 7.5; 95% confidence interval (CI) 1.52-37.06; P = 0.0134]. Median progression-free survival (PFS) and overall survival (OS) were 10 months (95% CI 6.2-13.8) and 14 months (95% CI 9.3-18.7), respectively. Cumulative 2-year PFS and OS were 19.0% (95% CI, SD +/-8.4) and 32.7% (95% CI, SD +/-9.8), respectively. CONCLUSIONS: The prognosis of patients with axial Ewing's sarcoma is dismal despite an intensive, multimodality approach including multiagent, alternating chemotherapy, surgery and/or radiotherapy. A more aggressive approach should be considered for this group of Ewing's sarcoma patients.  相似文献   
97.
98.
Apical hypertrophic cardiomyopathy (ApHCM) and apical displacement of papillary muscles (ADPM) are two different pathologies with a number of similar imaging findings that may hamper adequate diagnosis. While ApHCM is associated with increased rate of mortality, ADPM commonly presents with a benign course and differential diagnosis is of great importance. Clinical assessment and 2D echocardiography cannot sufficiently differentiate these conditions, however, and advanced echocardiographic methods may facilitate diagnosis. Although echocardiography is the first‐line imaging method in the diagnostic algorithm, cardiac magnetic resonance imaging (CMRI) is the gold standard for evaluating patients due to good spatial resolution and myocardial tissue characterization abilities. When CMRI is contraindicated, cardiac computed tomography may be an alternative reliable method that can also give information about the coronary anatomy. Nuclear imaging may also provide supplementary data regarding hypertrophy and coronary arteries when there is a suspicion of ischemia.  相似文献   
99.
Recent studies have suggested that protein kinase C (PKC) activation plays an important role in survival of chronic lymphocytic leukemia (CLL). In order to characterize the role of PKC in CLL, we investigated the expression pattern of PKC isoforms in CLL cells (7 cases) and evaluated the effect of PKC inhibition on the survival of CLL cells (20 cases). Expression of the classical PKC isoforms beta and gamma, the novel isoform delta and the atypical isoform zeta was seen in all analyzed patient samples by Western blot analysis. Expression of the PKC isoforms alpha, epsilon, and iota was variable. Following incubation with the PKC inhibitor, safingol, CLL cells underwent marked apoptosis in all cases. In order to characterize the molecular events associated with the apoptotic effect of PKC inhibition, gene expression patterns in CLL cells were evaluated by cDNA-microarray analysis. Following safingol treatment, several genes showed marked downregulation and PKC-related proteins demonstrated decreased hybridization signals. Among these proteins, CREB and Daxx were further studied by using Western blotting, nuclear binding assay and confocal immunofluorescent microscopy. These studies showed significant inhibition of these proteins, consistent with the results of microarray gene analysis. Overall, these findings suggest that PKC activation is important for CLL cell survival and that inhibitors of PKC may have a role in the treatment of patients with CLL.  相似文献   
100.
One of the solutions for the problem of white spot lesions has been the application of a polymer coating to the labial enamel surface. The aim of this study is to find out whether the liquid polish BisCover affects the bond strength of brackets bonded with a light-cured system (Transbond XT) and a no-mix system (Unite). Standard stainless steel premolar brackets were bonded to 100 permanent human premolars randomly divided into five equal groups. Two different enamel surface conditions were studied: dry and varnished with BisCover. For each enamel surface condition, two orthodontic adhesive systems were used: a light-cured system (Transbond XT) and a no-mix system (Unite). All teeth were conditioned with 37% phosphoric acid for 30 seconds, followed by thorough washing and drying. The teeth in groups 1 and 2 were bonded with Transbond XT and Unite, respectively. For groups 3, 4, and 5, a thin layer of BisCover was applied to the etched enamel with a brush and light cured for 15 seconds. In group 3, a thin layer of Transbond XT primer was applied, whereas in group 5, no additional primer was used on BisCover. In groups 3 and 5, the brackets were bonded with Transbond XT adhesive resin. Group 4 was bonded with no-mix Unite. Shear forces were applied to the samples by a Zwick Universal test machine, and bond strengths measured in megapascals. The results revealed that shear bond strengths of the groups did not differ significantly from each other.  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