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   1481篇
  免费   105篇
  国内免费   51篇
耳鼻咽喉   7篇
儿科学   34篇
妇产科学   19篇
基础医学   187篇
口腔科学   47篇
临床医学   119篇
内科学   333篇
皮肤病学   27篇
神经病学   62篇
特种医学   47篇
外科学   226篇
综合类   38篇
预防医学   102篇
眼科学   73篇
药学   115篇
中国医学   3篇
肿瘤学   198篇
  2024年   4篇
  2023年   12篇
  2022年   33篇
  2021年   69篇
  2020年   36篇
  2019年   40篇
  2018年   29篇
  2017年   35篇
  2016年   32篇
  2015年   35篇
  2014年   72篇
  2013年   78篇
  2012年   91篇
  2011年   90篇
  2010年   68篇
  2009年   63篇
  2008年   101篇
  2007年   126篇
  2006年   69篇
  2005年   80篇
  2004年   57篇
  2003年   65篇
  2002年   37篇
  2001年   32篇
  2000年   36篇
  1999年   37篇
  1998年   16篇
  1997年   9篇
  1996年   14篇
  1994年   6篇
  1993年   6篇
  1992年   11篇
  1991年   13篇
  1990年   10篇
  1989年   11篇
  1988年   11篇
  1987年   8篇
  1986年   15篇
  1985年   10篇
  1984年   7篇
  1983年   8篇
  1982年   6篇
  1978年   4篇
  1977年   3篇
  1976年   3篇
  1974年   4篇
  1973年   4篇
  1972年   3篇
  1969年   6篇
  1968年   3篇
排序方式: 共有1637条查询结果,搜索用时 22 毫秒
71.
Chen  Shuzhen  Issa  Malam Djibo  Wang  Chenghong  Feng  Liang  Teng  Fei  Li  Bing  Pan  Yougui  Zhang  Xiaolong  Xu  Yifei  Zhang  Zhuoyu  Su  Junhui  Ma  Hongxing  Jin  Lingjing 《Molecular imaging and biology》2020,22(4):1054-1061
Molecular Imaging and Biology - This study aimed to evaluate the usefulness of [99mTc]sestamibi ([99mTc]MIBI) single photon emission computed tomography (SPECT)/X-ray computed tomography (CT)...  相似文献   
72.
BackgroundNutritional disorders are common among patients with heart failure (HF) and associated with poor prognosis. Importantly, some populations of patients, like the ones with Chagas disease, are frequently excluded from most analyses.ObjectiveWe sought to study the occurrence of undernutrition and cachexia in patients with Chagas disease during episodes of decompensated HF (DHF) as compared to other etiologies, and to investigate the influence of these findings on hospital outcomes.MethodsWe performed a consecutive case series study with patients hospitalized with DHF. Patients underwent the Subjective Global Assessment of nutritional status (SGA), besides anthropometric and laboratorial measures, and were evaluated for the occurrence of cachexia, low muscle mass and strength. We studied the occurrence of death or urgent heart transplantation during hospitalization.ResultsAltogether, 131 patients were analyzed and 42 (32.1%) had Chagas disease. Patients with Chagas disease had lower Body Mass Index (BMI) (22.4 kg/m2[19.9-25.3] vs. 23.6 kg/m2 [20.8-27.3], p=0.03), higher frequency of undernutrition (76.2% vs 55.1%, p=0.015) and higher occurrence of death or transplant (83.3% vs. 41.6%, p<0.001). We found that, in patients with Chagas etiology, the occurrence of death or cardiac transplantation were associated with undernutrition (3 [42.9%] patients with hospital discharge vs 29 [82.9%] patients with death or heart transplant, p=0.043).ConclusionsTaken together, our results indicate that patients with Chagas disease hospitalized with DHF often present with nutritional disorders, especially undernutrition; importantly, this finding was associated with the occurrence of death and heart transplant during hospitalization.  相似文献   
73.
74.
Background: Reports indicate patients with feeding difficulties demonstrate signs of inflammation on biopsies, notably eosinophilia, but it is unknown whether mast cell density contributes to variety or volume limitation symptoms. The aim of our study was to evaluate eosinophil and mast cell density of EGD biopsies in pediatric patients with symptoms of decreased volume or variety of ingested foods. Methods: We conducted a single-center, retrospective chart review of EMRs for all new feeding clinic patients between 0 and 17 years of age. Patients were categorized by symptoms at the initial visit as well as eosinophil and mast cell densities in those with EGD biopsies. Ten patients were identified as controls. Results: We identified 30 patients each with volume and variety limitation. Antral mast cell density was increased in 32.1% of variety-limited patients, 37.5% of volume limited patients, and in no controls; Duodenal mast cell density was increased in 32.1% of variety-limited patients, 40.6% of volume-limited patients, and in no controls. Conclusions: In both variety- and volume-limited patients, antral and duodenal mast cell densities were increased. These associations warrant further investigation of the mechanism between mast cells and development of feeding difficulties, allowing more targeted pediatric therapies.  相似文献   
75.
<世界华人消化杂志>西安地区编委及作者读者座谈会于2007-12-18在西安交通大学医学院第二附属医院召开(图1).杂志社社长兼总编辑马连生教授、名誉总编辑潘伯荣教授、副总编辑王苑本教授和杨思凤教授及西安地区编委、作者读者共40余人出席会议.  相似文献   
76.
77.
PURPOSE: To measure for the first time the apparent diffusion coefficient (ADC) values in anatomical regions of the prostate for normal and patient groups, and to investigate its use as a differentiating parameter between healthy and malignant tissue within the patient group. MATERIALS AND METHODS: Single-shot diffusion-weighted echo-planar imaging (DW-EPI) was used to measure the ADC in the prostate in normal (N = 7) and patient (N = 19) groups. The spin-echo images comprised 96 x 96 pixels (field of view of 16 cm, TR/TE = 4000/120 msec) with six b-factor values ranging from 64 to 786 seconds/mm(2). RESULTS: The ADC values averaged over all patients in non-cancerous and malignant peripheral zone (PZ) tissues were 1.82 +/- 0.53 x 10(-3) (mean +/- SD) and 1.38 +/- 0.52 x 10(-3) mm(2)/second, respectively (P = 0.00045, N = 17, paired t-test). The ADC values were found to be higher in the non-cancerous PZ (1.88 +/- 0.48 x 10(-3)) than in healthy or benign prostatic hyperplasia central gland (BPH-CG) region (1.62 +/- 0.41 x 10(-3)). For the normal group, the mean values were 1.91 +/- 0.46 x 10(-3) and 1.63 +/- 0.30 x 10(-3) mm(2)/second for the PZ and CG, respectively (P = 0.011, N = 7). Significant overlap exists between individual values among all tissue types. Furthermore, ADC values for the same tissue type showed no statistically significant difference between the two subject groups. CONCLUSION: ADC is quantified in the prostate using DW-EPI. Values are lower in cancerous than in healthy PZ in patients, and in BPH-CG than PZ in volunteers.  相似文献   
78.
79.
The objective of the current study was to investigate the effect of vanadium (V5+) on Cyp1 expression and activity in C57BL/6 mice liver and isolated hepatocytes. For this purpose, C57BL6 mice were injected intraperitoneally with V5+ (5 mg/kg) in the absence and presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (15 μg/kg) for 6 and 24 h. Furthermore, isolated hepatocytes from C57BL6 mice were treated with V5+ (5, 10, and 20 μM) in the absence and presence of TCDD (1 nM) for 3, 6, 12, and 24 h. In vivo, V5+ alone did not significantly alter Cyp1a1, Cyp1a2, or Cyp1b1 mRNA, protein, or catalytic activity levels. Upon co-exposure to V5+ and TCDD, V5+ significantly potentiated the TCDD-mediated induction of the Cyp1a1, Cyp1a2, and Cyp1b1 mRNA, protein, and catalytic activity levels at 24 h. In vitro, V5+ decreased the TCDD-mediated induction of Cyp1a1 mRNA, protein, and catalytic activity levels. Furthermore, V5+ significantly inhibited the TCDD-induced AhR-dependent luciferase activity. V5+ also increased serum hemoglobin (Hb) levels in animals treated for 24 h. Upon treatment of isolated hepatocytes with Hb alone or in the presence of TCDD, there was an increase in the AhR-dependent luciferase activity. When isolated hepatocytes were treated for 2 h with V5+ in the presence of TCDD, followed by replacement of the medium with new medium containing Hb, there was further potentiation to the TCDD-mediated effect. The present study demonstrates that there is a differential modulation of Cyp1a1 by V5+ in C57BL/6 mice livers and isolated hepatocytes and demonstrates Hb as an in vivo specific modulator.  相似文献   
80.
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