首页 | 官方网站   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   1138篇
  免费   127篇
  国内免费   2篇
医药卫生   1267篇
  2024年   3篇
  2023年   25篇
  2022年   27篇
  2021年   46篇
  2020年   41篇
  2019年   43篇
  2018年   98篇
  2017年   56篇
  2016年   85篇
  2015年   74篇
  2014年   107篇
  2013年   147篇
  2012年   82篇
  2011年   73篇
  2010年   64篇
  2009年   37篇
  2008年   27篇
  2007年   28篇
  2006年   35篇
  2005年   23篇
  2004年   14篇
  2003年   19篇
  2002年   11篇
  2001年   19篇
  2000年   9篇
  1999年   14篇
  1998年   17篇
  1997年   6篇
  1996年   7篇
  1995年   10篇
  1994年   8篇
  1993年   2篇
  1992年   3篇
  1991年   2篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1981年   1篇
排序方式: 共有1267条查询结果,搜索用时 15 毫秒
91.
A case of Kaposi's sarcoma (KS) in a 70‐year‐old man who was using corticosteroid for the treatment of asthma is presented. KS lesions occurred in the skin, colon, and rectum. Macroscopic appearances of the lesions varied from polypoid, hemorrhagic mucosal nodules and ulcers to red macules in the mucosal plane to plaque‐like indurations of the wall. As the case was HIV negative, it is believed that KS developed due to corticosteroid‐induced immunosuppression.  相似文献   
92.
Malignant pleural mesothelioma (MPM) is a rare and asbestosis-associated tumor. MPM commonly invades locally, mostly in the lung, heart, pericardium, chest wall, and vertebrae. Distant metastasis of MPM is very rare. Here we report a patient with MPM who presented with multiple unusual distant metastases. The patient's thorax tomography demonstrated right-sided, irregularly-thickened pleura with nodular masses and invasion of the chest wall into the subcutaneous area. The patient underwent biopsy for a subcutaneous mass in the right anterior chest wall. Pathologic examination revealed a malignant mesenchymal tumor. During follow-up, he suffered from a painful nodule on the scalp and nodules on the fingers, as well as weakness in his right arm. Cranial magnetic resonance imaging illustrated a 1 cm nodule in the left cerebellar hemisphere. Histopathologic examination of the biopsy from the nodule on the scalp revealed a typical mixed type of MPM, with calretinin, vimentin and creatine 5/6 positivity. Distant metastases can be seen in MPM and a biopsy of metastatic regions can yield the diagnosis.  相似文献   
93.
94.
95.
96.
ObjectivesThis study's aim was to compare the efficiency levels of training and research hospitals in Turkey during 2014–2017 and find the factors affecting their efficiency scores.MethodsTo achieve the above objective, input oriented and variable returns to scale (VRS), data envelopment analysis (DEA), and Tobit regression model were used. The number of beds (BD), the number of intensive care beds (IBD), and the number of specialist doctors (SD) were used as the input variables of DEA while the number of polyclinic admissions (PA), number of inpatients (InP), and number of A, B, and C type surgeries as the output variables. The Tobit regression model was created by using some control variables as independent variables and transformed DEA scores as dependent variables. Average length of stay (ALS), bed turnover rate (BTR), bed occupancy rate (BOR), surgery number per specialist doctor (SNSD), polyclinic admission number per specialist doctor (PANSD), and metropolitan city status (MCS) were used as control variables.ResultsStatistically significant control variables of BTR (p < 0.001), SNSD (p = 0.001), and MCS (p = 0.015) affect the transformed DEA score while ALS, BOR, and PANSD do not (p > 0.05).ConclusionsThe research revealed that efficiency increased as BTR and SNSD increased, and that MCS also had a positive effect on efficiency. Policy makers should therefore consider the province's MCS status while allocating resources to relevant educational research hospitals for improving their efficiency. Likewise, policy makers should pay more attention to increasing BTR and SNSD compared to other variables.  相似文献   
97.
The aim of this study was to identify the effects of adding quercetin (Q) to Tris extender in order to identify levels of oxidative stress in bull sperm after freeze thawing. Ejaculates were collected via artificial vagina from Holstein bulls. Semen was divided into five tools and diluted to a final concentration of 15 × 106 spermatozoa/ml with the Tris extender containing Q (25, 50, 100 and 200 μg/ml) and no additive (control; C). All examples were equilibrated at 4°C during 4 hr then were loaded into 0.25‐ml straws and frozen using a controlled rate. Sperm motility and motility characteristics were determined using the computer‐assisted semen analyser. Sperm membrane integrity was assessed using the hypoosmotic swelling test. Sperm chromatin integrity was investigated using the single cell gel electrophoresis. Total antioxidant capacities were performed colorimetrically. Q supplementation used as an antioxidant did not produce better results in the proportion of sperm progressive and total motility, plasma membrane integrity and sperm abnormalities. Q supplementation exhibited the favourable tail length, tail DNA and tail moment. In conclusion, when whole parameters are considered, Q25 can be added to the Tris extender due to its positive effect on sperm DNA integrity and no adverse effect on the progressive and total motilities of sperm.  相似文献   
98.
The prevalence of chronic kidney disease (CKD) and end-stage renal disease (ESRD) is increasing steadily. CKD does not only relate to morbidity and mortality but also has impact on quality of life, depression and malnutrition. Such patients often have significantly decreased physical activity. Recent evidence suggests that low physical activity is associated with morbidity, mortality, muscle atrophy, quality of life impairment, cardiovascular outcomes and depression. Based on this, it is now recommended to regularly improve the physical activity of these patients. Furthermore, studies have shown the beneficial effects of various exercise programs with respect to outcomes such as low physical activity muscle atrophy, quality of life, cardiovascular outcomes and depression. Despite these encouraging findings, the subject is still under debate, with various aspects still unknown. In this review, we tried to critically summarize the existing studies, to explore mechanisms and describe future perspectives regarding physical activity in CKD/ESRD patients.  相似文献   
99.
Previously conducted studies revealed that smoking enhanced the efficacy of clopidogrel by increasing formation of the active metabolite (AM) from the prodrug through induction of the cytochrome CYP1A2. The expression of cytochrome enzymes depends on genotype and no data exists in literature conducted in Turkish patients comparing the clopidogrel responsiveness between active smokers and non-active smokers treated with clopidogrel. In this study, our aim was to investigate the clopidogrel responsiveness in clopidogrel-treated Turkish acute coronary syndrome (ACS) patients according to their smoking status. We retrospectively enrolled 258 patients who were hospitalized due to ACS. Clinical variables of the patients, especially smoking status were recorded. Clopidogrel resistance was evaluated by using adenosine diphosphate (ADP) induced platelet aggregometry. Clopidogrel resistance was detected as a change in maximal aggregation ≤20% from baseline. A total of 139 patients were active smokers while 12 were former smokers. 107 patients did not have a history of smoking. Ten of the smokers were hyporesponsive to clopidogrel, whereas 36 of non-smokers were hyporesponsive to clopidogrel (p?612.5 predicted the clopidogrel resistance with a sensitivity of 60% (OR: 100.65, %95 CI?=?19.996–506.615 p?相似文献   
100.
The aim of this study was to evaluate the effects of tamoxifen on tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) levels and ultrastructural changes in rats with spinal cord injury. Rats were divided into four groups: control group (laminectomy only), trauma group (laminectomy + spinal trauma), tamoxifen group (laminectomy + spinal trauma + tamoxifen), and vehicle group (laminectomy + spinal trauma + vehicle). Spinal cords were extirpated at the T7–T12 level and tissue samples from the spinal cords were gathered for TNF-α and IL-1β measurements at 1 and 6 hours. Spinal cords harvested at 6 hours were evaluated for ultrastructural changes. TNF-α and IL-1β levels at 6 hours were significantly lower in the tamoxifen group than in the trauma group. Electron microscopic examination of tissue from the trauma group revealed gross cell deformities with widespread edema of all structures as well as severe edema in the neuropil. At 6 hours after trauma, these ultrastructural changes were less marked in the tamoxifen group. Our findings support a neuroprotective and restorative role for tamoxifen in the context of secondary pathological biochemical events after SCI.  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-23

京公网安备 11010802026262号