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   626篇
  免费   31篇
  国内免费   2篇
耳鼻咽喉   13篇
儿科学   45篇
妇产科学   10篇
基础医学   66篇
口腔科学   19篇
临床医学   49篇
内科学   89篇
皮肤病学   2篇
神经病学   60篇
特种医学   49篇
外科学   188篇
综合类   7篇
预防医学   14篇
眼科学   12篇
药学   21篇
肿瘤学   15篇
  2024年   1篇
  2023年   7篇
  2022年   8篇
  2021年   18篇
  2020年   11篇
  2019年   12篇
  2018年   9篇
  2017年   10篇
  2016年   16篇
  2015年   23篇
  2014年   22篇
  2013年   41篇
  2012年   41篇
  2011年   34篇
  2010年   16篇
  2009年   16篇
  2008年   48篇
  2007年   39篇
  2006年   33篇
  2005年   39篇
  2004年   38篇
  2003年   36篇
  2002年   21篇
  2001年   13篇
  2000年   12篇
  1999年   14篇
  1998年   7篇
  1997年   1篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1993年   5篇
  1992年   3篇
  1991年   12篇
  1990年   9篇
  1989年   6篇
  1988年   6篇
  1987年   2篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1980年   3篇
  1979年   1篇
  1978年   4篇
  1976年   1篇
  1974年   2篇
  1972年   1篇
  1971年   1篇
  1966年   3篇
排序方式: 共有659条查询结果,搜索用时 0 毫秒
641.
Reperfusion of myocardium during coronary bypass activates matrix metalloproteinases (MMPs) with changes occurring in the levels of tissue inhibitors of metalloproteinases (TIMPs) in the myocardium. This study investigated the effects of insulin-blood cardioplegia on MMP activity and TIMP levels during reperfusion. Non-diabetic patients undergoing coronary artery bypass graft with cardiopulmonary bypass were randomized into a control group (n = 12) or an insulin group (n = 12). Blood cardioplegia was used for both groups; insulin and glucose were added to the insulin group. Blood samples were obtained from the coronary sinus just before aortic cross clamping and after 1 and 30 min of reperfusion. Plasma proenzyme MMPs (proMMP-2 and -9) and TIMPs (TIMP-1 and TIMP-2) levels were measured. There were no differences between groups for MMP-2 and TIMP-2 levels. However, insulin diminished proMMP-9 activation, although some still occurred. TIMP-1 consumption lessened during reperfusion which, we conclude, was as a result of the diminished MMP activation. This is the first open heart surgery study in which diminished MMP activation was achieved via a metabolic change.  相似文献   
642.

Background

Previous studies have demonstrated that ischemia-modified albumin (IMA) is a useful marker for the diagnosis of ischemic events. It was also recently demonstrated that IMA levels increase in the acute phase of cerebrovascular diseases. Yet the data regarding IMA levels in various types of cerebrovascular events are insufficient. The aim of this study was to evaluate IMA levels in various types of cerebrovascular events such as ischemic stroke, subarachnoid hemorrhage (SAH), and intracranial hemorrhage.

Methods

This case-controlled study consisted of 106 consecutive patients, 43 with brain infarction (BI), 11 with brain hemorrhage (ICH), 52 with SAH, and a 43-member control group. We investigated whether there was a statistical correlation between these 3 groups and the control group. The relations among the 3 groups were also examined. Comparisons among groups were done with analysis of variance.

Results

Mean serum IMA levels were 0.280 ± 0.045 absorbance units (ABSU) for BI patients, 0.259 ± 0.053 ABSU for ICH patients, 0.243 ± 0.061 ABSU for SAH patients, and 0.172 ± 0.045 ABSU for the control group.There was a statistically significant difference between the mean IMA levels of BI, ICH, and SAH patients and the mean control patient IMA levels (P < .0001).

Conclusions

Ischemia-modified albumin levels are high in cerebrovascular diseases. Ischemia-modified albumin measurement can also be used to distinguish SAH from BI during the acute phase of cerebrovascular event in the emergency department.  相似文献   
643.
Borazan A  Cavdar Z  Saglam F 《Renal failure》2007,29(8):1019-1023
BACKGROUND: The kidney is a major site for the inactivation, degradation, and clearance of a variety of peptide hormones. It has been shown that the uremia increases or decreases gastrointestinal system (GIS) hormones. Moreover, studies investigating the serum GIS hormones levels in chronic renal failure (CRF) were conducted mainly in a particular period of the renal replacement therapy, and the changes caused by continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) could not be fully demonstrated. In this study, we investigated the effect of CAPD and HD on serum GIS hormones (amylase, lipase, trypsinogen, and gastrin) levels in CRF patients who were diagnosed for the first time. METHODS: Serum amylase, lipase, trypsinogen, and gastrin levels were measured in 36 patients who were just diagnosed with CRF, 22 patients with CAPD and 14 patients with HD. GIS hormones of these patients were measured before treatment and three months from the beginning of CAPD and HD treatment. As the control group, 20 normal healthy cases with well-matched age and gender were used. RESULTS: The mean serum amylase, lipase, secretin, and gastrin levels were found meaningfully decreased according to the beginning values at third months of the CAPD and HD treatment. However, they were higher than control group. CONCLUSION: In patients receiving CAPD or HD as renal replacement therapy, GIS hormone levels were found to be lower, albeit higher than the healthy control group.  相似文献   
644.
Valproate is an effective anticonvulsant. Although it is usually well tolerated, it has been associated with many neurological, hematopoietic, hepatic, and digestive system side effects. Among these side effects, hyperammonemia without clinical or laboratory evidence of hepatotoxicity is rare and is an important clinical consideration. The aim of this article was to evaluate the reasons for the unexpected symptoms observed in seven patients with epilepsy patients during valproate treatment. We evaluated seven adult patients with localization-related epilepsy who presented with different acute or subacute neurological symptoms related to valproate-induced hyperammonemic encephalopathy. Four of the seven patients had acute onset of confusion, decline in cognitive abilities, and ataxia. Two had subacute clinical symptoms, and the other patient had symptoms similar to those of acute toxicity. These unusual clinical symptoms and similar cases had not been reported in the literature before. Serum ammonia levels were elevated in all seven patients. After discontinuation of valproate, complete clinical improvement was observed within 5-10 days. On the basis of our work, we suggest that the ammonia levels of a patient who has new neurological symptoms and has been taking valproate must be checked. Clinicians should be aware that these clinical symptoms may be related to valproate-induced hyperammonemic encephalopathy. The symptoms have been observed to resolve dramatically after withdrawal of the drug.  相似文献   
645.
AIM: Anatomical landmark technique for central venous catheter insertion preoperatively during renal transplantation may result in serious complications. In this prospective study, we sought to evaluate the results of ultrasonography-guided central venous catheter insertion before renal transplantation. PATIENTS AND METHODS: Since March 2004 routine ultrasonography-guided central venous catheter insertion was performed before the operation for living related renal transplantation. Chest X-ray was used as a control after catheter insertion. Visual pain scale was evaluated after the procedure. We recorded the duration of the procedure, amount of local anesthetic, number of punctures, and complications, namely, hematoma, carotid artery puncture, hemorrhage, and hemo-pneumothorax. RESULTS: Since March 2004, 120 jugular venous catheters were inserted into renal transplant recipients preoperatively. Mean visual pain scale was 2.5 +/- 1.2 cm (range, 0.6-4.1 cm). Mean duration of the procedure was 9 +/- 3 minutes (range, 6-15 minutes); the amount of local anesthetic injected was 1.6 +/- 0.6 mL (range, 0.9-2.3 mL). There was no carotid artery puncture, hemo-pneumothorax, or hematoma. During the study period, 3 of the first 10 catheter insertions required more than 1 puncture, for the rest 1 puncture was sufficient for catheter insertion. There was no bleeding or intravenous fluid leakage from the catheter insertion site. CONCLUSION: Ultrasonography-guided jugular venous catheter insertion is a successful safe method. Routine ultrasonography-guided procedures before renal transplantation avoided the complications related to catheter insertion.  相似文献   
646.
647.
TNF-related apoptosis-inducing ligand level in Alzheimer’s disease   总被引:1,自引:0,他引:1  
In the present study, we determined the significance of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in Alzheimer’s disease (AD). We characterized the expression of TRAIL protein in the cerebrospinal fluid (CSF) and serum with ELISA and TRAIL mRNA in the peripheral blood mononuclear cells (PBMCs) with real-time PCR in 22 patients with AD and 20 control cases. We could not find TRAIL protein in the CSF samples. The concentration of TRAIL protein in sera from patients with AD was not different from controls. However, there was an inverse correlation between serum TRAIL levels and Mini-Mental State Examination scores in AD patients. Also we did not find significant difference in TRAIL mRNA in the PBMCs of patients with AD when compared with control group. Our data indicate that TRAIL serum level decreases in the late stage of disease.  相似文献   
648.
649.
We prospectively investigated the complications associated with intraparenchymal intracranial pressure (ICP) monitoring using the Camino intracranial pressure device. A fiberoptic ICP monitoring transducer was implanted in 631 patients. About half of the patients (n = 303) also received an external ventricular drainage set (EVDS). The durations (mean ± SD) of ICP monitoring in patients without and with an EVDS were 6.5 ± 4.4 and 7.3 ± 5.1 days, respectively. Infection occurred in 6 patients with only an ICP transducer (6/328, 1.8%) and 24 patients with an EVDS also (24/303, 7.9%). The duration of monitoring had no effect on infection, whereas the use of an EVDS for more than 9 days increased infection risk by 5.11 times. Other complications included transducer disconnection (2.37%), epidural hematoma (0.47%), contusion (0.47%), defective probe (0.31%), broken transducer (0.31%), dislocation of the fixation screw (0.15%), and intraparenchymal hematoma (0.15%). In conclusion, intraparenchymal ICP monitoring systems can be safely used in patients who either have, or are at risk of developing, increased ICP.  相似文献   
650.
This study was aimed to assess the effects of contact isolation application on anxiety and depression levels of the patients, the effects of certain sociodemographics and patient characteristics on anxiety and depression levels, and the thoughts of the isolated patients about contact isolation. This non-randomized quasi-experimental study was carried out with 60 isolated and 57 non-isolated patients with hospital infection. The data were acquired from Hospital Anxiety and Depression Scale (HADS-A (anxiety) and HADS-D (depression)) and patient information form. There was no statistically significant difference between the anxiety and depression levels of the isolated and non-isolated patients. In the isolated patients, the depression points were higher in patients who were, women, received primary education and had lower income levels. Of the patients, 86.4% of them told that they were happy to be in the isolation room. Contact isolation application did not affect anxiety and depression levels of the patients. However, personal attributes increased the development of depression. In contact isolated patients, personal attributes should be taken into consideration in nursing care planning to prevent development of depression.  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