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   739篇
  免费   43篇
  国内免费   9篇
耳鼻咽喉   17篇
儿科学   35篇
妇产科学   14篇
基础医学   80篇
口腔科学   10篇
临床医学   46篇
内科学   195篇
皮肤病学   22篇
神经病学   13篇
特种医学   39篇
外国民族医学   3篇
外科学   111篇
综合类   10篇
预防医学   30篇
眼科学   14篇
药学   39篇
中国医学   2篇
肿瘤学   111篇
  2023年   9篇
  2022年   5篇
  2021年   22篇
  2020年   11篇
  2019年   9篇
  2018年   16篇
  2017年   20篇
  2016年   24篇
  2015年   11篇
  2014年   21篇
  2013年   42篇
  2012年   48篇
  2011年   40篇
  2010年   37篇
  2009年   25篇
  2008年   35篇
  2007年   34篇
  2006年   30篇
  2005年   23篇
  2004年   24篇
  2003年   21篇
  2002年   26篇
  2001年   19篇
  2000年   21篇
  1999年   17篇
  1998年   17篇
  1997年   12篇
  1996年   17篇
  1995年   9篇
  1994年   18篇
  1993年   14篇
  1992年   11篇
  1991年   8篇
  1990年   15篇
  1989年   6篇
  1988年   7篇
  1987年   4篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1983年   9篇
  1982年   4篇
  1981年   5篇
  1980年   4篇
  1976年   7篇
  1975年   3篇
  1974年   5篇
  1971年   2篇
  1969年   2篇
  1964年   2篇
排序方式: 共有791条查询结果,搜索用时 78 毫秒
11.
Pulmonary metastatectomy for soft tissue sarcomas: is it valuable?   总被引:2,自引:0,他引:2  
BACKGROUND: A retrospective study and analysis was performed to determine the value and benefit of pulmonary metastatectomy for soft tissue sarcomas, and which factors predict prognosis following resection. METHODS: Twenty-three patients underwent resections for pulmonary metastases from a soft tissue sarcoma (STS) at King Faisal Specialist Hospital and Research Center (KFSH&RC), between January 1985 and December 1998. There were 11 male and 12 female patients. Thirteen of 23 patients (57%) had one to three metastases, and 10 (43%) had four or more metastases. A total of 41 thoracic explorations was performed for the 23 evaluable patients. Median sternotomy was used only for three patients and lateral thoracotomy was used for 20 patients as an initial surgical approach. Pulmonary resections performed included one or more wedge resections (n=16), segmentectomy (n=5), and lobectomy (n=2). No one in this series underwent pneumonectomy. The number of resected metastatic nodules ranged from one-six with average three. Eight patients (35%) received various kinds of postoperative adjuvant chemotherapy. RESULTS: The overall and disease-free survival rate post-metastatectomy at five years was 24% and 21%, respectively. Various prognostic indicators were examined to evaluate their association with improved survival. Age, sex localization of the primary site and histologic type, tumor grade, size of the resected nodules, laterality (unilateral or bilateral), types of resection, adjuvant chemotherapy, and local recurrence did not significantly affect survival. However, patient with disease free interval >6 months, and those with three or fewer metastases showed a trend toward a higher five-year overall survival (p=0.06, 0.07, respectively). CONCLUSIONS: Surgical excision of lung metastases from soft tissue sarcomas is well accepted and should be considered as a first line of treatment if preoperative evaluation indicated that complete resection of the metastases is possible. Further investigation is needed before chemotherapy can be recommended as additional therapy.  相似文献   
12.

Background  

Some studies have found that lower parity and higher or lower social class (depending on the study) are associated with increased risks of childhood acute lymphoblastic leukaemia (ALL). Such findings have led to suggestions that infection could play a role in the causation of this disease. An earlier New Zealand study found a protective effect of parental marriage on the risk of childhood ALL, and studies elsewhere have reported increased risks in relation to older parental ages. This study aimed to assess whether lower parity, lower social class, unmarried status and older parental ages increase the risk of childhood ALL (primarily). These variables were also assessed in relation to the risks of childhood acute non-lymphoblastic leukaemia, non-Hodgkin's lymphomas and Hodgkin's disease.  相似文献   
13.
Patients with insulin resistance and type 2 diabetes have an excessive risk of cardiovascular disease (CVD); this increased risk is not fully explained by traditional risk factors such as hypertension and dyslipidaemias. There is now compelling evidence to suggest that abnormalities of insulin-like growth factor-I (IGF-I) and one of its binding proteins, insulin-like growth factor-binding protein-1 (IGFBP-1), occur in insulin-resistant states and may be significant factors in the pathophysiology of CVD. We reviewed articles and relevant bibliographies following a systematic search of MEDLINE for English language articles between 1966 and the present, using an initial search strategy combining the MeSH terms: IGF, diabetes and CVD. Our aim was first to review the role of IGF-I in vascular homeostasis and to explore the mechanisms by which it may exert its effects. We also present an overview of the physiology of the IGF-binding proteins, and finally, we sought to summarize the evidence to date describing the changes in the insulin/IGF-I/IGFBP-1 axis that occur in type 2 diabetes and CVD; in particular, we have focused on the potential vasculoprotective effects of both IGF-I and IGFBP-1. We conclude that this system represents an interesting and novel therapeutic target in the prevention of CVD in type 2 diabetes.  相似文献   
14.
The cardiovascular system is affected by a multitude of endocrine disorders, including dysfunction of the thyroid, calcium, glucocorticoids, insulin/glucose, and growth hormone axes. Since most of these changes in the cardiovascular system are reversible when treated, early diagnosis is important, as if left untreated, they may become fatal. This review focuses on the pathophysiology, clinical presentation, pathology, and treatment of patients with these endocrine diseases who present with a variety of cardiovascular manifestations. Neuroendocrine tumors presenting with the carcinoid syndrome and their cardiovascular manifestations are also discussed.  相似文献   
15.
Aging is an unavoidable fate that afflicts all life, during this process in mammals reactive oxygen species (ROS) are generated which stimulate tyrosinase, elastase and collagenase activities that actively participate in skin aging. Therefore, the maintenance of antioxidant homeostasis is an important anti-aging strategy for skin. Nature has excellent anti-aging remedies that act externally as well as internally to delay the visual signs of aging. In view of this fact, the present study investigates the in vitro anti-aging activity of five medicinal plants belonging to phenolic rich families namely Rosmarinus officinalis, Lavandula officinalis, Matricaria chamomilla, Camellia sinensis and Pelargonium graveolens. The selected plants are those most frequently used in the preparation of ethnomedicinal recipes for the prevention or treatment of aging. The inhibitory effects of the ethanolic and aqueous extracts of the five selected plants on the activity of tyrosinase, elastase, and collagenase enzymes were investigated. Furthermore, the chemical composition of the plants and the antioxidant capacity of their extracts were assessed. The results showed that R. officinalis had the highest total phenolics content which was correlated with its potent antioxidant and anti-aging activities. To pinpoint the active metabolites in the tested extracts, we evaluated the metabolite variations using ultra-performance liquid chromatography coupled with high resolution electrospray ionization-tandem mass spectrometry (UPLC-HR-ESI-MS/MS). Multivariate data analysis (MVDA) revealed that R. officinalis significantly accumulated metabolites from the aromatic diterpenoid, flavonoid and phenolic acid classes. These results indicate that rosemary can be used for further development of topical preparations with anti-aging properties.

Aging is an unavoidable fate that afflicts all life, during this process in mammals, reactive oxygen species (ROS) are generated which stimulate tyrosinase, elastase and collagenase activities that actively participate in skin aging.  相似文献   
16.
17.
18.
AIM:To investigate a dual labeling technique,which would enable real-time monitoring of transplanted embryonic stem cell(ESC) kinetics,as well as long-term tracking.METHODS:Liver damage was induced in C57/BL6 male mice(n = 40) by acetaminophen(APAP) 300 mg/kg administered intraperitoneally.Green fluorescence protein(GFP) positive C57/BL6 mouse ESCs were stained with the near-infrared fluorescent lipophilic tracer 1,1-dioctadecyl-3,3,3,3-tetramethylindotricarbocyanine iodide(DiR) immediately before transplantationinto the spleen.Each of the animals in the cell therapy group(n = 20) received 5 × 10 6 ESCs 4 h following treatment with APAP.The control group(n = 20) received the vehicle only.The distribution and dynamics of the cells were monitored in real-time with the IVIS Lumina-2 at 30 min post transplantation,then at 3,12,24,48 and 72 h,and after one and 2 wk.Immunohistochemical examination of liver tissue was used to identify expression of GFP and albumin.Plasma alanine aminotransferase(ALT) was measured as an indication of liver damage.RESULTS:DiR-stained ESCs were easily tracked with the IVIS using the indocyanine green filter due to its high background passband with minimal background autofluorescence.The transplanted cells were confined inside the spleen at 30 min post-transplantation,gradually moved into the splenic vein,and were detectable in parts of the liver at the 3 h time-point.Within 24 h of transplantation,homing of almost 90% of cells was confirmed in the liver.On day three,however,the DiR signal started to fade out,and ex vivo IVIS imaging of different organs allowed signal detection at time-points when the signal could not be detected by in vivo imaging,and confirmed that the highest photon emission was in the liver(P 0.0001).At 2 wk,the DiRsignal was no longer detectable in vivo ;however,immunohistochemistry analysis of constitutively-expressed GFP was used to provide an insight into the distribution of the cells.GFP +ve cells were detected in tissue sections resembling hepatocytes and were dispersed throughout the hepatic parenchyma,with the presence of a larger number of GFP +ve cells incorporated within the sinusoidal endothelial lining.Very faint albumin expression was detected in the transplanted GFP +ve cells at 72 h;however at 2 wk,few cells that were positive for GFP were also strongly positive for albumin.There was a significant improvement in serum levels of ALT,albumin and bilirubin in both groups at 2 wk when compared with the 72 h time-point.In the cell therapy group,serum ALT was significantly(P = 0.016) lower and albumin(P = 0.009) was significantly higher when compared with the control group at the 2 wk time-point;however there was no difference in mortality between the two groups.CONCLUSION:Dual labeling is an easy to use and cheap method for longitudinal monitoring of distribution,survival and engraftment of transplanted cells,and could be used for cell therapy models.  相似文献   
19.
BackgroundVentilator associated pneumonia (VAP) is an important source of morbidity and mortality in patients receiving mechanical ventilation. VAP is associated with prolongation of mechanical ventilation, ICU and hospital stay and increases in costs.MethodsQuality improvement project. Mechanically ventilated patients received oral care every 8 h with chlorhexidine 2%. A formal process was developed to evaluate compliance with the following ventilator bundle initiatives: head of the bed elevation to 30–45°, daily sedation vacation and assess the readiness to extubate, providing peptic ulcer disease prophylaxis and providing deep vein thrombosis prophylaxis (unless contraindicated).ResultsThe rate of VAP before starting the project, in the first 6 months of year 1431H, was 16.2 cases/1000 ventilator days. Six month after inception of the quality improvement project, the VAP rates decreased to 5.6 cases/1000 ventilator days at the end of 1431H, and at the end of 1432H, it was 5.5 cases/1000 ventilator days. This leads to significant reduction in mortality (adjusted according to APACHE II) from 23.4% to 19.1% (p value 0.024) and the length of stay in ICU from 9.7 to 6.5 days (p value 0.00002).ConclusionThe combination of regular oral hygiene with chlorhexidine 2% and rigorous implementation of ventilator care bundle was associated with significant reduction in VAP rate in mechanically ventilated patients. This has led to reduction in length of stay in ICU from 9.7 to 6.5 days and reduction in mortality from 23.4% to 19.1%.  相似文献   
20.
PurposeThe aim of study is to assess the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and correlation with tumour angiogenesis in evaluation of urinary bladder cancer.Material and MethodsThe study included 81 patients with recent presumed diagnosis of bladder tumour or who came for follow up after management of histopathologically proven bladder cancer. All had DCE-MRI with time–signal intensity curve. The radiologic results then correlated with the histopathologic results using both haematoxylin and eosin stain and immuno-histochemical staining for localization and evaluation of CD34 immunoreactivity as a detector for the microvessel density (MVD) and tumour angiogenesis.ResultsSeventy-one cases were pathologically proven to be malignant: 41 cases (58%) showed type III time–signal intensity curve (descending); 22 cases (31%) showed type II (plateau); and 8 cases (11%) showed type I (ascending) curve. The sensitivity of DCE-MRI in stage T1 bladder tumour was 80%; in stage T2, it was (90.9%); and in stage T3, it was (96.9%). Overall accuracy of DCE-MRI in tumour staging was 89.5% and P = .001 (significant). Values more than the cutoff value = 76.13 MVD are cystitis with sensitivity (90%), specificity (91%), and P value is .001, which is statistically highly significant.ConclusionThere is a strong positive association between DCE-MRI (staging and washout slope of the time–signal intensity curve) with histopathologic grade, tumour stage, and MVD in bladder cancer. So, DCE-MRI can be used as reliable technique in preoperative predictions of tumour behavior and affect the planning of antiangiogenetic therapy.  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