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   1826篇
  免费   78篇
  国内免费   18篇
耳鼻咽喉   59篇
儿科学   152篇
妇产科学   64篇
基础医学   164篇
口腔科学   114篇
临床医学   189篇
内科学   372篇
皮肤病学   76篇
神经病学   119篇
特种医学   81篇
外科学   267篇
综合类   25篇
一般理论   1篇
预防医学   31篇
眼科学   45篇
药学   84篇
中国医学   3篇
肿瘤学   76篇
  2024年   2篇
  2023年   21篇
  2022年   28篇
  2021年   47篇
  2020年   22篇
  2019年   54篇
  2018年   41篇
  2017年   34篇
  2016年   62篇
  2015年   70篇
  2014年   93篇
  2013年   108篇
  2012年   141篇
  2011年   145篇
  2010年   87篇
  2009年   68篇
  2008年   138篇
  2007年   148篇
  2006年   141篇
  2005年   131篇
  2004年   115篇
  2003年   100篇
  2002年   49篇
  2001年   15篇
  2000年   20篇
  1999年   18篇
  1998年   4篇
  1997年   5篇
  1996年   2篇
  1995年   2篇
  1993年   1篇
  1992年   5篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1968年   1篇
排序方式: 共有1922条查询结果,搜索用时 13 毫秒
1.
2.
3.
Introduction Delayed massive hemorrhage induced by pancreatic fistula after pancreaticoduodenectomy is a rare but life-threatening complication. The purpose of this study was to analyze the clinical course of patients with late hemorrhage, with or without sentinel bleeding, to better define treatment options in the future. Material and Methods From April 1998 to December 2006, 189 pancreaticoduodenectomies were performed. Eleven patients, including two patients referred from other hospitals, were treated with delayed massive hemorrhage occurring 5 days or more after pancreaticoduodenectomy. Sentinel bleeding was defined as minor blood loss via surgical drains or the gastrointestinal tract with an asymptomatic interval until development of hemorrhagic shock. The clinical data of patients with bleeding episodes were analyzed retrospectively. Results Eight of the 11 patients had sentinel bleeding, and seven of them had it at least 6 h before acute deterioration. Seven out of 11 patients died, five out of eight with sentinel bleeding. No differences could be detected between patients with or without sentinel bleeding before delayed massive hemorrhage. The only difference found was that non-surviving patients were significantly older than surviving patients. Delayed massive hemorrhage is a common cause of death after pancreaticoduodenostomy complicated by pancreatic fistula formation. The observation of sentinel bleeding should lead to emergency angiography and dependent from the result to emergency relaparotomy to increase the likelihood of survival.  相似文献   
4.
Airway hyper-responsiveness (AHR) to adenosine 5'-monophosphate (AMP) is closely associated with airway inflammation; however, not all asthmatic patients are responsive to it. This study was planned to investigate the predictive factors of AHR to AMP in asthmatic children aged between 3 and 6 yr. We performed a retrospective analysis of data from 63 asthmatic preschool-age children who were challenged by AMP in our department. All children were characterized by skin-prick tests, serum immunoglobulin E (IgE) levels, peripheral blood eosinophil percentage and bronchial challenge with methacholine (MCH) and AMP. Potential determinants for AHR to AMP were assessed within the group. AHR to AMP was found in 46% of preschool-age children with asthma, while that of MCH was 93.7%. All children responsive to AMP were also responsive to MCH. The geometric mean provocative concentration of MCH and AMP causing a 15% fall in transcutaneous oxygen tension (PC(15)PtcO(2)MCH and AMP) were 0.55 mg/ml (0.004-9.19) and 10.53 mg/ml (0.59-342.89), respectively. AMP-responsive children did not differ from non-responsive ones with respect to demographic factors, geometric mean PC(15)PtcO(2)MCH and atopic status. The median serum IgE level was significantly higher in AMP-responsive group than the non-responsive ones (p = 0.011). The peripheral blood eosinophilia was more frequent among responsive children (p = 0.019), and it was found as the only predictive factor for AMP responsiveness in preschool-age children with asthma in logistic regression model (odds ratio: 5.14; 95% CI: 1.23-21.47; p = 0.025). AMP responsiveness may be predicted by peripheral blood eosinophilia but not with atopy markers in young children with asthma.  相似文献   
5.
We investigated the brainstem integrity in children with primary nocturnal enuresis (PNE) using auditory brainstem responses (ABR), blink reflex and exteroceptive suppression of the masseter muscle. We examined 23 children with PNE (16 male, 7 female; mean age: 10.4 years) and 19 control subjects (11 male, 8 female; mean age: 11.8 years). ABR parameters such as wave latencies, amplitudes and interpeak latencies and blink reflex parameters such as R1 and R2 amplitude and latencies were not significantly different between the 2 groups. Although S2 parameters of the exteroceptive suppression of the masseter muscle were easily and completely obtained from the control subjects, in the PNE group S2 onset latency and duration were not recorded in 26% of the study children (n = 6) (P = 0.01). S2 duration time was significantly lowered in the enuretic group (left side: P = 0.001 and right side: P = 0.003). S2 duration time changes in the enuretic group supports a possible brainstem dysfunction in children with PNE.  相似文献   
6.
Several age-related alterations occur at the cellular level in the immune system leading to a decrease in the immune response. The present study was designed to determine the effect of L-carnitine on impaired neutrophil functions of aged rats. For this reason, superoxide anion radical production, chemotaxis and phagocytic activity were studied in the neutrophils obtained from the peripheral blood of young and old rats. We orally gavaged L-carnitine (50 mg/kg b.w. per day) or control vehicle into young (2 months) and aged (24 months) rats for 30 consecutive days. The neutrophils of aged rats exhibited an increase in superoxide anion production and decline in phagocytosis and chemotaxis when compared with that in young rat neutrophils. Superoxide anion production in aged rats was significantly decreased by L-carnitine treatment which was accompanied with a significant enhancement of chemotactic and phagocytic activity being restored to control levels. These findings demonstrated that L-carnitine is capable of restoring the age-related changes of neutrophil functions.  相似文献   
7.
OBJECTIVES: Beh?et's disease (BD) is a chronic inflammatory disorder of still unknown etiology, characterized by endothelial cell injury/dysfunction and thrombosis and/or aneurysm of large blood vessels. Thrombophilia may play a role in the pathogenesis of thrombosis in BD. The common inherited gene defects, factor V (FV) 1691A (Leiden) and prothrombin (PT) 20210A, are known risk factors for thrombosis. The FV 4070G polymorphism was shown to influence circulating FV levels and to contribute to the activated protein C resistance phenotype. The aim of the study was to evaluate the role of FV 1691A, FV 4070G and PT 20210A gene mutations in Turkish BD patients with and without venous thrombosis. METHODS: Seventy-one patients with BD (27 with venous thrombosis) and 91 healthy subjects were included in the study. FV 1691A, FV 4070G, and PT 20210A mutations were determined by a method based on PCR-RFLP. RESULTS: The frequency of FV 1691A heterozygous mutation in BD patients with venous thrombosis (25.9%) was significantly higher than that in healthy subjects (8.8%; OR = 3.63; 95% CI 1.18-11.2). Although the frequency of this mutation in patients with venous thrombosis was higher than that in the patients without venous thrombosis (11.4%), the difference did not reach a statistically significant level (OR = 2.73; 95% CI 0.77-9.70). In BD patients with thrombosis, the frequencies of FV 4070G and PT 20210A were not significantly different compared to the BD patients without venous thrombosis and healthy subjects. CONCLUSIONS: Our results suggest that the FV 1691A, FV 4070G, and PT 20210A mutations are unlikely to play an important role in the pathogenesis of thrombosis in patients with BD.  相似文献   
8.
Purpose

Cardiovascular disease is one of the major causes of mortality in anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Metabolic syndrome (MetS) is associated with increased cardiovascular risk in the normal population. However, MetS in AAV has not been adequately investigated. We aimed to determine MetS prevalence and associated factors in AAV patients.

Methods

Thirty-seven AAV patients and 42 healthy controls were enrolled. MetS was determined by International Diabetes Federation (IDF) and National Cholesterol Education Program Adult Treatment Panel III (NCEP-ATPIII) criteria. The relationship between clinical features of AAV and MetS was also investigated.

Results

MetS was significantly higher in AAV patients than controls by NCEP-ATPIII (51.4% vs. 26.2%, p 0.022) and IDF (62.2% vs. 35.7%, p 0.020). When AAV patients with MetS were compared to those without, there were significant differences in age, CRP, GFR and NT-pro-BNP. Age [58 (13) vs. 50 (8) years p: 0.028], CRP [4.0 (3.6) vs. 3.2 (1.0) mg/l, p 0.021] and NT-pro-BNP [173.5 (343.7) vs. 106.0 (103.0) pg/ml, p 0.013] were significantly higher in AAV patients with MetS than those without; GFR was significantly lower [38 (46) vs. 83 (51) ml/min/1.73 m2, p 0.004]. ROC curve analysis showed NT-pro-BNP?>?58.0 ng/ml predicted MetS with 87.1% sensitivity and 46.7% specificity (Area under curve: 0.71, CI 0.536–0.902, p 0.041). Multivariate analysis revealed age [OR (95% CI): 1.180 (1.010–1.370), p 0.039] and NT-pro-BNP?>?58 pg/ml [OR (95% CI): 5.5 (1.02–30.1) p 0.047] were independent predictors of MetS in AAV patients.

Conclusion

MetS is significantly higher in AAV patients than controls and is associated with age and NT-pro-BNP. Screening and treating MetS may improve prognosis in AAV patients.

  相似文献   
9.
Mesoatrial shunt in Budd-Chiari syndrome   总被引:2,自引:0,他引:2  
BACKGROUND: The operations with proven effects on survival in Budd-Chiari syndrome are shunt operations and liver transplantation. PATIENTS AND METHODS: Between 1993 and 1999 (June), 13 cases of Budd-Chiari syndrome have been treated surgically. Four cases had concomitant thrombosis of the inferior vena cava; the others had marked narrowing of the lumen due to the enlarged caudate lobe. Mesoatrial (n = 12) or mesosuperior vena caval (n = 1) shunts were constructed with ringed polytetrafluoroethylene grafts. RESULTS: The median portal pressure fell from 45 (range 32 to 55) to 20 (range 11 to 27) cm H(2)O (P <0.001). Two patients died in the early postoperative period. One patient who did not comply with anticoagulant treatment had a shunt thrombosis in the second postoperative year. The other 10 patients are alive without problems during a median 42 (range 1 to 76) months of follow-up. CONCLUSION: Mesoatrial shunt with a ringed polytetrafluoroethylene graft is effective in Budd-Chiari syndrome cases with thrombosis or significant stenosis in the inferior vena cava.  相似文献   
10.
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