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   138篇
  免费   3篇
  国内免费   1篇
儿科学   6篇
妇产科学   2篇
基础医学   19篇
口腔科学   3篇
临床医学   10篇
内科学   15篇
神经病学   9篇
特种医学   6篇
外科学   19篇
综合类   4篇
预防医学   16篇
眼科学   20篇
药学   7篇
肿瘤学   6篇
  2023年   1篇
  2022年   2篇
  2021年   6篇
  2020年   5篇
  2019年   6篇
  2018年   4篇
  2017年   2篇
  2016年   1篇
  2015年   3篇
  2014年   6篇
  2013年   9篇
  2012年   8篇
  2011年   15篇
  2010年   6篇
  2009年   3篇
  2008年   9篇
  2007年   4篇
  2006年   10篇
  2005年   6篇
  2004年   5篇
  2003年   2篇
  2002年   2篇
  2001年   3篇
  2000年   5篇
  1999年   7篇
  1998年   1篇
  1994年   1篇
  1991年   1篇
  1987年   2篇
  1986年   4篇
  1980年   1篇
  1979年   1篇
  1967年   1篇
排序方式: 共有142条查询结果,搜索用时 15 毫秒
1.
Background Beating heart surgery has now become the commonest technique of doing Coronary Artery Bypass Graft Surgery (CABG) in our country. It is being used even in such high risk situations like diffuse coronary disease and Critical Left Main stem Stenosis (LMCS) with good results. The aim of this study is to retrospectively review our results in Off-Pump Coronary Artery Bypass Surgery (OPCAB) in patients with critical left main stem stenosis. Methods This study is a retrospective analysis of the data of patients who underwent primary coronary artery bypass surgery. During the period from April 2003 to September 2005 a total of 64 patients underwent OPCAB procedure for critical LMCS. During the same period 10 patients underwent CABG on Cardio Pulmonary Bypass (CPB). The age range was 36–77yrs. The sex distribution was M: F 53∶10. Ten patients were done as emergency. 2 of them were on Intra Aortic Balloon Pump (IABP) support preoperatively. 10 patients were high risk with a Euro score of ≥5. Results Left Internal Mammary Artery (LIMA) was used in 78% of cases. Average grafts per patient was 2.96. The median ventilation time was 5.91 hrs. New IABP insertion in postoperative period was required in 1 patient. One patient was reexplored for bleeding. There was one perioperative myocardial infarction. 57% of patients did not need any blood transfusion. There was no conversion to CPB. There was no operative mortality. Inotropes were used in ten cases. Conclusions OPCAB is a safe method of revascularization in patients with critical LMCS. Preoperative IABP is useful in patients with cardiogenic shock. However, there is a place for CPB in patients needing additional procedures like Mitral Valve repair (MV repair) or Dor's procedure or when the vessels are very diffusely diseased. Those patients who are unstable despite IABP support may be managed by Beating heart On Pump (BHOP) technique.  相似文献   
2.
Many polycyclic aromatic hydrocarbons containing peripherallyfused cyclopenta rings are believed to be activated primarilyby epoxidation of the cyclopenta ring. The cyclopenta epoxidesof a series of four cyclopenta benzanthracene derivatives, benz[e]aceanthrylene-5,6-oxide,benz[j]ace-anthrylene-1,2-oxide, benz(l)anthrylene-1,2-oxideand benz[k]acephenaceanthrylene-4,5-oxide were synthesized fromtheir parent hydrocarbons by formation of the bromohydrin followedby dehydrobromination, and characterized by u.v. – vis,and 1H n.m.r. spectroscopy and mass spectrometry. The mutagenicityof these compounds was investigated in the Ames plate incorporationassay with Salmonella typhimurium strain TA98. All the oxideswere active without exogenous metabolic activation (170–320His+ revertants per nanomole) and also toxic above 0.5 µg/plate.Addition of S9 protein did not increase, and generally decreased,the mutagenicity of the oxides, while toxicity was largely unchanged.These results are consistent with the postulated role of cyclopentaoxides as major contributors to the mutagenicity of the parentcompounds in the Ames assay.  相似文献   
3.
The biophysical mechanisms that drive and regulate cardiac looping are not well understood, but mechanical forces likely play a central role. Previous studies have shown that cardiac torsion, which defines left-right directionality, is caused largely by forces exerted on the heart tube by a membrane called the splanchnopleure (SPL). Here we show that, when the SPL is removed from the embryonic chick heart, torsion is initially suppressed. Several hours later, however, normal torsion is restored. This delayed torsion coincides with increased myocardial stiffness, especially on the right side of the heart. Exposure to the myosin inhibitor Y-27632 suppressed both responses, suggesting that the delayed torsion is caused by an abnormal cytoskeletal contraction. This hypothesis is supported further by computational modeling. These results suggest that the looping embryonic heart has the ability to adapt to changes in the mechanical environment, which may play a regulatory role during morphogenesis.  相似文献   
4.
Increased lung vascular permeability leading to increased plasma protein extravasation and accumulation (PPA) is a characteristic feature of acute lung injury. Using a previously described technique, PPA was monitored in the lungs of patients with the adult respiratory distress syndrome (ARDS) — an extreme example of acute lung injury in man. An external radiation probe detector was used to monitor the pulmonary accumulation of the plasma protein transferrin radiolabelled in-vivo with 113mIn. Ten patients with ARDS exhibiting increased PPA indices (>1.0x10-3/min) were given an intravenous infusion of terbutaline (7 g/kg) over 30 min. Of the four patients in whom the post-drug PPA indices remained within the ARDS range, none survived, whilst five of the six patients in whom the post-drug PPA indices were reduced to below 1.0x10-3/min survived. PPA indices prior to the administration of terbutaline were not significantly different between the survivor (n=5) and non-survivor (n=5) groups. There was a significant decrease in the PPA indices following terbutaline in survivors (p<0.01) but not in non-survivors. Thus beta-2-agonists in therapeutic doses can inhibit increased lung vascular permeability in man. These findings may have prognostic and therapeutic implication for beta-2-agonists in ARDS.  相似文献   
5.
Dissipation kinetics of chlorantraniliprole was studied in sandy loam soils of sugarcane ecosystem by adopting a rapid analytical method. The recovery of chlorantraniliprole was 91.67 % when extracted with ethyl acetate as against only 65.58 % in acetonitrile-based extraction. An additional cleanup step with primary secondary amine did not enhance the recovery significantly over the no-cleanup method. The ethyl acetate-based extraction followed by direct quantification in HPLC (High-performance liquid chromatography) without any cleanup facilitated rapid quantification of chlorantraniliprole residues. The LOQ (limit of quantification) of the method was 0.01 μg/g. The half-life of chlorantraniliprole was 6.50 and 6.81 days for the recommended and double the recommended doses, respectively.  相似文献   
6.
AimsModerately hypofractionated breast irradiation has been evaluated in several prospective studies, resulting in wide acceptance of shorter treatment protocols for postoperative breast irradiation. Reimbursement for radiation therapy varies between private and public systems and between countries, impacting variably financial considerations in the use of hypofractionation. The aim of this study was to evaluate the financial impact of moderately hypofractionated breast irradiation by reimbursement system in different countries.Materials and methodsThe study was designed by an international group of radiation oncologists. A web-questionnaire was distributed to representatives from each country. The participants were asked to involve the financial consultant at their institution.ResultsData from 13 countries from all populated continents were collected (Europe: Denmark, France, Italy, the Netherlands, Spain, UK; North America: Canada, USA; South America: Brazil; Africa: South Africa; Oceania: Australia; Asia: Israel, Taiwan). Clinicians and/or departments in most of the countries surveyed (77%) receive remuneration based on the number of fractions delivered to the patient. The financial loss per patient estimated resulting from applying moderately hypofractionated breast irradiation instead of conventional fractionation ranged from 5–10% to 30–40%, depending on the healthcare provider.ConclusionAlthough a generalised adoption of moderately hypofractionated breast irradiation would allow for a considerable reduction in social and economic burden, the financial loss for the healthcare providers induced by fee-for-service remuneration may be a factor in the slow uptake of these regimens. Therefore, fee-for-service reimbursement may not be preferable for radiation oncology. We propose that an alternative system of remuneration, such as bundled payments based on stage and diagnosis, may provide more value for all stakeholders.  相似文献   
7.
Thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder characterized by microangiopathic hemolytic anemia and thrombocytopenia often accompanied by microvascular ischemia, which may manifest as sensorimotor signs, visual changes, renal impairment, cardiac ischemia, and abdominal pain, depending on the organs affected. Until a few decades ago, TTP remained an almost universally fatal disorder. The introduction of plasma exchange therapy (PE) with replacement of fresh frozen plasma has improved the survival of patients with acute TTP dramatically from less than 10% to approximately 80 to 90% and is now considered the therapy of choice. During the last decade, the understanding of the pathophysiology of thrombotic microangiopathies, especially TTP, has increased considerably. The clinical features of thrombotic sequelae in TTP are diverse and usually secondary to microvascular thrombosis. Clinical and laboratory evidence for disruption of primary and secondary hemostasis, the role of endothelial integrity and fibrinolysis, the relevance of large vessel thrombosis, and the prevalence of thrombophilic states in TTP are discussed in this review. In summary, although the syndrome of TTP can sometimes be confused with other thrombotic diatheses, it is clear that the phenomenon of thrombosis in TTP appears to be distinctly different, both biologically and clinically, from other causes of microangiopathy and/or antibody-mediated thrombosis. Traditional anticoagulant and antiplatelet strategies are generally not effective in patients with TTP, despite the predominance of thrombotic manifestations, and common prothrombotic polymorphisms detected in patients with venous thromboembolism are seldom present.  相似文献   
8.
We describe a single centre experience of 33 patients allografted for multiple myeloma, of which 28 received matched sibling marrow, one haploidentical family donor marrow and four matched but unrelated donor marrow. Median follow-up after transplant is 27 months, and 13 patients are currently alive. One out of four patients with an unrelated donor survives and 12 out of 28 (42.8%) with matched sibling donors. Four patients were unevaluable because of early death (相似文献   
9.

Background

The aim of the study was to identify the epidemiology of chronic kidney disease of uncertain etiology in Sri Lanka.

Methods

A cross-sectional study was carried out by analyzing health statistics, and three cohort studies were conducted (n = 15 630, 3996, and 2809) to analyze the demographic information, age-specific prevalence, etiology, and stage of presentation. We screened 7604 individuals for chronic kidney disease of uncertain etiology.

Results

The results showed that the male:female ratio was 2.4:1, the mean age of patients was 54.7 ± 8 years, 92% of the patients were farmers, and 93% consumed water from shallow dug wells. Familial occurrence was common (36%). The prevalence of chronic kidney disease in different age groups was 3% in those aged 30–40 years; 7% in those aged 41–50 years, 20% in those aged 51–60 years, and 29% in those older than 60 years. Chronic kidney disease of uncertain etiology was diagnosed in 70.2% of patients, while 15.7% and 9.6% were due to hypertension and diabetic mellitus, respectively. The majority of patients were stage 4 (40%) at first presentation, while 31.8% were stage 3 and 24.5% were stage 5. Stage 1 and 2 presentation accounted for only 3.4%.

Conclusions

Low prevalence of CKDU was noticed (1.5%) among those who consumed water from natural springs. Prevalence was highest among males, rice farming communities, and those presenting at later disease stages.Key words: chronic kidney disease, uncertain etiology, epidemiology, North Central Province, male farmers, natural spring water  相似文献   
10.
Journal of Autism and Developmental Disorders - Although 70% of autistic children and young people meet criteria for co-occurring psychiatric conditions, there are few screening measures...  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