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   1004篇
  免费   65篇
  国内免费   9篇
耳鼻咽喉   12篇
儿科学   43篇
妇产科学   7篇
基础医学   114篇
口腔科学   55篇
临床医学   89篇
内科学   199篇
皮肤病学   44篇
神经病学   38篇
特种医学   158篇
外国民族医学   1篇
外科学   88篇
综合类   40篇
预防医学   94篇
眼科学   8篇
药学   52篇
中国医学   1篇
肿瘤学   35篇
  2023年   3篇
  2022年   13篇
  2021年   11篇
  2020年   11篇
  2019年   18篇
  2018年   24篇
  2017年   22篇
  2016年   24篇
  2015年   32篇
  2014年   20篇
  2013年   39篇
  2012年   29篇
  2011年   34篇
  2010年   35篇
  2009年   50篇
  2008年   35篇
  2007年   20篇
  2006年   22篇
  2005年   22篇
  2004年   38篇
  2003年   18篇
  2002年   9篇
  2001年   7篇
  2000年   8篇
  1999年   18篇
  1998年   55篇
  1997年   63篇
  1996年   56篇
  1995年   42篇
  1994年   40篇
  1993年   39篇
  1992年   9篇
  1991年   13篇
  1990年   16篇
  1989年   17篇
  1988年   23篇
  1987年   23篇
  1986年   24篇
  1985年   11篇
  1984年   5篇
  1983年   9篇
  1982年   18篇
  1981年   3篇
  1980年   9篇
  1979年   4篇
  1978年   4篇
  1977年   6篇
  1976年   6篇
  1975年   4篇
  1968年   3篇
排序方式: 共有1078条查询结果,搜索用时 15 毫秒
101.

Background

Direct stenting without balloon dilatation may reduce procedural costs and duration, and hypothetically, the restenosis rate. This study was designed to compare the in-hospital and long-term outcomes of direct stenting (DS) versus stenting after pre-dilatation (PS) in our routine clinical practice.

Methods

The 1 603 patients treated with stenting for single coronary lesions were enrolled into a prospective registry. Patients with acute myocardial infarction (MI) within the preceding 48 hours, and those with highly calcified lesions, total occlusions, or a lesion in a saphenous graft were excluded. The baseline, angiographic and procedural data, inhospital outcomes and follow-up data were recorded in our database and analysed with appropriate statistical methods.

Results

Eight hundred and fifty-seven patients (53.5%) were treated with DS and 746 (46.5%) underwent PS. In the DS group, lesions were shorter in length, larger in diameter and had lower pre-procedural diameter stenosis. Type C and diffuse lesions and drug-eluting stents were found less often (p < 0.001). With univariate analysis, dissection and non-Q-wave MI occurred less frequently in this group (0.2 and 0.6% vs 3.9 and 2.1%, p < 0.001 and p = 0.01, respectively). However, the cumulative major adverse cardiac events (MACE) did not differ significantly (4.9 vs 4.6%, p = 0.79). With multivariate analysis, direct stenting reduced the risk of dissection (OR = 0.07, 95% CI: 0.01–0.33, but neither the cumulative endpoint of MACE (OR = 1.1, 95% CI = 0.58–2.11, p = 0.7) nor its constructing components were different between the groups.

Conclusions

Direct stenting in the real world has at least similar long-term outcomes in patients treated with stenting after pre-dilatation, and is associated with lower dissection rates.  相似文献   
102.
Visceral leishmaniasis is one of the most important parasitic diseases that is endemic in some parts of Iran. This study aimed to determine current distribution of visceral leishmaniasis in four distinct geographical zones of Iran. A cross-sectional study was conducted using direct agglutination test (DAT) on 9396 and 2559 serum samples collected from humans and domestic dogs, respectively during the period of 2007 through 2009. Altogether, 403 (4.3%) out of 9396 human serum samples collected from 4 distinct geographical locations showed anti-Leishmania antibodies with titers ≥ 1:3200. Physical examinations performed on 142 sero-positive cases with anti-Leishmania antibodies at titers of 1: 3200 to 1:102400 among whom fever (94.4%), paleness (67.6%) and hepato-splenomegaly (42.2%) were the predominant clinical signs and symptoms. The highest sero-prevalence rate (1.55%) was found in children ≤ 5 years old. Out of 2559 serum samples collected from domestic dogs, 212 (8.3%) were DAT positive (≥ 1:320). Leishmania infantum is the principal causative agent of the disease was isolated from both infected humans and dogs in Iran. Our findings indicate that Mediterranean visceral leishmaniasis with different distribution occurs in different geographical locations of Iran.  相似文献   
103.
104.
Cleland JG  Torabi A  Khan NK 《Heart (British Cardiac Society)》2005,91(Z2):ii7-13; discussion ii31, ii43-8
Robust epidemiological data on the incidence of myocardial infarction (MI) are hard to find, but synthesis of data from a number of sources indicates that the average hospital in the UK should admit about two patients with a first MI and one recurrent MI per 1000 population per year. Possibly the most relevant data on the incidence, prevalence, and persistence of post-MI heart failure can be derived from the TRACE study. Most patients will develop heart failure or major left ventricular systolic dysfunction (LVSD) at some time after an MI, most commonly during the index admission. In up to 20% of cases this will be transient, but such patients still have a poor prognosis. There is likely to be around one patient discharged per thousand population per year with heart failure or major LVSD after an acute MI. It is important to organise care structures to ensure that patients with post-MI heart failure and LVSD are identified and managed appropriately.  相似文献   
105.

Objective

To identify the vector(s), the parasite and the species composition of sand flies in the district during May-October 2012.

Methods

For reaching our objectives we used polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphism.

Results

Two species of Phlebotomus sergenti and Phlebotomus tobbi were the most prevalent among 8 species identified comprising 51.1% and 32.9% respectively. Among the 160 specimens of female sand flies tested by polymerase chain reaction of kDNA, ITS1-rDNA, followed by restriction fragment length polymorphisms, only 1 out of 80 Phlebotomus tobbi (1.25%) were positive to Leishmania infantum parasites.

Conclusions

Our finding showed that Phlebotomus tobbi may play as a vector to circulate the parasite of Leishmania infantum among reservoir(s) and human.  相似文献   
106.
This article provides information and a commentary on key trials relevant to the pathophysiology, prevention, and treatment of heart failure (HF) presented at the annual meeting of the European Society of Cardiology held in Stockholm in 2010. Unpublished reports should be considered as preliminary, since analyses may change in the final publication. The SHIFT study supports the use of ivabradine in patients with HF due to left ventricular systolic dysfunction and resting sinus rhythm rate ≥70 b.p.m. despite treatment with beta-blockers or where beta-blockers are contra-indicated. Results from PEARL-HF suggest that the potassium binding polymer RLY5016 may be useful for both prevention and treatment of hyperkalaemia in HF patients with or without concomitant chronic kidney disease. The STAR-heart study provides encouraging observational data about the potential for intracoronary stem cell transplantation in patients with HF. Results from HEBE-III showed no effect of erythropoietin on ejection fraction measured 6 weeks post-MI; although there were fewer cardiovascular events in patients assigned to erythropoietin, the study was too small to provide conclusive evidence of effect.  相似文献   
107.
This article provides information and a commentary on trials relevant to the pathophysiology, prevention, and treatment of heart failure presented at the annual meeting of the European Society of Cardiology held in Barcelona in 2009. The AAA study does not support the routine use of aspirin for the prevention of vascular events in patients with asymptomatic atherosclerosis. RELY suggests that dabigatran may be more effective than warfarin for the prevention of stroke in patients with atrial fibrillation. Rolofylline was not superior to placebo in improving outcomes in patients with acute heart failure enrolled in the PROTECT study, but dyspnoea was improved. Data from ACTIVE‐I suggest that irbesartan does not provide additional therapeutic benefit in patients with atrial fibrillation who are well controlled on current therapy. The European cardiac resynchronization therapy (CRT) survey provides interesting epidemiological data on current CRT device usage. The German pre‐SCD II registry identified a low prevalence of patients with a reduced ejection fraction following myocardial infarction. Implantation of CRT‐D rather than an implantable cardioverter defibrillator in patients with mild heart failure and QRS ≥130 ms reduced the risk of hospitalization for heart failure in MADIT‐CRT; mortality was similarly low with each device.  相似文献   
108.
Southeast Asian ovalocytosis (SAO) is an asymptomatic trait characterized by rigid, poorly deformable red cells that resist invasion by several strains of malaria parasites. The underlying molecular genetic defect involves simple heterozygous state for a mutant band 3 protein, which contains a deletion of amino acids 400 through 408, linked with a Lys 56-to-Glu substitution (band 3-Memphis polymorphism). To elucidate the contribution of the mutant SAO band 3 protein to increased SAO red blood cell (RBC) rigidity, we examined the participation of the mutant SAO band 3 protein in increased band 3 attachment to the skeleton and band 3 oligomerization. We found first that SAO RBC skeletons retained more band 3 than normal cells and that this increased retention preferentially involved the mutant SAO band 3 protein. Second, SAO RBCs contained a higher percentage of band 3 oligomer-ankyrin complexes than normal cells, and these oligomers were preferentially enriched by the mutant SAO protein. At the ultrastructural level, the increased oligomer formation of SAO RBCs was reflected by stacking of band 3-containing intramembrane particles (IMP) into longitudinal strands. The IMP stacking was not reversed by treating SAO RBCs in alkaline pH (pH 11), which is known to weaken ankyrin-band 3 interactions, or by removing the cytoplasmic domain of band 3 from SAO membranes with trypsin. Finally, we found that band 3 protein in intact SAO RBCs exhibited a markedly decreased rotational mobility, presumably reflecting the increased oligomerization and the membrane skeletal association of the SAO band 3 protein. We propose that the mutant SAO band 3 has an increased propensity to form oligomers, which appear as longitudinal strands of IMP and exhibit increased association with membrane skeleton. This band 3 oligomerization underlies the increase in membrane rigidity by precluding membrane skeletal extension, which is necessary for membrane deformation.  相似文献   
109.
We report the treatment outcome of allogeneic bone marrow transplantation in ten patients with Philadelphia chromosome-positive acute lymphoblastic leukemia. Six patients are alive and well for 6 to 30 months (median 19 months) after transplantation. Four patients died with transplant related complications. In view of the poor prognosis associated with this disease, marrow ablation followed by allogeneic or syngeneic marrow grafting may be the preferred treatment modality if a suitable marrow donor is available.  相似文献   
110.
A deficiency of adenosine deaminase, an enzyme important in purine nucleoside catabolism, is associated with a severe combined immunodeficiency disease in children. Inhibition of this enzyme in vitro and in vivo results in an impairment in lymphoblast proliferation. We have investigated the pharmacologic inhibition of this enzyme by 2'-deoxycoformycin in 15 patients with hematologic malignancies. Biochemical consequences of the administration of this agent were closely monitored in erythrocytes, nucleated peripheral blood and bone marrow cells, serum, and urine. A marked rise in erythrocyte dATP was accompanied by a depletion of ATP in those patients exhibiting toxicity. Most patients excreted large amounts of deoxyadenosine but not adenosine in the urine. Serum deoxyadenosine rose in patients demonstrating a marked decrease in cell mass. The biochemical disturbances and clinical toxicity, including hepatic, renal, and conjunctival abnormalities, were usually reversible. Central nervous system toxicity, which potentially was the most serious consequence, was associated with high erythrocyte dATP/ATP ratios and high levels of cerebrospinal fluid deoxyadenosine. In patients with lymphoma and leukemia, objective responses were observed but were short- lived. Patients with chronic lymphocytic leukemia receiving weekly low doses of the drug demonstrated minimal toxicity and some efficacy. The chemotherapeutic potential o 2'-deoxycoformycin, as either a single agent or in combination with Ara-A, merits further exploration.  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