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   482篇
  免费   39篇
  国内免费   2篇
儿科学   44篇
妇产科学   1篇
基础医学   46篇
口腔科学   14篇
临床医学   30篇
内科学   91篇
皮肤病学   5篇
神经病学   32篇
特种医学   86篇
外科学   34篇
综合类   13篇
预防医学   13篇
眼科学   61篇
药学   19篇
肿瘤学   34篇
  2022年   1篇
  2021年   2篇
  2020年   2篇
  2019年   3篇
  2018年   8篇
  2017年   7篇
  2016年   8篇
  2015年   14篇
  2014年   24篇
  2013年   12篇
  2012年   11篇
  2011年   6篇
  2010年   12篇
  2009年   21篇
  2008年   15篇
  2007年   13篇
  2006年   15篇
  2005年   8篇
  2004年   10篇
  2003年   12篇
  2002年   9篇
  2001年   23篇
  2000年   7篇
  1999年   12篇
  1998年   21篇
  1997年   29篇
  1996年   29篇
  1995年   15篇
  1994年   26篇
  1993年   14篇
  1992年   15篇
  1991年   15篇
  1990年   14篇
  1989年   14篇
  1988年   11篇
  1987年   7篇
  1986年   9篇
  1985年   8篇
  1984年   9篇
  1983年   10篇
  1982年   3篇
  1981年   4篇
  1980年   7篇
  1979年   3篇
  1976年   5篇
排序方式: 共有523条查询结果,搜索用时 16 毫秒
91.
Baird  DM; Royle  NJ 《Human molecular genetics》1997,6(13):2291-2299
A high level of sequence polymorphism combined with linkage disequilibrium has created a limited number of highly diverged haplotypes across the human Xp/Yp telomere junction region. To gain insight into the unusual genetic characteristics of this region, we have examined the orthologous sequences in the common chimpanzee (Pan troglodytes ), the gorilla (Gorilla gorilla) and the orang-utan (Pongo pygmaeus). Divergence from the human Xp/Yp sequence is higher (average 2.6-fold) than that observed at other loci. The position of the human Xp/Yp telomere is unique, as additional sequences are present at this location in the other three species. These included an array of subterminal satellite in the chimpanzee and, in the gorilla a small interstitial array of telomere-like repeats followed by sequences with strong homology to the human 18p subterminal region. In the orang-utan, two alleles with different structures were identified. These differ by the presence or absence of a short interspersed nuclear element (SINE) sequence just proximal to long arrays of telomere-like repeat sequences that probably represent the proximal end of the orang-utan Xp/Yp telomere. In addition, a high level of sequence divergence between the two orang-utan structures was identified. This divergence is similar to that observed between the human Xp/Yp telomere-adjacent haplotypes. The high sequence divergence and evidence of gross rearrangements indicate that the Xp/Yp telomeric region has evolved faster than the rest of the genome.   相似文献   
92.
We studied a large kindred with a chronic progressive neurologic disorder affecting at least 10 men and 11 women in four generations in a pattern compatible with autosomal dominant inheritance. In 20 of the affected subjects, evaluated before the availability of computerized tomography and without regard to family history, the diagnosis was multiple sclerosis. Symptoms of the neurologic disorder begin in the fourth and fifth decades and include cerebellar, pyramidal, and autonomic abnormalities. The autonomic symptoms, which involve bowel and bladder regulation and orthostatic hypotension, may be the earliest changes but are frequently disregarded. Survival for 20 years after onset is common. The CT scan is striking and shows a symmetrical decrease in white-matter density, beginning in the frontal lobes but extending to all of the centrum ovale and the cerebellar white matter. Limited pathological observation reveals gross white-matter degeneration with microscopic vacuolation, preservation of U fibers and cortical structures, and no inflammatory changes or reactive gliosis. Because of its hereditary basis, the disorder should be susceptible to genetic definition and ultimately to treatment or prevention.  相似文献   
93.
Ninety-five patients suspected of having multiple sclerosis (MS) were evaluated by medical history and neurologic examination. Based on this evidence they were divided into three groups: clinically definite MS, not-definite MS, and not MS. The adjunct tests, chemical analysis, and magnetic resonance imaging (MRI), were also performed to assess the diagnosis of MS. Chemical analyses of paired serum and cerebrospinal fluid (CSF) samples were performed to identify oligoclonal immunoglobulin bands and to estimate both the albumin quotient and the IgG index. A positive correlation was found between the chemical test results and definite MS in 73 of 73 cases. In 11 of 12 cases of not-definite MS the chemical results were positive for MS. A positive correlation was also found between ten of ten cases that were not MS and negative chemical test results. MRI scans were positive for MS in 48 of 51 clinically definite MS cases and in 4 of 4 not-definite MS cases. MRI scans were negative for MS in five of six cases that were not MS. These findings demonstrate that combined determinations of serum and CSF proteins by simple zone electrophoresis and commercial immunochemical tests can be useful laboratory aids in the diagnosis of MS. The MRI scans provide additional evidence to support the diagnosis of MS.  相似文献   
94.
Pseudophakic cystoid macular oedema (PCMO) remains a significant cause of compromised postoperative vision in contemporary cataract surgery. Well‐established risk factors include intraoperative complications such as posterior capsule rupture and preoperative factors including: diabetes mellitus, uveitis, retinal vein occlusion, epiretinal membrane. The role of topical glaucoma medications in PCMO continues to be debated. Current treatment strategies largely target suppression of inflammation. Topical NSAIDs remain the mainstay in prophylaxis and treatment of PCMO. Topical corticosteroids are commonly used as monotherapy or in combination with NSAIDs. Unfortunately, high‐quality trials are notably lacking for other PCMO treatment modalities such as: periocular corticosteroids, orbital floor triamcinolone, intravitreal triamcinolone, corticosteroid implants, intravitreal bevacizumab and pars‐plana vitrectomy. A lack of consistency in defining PCMO and resolution of PCMO explains why even large systematic reviews may come to contradictory conclusions. This review explores the varied contemporary evidence‐base in relation to the aetiology, diagnosis, prophylaxis and treatment of PCMO.  相似文献   
95.
Sepsis-induced cardiogenic shock in combination with severe acute respiratory failure represents a life-threatening combination that is often refractory to the conventional methods of treatment. We describe the case of a 33-year-old patient who developed acute cardiovascular collapse and ARDS secondary to superinfection of Panton–Valentine leukocidin—positive Staphylococcus aureus and H1N1 pneumonia who underwent successful combination therapy for severe sepsis-related cardiomyopathy and respiratory failure using extracorporeal membrane oxygenation and cytokine adsorption therapy.  相似文献   
96.
97.
Here, we report pathogenetic aspects of spinal epidural lipomatosis (SEL) based on a literature review. SEL is a rare entity but can cause significant morbidity. Its symptoms can be identical to those of more common disorders such as vertebral and disc disease, and cord lesions (for example, transverse myelitis, multiple sclerosis and syringomyelia). Therefore, it often goes undiagnosed. In addition, SEL occurs in patients on glucocorticoid therapy, which can lead to myopathy, thereby mimicking the motor symptoms of SEL. Glucocorticoids seem to play a major role in the development of SEL, although idiopathic SEL has also been reported. The latter occurs almost exclusively in obese individuals who may have concurrent hypercortisolism. Once clinically suspected, SEL is best diagnosed by magnetic resonance imaging (MRI). Treatment of SEL is directed at reducing body weight in patients with idiopathic SEL, and at decreasing glucocorticoid excess in patients with endogenous or exogenous hypercortisolism. In severe cases, decompressive laminectomy might become necessary to alleviate the neurological symptoms caused by spinal cord compression.  相似文献   
98.
Abstract: Aim: The aim was to compare the working profiles of Finnish and Norwegian dental hygienists in public and private practice. To this end, we compared the procedures performed, the type of patients and the time devoted to different tasks. Subjects and methods: A questionnaire survey was originally conducted among a representative sample of dental hygienists in Finland (n = 595) and all authorized dental hygienists in Norway (n = 1 138) in 2004. The questionnaires collected data on the dental hygienists’ age, gender, year of graduation, working experience, work sector (private or public), working time spent on different activities and patient groups. The questionnaire also assessed how frequently the dental hygienists performed 25 different treatment measures. Results: The Norwegian dental hygienists spent 45.4% of their clinical time on check‐ups, whereas the Finns spent 49.9% of their time scaling. Dental hygienists in Finland and Norway working in the public sector spent 42.9% and 74.6% of their working time dealing with children and youth respectively. Conclusions: The working profiles of dental hygienists in Finland and Norway were quite similar, although differences in distribution by activities, type of patients and treatment measures do exist. The main activity of the dental hygienists was clinical work. The most commonly practised clinical activity among Finnish dental hygienists was scaling, and among Norwegians, check‐ups. Public dental hygienists in both countries dealt mainly with children and youths. Oral hygiene instruction was the most commonly reported treatment measure among both Finns and Norwegians.  相似文献   
99.
Summary. Background: Osteoprotegerin (OPG) concentration in serum is associated with the presence and severity of atherosclerosis. Objective: To investigate the association between serum osteoprotegerin and the risk of a future myocardial infarction, ischemic stroke and mortality in a general population. Patients/methods: OPG was measured in serum collected from 6265 subjects recruited from a general population without a prior myocardial infarction and ischemic stroke (the Tromsø Study). Incident myocardial infarction, ischemic stroke and mortality were registered during follow‐up. Cox regression models were used to estimate crude and adjusted hazard ratios and 95% confidence intervals (HR; 95% CI). Results: There were 575 myocardial infarctions, 284 ischemic strokes and 824 deaths (146 deaths as a result of ischemic heart disease, 78 deaths because of stroke and 600 deaths due to other causes) in the cohort during a median of 10.6 years of follow‐up. Serum OPG (per SD [1.13 ng mL?1] increase in OPG) was associated with an increased risk of a myocardial infarction (1.20; 1.11–1.31), ischemic stroke (1.32; 1.18–1.47), total mortality (1.34; 1.26–1.42), death because of ischemic heart disease, (1.35; 1.18–1.54), stroke (1.44; 1.19–1.75) and non‐vascular causes (1.31; 1.22–1.41) after adjustment for age, gender, current smoking, systolic blood pressure, body mass index, high density lipoprotein cholesterol, total cholesterol, creatinine, high sensitivity C‐reactive protein (CRP) and diabetes mellitus or HbA1c > 6.1%. No association was detected between OPG and incident hemorrhagic stroke (1.02; 0.73–1.43). Conclusions: Serum OPG was associated with future risk of myocardial infarction, ischemic stroke, total mortality, mortality of ischemic heart disease, stroke and of non‐vascular causes independent of traditional cardiovascular risk factors.  相似文献   
100.
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