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   2748篇
  免费   95篇
  国内免费   15篇
耳鼻咽喉   130篇
儿科学   93篇
妇产科学   142篇
基础医学   169篇
口腔科学   145篇
临床医学   228篇
内科学   482篇
皮肤病学   63篇
神经病学   143篇
特种医学   157篇
外科学   652篇
综合类   47篇
预防医学   56篇
眼科学   127篇
药学   102篇
中国医学   4篇
肿瘤学   118篇
  2024年   1篇
  2023年   29篇
  2022年   42篇
  2021年   61篇
  2020年   33篇
  2019年   55篇
  2018年   51篇
  2017年   47篇
  2016年   79篇
  2015年   83篇
  2014年   101篇
  2013年   135篇
  2012年   161篇
  2011年   187篇
  2010年   112篇
  2009年   106篇
  2008年   219篇
  2007年   239篇
  2006年   236篇
  2005年   240篇
  2004年   197篇
  2003年   151篇
  2002年   116篇
  2001年   61篇
  2000年   33篇
  1999年   28篇
  1998年   14篇
  1997年   10篇
  1996年   5篇
  1995年   4篇
  1994年   4篇
  1993年   2篇
  1992年   2篇
  1991年   2篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1982年   1篇
  1981年   1篇
  1974年   1篇
  1971年   1篇
  1966年   1篇
排序方式: 共有2858条查询结果,搜索用时 15 毫秒
61.
62.
The predictive accuracy of electrocardiographic markers in identifying the infarct-related artery of myocardial infarctions has been a subject of extensive investigation. The present study was designed to test whether the index L II/L III ratio adapted to exercise electrocardiograms could be utilized as a marker to distinguish right coronary and left circumflex arteries as culprit coronaries in acute inferior myocardial infarctions. For this purpose, 82 patients with a positive-symptom-limited and/or submaximal treadmill exercise test with modified Bruce protocol after an acute inferior myocardial infarction were studied. Those patients with ST segment elevation during the stress test were included in the study. ST segment index was defined as the ratio of exercise-induced ST elevation amplitude in L II/L III. Patients were classified as having an index > 1 (n=24) and < 1 (n=58), and the findings were compared with the findings on coronary angiography. The groups were comparable with respect to age, gender, peak exercise level, and double products achieved. Circumflex artery was the infarct-related one in the majority (21/24; 88%) of patients with an index > 1, whereas most (51/58; 88%) patients with an index < 1 had the culprit lesion in their right coronary artery (p<0.001). The ratio of exercise-induced ST elevations in leads L II and L III has a significantly high ability to discriminate the infarct-related coronary artery in patients with uncomplicated inferior myocardial infarction. Considering the prognostic importance of the type of coronary involvement, this index could be a part of predischarge evaluation in this patient group.  相似文献   
63.
64.
[Purpose] This study aimed to investigate the effect of ankle proprioceptive training on static body balance. [Subjects and Methods] In this randomized-controlled, single-blind study, 59 university students (35 females, 24 males) were randomized into study (n=29) and control (n=30) groups. The study group received a foot and ankle proprioceptive exercise program including stretching, strengthening (plantar and dorsi-flexors, invertor and evertor muscles), and balance board exercises, each with 10 repetitions per session, 5 days a week, for a total of 10 sessions. The control group did not receive any intervention. Static body balance was evaluated by a kinesthetic ability trainer, which showed the balance index scores under both single foot and both feet conditions. This evaluation was repeated at the end of two weeks for both groups. [Results] Outcome measures of the groups were similar at the baseline. Balance index scores of both groups improved at the end of two weeks, and the study group had significantly lower index scores than those of the control group, indicating better balance. [Conclusion] Ankle proprioceptive training had positive effects on static body balance parameters in healthy individuals, and it is worth investigating the effects of this type of training in patients with balance disorders.Key words: Ankle proprioception, Static balance, Sport KAT  相似文献   
65.
66.

Purpose

Retina is a unique part of the central nervous system (CNS) for visualizing the processes of axonal and neuronal degeneration. Optical coherence tomography (OCT) allows direct visualization and measurement of retinal nerve fiber layer (RNFL) thickness, macular volume, and optic disc (OD) parameters. One of the disorders associated with atrophy in different brain regions is obstructive sleep apnea syndrome (OSAS). In the present study, we aimed to determine OD and RNFL changes measured by OCT for investigating the progress of neurodegeneration development in OSAS, excluding all the other conditions that can directly affect RNFL thickness and optic nerve parameters.

Methods

Both eyes of 101 patients with OSAS and 20 controls were investigated by OCT. Full-night polysomnography (PSG) and ophthalmologic examination including automated visual field (VF) examination and OCT were performed in all of the patients.

Results

According to the OSAS grading, patients were grouped as mild (n?=?15), moderate (n?=?27), and severe (n?=?59). We found significant decrease in RNFL thickness only in the patients with severe OSAS compared with the other groups and decreased macular ganglion cell thickness in the severe OSAS group compared with the control group. VF parameters were significantly worsened in all the OSAS subgroups compared to the control group. We found different data such as normal or increased optic nerve parameters as result of subtle OD edema, which may mask possible peripapillar axonal loss.

Conclusions

We think that evaluation of neurodegeneration in OSAS is not always possible by examining OD and RNFL because there are difficulties due to the confounding issues of cerebral atrophy and OD edema.  相似文献   
67.
Using a combination of homozygosity mapping and whole‐exome sequencing (WES), we identified a novel missense c.1819G>A mutation (G607S) in the endothelin‐converting enzyme‐like 1 (ECEL1) gene in a consanguineous pedigree of Turkish origin presenting with a syndrome of camptodactyly, scoliosis, limited knee flexion, significant refractive errors and ophthalmoplegia. ECEL1 mutations were recently reported to cause recessive forms of distal arthrogryposis. This report expands on the molecular basis and the phenotypic spectrum of ECEL1‐associated congenital contracture syndromes.  相似文献   
68.
Isolated atrial septal defect (ASD) is the most common form of congenital heart abnormalities in adults and approximately 80% are located in the region of the fossa ovalis (ostium secundum ASD).1 Indications for closure are in cases where the ratio of pulmonary-to-systemic flow (Qp/Qs) is higher than 1.5, without significant elevation of pulmonary vascular resistance.Surgical closure of ASDs has been performed for over 60 years and techniques have steadily improved, using smaller incisions and minimally invasive techniques. On the other hand, in the last 20 years, various transcatheter ASD closure techniques and devices have been developed, among which, percutaneous treatment with a septal occluder device is the most popular.2,3Despite increasing use of occluder devices and the fact that studies have been published internationally pointing out some of the advantages and disadvantages compared with surgery in adults, no formal comparison of efficacy, morbidity and complications has been published.2-4 We present a retrospective comparison of short-term (three months) results for transcatheter and surgical closure of 163 ostium secundum ASD patients in a university hospital.  相似文献   
69.
The effects of annealing temperatures on composition and strain in SixGe1−x, obtained by rapid melting growth of electrodeposited Ge on Si (100) substrate were investigated. Here, a rapid melting process was performed at temperatures of 1000, 1050 and 1100°C for 1 s. All annealed samples show single crystalline structure in (100) orientation. A significant appearance of Si-Ge vibration mode peak at ~00 cm−1 confirms the existence of Si-Ge intermixing due to out-diffusion of Si into Ge region. On a rapid melting process, Ge melts and reaches the thermal equilibrium in short time. Si at Ge/Si interface begins to dissolve once in contact with the molten Ge to produce Si-Ge intermixing. The Si fraction in Si-Ge intermixing was calculated by taking into account the intensity ratio of Ge-Ge and Si-Ge vibration mode peaks and was found to increase with the annealing temperatures. It is found that the strain turns from tensile to compressive as the annealing temperature increases. The Si fraction dependent thermal expansion coefficient of SixGe1−x is a possible cause to generate such strain behavior. The understanding of compositional and strain characteristics is important in Ge/Si heterostructure as these properties seem to give significant effects in device performance.  相似文献   
70.
Rhinoliths are nasal stones that result from mineralisation of salts around an endogenous or exogenous nidus within the nasal cavity. They are uncommon nasal masses and usually unilateral and single, situated in the floor of the nose. The patient typically presents with nasal obstruction, facial pain and foul-smelling nasal secretion. To the best of our knowledge, the occurrence of squamous cell carcinoma with rhinolithiasis has not been previously reported in the English-language literature. In this article, we present a 63-year-old man, who had unilateral rhinolithiasis with squamous cell carcinoma within the nasal cavity.  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