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   6107篇
  免费   465篇
  国内免费   56篇
耳鼻咽喉   26篇
儿科学   134篇
妇产科学   113篇
基础医学   941篇
口腔科学   103篇
临床医学   580篇
内科学   1603篇
皮肤病学   105篇
神经病学   742篇
特种医学   154篇
外科学   499篇
综合类   15篇
一般理论   1篇
预防医学   399篇
眼科学   65篇
药学   496篇
中国医学   13篇
肿瘤学   639篇
  2024年   6篇
  2023年   57篇
  2022年   154篇
  2021年   268篇
  2020年   133篇
  2019年   166篇
  2018年   234篇
  2017年   169篇
  2016年   188篇
  2015年   244篇
  2014年   279篇
  2013年   320篇
  2012年   534篇
  2011年   551篇
  2010年   276篇
  2009年   244篇
  2008年   438篇
  2007年   454篇
  2006年   389篇
  2005年   389篇
  2004年   324篇
  2003年   326篇
  2002年   246篇
  2001年   33篇
  2000年   15篇
  1999年   19篇
  1998年   29篇
  1997年   28篇
  1996年   24篇
  1995年   15篇
  1994年   17篇
  1993年   12篇
  1992年   7篇
  1991年   10篇
  1990年   5篇
  1989年   3篇
  1988年   4篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1983年   3篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   1篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1969年   2篇
  1918年   1篇
排序方式: 共有6628条查询结果,搜索用时 15 毫秒
81.
Numerous data have pointed to an association between migraine and cardiovascular diseases. The majority of the available data have indicated that migraine with aura can be considered a risk factor for ischemic stroke, whereas migraine without aura cannot be reliably considered as such. High frequency of attacks and a recent onset of migraine have been related to an increased ischemic stroke risk. In addition, in young subjects with ischemic stroke migraine with aura represents an independent risk factor of overall recurrent vascular events and of recurrent ischemic stroke. Also the risk of transient ischemic attack seems to be increased in migraineurs, although this issue has not been extensively investigated. Several studies have also addressed the possible association between migraine and hemorrhagic stroke. Although the results of these individual studies were conflicting, their meta-analysis showed that migraine is associated with a 1.5-fold increase in the risk of hemorrhagic stroke (including intracerebral and subarachnoid hemorrhage). Some studies have identified migraine also as a possible risk factor for cardiac vascular events while others have yielded negative results. A meta-analysis did not show an increased risk of myocardial infarction in subjects with any migraine vs no migraine but subsequently, data has pointed to an association between any migraine with cardiac ischemic disease. Migraine has also been associated by some studies with vascular mortality and with vascular diseases in regions other than the brain and the heart. Several studies have also indicated that compared with nonmigraineurs, migraineurs have a higher burden of asymptomatic white matter brain lesions and, according to some studies, also infarct-like lesions at brain magnetic resonance. The mechanisms underlying the relationship between migraine and cardiovascular disease are still unclear. The possible explanation may rely on a peculiar vascular vulnerability of migraineurs that may contribute to the pathogenesis of migraine and, in the presence of some other unknown factors may also contribute, over time, to the development of cardiovascular disease. At the moment, there are no reliable features that may indicate which subjects, across the overall migraine population, will develop vascular events and so far, no drugs are recommended for the vascular prevention in migraineurs unless other clear indications are present. In general, the acute treatment and the secondary prevention measures of a patient with stroke who has a history of migraine do not differ from that of other stroke patients. There is currently no direct evidence to support that a migraine prophylactic treatment will reduce future stroke risk in secondary prevention.  相似文献   
82.
Aims: The aim of this study was to examine 24 cases of obstetric brachial plexus palsy (OBPP) in 41,002 deliveries occurred at San Camillo–Forlanini Hospital in Rome, during the period 2000–2012.

Materials and methods: A population-based retrospective case-control study was designed and the database of the hospital was searched; for each case, maternal and fetal records were examined and some risk factors were evaluated.

Results: A statistically significant association between the 24 cases OBPP and the following risk factors: primiparity (p?p?p?p?p?Conclusions: The absence of OBPP cases in cesarean deliveries highlighted in this study supports the option of proposing an elective cesarean in the presence of known risk factors after a full disclosure with the mother of risks and benefits in order to obtain a valid consent. Furthermore, when cases of OBPP occur, communication between the physician and the parents of newborns is crucial and it may represent a valid risk-management tool to reduce malpractice lawsuits.  相似文献   
83.
There are no clear recommendations regarding cirrhotic cardiomyopathy (CC) evaluation in patients with pre-transplant liver cirrhosis. The roles of new methods, tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE) in the diagnosis and prognosis of cirrhotic cardiomyopathy remain controversial. We investigated the utility of TDI/STE parameters in cirrhotic cardiomyopathy diagnosis and also in predicting mortality in patients with liver cirrhosis. Left/right ventricular function was studied using conventional TDI (velocities) and STE (strain/strain rate). We assessed left ventricular diastolic dysfunction, graded into four new classes (I/Ia/II/III). Serum NTproBNP (N-terminal prohormone of brain natriuretic peptide), troponin I, β-crosslaps, QTc interval, arterial compliance and endothelial function were measured. Liver-specific scores (Child–Pugh, MELD, MELDNa) were computed. There was a 1-y follow-up visit to determine mortality. We observed resting biventricular diastolic myocardial dysfunction, not presently included in the definition of cirrhotic cardiomyopathy. We provided an improved characterization of cardiac dysfunction in patients with liver cirrhosis. This might change the current definition. However, the utility of STE/TDI parameters in predicting long-term mortality in patients with liver cirrhosis remains controversial.  相似文献   
84.
85.
Brain Imaging and Behavior - The neural correlates of action language processing are still debated within embodied cognition research and little is known about the flexible involvement of...  相似文献   
86.
Epidermal growth factor receptor (EGFR) is a transmembrane glycoprotein with tyrosine-kinase signaling activity, involved in many cellular functions including cell growth and differentiation. Germ line loss-of-function mutations in EGFR lead to a severe neonatal skin disorder (Online Mendelian Inheritance in Man #131550). We report 18 premature Roma children from 16 families with birthweights ranging 440–1470 g and multisystem diseases due to the homozygous mutation c.1283G˃A (p.Gly428Asp) in EGFR. They presented with thin, translucent, fragile skin (14/15), skin desquamation (10/17), ichthyosis (9/17), recurrent skin infections and sepsis (9/12), nephromegaly (10/16) and congenital heart defects (7/17). Their prognosis was poor, and all died before the age of 6 months except one 13-year-old boy with a severe skin disorder, dentinogenesis imperfecta, Fanconi-like syndrome and secondary hyperaldosteronism. Management of ion and water imbalances and extremely demanding skin care may improve the unfavorable outcome of such patients.  相似文献   
87.
Oro-antral communications (OAC) greater than 4-5mm in diameter can seldom be counted on to heal spontaneously without the necessity for surgical closure. The initial experience in applying an absorbable polyglactin/polydioxanon implant (Ethisorb®), in non-surgical closure of OAC ranging from 5 to 7 mm in diameter, is presented. Twelve patients of varying ages with OAC up to72 h in duration, have been treated with Ethisorb®. Failures were not demonstrated in the form of the creation of an oro-antral fistula (OAF), and in all patients, OAC-s were closed with the epithelization of post-extraction wounds up to 21 days after implantation of Ethisorb®. Based on these initial encouraging results, we propose that an Ethisorb® biopolymeric absorbable implant can be used in selected clinical cases for non-surgical closure of OAC.  相似文献   
88.
Our aim was to evaluate the link between diffusion parameters measured by intravoxel incoherent motion (IVIM) diffusion‐weighted imaging (DWI) and the perfusion metrics obtained with dynamic contrast‐enhanced (DCE) MRI in soft tissue tumors (STTs). Twenty‐eight patients affected by histopathologically confirmed STT were included in a prospective study. All patients underwent both DCE MRI and IVIM DWI. The perfusion fraction f, diffusion coefficient D and perfusion‐related diffusion coefficient D* were estimated using a bi‐exponential function to fit the DWI data. DCE MRI was acquired with a temporal resolution of 3–5 s. Maps of the initial area under the gadolinium concentration curve (IAUGC), time to peak (TTP) and maximum slope of increase (MSI) were derived using commercial software. The relationships between the DCE MRI and IVIM DWI measurements were assessed by Spearman's test. To exclude false positive results under multiple testing, the false discovery rate (FDR) procedure was applied. The Mann–Whitney test was used to evaluate the differences between all variables in patients with non‐myxoid and myxoid STT. No significant relationship was found between IVIM parameters and any DCE MRI parameters. Higher f and D*f values were found in non‐myxoid tumors compared with myxoid tumors (p = 0.004 and p = 0.003, respectively). MSI was significantly higher in non‐myxoid tumors than in myxoid tumors (p = 0.029). From the visual assessments of single clinical cases, both f and D*f maps were in satisfactory agreement with DCE maps in the extreme cases of an avascular mass and a highly vascularized mass, whereas, for tumors with slight vascularity or with a highly heterogeneous perfusion pattern, this association was not straightforward. Although IVIM DWI was demonstrated to be feasible in STT, our data did not support evident relationships between perfusion‐related IVIM parameters and perfusion measured by DCE MRI. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   
89.

Background/Objectives

A few studies have documented the effect of local anesthesia for minor dermatologic surgical procedures on children and their parents. Our objective was to evaluate the psychological effect and global satisfaction of a patient‐centered approach to dermatologic surgery under local anesthesia.

Methods

Two self‐administered questionnaires were used to evaluate the distress and global satisfaction of 388 children who underwent dermatologic surgery under local anesthesia, accompanied by oral and written therapeutic education measures (structured information and a cartoon brochure illustrating the procedure) addressed to children and parents. Distraction techniques were also used during the procedures.

Results

Although 54.5% of patients manifested some degree of fear, all other parameters analyzed (pain, surgery‐related distress, surgical team–patient and –family relationship, global satisfaction) indicated that the procedures resulted in limited distress and that the large majority of children and parents tolerated them well.

Conclusion

Specific measures for therapeutic pediatric patient education may be helpful in limiting discomfort, anxiety, and pain perception linked to procedures performed under local anesthesia. Further controlled studies are required to more precisely assess the benefits of specific therapeutic education measures.  相似文献   
90.
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