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   667篇
  免费   36篇
  国内免费   4篇
耳鼻咽喉   3篇
儿科学   13篇
妇产科学   5篇
基础医学   74篇
口腔科学   15篇
临床医学   59篇
内科学   130篇
皮肤病学   2篇
神经病学   84篇
特种医学   61篇
外科学   99篇
综合类   7篇
预防医学   34篇
眼科学   4篇
药学   77篇
中国医学   11篇
肿瘤学   29篇
  2023年   9篇
  2022年   17篇
  2021年   23篇
  2020年   17篇
  2019年   21篇
  2018年   29篇
  2017年   16篇
  2016年   27篇
  2015年   19篇
  2014年   20篇
  2013年   43篇
  2012年   55篇
  2011年   81篇
  2010年   40篇
  2009年   30篇
  2008年   52篇
  2007年   39篇
  2006年   42篇
  2005年   33篇
  2004年   31篇
  2003年   22篇
  2002年   18篇
  2001年   6篇
  2000年   2篇
  1999年   4篇
  1997年   3篇
  1996年   2篇
  1995年   2篇
  1991年   2篇
  1983年   1篇
  1982年   1篇
排序方式: 共有707条查询结果,搜索用时 15 毫秒
701.

Background

Recently few studies tried to confirm the association between AF and lipoprotein(a) (Lp(a)), however the results remained conflicted. In present study we evaluated the possible interaction between Lp(a), inflammatory state and echocardiographic characteristics in patients after successful electrical cardioversion (EC) of persistent AF. We also tried to investigate the role of Lp(a) as a possible prognostic factor for AF recurrence after successful EC.

Results

Data of 79 patients admitted due to planned EC was analyzed. After successful procedure patients were monitored for 2 years. For analytical purposes patients were divided in two groups according to AF recurrence. There was no significant difference between Lp(a) levels in both groups. We also didn't find any positive correlation between Lp(a) and CRP levels, as well as between Lp(a) levels and left atrium diameter. For logistic and survival analysis optimal cut-off value of Lp(a) ≥ 0.32 (upper quartile) was used. In logistic regression model with AF recurrence as dependent variable Lp(a) didn't show any statistically significant association with AF recurrence. Survival analysis showed slightly higher AF recurrence rate in group with higher Lp(a) levels but not to the level of statistical significance (log rank test, p = 0.62).

Conclusions

We weren't able to confirm the association between Lp(a) levels and AF recurrence, inflammation and left atrium diameter in patients after successful EC of persistent AF. Further studies are needed to elucidate the role of Lp(a) in this clinical setting.  相似文献   
702.
Intense seizure activity associated with status epilepticus and excitatory amino acid (EAA) imbalance initiates oxidative damage and neuronal injury in CA1 of the ventral hippocampus. We tested the hypothesis that dendritic degeneration of pyramidal neurons in the CA1 hippocampal area resulting from seizure-induced neurotoxicity is modulated by cerebral oxidative damage. Kainic acid (KA, 1 nmol/5 microl) was injected intracerebroventricularly to C57Bl/6 mice. F2-isoprostanes (F2-IsoPs) and F4-neuroprostanes (F4-NeuroPs) were used as surrogate measures of in vivo oxidative stress and biomarkers of lipid peroxidation. Nitric oxide synthase (NOS) activity was quantified by evaluating citrulline level and pyramidal neuron dendrites and spines were evaluated using rapid Golgi stains and a Neurolucida system. KA produced severe seizures in mice immediately after its administration and a significant (p<0.001) increase in F2-IsoPs, F4-NeuroPs and citrulline levels were seen 30 min following treatment. At the same time, hippocampal pyramidal neurons showed significant (p<0.001) reduction in dendritic length and spine density. In contrast, no significant change in neuronal dendrite and spine density or F2-IsoP, F4-NeuroPs and citrulline levels were found in mice pretreated with vitamin E (alpha-tocopherol, 100mg/kg, i.p.) for 3 days, or with N-tert-butyl-alpha-phenylnitrone (PBN, 200mg/kg, i.p.) or ibuprofen (inhibitors of cyclooxygenase, COX, 14 microg/ml of drinking water) for 2 weeks prior to KA treatment. These findings indicate novel interactions among free radical-induced generation of F2-IsoPs and F4-NeuroPs, nitric oxide and dendritic degeneration, closely associate oxidative damage to neuronal membranes with degeneration of the dendritic system, and point to possible interventions to limit severe damage in acute neurological disorders.  相似文献   
703.
Deoxycholic acid-derived tetraoxane antimalarials and antiproliferatives(1)   总被引:1,自引:0,他引:1  
The synthesis of deoxycholic acid (DCA)- and cholic acid (CA)-derived mixed tetraoxanes revealed that N-(2-dimethylamino)ethyl derivatives are potent antimalarials in vitro and in vivo. The tetraoxanes presented in this paper are dual inhibitors: besides curing mice in vivo without observed toxic effects, they kill cancer cell lines at very low concentrations. For example, DCA and CA derivatives 16 and 25 cured 3/5 (160 mg/kg/day) and 2/5 (40 mg/kg/day, MTD >960 mg/kg), respectively, and they were extremely active against melanoma LOX IMVI cancer, LC50 = 22 nM and 69 nM, respectively.  相似文献   
704.
Lumbosacral vertebral abnormalities are a common association of anorectal malformations (ARMs) and are one of the determinants of the eventual level of fecal continence that can be achieved. This study used a fetal rat model to investigate the spectrum of axial skeletal maldevelopment that may occur with ARMs. Time-mated pregnant rats received 125 mg/kg of 1% ethylenethiourea (ETU) (experimental group) or vehicle only (control). Their fetuses were examined for external malformations and prepared for staining of their skeletons using Alcian blue and Alizarin red S. ARMs developed in 67/68 (98%) of ETU-exposed fetuses, of which 28 (42%) also developed rachischisis, mainly involving the lumbosacral vertebrae. No skeletal abnormality was found in control fetuses. ETU-exposed fetuses with ARMs and rachischisis had abnormal ossification of the vertebral centrum, abnormal fusion between the neural arches of vertebrae, localized narrow or interrupted thoracic vertebral canal, a widely open vertebral canal in the lumbosacral area (rachischisis), and absence of the lower two sacral and coccygeal vertebrae. Rib abnormalities included absence of two to three floating ribs, abnormal fusion of adjacent proximal segments, and abnormal ramification, irregularity, and angulation of their distal segments. The vertebral and rib abnormalities found in ETU-exposed fetuses with ARMs but no rachischisis were much less severe. In addition to the lumbosacral anomalies that are common with ARMs, severe abnormalities of the thoracic vertebrae and their corresponding ribs may occur also. Fetuses with both ARM and rachischisis tend to have more extensive and severe vertebral and rib anomalies. These observations imply a possible common aetiology for ARMs and vertebral anomalies and are consistent with our understanding of the perceived role of the notochord in axial development.  相似文献   
705.
Rehabilitation with augmented electrical stimulation can enhance functional recovery after stroke, and cortical plasticity may play a role in this process. The purpose of this study was to compare the effects of three training paradigms on cortical excitability in healthy subjects. Cortical excitability was evaluated by analysing the input–output relationship between transcranial magnetic stimulation intensity and motor evoked potentials (MEPs) from the flexor muscles of the fingers. The study was performed with 25 healthy volunteers who underwent 20-min simulated therapy sessions of: (1) functional electrical stimulation (FES) of the finger flexors and extensors, (2) voluntary movement (VOL) with sensory stimulation, and (3) therapeutic FES (TFES) where the electrical stimulation augmented voluntary activation. TFES training produced a significant increase in MEP magnitude throughout the stimulation range, suggesting an increase in cortical excitability. In contrast, neither the FES nor voluntary movement alone had such an effect. These results suggest that the combination of voluntary effort and FES has greater potential to induce plasticity in the motor cortex and that TFES might be a more effective approach in rehabilitation after stroke than FES or repetitive voluntary training alone.  相似文献   
706.
Chronic low-frequency stimulation (CLFS) of rat fast-twitch muscles induces sequential transitions in myosin heavy chain (MHC) expression from MHCIIb MHCIId/x MHCIIa. However, the final step of the fast-to-slow transition, i.e., the upregulation of MHCI, has been observed only after extremely long stimulation periods. Assuming that fibre degeneration/regeneration might be involved in the upregulation of slow myosin, we investigated the effects of CLFS on extensor digitorum longus (EDL) muscles regenerating after bupivacaine-induced fibre necrosis. Normal, non-regenerating muscles responded to both 30- and 60-day CLFS with fast MHC isoform transitions (MHCIIb MHCIId MHCIIa) and only slight increases in MHCI. CLFS of regenerating EDL muscles caused similar transitions among the fast isoforms but, in addition, caused significant increases in MHCI (to 30% relative concentration). Stimulation periods of 30 and 60 days induced similar changes in the regenerating bupivacaine-treated muscles, indicating that the upregulation of slow myosin was restricted to regenerating fibres, but only during an early stage of regeneration. These results suggest that satellite cells and/or regenerating fast rat muscle fibres are capable of switching directly to a slow program under the influence of CLFS and, therefore, appear to be more malleable than adult fibres.  相似文献   
707.
IntroductionThe aim was to evaluate patients’ perception of function and physical and mental dimensions of health-related quality of life (HRQoL) in patients with end-stage knee or hip osteoarthritis (OA) immediately prior to surgery and to identify the factors associated with the outcomes.Material and methodsThe study included 200 patients with end-stage OA (100 knee OA and 100 hip OA patients). Self-reported physical function was assessed using the Oxford Knee Score or Oxford Hip Score. Physical and mental dimensions of HRQoL were assessed using the physical and mental component summary scores of the 36-Item Short-Form Health Survey. Multivariate linear regression analysis was used to identify the sociodemographic, clinical and psychological factors associated with self-reported function and physical and mental dimensions of HRQoL.ResultsEnd-stage knee or hip OA patients had poor function and physical dimension of HRQoL, while the mental dimension of HRQoL was not impaired. In knee OA, pain, flexion range of motion (ROM), catastrophizing, and anxiety were significantly associated with self-reported function (explained 56% of the variance), whereas catastrophizing explained 10% of the variance of the physical dimension of HRQoL. In hip OA, flexion ROM, catastrophizing and being employed were significantly associated with self-reported function (explained 44% of the variance), whereas catastrophizing and flexion ROM explained 34% of the variance of the physical dimension of HRQoL.ConclusionsMany investigated factors were associated with poor self-reported function and HRQoL in knee and hip OA. However, the most important factors for both knee and hip OA were catastrophizing and flexion ROM.  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