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   436篇
  免费   25篇
  国内免费   1篇
耳鼻咽喉   1篇
儿科学   10篇
妇产科学   6篇
基础医学   47篇
口腔科学   28篇
临床医学   34篇
内科学   79篇
皮肤病学   5篇
神经病学   55篇
特种医学   16篇
外科学   61篇
综合类   7篇
预防医学   6篇
眼科学   19篇
药学   58篇
中国医学   2篇
肿瘤学   28篇
  2023年   6篇
  2022年   8篇
  2021年   32篇
  2020年   18篇
  2019年   21篇
  2018年   26篇
  2017年   14篇
  2016年   25篇
  2015年   20篇
  2014年   25篇
  2013年   27篇
  2012年   44篇
  2011年   42篇
  2010年   28篇
  2009年   18篇
  2008年   31篇
  2007年   30篇
  2006年   22篇
  2005年   5篇
  2004年   3篇
  2003年   8篇
  2002年   4篇
  2000年   1篇
  1999年   2篇
  1997年   2篇
排序方式: 共有462条查询结果,搜索用时 486 毫秒
61.
62.
Surgical repair of acquired tracheo-esophageal fistula may result in tracheal stenosis or esophageal stricture. We used fistula with esophageal cuff as flap to repair the tracheal defect. Esophageal repair was performed by rotating ends through 90° in opposite direction. This technique offers excellent repair in a single stage.  相似文献   
63.
64.
Neuroimaging studies have identified alterations in frontostriatal circuitry in obsessive-compulsive disorder (OCD). Voxel-based morphometry (VBM) allows for the assessment of differences in gray matter density across the whole brain. VBM has not previously been used to examine regional gray matter density in pediatric OCD patients and the siblings of pediatric OCD patients. Volumetric magnetic resonance imaging (MRI) studies were conducted in 10 psychotropic naïve pediatric patients with OCD, 10 unaffected siblings of pediatric patients with OCD, and 10 healthy controls. VBM analysis was conducted using SPM2. Statistical comparisons were performed with the general linear model, implementing small volume random field corrections for a priori regions of interest (anterior cingulate cortex or ACC, striatum and thalamus). VBM analysis revealed significantly lower gray matter density in OCD patients compared to healthy in the left ACC and bilateral medial superior frontal gyrus (SFG). Furthermore, a small volume correction was used to identify a significantly greater gray matter density in the right putamen in OCD patients as compared to unaffected siblings of OCD patients. These findings in patients, siblings, and healthy controls, although preliminary, suggest the presence of gray matter structural differences between affected subjects and healthy controls as well as between affected subjects and individuals at risk for OCD.  相似文献   
65.
Nectin-1 is an adherens junction protein that serves as an entry receptor for neurotropic herpes simplex virus (HSV). The expression of nectin-1 in the central nervous system (CNS) has not been well defined. Furthermore, it is not known whether HSV infection has an effect on nectin-1 expression in the brain. To better understand nectin-1 expression in normal and HSV-infected brain, the authors used immunohistochemistry to characterize the expression of nectin-1 in brain tissue of uninfected adult mice and mice infected with HSV-1. In the CNS of untreated and mock-infected mice, virtually all neurons, ependymal cells, choroid plexus epithelial cells, meningothelial cells, and vascular endothelial cells expressed nectin-1. Many oligodendrocytes, astrocytes, and vascular smooth muscle cells also demonstrated nectin-1 expression, but a minority of these cells did not stain for nectin-1. Brain tissue derived from mice euthanized 5 to 8 days after intracerebral inoculation of HSV-1 showed inflammation and widespread expression of HSV-1 proteins in neurons. In HSV-1-infected brains, many inflammatory cells showed nectin-1 expression and neuronal nectin-1 staining showed a wider variation in signal strength than that detected in uninfected tissues. Many neurons showing nuclear fragmentation consistent with the morphologic appearance of apoptosis showed little or no evidence of nectin-1 expression, whereas occasional neurons stained more intensely positive for nectin-1 than those in uninfected brain tissue. These findings confirm and extend previous observations of nectin-1 expression in the nervous system and suggest that HSV-1 infection leads to changes in nectin-1 expression in the CNS, which may contribute to HSV-induced pathology and dissemination.  相似文献   
66.
Cells of the osteoblast lineage are increasingly identified as participants in whole‐body metabolism by primarily targeting pancreatic insulin secretion or consuming energy. Osteocytes, the most abundant bone cells, secrete a Wnt‐signaling inhibitor called sclerostin. Here we examined three mouse models expressing high sclerostin levels, achieved through constitutive or inducible loss of the stimulatory subunit of G‐proteins (Gsα in mature osteoblasts and/or osteocytes). These mice showed progressive loss of white adipose tissue (WAT) with tendency toward increased energy expenditure but no changes in glucose or insulin metabolism. Interestingly beige adipocytes were increased extensively in both gonadal and inguinal WAT and had reduced canonical β‐catenin signaling. To determine if sclerostin directly contributes to the increased beige adipogenesis, we engineered an osteocytic cell line lacking Gsα which has high sclerostin secretion. Conditioned media from these cells significantly increased expression of UCP1 in primary adipocytes, and this effect was partially reduced after depletion of sclerostin from the conditioned media. Similarly, treatment of Gsα‐deficient animals with sclerostin‐neutralizing antibody partially reduced the increased UCP1 expression in WAT. Moreover, direct treatment of sclerostin to wild‐type mice significantly increased UCP1 expression in WAT. These results show that osteocytes and/or osteoblasts secrete factors regulating beige adipogenesis, at least in part, through the Wnt‐signaling inhibitor sclerostin. Further studies are needed to assess metabolic effects of sclerostin on adipocytes and other metabolic tissues. © 2016 American Society for Bone and Mineral Research.  相似文献   
67.
This study aims to develop amorphous solid dispersion (ASD) of lumefantrine with a cost-effective approach of spray anti-solvent precipitation. Four acidic polymers, hydroxypropylmethylcellulose phthalate (HPMCP), hydroxypropylmethylcellulose acetate succinate (HPMCAS), poly(methacrylic acid–ethyl acrylate) (EL100) and cellulose acetate phthalate (CAP) were studied as excipients at various drug-polymer ratios. Of the studied polymers, satisfactory physical stability was demonstrated for HPMCP- and HPMCAS-based ASDs with no observed powder X-ray diffraction peaks for up to 3 months of storage at 40 °C/75% RH. HPMCP and HPMCAS ASDs also achieved greater drug release levels in the dissolution study than other polymers. The HPMCP-based ASDs with a drug:polymer ratio of 2:8 exhibited a maximum drug release of 140 μg/mL for up to 2 h, which is significantly higher than the currently marketed formulation of Coartem® (<80 ng/mL). Relatively, the CAP and EL100 ASDs indicated a higher water content and crystallized within a day when stored at 40 °C/75% RH. The choice of polymer, and the drug-polymer ratio played a crucial role in the solubility enhancement of lumefantrine. Our study indicates that the developed spray anti-solvent precipitation method could be an affordable approach for producing ASDs.  相似文献   
68.

Background

Pharyngoesophageal stricture (PES) is an Achilles’ heel in the management of corrosive injury. Advances in endoscopic techniques were utilized in its management. We classified the stricture as per its dilatability and then planned their treatment.

Methods

PES was sub-categorized based on endoscopic dilatation and availability of cervical oesophagus: group-1 stricture with available cervical oesophagus; group-2 stricture with some part of upper oesophagus made available after endoscopic dilatation and anastomosis in cervico-pharyngeal area; group-3 stricture not amenable for dilatation, anastomosis done at the pharynx. Endoscopic dilatation was performed using through-the-scope pyloric balloon. Number and duration of dilatation sessions before surgery, incidence of tracheostomy, time and incidence for re-stricture and present status of swallowing were evaluated.

Results

Of 226 patients managed, 46 underwent oesophageal replacement for PES. Group 1, 2 and 3 had 12, 14 and 20 patients, respectively. An average 3 (2–4) preoperative balloon dilatation sessions were performed over 6–8 weeks. Tracheostomy was required in 1, 0, 8 patients (p = 0.010), and median hospital stay was 10, 9 and 13 days (p = 0.09) in group 1, 2, 3, respectively. Re-stricture developed in 4/12, 4/14, 9/20 patients with average sessions of dilatation required in post-operative period was 4, 3.5 and 8 in group 1, 2, 3, respectively. >90% of patients are taking normal diet in each group.

Conclusion

We attempted to avoid the high anastomosis by dilating the PES and step down the level of anastomosis in two-third patients. We thereby avoided tracheostomy, aspiration and swallowing problems related to high strictures.
  相似文献   
69.
Our aim in the present investigation was to develop a nanoparticulate carrier of amphotericin B (AmB) for controlled delivery as well as reduced toxicity. Nanoparticles of different gelatins (GNPs) (type A or B) were prepared by two-step desolvation method and optimized for temperature, pH, amount of cross-linker, and theoretical drug loading. AmB-loaded GNPs were characterized for size, polydispersity index (PI), shape, morphology, surface charge, drug release, and hemolysis. The developed GNPs (GNP(A300)) were found to be of nanometric size (213 +/- 10 nm), having low PI (0.092 +/- 0.015) and good entrapment efficiency (49.0 +/- 2.9%). All GNPs showed biphasic release characterized by an initial burst followed by controlled release. The in vivo hematological toxicity results suggest nonsignificant reduction (P > .05) in hemoglobin concentration and hematocrit. Nephrotoxicity results showed that there was a nonsignificant (P > .05) increase in blood urea nitrogen and serum creatinine levels. The results confirm that developed GNPs could optimize AmB delivery in terms of cost and safety, and type A gelatin with bloom number 300 was found suitable for such preparation.  相似文献   
70.

Objectives:

The present study was undertaken to investigate the effect of the ethanolic extract of Allium sativum L. (Family: Lilliaceae), commonly known as garlic, on depression in mice.

Materials and Methods:

Ethanolic extract of garlic (25, 50 and 100 mg/kg) was administered orally for 14 successive days to young Swiss albino mice of either sex and antidepressant-like activity was evaluated employing tail suspension test (TST) and forced swim test (FST). The efficacy of the extract was compared with standard antidepressant drugs like fluoxetine and imipramine. The mechanism of action of the extract was investigated by co-administration of prazosin (α1-adrenoceptor antagonist), sulpiride (selective D2-receptor antagonist), baclofen (GABAB agonist) and p-CPA (serotonin antagonist) separately with the extract and by studying the effect of the extract on brain MAO-A and MAO-B levels.

Results:

Garlic extract (25, 50 and 100 mg/kg) significantly decreased immobility time in a dose-dependent manner in both TST and FST, indicating significant antidepressant-like activity. The efficacy of the extract was found to be comparable to fluoxetine (20 mg/kg p.o.) and imipramine (15 mg/kg p.o.) in both TST and FST. The extract did not show any significant effect on the locomotor activity of the mice. Prazosin, sulpiride, baclofen and p-CPA significantly attenuated the extract-induced antidepressant-like effect in TST. Garlic extract (100 mg/kg) administered orally for 14 successive days significantly decreased brain MAO-A and MAO-B levels, as compared to the control group.

Conclusion:

Garlic extract showed significant antidepressant-like activity probably by inhibiting MAO-A and MAO-B levels and through interaction with adrenergic, dopaminergic, serotonergic and GABAergic systems.  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