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   45篇
  免费   5篇
基础医学   12篇
临床医学   1篇
内科学   14篇
神经病学   6篇
外科学   4篇
预防医学   4篇
药学   7篇
肿瘤学   2篇
  2022年   1篇
  2021年   3篇
  2019年   1篇
  2018年   5篇
  2017年   1篇
  2016年   4篇
  2015年   1篇
  2014年   2篇
  2013年   3篇
  2012年   3篇
  2011年   2篇
  2010年   2篇
  2009年   3篇
  2008年   2篇
  2007年   2篇
  2006年   2篇
  2004年   1篇
  2003年   1篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1991年   1篇
  1987年   2篇
  1930年   1篇
  1907年   1篇
  1899年   1篇
  1861年   1篇
  1854年   1篇
排序方式: 共有50条查询结果,搜索用时 29 毫秒
1.
Copper, manganese and zinc were measured by flameless atomic absorption spectrophotometry in the developing brain of normal and quaking mice. The latter is a neurological mutant presenting early arrest of myelination. Copper concentration was increased by 200% between 10 and 20 days after birth and then leveled off in adult mice. Manganese concentration increased both in control mice and in quaking mice from 3 to 20 days by 200% and then decreased by 19% in control mice and 24% in quaking mice at adult age. Zinc increased by 93% in control and 173% in quaking mice between 10 and 20 days of age, and then progressively declined until 62 days. The mouse brain accumulates considerably all the 3 metals during early development. During the first 20 days, the augmentation is 6-fold for copper, 5-fold for manganese and 5.5-fold for zinc. In quaking, alterations are not very important.  相似文献   
2.

Sexual fantasies represent a vast and highly personal dimension of human sexuality that remains understudied empirically. This article used a person-oriented approach to examine the reactions of arousal and discomfort that individuals experienced in response to four proposed fantasy scenarios depicting themes of romance, power dynamics (i.e., submission and domination), pain (i.e., sadism and masochism), and sexual violence. Using an online sample of 566 adult participants (250 men and 291 women) from the general population of Canada and the U.S., four classes were identified based on reactions of arousal and discomfort toward the proposed scenarios: Indifferent (relatively low arousal and discomfort to all scenarios, 37%), Romantic (high arousal solely for the romance scenario, high discomfort toward other scenarios, 22%), Enthusiastic (high arousal and low discomfort in response to all scenarios, 26%), and Dissonant (relatively high arousal and discomfort toward all scenarios, 15%). These classes were then compared to examine differences in terms of the following psychosexual characteristics: gender, experiences of childhood sexual abuse, sexual compulsion, and romantic attachment. Findings illustrated distinct patterns of reactions toward fantasies and confirmed the presence of links between reactions toward sexual fantasies, psychosexual characteristics, and traumatic life experiences. This suggests that the relationship between individuals and their sexual fantasies may be indicative of their overall relationship with sexuality.

  相似文献   
3.
Antiphospholipid syndrome (APS) is characterized by recurrent thrombosis and pregnancy morbidity in association with the persistent presence of circulating antiphospholipid antibodies (aPL). APS remains the most frequent cause of acquired hypercoagulability and recurrent miscarriage. Long-term anticoagulation therapy is the only treatment with proven benefit in the APS. Anticoagulation is not effective in all patients and carries a risk of bleeding. Recent improvements in the understanding of the pathogenic mechanisms have led to the identification of potential targets and future therapies for APS. In contrast to non-specific anticoagulation, the emergence of immunomodulatory drugs provides the possibility of interfering with specific pathogenic pathways. Novel therapies might be used in the future for APS.  相似文献   
4.
5.
Ohne ZusammenfassungIm Wintersemester 1904/5 bat mich Kollege Giovanni Cloëtta aus Bergün um ein Thema für seine Dissertation. Wir kamen überein, dass er während seiner Assistentenzeit in Zürich den Fall K. beobachten und als Ausgangspunkt für seine Arbeit nehmen sollte. Cloëtta hat sich mit Interesse dieser Aufgabe unterzogen und hatte sie nach Antritt seiner Praxis so weit gefördert, dass er binnen kurzem mir einen ersten Entwurf hätte einsenden können. Da starb der liebenswürdige Kollege im September 1906 plötzlich, dem Vernehmen nach an einer foudroyant verlaufenden Septikämie. Ich benutze seine Notizen mit, um unter unser beider Namen die geplante Arbeit zu Ende zu führen. V.  相似文献   
6.
Elevated brain monoamine concentrations resulting from monoamine oxidase A genetic ablation (MAOA knock-out mice) lead to changes in other neurotransmitter systems. To investigate the consequences of MAOA deficiency on the cholinergic system, we measured ligand binding to the high-affinity choline transporter (CHT1) and to muscarinic and nicotinic receptors in brain sections of MAOA knock-out (KO) and wild-type mice. A twofold increase in [3H]-hemicholinium-3 ([3H]-HC-3) binding to CHT1 was observed in the caudate putamen, nucleus accumbens, and motor cortex in MAOA KO mice as compared with wild-type (WT) mice. There was no difference in [3H]-HC-3 labeling in the hippocampus (dentate gyrus) between the two genotypes. Binding of [125I]-epibatidine ([125I]-Epi), [125I]-α-bungarotoxin ([125I]-BGT), [3H]-pirenzepine ([3H]-PZR), and [3H]-AFDX-384 ([3H]-AFX), which respectively label high- and low-affinity nicotinic receptors, M1 and M2 muscarinic cholinergic receptors, was not modified in the caudate putamen, nucleus accumbens, and motor cortex. A small but significant decrease of 19% in M1 binding densities was observed in the hippocampus (CA1 field) of KO mice. Next, we tested acetylcholinesterase activity and found that it was decreased by 25% in the striatum of KO mice as compared with WT mice. Our data suggest that genetic deficiency in MAOA enzyme is associated with changes in cholinergic activity, which may account for some of the behavioral alterations observed in mice and humans lacking MAOA.  相似文献   
7.
Airway epithelial basal cells are known to be critical for regenerating injured epithelium and maintaining tissue homeostasis. Recent evidence suggests that the α7 nicotinic acetylcholine receptor (nAChR), which is highly permeable to Ca2+, is involved in lung morphogenesis. Here, we have investigated the potential role of the α7 nAChR in the regulation of airway epithelial basal cell proliferation and the differentiation of the human airway epithelium. In vivo during fetal development and in vitro during the regeneration of the human airway epithelium, α7 nAChR expression coincides with epithelium differentiation. Inactivating α7 nAChR function in vitro increases cell proliferation during the initial steps of the epithelium regeneration, leading to epithelial alterations such as basal cell hyperplasia and squamous metaplasia, remodeling observed in many bronchopulmonary diseases. The regeneration of the airway epithelium after injury in α7−/− mice is delayed and characterized by a transient hyperplasia of basal cells. Moreover, 1-year-old α7−/− mice more frequently present basal cells hyperplasia. Modulating nAChR function or expression shows that only α7 nAChR, as opposed to heteropentameric αxβy nAChRs, controls the proliferation of human airway epithelial basal cells. These findings suggest that α7 nAChR is a key regulator of the plasticity of the human airway epithelium by controlling basal cell proliferation and differentiation pathway and is involved in airway remodeling during bronchopulmonary diseases.The respiratory epithelium, which is constantly exposed to airborne pollutants, is frequently injured, which results in altered epithelial functions. To restore these functions, the respiratory epithelium must undergo rapid repair via epithelial cell spreading and migration and regenerate its structure via basal cell proliferation and differentiation.1 These processes are tightly controlled to restore the pseudostratified architecture of the normal mucociliary epithelium. However, in most respiratory diseases, alterations of the regeneration processes induce epithelial remodeling such as hyperplasia, metaplasia, and fibrosis. Understanding the sequence of processes involved in cell proliferation and differentiation is therefore of crucial importance. Both in vivo and in vitro, human airway basal cells are able to proliferate and reconstitute a fully differentiated and functional epithelium.2 These cells are such considered as progenitors of the human airway epithelium and important actors of the airway epithelium regeneration.The nonneuronal cholinergic system is thought to be involved in the regulation of cell functions such as cell-cell interaction, apoptosis, and proliferation.3 It is now established that human bronchial epithelial cells contain all of the machinery for the production, storage, secretion, and degradation of acetylcholine, which acts as an autocrine or paracrine hormone.4,5 Acetylcholine exerts its effects through muscarinic and nicotinic acetylcholine receptors. Nicotinic acetylcholine receptors (nAChRs) are composed of five subunits, arranged as α/β heteromeric or α homomeric nAChRs, and assembled around a central ion channel, mediating the influx of Ca2+.6 The airway epithelium expresses α3, α4, α5, α7, α9, β2, and β4 subunits for nAChRs.7,8,9α7 nAChR is characterized by an elevated Ca2+ permeability10 and has been involved in several important biological processes such as cell proliferation, apoptosis, and angiogenesis in cancer.11,12 Prenatal nicotine exposure significantly increases pulmonary α7 nAChR expression and alters fetal lung development13 and subsequently pulmonary function in newborn.14 In particular, alteration of lung branching morphogenesis induced by nicotine is mediated by α7 nAChR.15 Altogether, these observations led us to investigate whether the α7 nAChR could be involved in the differentiation of the respiratory epithelium. In the human airway epithelium, we observed α7 nAChR expression in basal cells, which play a critical role in the epithelial regeneration. Both in vivo and in vitro, the α7 nAChR expression is associated with the airway epithelium differentiation. Moreover, in vitro inactivating α7 nAChR or in vivo disrupting genetic α7 nAChR expression induces airway epithelium remodeling by modulating basal cell proliferation. This study thus provides several lines of evidence that α7 nAChR is significant for airway epithelial differentiation and suggests that α7 nAChR is a key regulator of the plasticity of the airway epithelium.  相似文献   
8.
9.
Nicotine and serotonin modulate the innate and adaptive immune responses and the inflammatory states. Several nicotinic cholinergic and serotonergic receptor subtypes have been characterized in B and T lymphocytes, monocytes, macrophages, and dendritic cells. The use of knockout mice has allowed a better characterization of nicotinic receptors and their role in anti-inflammatory processes in these cells. Cytokines play a crucial role in controlling inflammatory reactions. Nicotine and serotonin have been reported to regulate cytokine release. Cholinergic mechanisms also play an important role in inflammation through endogenous acetylcholine. Nicotine mimics this effect by activating the cholinergic anti-inflammatory pathways. New concepts of reciprocal interactions between nicotine and serotonin are emerging. The role of nicotine as an anti-inflammatory agent has been established, whereas that of serotonin remains more controversial.  相似文献   
10.
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