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   1789篇
  免费   145篇
  2023年   4篇
  2022年   11篇
  2021年   27篇
  2020年   20篇
  2019年   26篇
  2018年   43篇
  2017年   28篇
  2016年   48篇
  2015年   78篇
  2014年   77篇
  2013年   131篇
  2012年   138篇
  2011年   135篇
  2010年   100篇
  2009年   90篇
  2008年   138篇
  2007年   122篇
  2006年   110篇
  2005年   110篇
  2004年   101篇
  2003年   90篇
  2002年   80篇
  2001年   9篇
  2000年   19篇
  1999年   20篇
  1998年   23篇
  1997年   16篇
  1996年   12篇
  1995年   10篇
  1994年   15篇
  1993年   14篇
  1992年   10篇
  1991年   10篇
  1990年   9篇
  1989年   7篇
  1988年   6篇
  1987年   3篇
  1986年   4篇
  1985年   4篇
  1984年   3篇
  1983年   5篇
  1982年   4篇
  1981年   3篇
  1980年   8篇
  1979年   4篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1974年   2篇
  1972年   1篇
排序方式: 共有1934条查询结果,搜索用时 46 毫秒
41.
42.
43.
Allergy to citrus fruits is often associated with pollinosis and sensitization to other plants due to a phenomenon of cross-reactivity. The aims of the present study were to highlight the cross-reactivity among citrus and the major allergenic pollens/fruits, throughout clinical and molecular investigations, and to evaluate the sensitization frequency to citrus fruits in a population of children and adults with pollinosis. We found a relevant percentage of sensitisation (39%) to citrus fruits in the patients recruited and in all of them the IgE-mediated mechanism has been confirmed by the positive response to the prick-to-prick test. RT-PCR experiments showed the expression of Cit s 1, Cit s 3 and a profilin isoform, already described in apple, also in Citrus clementine pollen. Data of multiple sequence alignments demonstrated that Citrus allergens shared high percentage identity values with other clinically relevant species (i.e. Triticum aestivum, Malus domestica), confirming the possible cross-allergenicity citrus/grasses and citrus/apple. Finally, a novelty of the present work has been the expression of two phospholipaseA2 isoforms (PLA2 α and β) in Citrus as well as in Triticum pollens; being PLA2 able to generate pro-inflammatory factors, this enzyme could participate in the activation of the allergenic inflammatory cascade.  相似文献   
44.
Oxidative stress is considered the common effector of the cascade of degenerative events in many neurological conditions. Thus, in this paper we tested different nutraceuticals in H2O2 in vitro model to understand if could represent an adjuvant treatment for neurological diseases. In this study, nutraceuticals bacopa, lycopene, astaxanthin, and vitamin B12 were used alone or in combination in human neuronal differentiated SH-SY5Y cells upon hydrogen peroxide-induced injury and neuroprotective, neuronal death pathways were analyzed. The nutraceuticals analyzed were able to protect H2O2 cytotoxic effects, through increasing cell viability and proteins involved in neuroprotection pathways and restoring proteins involved in cell death pathways. On this basis, it is possible to propose the use of these compounds as dietary supplement for the prevention or as adjuvant to the only symptomatic treatments so far available for neurodegenerative diseases.  相似文献   
45.
46.
Tinea capitis (TC) is the most common type of dermatophytosis in children. The epidemiology of TC depends on the geographical areas, and it changes over time. The aim of the study is to determine the incidence of TC and to identify the causative species in children observed at Dermatology Outpatient Department of the University of Milan, Italy, between January 2004 and December 2011. Four hundred and eighty-six children with suspected dermatomycosis were observed; TC was the most prevalent dermatomycoses with 86 cases. The most common isolated dermatophyte in scalp lesions was Trichophyton violaceum with 33 cases. The most recent epidemiological Italian studies still show zoophilic fungi as primary cause of TC. We are the first medical team in Italy to demonstrate a dominance of anthropophilic fungi, in particular T. violaceum.  相似文献   
47.
48.
The present study was undertaken to investigate the existence of intraocular pressure (IOP) rhythms in athletic thoroughbred horses maintained under a 24 h cycle of light and darkness (LD) or under constant light (LL) or constant dark (DD) conditions. We identified an IOP circadian rhythm that is entrained to the 24 h LD cycle. IOP was low during the dark phase and high during the light phase, with a peak at the end of the light phase (ZT10). The circadian rhythm of IOP persisted in DD (with a peak at CT9.5), demonstrating an endogenous component in IOP rhythm. As previously shown in other mammalian species, horse IOP circadian rhythmicity was abolished in LL. Because tonometry is performed in horses for the diagnosis of ophthalmologic diseases, such as glaucoma or anterior uveitis, the daily variation in IOP must be taken into account in clinical practice to properly time tests and to interpret clinical findings.  相似文献   
49.
This article focuses on ageing in transnationalism. Drawing on the experiences of Italians in the UK as a paradigmatic example of settled European migrants, it explores the lived experiences of this group of older migrants. Using Levitt and Glick Schiller's framework, it concentrates first on migrants' ways of being and then on their ways of belonging. The article argues that a transnational lens is necessary to understand the experiences of older migrants and that a focus on older people needs to be incorporated into studies of transnationalism. Through a discussion of their narratives and experiences, the article offers a long view on the migration process and brings attention to the significance of gender, time and the life course to understand both migrants' transnationalism and their integration.  相似文献   
50.
Intellectual disability in Down syndrome (DS) appears to be related to severe proliferation impairment during brain development. Recent evidence shows that it is not only cellular proliferation that is heavily compromised in DS, but also cell fate specification and dendritic maturation. The amyloid precursor protein (APP), a gene that is triplicated in DS, plays a key role in normal brain development by influencing neural precursor cell proliferation, cell fate specification, and neuronal maturation. APP influences these processes via two separate domains, the APP intracellular domain (AICD) and the soluble secreted APP. We recently found that the proliferation impairment of neuronal precursors (NPCs) from the Ts65Dn mouse model for DS was caused by derangement of the Shh pathway due to overexpression of patched1(Ptch1), its inhibitory regulator. Ptch1 overexpression was related to increased levels within the APP/AICD system. The overall goal of this study was to determine whether APP contributes to neurogenesis impairment in DS by influencing in addition to proliferation, cell fate specification, and neurite development. We found that normalization of APP expression restored the reduced neuronogenesis, the increased astrogliogenesis, and the reduced neurite length of trisomic NPCs, indicating that APP overexpression underpins all aspects of neurogenesis impairment. Moreover, we found that two different domains of APP impair neuronal differentiation and maturation in trisomic NPCs. The APP/AICD system regulates neuronogenesis and neurite length through the Shh pathway, whereas the APP/secreted AP system promotes astrogliogenesis through an IL-6-associated signaling cascade. These results provide novel insight into the mechanisms underlying brain development alterations in DS.  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