全文获取类型
收费全文 | 285篇 |
免费 | 26篇 |
出版年
2023年 | 4篇 |
2022年 | 13篇 |
2021年 | 14篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 16篇 |
2015年 | 16篇 |
2014年 | 18篇 |
2013年 | 37篇 |
2012年 | 24篇 |
2011年 | 29篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 18篇 |
2007年 | 8篇 |
2006年 | 13篇 |
2005年 | 13篇 |
2004年 | 4篇 |
2003年 | 6篇 |
2002年 | 9篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有311条查询结果,搜索用时 15 毫秒
21.
Komal Sodhi Nitin Puri Gaia Favero Sarah Stevens Charles Meadows Nader G. Abraham Rita Rezzani Hayden Ansinelli Edward Lebovics Joseph I. Shapiro 《PloS one》2015,10(6)
Background
Oxidative stress underlies the etiopathogenesis of nonalcoholic fatty liver disease (NAFLD), obesity and cardiovascular disease (CVD). Heme Oxygenase-1 (HO-1) is a potent endogenous antioxidant gene that plays a key role in decreasing oxidative stress. Sirtuin1 (SIRT1) belongs to the family of NAD-dependent de-acyetylases and is modulated by cellular redox.Hypothesis
We hypothesize that fructose-induced obesity creates an inflammatory and oxidative environment conducive to the development of NAFLD and metabolic syndrome. The aim of this study is to determine whether HO-1 acts through SIRT1 to form a functional module within hepatocytes to attenuate steatohepatitis, hepatic fibrosis and cardiovascular dysfunction.Methods and Results
We examined the effect of fructose, on hepatocyte lipid accumulation and fibrosis in murine hepatocytes and in mice fed a high fructose diet in the presence and absence of CoPP, an inducer of HO-1, and SnMP, an inhibitor of HO activity. Fructose increased oxidative stress markers and decreased HO-1 and SIRT1 levels in hepatocytes (p<0.05). Further fructose supplementation increased FAS, PPARα, pAMPK and triglycerides levels; CoPP negated this increase. Concurrent treatment with CoPP and SIRT1 siRNA in hepatocytes increased FAS, PPARα, pAMPK and triglycerides levels suggesting that HO-1 is upstream of SIRT1 and suppression of SIRT1 attenuates the beneficial effects of HO-1. A high fructose diet increased insulin resistance, blood pressure, markers of oxidative stress and lipogenesis along with fibrotic markers in mice (p<0.05). Increased levels of HO-1 increased SIRT1 levels and ameliorated fructose-mediated lipid accumulation and fibrosis in liver along with decreasing vascular dysfunction (p<0.05 vs. fructose). These beneficial effects of CoPP were reversed by SnMP.Conclusion
Taken together, our study demonstrates, for the first time, that HO-1 induction attenuates fructose-induced hepatic lipid deposition, prevents the development of hepatic fibrosis and abates NAFLD-associated vascular dysfunction; effects that are mediated by activation of SIRT1 gene expression. 相似文献22.
23.
Immunostaining for nucleophosmin in bone marrow trephine biopsy specimens in acute myeloid leukemias
24.
Kremer MC Christiansen F Leiss F Paehler M Knapek S Andlauer TF Förstner F Kloppenburg P Sigrist SJ Tavosanis G 《Current biology : CB》2010,20(21):1938-1944
How does the sensory environment shape circuit organization in higher brain centers? Here we have addressed the dependence on activity of a defined circuit within the mushroom body of adult Drosophila. This is a brain region receiving olfactory information and involved in long-term associative memory formation. The main mushroom body input region, named the calyx, undergoes volumetric changes correlated with alterations of experience. However, the underlying modifications at the cellular level remained unclear. Within the calyx, the clawed dendritic endings of mushroom body Kenyon cells form microglomeruli, distinct synaptic complexes with the presynaptic boutons of olfactory projection neurons. We developed tools for high-resolution imaging of pre- and postsynaptic compartments of defined calycal microglomeruli. Here we show that preventing firing of action potentials or synaptic transmission in a small, identified fraction of projection neurons causes alterations in the size, number, and active zone density of the microglomeruli formed by these neurons. These data provide clear evidence for activity-dependent organization of a circuit within the adult brain of the fly. 相似文献
25.
Gaia Luziatelli Marten Sørensen Ida Theilade Per Mølgaard 《Journal of ethnobiology and ethnomedicine》2010,6(1):1-23
Background
The Asháninka Native Community Bajo Quimiriki, District Pichanaki, Junín, Peru, is located only 4 km from a larger urban area and is dissected by a major road. Therefore the loss of traditional knowledge is a main concern of the local headman and inhabitants. The present study assesses the state of traditional medicinal plant knowledge in the community and compares the local pharmacopoeia with the one from a related ethnic group.Methods
Fieldwork was conducted between July and September 2007. Data were collected through semi-structured interviews, collection of medicinal plants in the homegardens, forest walks, a walk along the river banks, participant observation, informal conversation, cross check through voucher specimens and a focus group interview with children.Results
Four-hundred and two medicinal plants, mainly herbs, were indicated by the informants. The most important families in terms of taxa were Asteraceae, Araceae, Rubiaceae, Euphorbiaceae, Solanaceae and Piperaceae. Eighty-four percent of the medicinal plants were wild and 63% were collected from the forest. Exotics accounted to only 2% of the medicinal plants. Problems related to the dermal system, digestive system, and cultural belief system represented 57% of all the medicinal applications. Some traditional healers received non-indigenous customers, using their knowledge as a source of income. Age and gender were significantly correlated to medicinal plant knowledge. Children knew the medicinal plants almost exclusively by their Spanish names. Sixteen percent of the medicinal plants found in this community were also reported among the Yanesha of the Pasco Region.Conclusions
Despite the vicinity to a city, knowledge on medicinal plants and cultural beliefs are still abundant in this Asháninka Native Community and the medicinal plants are still available in the surroundings. Nevertheless, the use of Spanish names for the medicinal plants and the shift of healing practices towards a source of income with mainly non-indigenous customers, are signs of acculturation. Future studies on quantification of the use of medicinal plants, dynamics of transmission of ethno-medicinal knowledge to the young generations and comparison with available pharmacological data on the most promising medicinal plants are suggested. 相似文献26.
Colon cancer is the fourth most common cancer globally with 639,000 deaths reported annually. Typical chemotherapy is provided
by injection route to reduce tumor growth and metastasis. Recent research investigates the oral delivery profiles of chemotherapeutic
agents. In comparison to injection, oral administration of drugs in the form of a colon-specific delivery system is expected
to increase drug bioavailability at target site, reduce drug dose and systemic adverse effects. Pectin is suitable for use
as colon-specific drug delivery vehicle as it is selectively digested by colonic microflora to release drug with minimal degradation
in upper gastrointestinal tract. The present review examines the physicochemical attributes of formulation needed to retard
drug release of pectin matrix prior to its arrival at colon, and evaluate the therapeutic value of pectin matrix in association
with colon cancer. The review suggests that multi-particulate calcium pectinate matrix is an ideal carrier to orally deliver
drugs for site-specific treatment of colon cancer as (1) crosslinking of pectin by calcium ions in a matrix negates drug release
in upper gastrointestinal tract, (2) multi-particulate carrier has a slower transit and a higher contact time for drug action
in colon than single-unit dosage form, and (3) both pectin and calcium have an indication to reduce the severity of colon
cancer from the implication of diet and molecular biology studies. Pectin matrix demonstrates dual advantages as drug carrier
and therapeutic for use in treatment of colon cancer. 相似文献
27.
Blood glucose is the primary cellular substrate and in vivo must be tightly maintained. The liver plays a key role in glucose homeostasis increasing or decreasing glucose output and uptake during fasting and feeding. Glucokinase (GCK) is central to this process. Its activity is modulated in a coordinated manner via a complex set of mechanisms: in the postprandial period, the simultaneous rise in glucose and insulin increases GCK activity by enhanced gene expression, changes in cellular location, and interaction with regulatory proteins. Conversely, in the fasting state, the combined decrease in glucose and insulin concentrations and increase in glucagon concentrations, halt GCK activity. Herein we summarize the current knowledge regarding the regulation of hepatic GCK activity. 相似文献
28.
Gai M Camera P Dema A Bianchi F Berto G Scarpa E Germena G Di Cunto F 《Molecular biology of the cell》2011,22(20):3768-3778
The small GTPase RhoA plays a crucial role in the different stages of cytokinesis, including contractile ring formation, cleavage furrow ingression, and midbody abscission. Citron kinase (CIT-K), a protein required for cytokinesis and conserved from insects to mammals, is currently considered a cytokinesis-specific effector of active RhoA. In agreement with previous observations, we show here that, as in Drosophila cells, CIT-K is specifically required for abscission in mammalian cells. However, in contrast with the current view, we provide evidence that CIT-K is an upstream regulator rather than a downstream effector of RhoA during late cytokinesis. In addition, we show that CIT-K is capable of physically and functionally interacting with the actin-binding protein anillin. Active RhoA and anillin are displaced from the midbody in CIT-K-depleted cells, while only anillin, but not CIT-K, is affected if RhoA is inactivated in late cytokinesis. The overexpression of CIT-K and of anillin leads to abscission delay. However, the delay produced by CIT-K overexpression can be reversed by RhoA inactivation, while the delay produced by anillin overexpression is RhoA-independent. Altogether, these results indicate that CIT-K is a crucial abscission regulator that may promote midbody stability through active RhoA and anillin. 相似文献
29.
J.V. Lee S. Lai M. Exner J. Lenz V. Gaia S. Casati P. Hartemann C. Lück B. Pangon M.L. Ricci M. Scaturro S. Fontana M. Sabria I. Sánchez S. Assaf S. Surman‐Lee 《Journal of applied microbiology》2011,110(4):1032-1044
Aims: To perform an international trial to derive alert and action levels for the use of quantitative PCR (qPCR) in the monitoring of Legionella to determine the effectiveness of control measures against legionellae. Methods and Results: Laboratories (7) participated from six countries. Legionellae were determined by culture and qPCR methods with comparable detection limits. Systems were monitored over ≥10 weeks. For cooling towers (232 samples), there was a significant difference between the log mean difference between qPCR (GU l?1) and culture (CFU l?1) for Legionella pneumophila (0·71) and for Legionella spp. (2·03). In hot and cold water (506 samples), the differences were less, 0·62 for Leg. pneumophila and 1·05 for Legionella spp. Results for individual systems depended on the nature of the system and its treatment. In cooling towers, Legionella spp. GU l?1 always exceeded CFU l?1, and usually Legionella spp. were detected by qPCR when absent by culture. The pattern of results by qPCR for Leg. pneumophila followed the culture trend. In hot and cold water, culture and qPCR gave similar results, particularly for Leg. pneumophila. There were some marked exceptions with temperatures ≥50°C, or in the presence of supplementary biocides. Action and alert levels for qPCR were derived that gave results comparable to the application of the European Guidelines based on culture. Algorithms are proposed for the use of qPCR for routine monitoring. Conclusions: Action and alert levels for qPCR can be adjusted to ensure public health is protected with the benefit that remedial actions can be validated earlier with only a small increase in the frequency of action being required. Significance and Impact of the Study: This study confirms it is possible to derive guidelines on the use of qPCR for monitoring the control of legionellae with consequent improvement to response and public health protection. 相似文献
30.
Santini D Schiavon G Vincenzi B Gaeta L Pantano F Russo A Ortega C Porta C Galluzzo S Armento G La Verde N Caroti C Treilleux I Ruggiero A Perrone G Addeo R Clezardin P Muda AO Tonini G 《PloS one》2011,6(4):e19234