全文获取类型
收费全文 | 123篇 |
免费 | 9篇 |
出版年
2023年 | 3篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 5篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 5篇 |
2013年 | 11篇 |
2012年 | 5篇 |
2011年 | 13篇 |
2010年 | 6篇 |
2009年 | 1篇 |
2008年 | 4篇 |
2007年 | 2篇 |
2006年 | 5篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 7篇 |
2002年 | 10篇 |
2001年 | 5篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有132条查询结果,搜索用时 31 毫秒
1.
Joseph A. Gebbia Edward M. Bosler Robert D. Evans Edward M. Schneider 《Experimental & applied acarology》1995,19(10):593-605
The purpose of this study was to determine whether dogs develop acquired resistance to adult Ixodes scapularis infestation in an experimental model. Five dogs were each infested with ten mating pairs of ticks every week for 7 consecutive weeks, another five dogs were each infested with ten mating pairs once every 2 weeks for 10 weeks and four dogs served as controls not exposed to ticks. All ticks were allowed to feed to repletion and were collected only after dropping from the host. Several variables were measured to determine the extent of blood feeding success. Regression analysis indicated that the engorgement success, survival and mean tick engorgement weight declined with repeated infestation in both groups of dogs (p<0.05). Tick oviposition as well as the F1 viability declined with each successive infestation in both groups. These results suggest that repeated infestation with I. scapularis elicits a protective immune response against tick feeding and could serve as a limiting factor in the spread and transmission of Borrelia burgdorferi. 相似文献
2.
Aline Queiroz Emmanuel Albuquerque-Souza Leticia Miquelitto Gasparoni Bruno Nunes de Fran a Cibele Pelissari Mar lia Trierveiler Marinella Holzhausen 《World journal of stem cells》2021,13(6):605-618
Inflammatory periodontal disease known as periodontitis is one of the most common conditions that affect human teeth and often leads to tooth loss. Due to the complexity of the periodontium, which is composed of several tissues, its regeneration and subsequent return to a homeostatic state is challenging with the therapies currently available. Cellular therapy is increasingly becoming an alternative in regenerative medicine/dentistry, especially therapies using mesenchymal stem cells, as they can be isolated from a myriad of tissues. Periodontal ligament stem cells (PDLSCs) are probably the most adequate to be used as a cell source with the aim of regenerating the periodontium. Biological insights have also highlighted PDLSCs as promising immunomodulator agents. In this review, we explore the state of knowledge regarding the properties of PDLSCs, as well as their therapeutic potential, describing current and future clinical applications based on tissue engineering techniques. 相似文献
3.
4.
Gorman Daniel Pucci Marinella Soares Lucy S. H. Turra Alexander Schlacher Thomas A. 《Ecosystems》2019,22(4):796-804
Ecosystems - Land–ocean coupling in the form of riverine inputs of terrestrial matter can constitute an energetic subsidy to food webs in nearshore coastal areas. In regions with distinctly... 相似文献
5.
G Leto F M Tumminello N Gebbia L Rausa 《The International journal of biochemistry》1988,20(9):917-920
1. We have investigated the kinetics of inhibition of cathepsin D in heart, liver and skeletal muscle of CD-1 mice following administration of 25, 50, 100 and 200 mg/kg i.p. of pepstatin A, a specific inhibitor of this protease. 2. In the liver, a significant inhibition of cathepsin D occurred up to at least 15 days, whereas, in heart and skeletal muscle, this inhibition lasted for a much shorter period of time. 3. These results show that the recovery of enzyme activity to normal values is dose-dependent and that, at the same dose level, marked differences occur in the recovery of enzyme activity in these organ tissues, the liver being the most sensitive one. 相似文献
6.
The extracellular cAMP-adenosine pathway refers to the local production of adenosine mediated by cAMP egress into the extracellular space, conversion of cAMP to AMP by ectophosphodiesterase (PDE), and the metabolism of AMP to adenosine by ecto-5'-nucleotidase. The goal of this study was to assess whether the cAMP-adenosine pathway is expressed in oviduct cells. Studies were conducted in cultured bovine oviduct cells (mixed cultures of fibroblasts and epithelial cells, 1:1 ratio). Confluent monolayers of oviduct cells were exposed to cAMP (0.01-100 micromol/L) in the presence and absence of 3-isobutyl-1-methylxanthine (IBMX, 1 mmol/L, an inhibitor of both extracellular and intracellular PDE activity), 1,3-dipropyl-8-p-sulfophenylxanthine (DPSPX, 100 micromol/L, a xanthine that can inhibit extracellular or ecto-PDE activity at high concentrations), or alpha,beta-methylene-adenosine-5'-diphosphate (AMPCP, 100 micromol/L, an ecto-5'-nucleotidase inhibitor) for 0-60 min. The medium was then sampled and assayed for AMP, adenosine, and inosine. Addition of exogenous cAMP to oviduct cells increased extracellular levels of AMP, adenosine, and inosine in a concentration- and time-dependent manner. This effect was attenuated by blockade of total (extracellular and intracellular) PDE activity (IBMX), ecto-PDE activity (DPSPX), or ecto-5'-nucleotidase (AMPCP). The functional relevance of the cAMP-adenosine pathway is supported by the findings that treatment with adenylyl cyclase stimulants (forskolin plus isoproterenol) resulted in the egress of cAMP (97% extracellular) into the extracellular space and its conversion into adenosine. The extracellular cAMP-adenosine pathway exists in oviduct cells and may play an important role in regulating the biology and physiology of the oviduct. This pathway also may play a critical role in regulating sperm function, fertilization, and early embryo development. 相似文献
7.
Requirement for PAK4 in the anchorage-independent growth of human cancer cell lines 总被引:10,自引:0,他引:10
Callow MG Clairvoyant F Zhu S Schryver B Whyte DB Bischoff JR Jallal B Smeal T 《The Journal of biological chemistry》2002,277(1):550-558
p21-activated protein kinase (PAK) serine/threonine kinases are important effectors of Rho family GTPases and have been implicated in the regulation of cell morphology and motility, as well as in cell transformation. To further investigate the possible involvement of PAK kinases in tumorigenesis, we analyzed the expression of several family members in tumor cell lines. Here we demonstrate that PAK4 is frequently overexpressed in human tumor cell lines of various tissue origins. We also have identified serine (Ser-474) as the likely autophosphorylation site in the kinase domain of PAK4 in vivo. Mutation of this serine to glutamic acid (S474E) results in constitutive activation of the kinase. Phosphospecific antibodies directed against serine 474 detect activated PAK4 on the Golgi membrane when PAK4 is co-expressed with activated Cdc42. Furthermore, expression of the active PAK4 (S474E) mutant has transforming potential, leading to anchorage-independent growth of NIH3T3 cells. A kinase-inactive PAK4 (K350A,K351A), on the other hand, efficiently blocks transformation by activated Ras and inhibits anchorage-independent growth of HCT116 colon cancer cells. Taken together, our data strongly implicate PAK4 in oncogenic transformation and suggest that PAK4 activity is required for Ras-driven, anchorage-independent growth. 相似文献
8.
Rozkowicz A Picco AM Rodolfi M Pinamonti S Forlani G 《Journal of plant physiology》2003,160(9):1033-1040
Suspension cultured cells of six rice cultivars differing in their sensitivity to blast were treated with mycelial wall hydrolysates prepared from seven isolates belonging to different Pyricularia grisea lineages. Soon after elicitor addition, rice cells produced significant amounts of superoxide anion, which was rapidly converted into diffusible peroxide. Maximal effects were achieved at 50 mg L-1 elicitor. In all cases, a 7 to 13-fold increase in the basal rate of reactive oxygen species production was found. Neither differential effects among strains nor clear relationships between lineage and the resulting oxidative burst were evident. Interestingly, a good correlation was found between basal (and elicited) levels of peroxide generation and the overall tolerance of rice cultivars to the pathogen. About two days after elicitation, cell death occurred proportional to the amount of hydrogen peroxide released. Peroxide was required to trigger loss of cell viability, but the latter was not due to a direct toxic effect, suggesting the induction of programmed cell death. Results represent the first data aimed to develop in vitro tests for pathogenicity prediction of Italian blast lineages toward rice cultivars. 相似文献
9.
Micheli F Antolini M Di Fabio R Pellacani A Pozzan A 《Bioorganic & medicinal chemistry letters》2010,20(22):6405-6407
A new class of selective orexin 2 antagonist was identified among commercial products. Initial SAR was obtained using commercial derivatives only prior to starting ad hoc medicinal chemistry activities. 相似文献
10.
Alfano C Viola L Heng JI Pirozzi M Clarkson M Flore G De Maio A Schedl A Guillemot F Studer M 《Development (Cambridge, England)》2011,138(21):4685-4697
During corticogenesis, late-born callosal projection neurons (CPNs) acquire their laminar position through glia-guided radial migration and then undergo final differentiation. However, the mechanisms controlling radial migration and final morphology of CPNs are poorly defined. Here, we show that in COUP-TFI mutant mice CPNs are correctly specified, but are delayed in reaching the cortical plate and have morphological defects during migration. Interestingly, we observed that the rate of neuronal migration to the cortical plate normally follows a low-rostral to high-caudal gradient, similar to that described for COUP-TFI. This gradient is strongly impaired in COUP-TFI(-/-) brains. Moreover, the expression of the Rho-GTPase Rnd2, a modulator of radial migration, is complementary to both these gradients and strongly increases in the absence of COUP-TFI function. We show that COUP-TFI directly represses Rnd2 expression at the post-mitotic level along the rostrocaudal axis of the neocortex. Restoring correct Rnd2 levels in COUP-TFI(-/-) brains cell-autonomously rescues neuron radial migration and morphological transitions. We also observed impairments in axonal elongation and dendritic arborization of COUP-TFI-deficient CPNs, which were rescued by lowering Rnd2 expression levels. Thus, our data demonstrate that COUP-TFI modulates late-born neuron migration and favours proper differentiation of CPNs by finely regulating Rnd2 expression levels. 相似文献