全文获取类型
收费全文 | 98篇 |
免费 | 8篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 9篇 |
2018年 | 3篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 6篇 |
2010年 | 1篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有106条查询结果,搜索用时 15 毫秒
51.
Christensen MJ Bennett RJ Ansari HA Koga H Johnson RD Bryan GT Simpson WR Koolaard JP Nickless EM Voisey CR 《Fungal genetics and biology : FG & B》2008,45(2):84-93
A fundamental hallmark of fungal growth is that vegetative hyphae grow exclusively by extension at the hyphal tip. However, this model of apical growth is incompatible with endophyte colonization of grasses by the symbiotic Neotyphodium and Epichlo? species. These fungi are transmitted through host seed, and colonize aerial tissues that develop from infected shoot apical meristems of the seedling and tillers. We present evidence that vegetative hyphae of Neotyphodium and Epichlo? species infect grass leaves via a novel mechanism of growth, intercalary division and extension. Hyphae are attached to enlarging host cells, and cumulative growth along the length of the filament enables the fungus to extend at the same rate as the host. This is the first evidence of intercalary growth in fungi and directly challenges the centuries-old model that fungi grow exclusively at hyphal tips. A new model describing the colonization of grasses by clavicipitaceous endophytes is described. 相似文献
52.
Mona A. M. Helal 《Biological trace element research》2011,140(1):114-126
The present study was carried out to evaluate the effects of sodium selenite on fetal development and DNA in liver of rats.
Pregnant rats were divided into three groups: control group, group treated orally with 5 μg Se/kg body wt. and group treated
orally with 10 μg Se/kg body wt. Dams were treated orally with sodium selenite from day 7 to 19 of gestation. Sodium selenite
treatment revealed decrease in maternal body weight, reduction in fetal weight, length and number of viable fetuses, increased
number of resorbed fetuses and post-implantation loss at the two doses tested. Fetal skeleton showed signs of developmental
delay in skull and limbs of the treated groups. Sodium selenite treatment revealed significant reduction of placental and
liver weights in treated dams. Sodium selenite-induced oxidative stress in liver tissue of rats as evidenced by increase in
lipid peroxidation and glutathione peroxidase activity, while catalase was significantly decreased. Also, increase in DNA
fragmentation, marked reduction of hepatic DNA content, and many histopathological changes in the liver were recorded. The
results demonstrated that treatment of pregnant rats with sodium selenite at the toxic dosages chosen showed maternal and
fetal toxicity that may be concerned with hepatic oxidative stress accompanied with DNA fragmentation and depletion of total
DNA content. 相似文献
53.
Racha Helal Matthias F. Melzig 《In vitro cellular & developmental biology. Animal》2010,46(6):492-496
The main purpose of this study was to investigate lysozyme synthesis and secretion in three human monocyte cell lines: U-937,
HL-60, and THP-1, using sensitive fluorescence-based assay of lysozyme activity. PMA and hIFN-γ were evaluated for inducing
lysozyme activity. Using well-defined cell lines from the cell culture collection, no lysozyme activity could be detected
in the cultured U-937 cells either with or without addition of the inducing factors. These data suggested, contrary to previous
reports, that U-937 cell line cannot synthesize or secrete active lysozyme. THP-1 and HL-60 cells were proved to produce enzymatically
active lysozyme in increasing amounts with the time course. PMA and hIFN-γ had no significant inducing effect on the production
or the release of active lysozyme in THP-1 and HL-60 cells. We showed inhibiting effect of PMA and hIFN-γ on the lysozyme
activity, particularly in HL-60 cell line. 相似文献
54.
Biswas MH Hasegawa HH Rahman MA Huang P Mon NN Ruhul Amin AR Senga T Kannagi R Hamaguchi M 《Biochemical and biophysical research communications》2006,348(3):1145-1149
To search for the signaling critical for the production of tissue inhibitor of metalloproteinase-2 (TIMP-2), we investigated the role of SHP-2 in TIMP-2 production with Concanavalin A (Con A)-treated cells. In wild-type fibroblasts, Con A-treatment dramatically activated TIMP-2 production. In contrast, production of TIMP-2 in response to Con A-treatment was severely impaired in cells expressing mutant SHP-2 whose 65 amino acids in the SH2-N domain were deleted. Con A-treatment activated dual signaling pathways, Erk and p38, in a SHP-2-dependent manner. Pretreatment of wild-type cells with U0126, a potent inhibitor of MEK1, significantly inhibited the production of TIMP-2, whereas SB203580, a specific inhibitor for p38, could not. Finally, expression of exogenous wild-type SHP-2 in SHP-2 mutant cells clearly rescued Erk activation and TIMP-2 production in response to Con A-treatment. Taken together, our results strongly suggest that SHP-2 plays a critical role as a positive modulator for the production of TIMP-2 via MEK1-Erk signaling in fibroblasts. 相似文献
55.
Boussaada O Ammar S Saidana D Chriaa J Chraif I Daami M Helal AN Mighri Z 《Microbiological research》2008,163(1):87-95
The chemical composition of the volatile fractions obtained by steam distillation from the capitula (C) and the aerial parts of Rhaponticum acaule DC were analysed by GC-MS. From the 57 identified constituents, representing 95.5% and 96.3% of the two oils, respectively, methyl eugenol, epi-13 manool, beta-ionone, beta-bisabolol, 1-octadecanol, phytol and farnesyl acetate were found to be the main components. Furthermore, the oils were tested against six Gram-positive and Gram-negative bacteria and four phytopathogenic fungi. It was found that oils from both parts of R. acaule, and especially that of C, exhibited interesting antibacterial activity, but no antifungal activity was observed. 相似文献
56.
Al Sattar Abdullah Irin Nusrat Belgrad Joseph P. Haider Najmul Chisty Nurun Nahar Mohsin Md. Abu Shoieb Foysal Mohammad Das Tridip Uddin Md. Helal Hasan Rubyath Binte Ferdous Jinnat Hasan Mahmudul Mahmud Rashed Samad Mohammed Abdus Giasuddin Mohammad Biswas Paritosh Kumar Pfeiffer Dirk Udo Debnath Nitish Chandra Fournié Guillaume Tomley Fiona M. Hoque Md. Ahasanul 《EcoHealth》2022,19(3):378-389
EcoHealth - The Coronavirus Disease 2019 (COVID-19) spread rapidly from China to most other countries around the world in early 2020 killing millions of people. To prevent virus spread, world... 相似文献
57.
58.
Muhammad Azeem Hidaya Kader Andreas Kerstan Helal F. Hetta Edgar Serfling Matthias Goebeler Khalid Muhammad 《The Yale journal of biology and medicine》2020,93(5):699
Allergic contact dermatitis (ACD) is a complex immunological allergic disease characterized by the interplay between the innate and adaptive immune system. Initially, the role of the innate immune system was believed to be confined to the initial sensitization phase, while adaptive immune reactions were linked with the advanced elicitation phase. However, recent data predicted a comparatively mixed and interdependent role of both immune systems throughout the disease progression. Therefore, the actual mechanisms of disease progression are more complex and interlinked. The aim of this review is to combine such findings that enhanced our understanding of the pathomechanisms of ACD. Here, we focused on the main cell types from both immune domains, which are involved in ACD, such as CD4+ and CD8+ T cells, B cells, neutrophils, and innate lymphoid cells (ILCs). Such insights can be useful for devising future therapeutic interventions for ACD. 相似文献
59.
To examine if a single or multiple oral administration of metformin, a member of the biguanide class of anti-diabetic agents, has any genotoxic and cytotoxic potential in normal and diabetic rats, a mammalian model, cytogenetic assays through several endpoints such as induction of micronuclei, chromosome aberrations, mitotic activity of bone marrow cells, sperm-head anomaly and assays of some oxidative stress markers have been conducted by the use of standard techniques. Diabetes was induced by streptozotocin injection. Metformin was administrated to both diabetic and non-diabetic rats in single doses of 100, 500 or 2500 mg/kg along with vehicle control groups for diabetic and non-diabetic rats. The animals were killed by cervical dislocation at 24 h after treatment, and then bone marrow cells were sampled. Also, a multiple dose study has done in which diabetic and non-diabetic animals were treated with 100 or 500 mg/kg of metformin daily for 4 or 8 weeks after which the animals were killed by cervical dislocation, and then bone marrow and sperm cells were collected. Concurrent control groups were also included in each experiment. The obtained results revealed that metformin was neither genotoxic nor cytotoxic for the rats in all groups at all tested doses. Moreover, metformin significantly reduced the diabetes-induced genomic instability and cell proliferation changes in somatic and germinal cells in a dose-dependent manner (2500, 500, >100 mg/kg). In addition, diabetes induced marked biochemical alterations characteristic of oxidative stress including, enhanced lipid peroxidation and reduction in the reduced glutathione level. Treatment with metformin ameliorated these biochemical markers. In conclusion, metformin is a non-genotoxic or cytotoxic compound and may protect from genomic instability induced by hyperglycemia. Apart from its well-known anti-diabetic effect, the antigenotoxic effect of metformin could be possibly ascribed to its radical scavenger effect that modulated the genomic instability responses and cell proliferation changes induced by hyperglycemia. 相似文献
60.
Plasmodium falciparum calcium-ATPase (PfATP6) has been reported to be a target of artemisinin and related endoperoxides. In this study, a series of previously reported guaianolide-endoperoxides (thaperoxides) were docked into a homology model of PfATP6 and also used to develop a pharmacophore model. This combined approach led to useful insights into the binding determinants of thaperoxides to the malarial enzyme. In addition, in silico mutagenesis and molecular dynamics suggested the importance of Phe264 and the electrostatic interactions between Lys260 in helix H3 and Lys1036 and Asp1038 in L6/7 loop for the binding of thaperoxides. These results could help in the design of more potent inhibitors of PfATP6. 相似文献