全文获取类型
收费全文 | 127篇 |
免费 | 21篇 |
专业分类
148篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 2篇 |
2019年 | 5篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 10篇 |
2012年 | 13篇 |
2011年 | 5篇 |
2010年 | 6篇 |
2009年 | 9篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 8篇 |
2005年 | 4篇 |
2004年 | 7篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 1篇 |
1999年 | 4篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
排序方式: 共有148条查询结果,搜索用时 15 毫秒
141.
142.
M C Sampedro C Motrán A Gruppi S C Kivatinitz 《Biochemical and biophysical research communications》2001,285(2):393-399
Human very-low-density lipoprotein (VLDL) inhibits DNA synthesis in lymphocytes activated by the nonspecific mitogen concanavalin A (Con A). We studied the effects of VLDL on lymphocyte activation (IL-2 receptor expression), cell cycle progression, and production of IL-2 and of IL-4 (a proinflammatory and an anti-inflammatory interleukin, respectively) to understand why an atherogenic lipoprotein inhibits cell proliferation. After 48 h of stimulation with the mitogen, VLDL decreased the population of cells bearing IL-2 receptor and the population of T-cells that progress through the cell cycle, increasing the population of T-cells in G(0)/G(1). Cells cultured in the presence of Con A and VLDL produced higher levels of IL-2 and lower levels of IL-4 than cells cultured without VLDL. These results suggest that VLDL inhibits lymphocyte proliferation by reducing IL-2 receptor and enhancing the levels of IL-2. Probably, one atherogenic effect of VLDL is to modulate the cytokine secretion profile of lymphocytes to a predominantly proinflammatory response. 相似文献
143.
Alfonso Ruiz-Bravo Encarnacion Moreno Antonio Sampedro Maria Jimenez-Valera 《Current microbiology》1999,38(5):257-263
An isogenic pair of Yersinia enterocolitica serotype O9 strains, with and without virulence plasmid, was used to study the plasmid role in the infection of BALB/c mice
by oral, intraperitoneal, and intravenous routes. The plasmid-bearing strain, but not its plasmid-less derivative, caused
enteric infection after challenge by all three routes. The virulence plasmid did not influence the peritoneal clearance of
yersiniae, but only the plasmid-bearing yersiniae were able to move from the peritoneal cavity to the bloodstream, and thus
they spread to spleen and liver. Moreover, plasmid-bearing yersiniae were able to move from the liver to the gallbladder,
and they shed in bile into the intestine. Western blot analysis of antibody responses to chromosomally encoded outer membrane
proteins revealed similar patterns with sera from mice challenged with each one of the two strains by intraperitoneal route.
In contrast, only the plasmid-bearing strain elicited an antibody response to these antigens in mice challenged by oral route.
Although mice experimentally infected with plasmid-bearing O9 yersiniae developed an enteric infection, irrespective of the
inoculation route, differences between the first steps in infection by oral and parenteral routes may be important, especially
when the infection model is used as an approach to study the yersinia-host interactions.
Received: 31 August 1998 / Accepted: 13 November 1998 相似文献
144.
E. Aranda I. Sampedro R. Díaz M. García-Sánchez C. A. Arriagada J. A. Ocampo I. García-Romera 《Symbiosis (Philadelphia, Pa.)》2009,47(3):133-140
Olive oil extraction generates large amounts of olive mill residues (DOR) which may be used as fertilizer. The influence of
arbuscular mycorrhizal (AM) on the phytotoxicity of dry olive residue (DOR) transformed with saprophytic fungi was studied.
Aqueous extraction of DOR gave an (ADOR) fraction and an exhausted (SDOR) fraction, both of which had less phytotoxicity for
tomato than the original DOR. The saprophytic fungiTrametes versicolor andPycnoporus cinnabarinus further decreased the phytotoxicity of ADOR and SDOR on tomato. The decrease of phenols concentration and the differences
in the level of laccase activity caused by these fungi suggest did not account fully for the reduced phytoxicity but the fact
that the higher hydrolytic enzyme activity ofP. cinnabarinus, paralleled the decrease of phytotoxicity, indicates that these enzymes seem to be involved. The AM fungusGlomus deserticola increased or exacerbated the beneficial effect of SDOR incubated with saprophytic fungi, in terms of dry weight of tomato
plants. The percentage of root length colonized byG. deserticola strongly decreased in presence of DOR, but the level of mycorrhization was higher in presence of ADOR or SDOR. Our results
suggest that the combination of aqueous extraction and incubation with saprophytic fungi will open the way for the use of
olive oil extraction residues as organic amendment in agricultural soils. 相似文献
145.
I. Martín-Lacave R. Bernabé C. Sampedro E. Conde J. M. Fernández-Santos M. V. San Martín A. Beato H. Galera-Davidson 《Cell and tissue research》1999,297(3):451-457
In many rat strains, C-cell hyperplasia occurs in an age-dependent manner and is often associated with multifocal C-cell carcinoma. The purpose of this study was to investigate the spectrum of spontaneous, proliferative C-cell disorders by gender in Wistar rats throughout their lifespan. The incidence of C-cell hyperplasia shows a significant increase with age (P<0.001) and is much higher in female rats than in male rats (P<0.05). From 3 to 24 months of life, 27.5% of female rats showed a normal C-cell pattern, 55.0% showed C-cell hyperplasia, and 17.5% showed C-cell tumors; while 57.5% of male rats showed a normal C-cell pattern, 32.5% showed C-cell hyperplasia, and 10% showed C-cell tumors. Although the overall frequency of C-cell neoplasms in females was nearly double that in males, these data are not statistically significant. However, the number of C-cell tumors showed a significant increase with age (P<0.05). Therefore, we can conclude that there were significant differences in the incidence of the total spectrum of C-cell proliferative abnormalities in the thyroid gland of Wistar rats that were both age-dependent and gender-dependent. 相似文献
146.
Inmaculada Sampedro Mariangela Giubilei Tomas Cajthaml Ermanno Federici Federico Federici Maurizio Petruccioli Alessandro Dannibale 《Bioresource technology》2009,100(23):6098-6106
The short-term response of the resident soil bacterial and fungal communities to the addition of 5% (w/w) of either dry olive mill residue (DOR), DOR treated with Phlebia sp. (PTDOR) or DOR previously extracted with water (WEDOR) was investigated. As opposed to bacteria, the diversity of fungi increased upon the amendments as assessed by denaturing gradient gel electrophoresis of 18S rDNA. Over the first 30 days, phospholipid fatty acids analyses indicated a gradual decrease in the relative abundances of Gram+ bacteria (from 44.8% to 37.9%) and a concomitant increase of Gram− bacteria (from 37.3% to 51.2%) in DOR-amended soil. A considerable increase in the fungal/bacterial ratio was observed after 7 days in DOR, WEDOR and PTDOR-amended soils with respect to the control (0.316, 0.165 and 0.265, respectively, vs. 0.011). The overall microbial activity was stimulated by the amendments as indicated by the higher activity levels of both dehydrogenase and fluorescein diacetate hydrolase. These results indicate that DOR at the application level examined is not toxic on soil microorganisms. 相似文献
147.
Summary The chitinase, protease and lipase activities of aggressive (Ag+) and non-aggressive (Ag−) strains ofConidiobolus obscurus (Hall & Dunn) Remaudière & keller have been studied in agar and agitated liquid cultures. The strains produced different
quantities of proteases, but no relationship could be established between protease activity and pathogenicity. In contrast,
the lipase-esterase activity of Ag− strains observed in liquid media is greater than that of Ag+ strains. All Ag+ strains produced a chitinase and are capable of metabolising the N-acetyl glucosamine (NAG) liberated. In contrast, of the
Ag− strains, some do not possess chitinase activity while others secrete this enzyme but cannot metabolize the NAG liberated.
Résumé Les activités chitinasique, protéasique et lipasique de souches deConidio bolus obecurus (Hall& Dunn) Remaudière & Keller ont été étudiées en milieu gélosé et en culture liquide agitée. Les souches sécrètent des protéases à des taux diffℰrents mais aucune relation n'a pu être établie entre l'intensité des protéases étudiées et l'agressivité des souches. Par contre, l'activité lipasique-estérasique des souches non agressives (Ag−) observée en milieu liquide est plus importante que celle des souches agressives (Ag+). Toutes les souches Ag+ produisent une chitinase et sont capables de métaboliser la N-acétylglucosamine (NAG) libérée. Au contraire, les souches Ag− n'ont pas d'activité chitinasique ou celles qui excrètent cette enzyme ne peuvent métaboliser la NAG libérée.相似文献
148.
José Miguel Mancheño Estíbaliz Atondo Julen Tomás-Cortázar José Luís Lavín Laura Plaza-Vinuesa Itziar Martín-Ruiz Diego Barriales Ainhoa Palacios Claudio Daniel Navo Leticia Sampedro Ainize Peña-Cearra Miguel Ángel Pascual-Itoiz Janire Castelo Ana Carreras-González Donatello Castellana Aize Pellón Susana Delgado Patricia Ruas-Madiedo Blanca de las Rivas Leticia Abecia Rosario Muñoz Gonzalo Jiménez-Osés Juan Anguita Héctor Rodríguez 《Microbial biotechnology》2022,15(2):648-667
Colorectal cancer pathogenesis and progression is associated with the presence of Fusobacterium nucleatum and the reduction of acetylated derivatives of spermidine, as well as dietary components such as tannin-rich foods. We show that a new tannase orthologue of F. nucleatum (TanBFnn) has significant structural differences with its Lactobacillus plantarum counterpart affecting the flap covering the active site and the accessibility of substrates. Crystallographic and molecular dynamics analysis revealed binding of polyamines to a small cavity that connects the active site with the bulk solvent which interact with catalytically indispensable residues. As a result, spermidine and its derivatives, particularly N8-acetylated spermidine, inhibit the hydrolytic activity of TanBFnn and increase the toxicity of gallotannins to F. nucleatum. Our results support a model in which the balance between the detoxicant activity of TanBFnn and the presence of metabolic inhibitors can dictate either conducive or unfavourable conditions for the survival of F. nucleatum. 相似文献