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排序方式: 共有150条查询结果,搜索用时 31 毫秒
51.
Lamia Lahouar Fatma Ghrairi Mouldi El Felah Hichem Ben Salem Abdel Hedi Miled Mohamed Hammami Lotfi Achour 《Journal of physiology and biochemistry》2011,67(1):27-34
The aim of the present study is to evaluate the effects of diet enriched with dietary fiber of barley variety “Rihane” and
azoxymethane on serum and liver lipid variables in male rats. Forty male rats were divided into four groups and fed on control
diet or experimental diet that contained control enriched with dietary fiber of barley variety “Rihane”. Animals were injected
with saline (controls) or azoxymethane (20 mg/kg body weight s.c.) at 7 and 8 weeks of age. The experimental diet significantly
decreased cholesterol level compared with the control diet. Rats fed with BR diet significantly increased the serum high-density
lipoprotein (HDL) cholesterol and significantly decreased low-density lipoprotein (LDL) cholesterol concentrations. The experimental
diet decreased the atherogenic index (p < 0.05) compared with the control diet. Whereas the azoxymethane induced a significant increase of liver lipid, serum LDL
and triglyceride concentrations, but it caused a significant reduction of HDL. Consequently, the ratio of HDL/TC decreased
significantly compared with the control (p < 0.05). Accordingly, these results indicated that the diet enriched with dietary fiber of barley variety “Rihane” could
be effective in decreasing the atherogenic risk factors in rats whereas the use of the azoxymethane as colon-specific carcinogen
substance altered the lipid metabolism. 相似文献
52.
Borggren M Repits J Sterjovski J Uchtenhagen H Churchill MJ Karlsson A Albert J Achour A Gorry PR Fenyö EM Jansson M 《PloS one》2011,6(6):e20135
Background
Induction of broadly neutralizing antibodies, such as the monoclonal antibodies IgGb12, 2F5 and 2G12, is the objective of most antibody-based HIV-1 vaccine undertakings. However, despite the relative conserved nature of epitopes targeted by these antibodies, mechanisms underlying the sensitivity of circulating HIV-1 variants to broadly neutralizing antibodies are not fully understood. Here we have studied sensitivity to broadly neutralizing antibodies of HIV-1 variants that emerge during disease progression in relation to molecular alterations in the viral envelope glycoproteins (Env), using a panel of primary R5 HIV-1 isolates sequentially obtained before and after AIDS onset.Principal Findings
HIV-1 R5 isolates obtained at end-stage disease, after AIDS onset, were found to be more sensitive to neutralization by TriMab, an equimolar mix of the IgGb12, 2F5 and 2G12 antibodies, than R5 isolates from the chronic phase. The increased sensitivity correlated with low CD4+ T cell count at time of virus isolation and augmented viral infectivity. Subsequent sequence analysis of multiple env clones derived from the R5 HIV-1 isolates revealed that, concomitant with increased TriMab neutralization sensitivity, end-stage R5 variants displayed envelope glycoproteins (Envs) with reduced numbers of potential N-linked glycosylation sites (PNGS), in addition to increased positive surface charge. These molecular changes in Env also correlated to sensitivity to neutralization by the individual 2G12 monoclonal antibody (mAb). Furthermore, results from molecular modeling suggested that the PNGS lost at end-stage disease locate in the proximity to the 2G12 epitope.Conclusions
Our study suggests that R5 HIV-1 variants with increased sensitivity to broadly neutralizing antibodies, including the 2G12 mAb, may emerge in an opportunistic manner during severe immunodeficiency as a consequence of adaptive molecular Env changes, including loss of glycosylation and gain of positive charge. 相似文献53.
Lise M. Billon Chris J. Blackman Hervé Cochard Eric Badel Adnane Hitmi Julien Cartailler Romain Souchal José M. Torres-Ruiz 《Plant, cell & environment》2020,43(6):1584-1594
Xylem hydraulic failure is a major driver of tree death during drought. However, to better understand mortality risk in trees, especially during hot-drought events, more information is required on both rates of residual water-loss from small branches (gres) after stomatal closure, as well as the phase transition temperature (Tp), beyond which gres significantly increases. Here, we describe and test a novel low-cost tool, the DroughtBox, for phenotyping gres and Tp across species. The system consists of a programmable climatically controlled chamber in which branches dehydrate and changes in the mass recorded. Test measurements show that the DroughtBox maintains stable temperature and relative humidity across a range of set points, a prerequisite for getting accurate gres and Tp values. Among a study group of four conifer and one angiosperm species, we observed a range of gres (0.44–1.64 mmol H2O m−2 s−1) and Tp (39.4–43.8°C) values. Furthermore, the measured time to hydraulic failure varied between two conifers species and was shortened in both species following a heatwave event. The DroughtBox is a reliable and customizable tool for phenotyping gres and Tp, as well as for testing models of time to hydraulic failure that will improve our ability to assess climate change impacts on plants. 相似文献
54.
55.
Davide Angeletti Letusa Albrecht Karin Blomqvist María del Pilar Quintana Tahmina Akhter Susanna M. B?chle Alan Sawyer Tatyana Sandalova Adnane Achour Mats Wahlgren Kirsten Moll 《PloS one》2012,7(12)
The ability of Plasmodium falciparum parasitized RBC (pRBC) to form rosettes with normal RBC is linked to the virulence of the parasite and RBC polymorphisms that weaken rosetting confer protection against severe malaria. The adhesin PfEMP1 mediates the binding and specific antibodies prevent sequestration in the micro-vasculature, as seen in animal models. Here we demonstrate that epitopes targeted by rosette disrupting antibodies converge in the loop of subdomain 3 (SD3) which connects the h6 and h7 α-helices of PfEMP1-DBL1α. Both monoclonal antibodies and polyclonal IgG, that bound to epitopes in the SD3-loop, stained the surface of pRBC, disrupted rosettes and blocked direct binding of recombinant NTS-DBL1α to RBC. Depletion of polyclonal IgG raised to NTS-DBL1α on a SD3 loop-peptide removed the anti-rosetting activity. Immunizations with recombinant subdomain 1 (SD1), subdomain 2 (SD2) or SD3 all generated antibodies reacting with the pRBC-surface but only the sera of animals immunized with SD3 disrupted rosettes. SD3-sequences were found to segregate phylogenetically into two groups (A/B). Group A included rosetting sequences that were associated with two cysteine-residues present in the SD2-domain while group B included those with three or more cysteines. Our results suggest that the SD3 loop of PfEMP1-DBL1α is an important target of anti-rosetting activity, clarifying the molecular basis of the development of variant-specific rosette disrupting antibodies. 相似文献
56.
Astrocyte–neuron communication has recently been proposed as a potential mechanism participating to synaptic transmission. With the development of this concept and accumulating evidences in favor of a modulation of synaptic transmission by astrocytes, has emerged the term gliotransmission. It refers to the capacity of astrocytes to release various transmitters, such as ATP, glutamate, d-serine, and GABA in the vicinity of synapses. While the cellular mechanisms involved in gliotransmission still need to be better described and, for some, identified, the aim of more and more studies is to determine the role of astrocytes from a functional point of view. This review will summarize the principal studies that have investigated a potential role of astrocytes in the various functions regulated by the brain (sleep, breathing, perception, learning and memory…). This will allow us to highlight the similarities and discrepancies in the signaling pathways involved in the different areas of the brain related to these functions. 相似文献
57.
Laila Oukhattar Tarik Baibai Adnane Moutaouakkil Omar Assobhei Abdelaziz Soukri 《Reviews in Fish Biology and Fisheries》2008,18(3):263-271
The NAD+ dependent cytosolic Glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) from arms of Octopus vulgaris, Cuvier, 1787, (Octopoda, Cephalopoda) was purified to homogeneity and its kinetic properties investigated. The purification
method consisted of ammonium sulfate fractionation followed by Blue Sepharose CL-6B chromatography resulting in a 26-fold
increase in specific activity and a final yield of approximately 16%. The apparent molecular weight of the purified native
enzyme was 153 kDa. The protein is an homotetramer, composed of identical subunits with an apparent molecular weight of approximately
36 kDa. The Michaelis constants Km for both NAD+ and d-G3P were 66 μM and 320 μM, respectively. The maximal velocity Vmax of the purified enzyme was estimated to be 21.8 U/mg. Only one GAPDH isoform (pI 6.6) was obtained by isoelectrofocusing in polyacrylamide slab gels holding ampholyte generated pH gradients. Under the conditions
of assay, the optimum activity occurs at pH 7.0 and at temperature of 35°C. Polyclonal antibodies raised in rabbits against
the purified GAPDH immunostained a single 36 kDa GAPDH band on crude extract protein preparations blotted onto nitrocellulose. 相似文献
58.
Jonas Sundb?ck Adnane Achour Jakob Micha?lsson Hannah Lindstr?m Klas K?rre 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(2):793-800
Mouse NK cells express Ly-49 receptors specific for classical MHC class I molecules. Several of the Ly-49 receptors have been characterized in terms of function and ligand specificity. However, the only Ly-49 receptor-ligand interaction previously described in detail is that between Ly-49A and H-2D(d), as studied by point mutations in the ligand and the crystal structure of the co-complex of these molecules. It is not known whether other Ly-49 receptors bind MHC class I in a similar manner as Ly-49A. Here we have studied the effect of mutations in Ly-49C on binding to the MHC class I molecules H-2K(b), H-2D(b), and H-2D(d). The MHC class I molecules were used as soluble tetramers to stain transiently transfected 293T cells expressing the mutated Ly-49C receptors. Three of nine mutations in Ly-49C led to loss of MHC class I binding. The three Ly-49C mutations that affected MHC binding correspond to Ly-49A residues that are in contact or close to H-2D(d) in the co-crystal, demonstrating that MHC class I binding by Ly-49C is dependent on residues in the same area as that used by Ly-49A for ligand contacts. 相似文献
59.
Induction of anti-gp160 cytotoxic T cells cross-reacting with various V3 loop P18 peptides in human immunodeficiency virus type 1 envelope-immunized individuals. 下载免费PDF全文
Cytotoxic T lymphocytes (CTL) may be important to prevent cell-to-cell transmission of human immunodeficiency virus type 1 (HIV-1), the agent responsible for AIDS. In this study, we investigated the epitope specificity of CTLs induced in individuals immunized against the virus envelope glycoprotein gp160. The determinant of HIV-1 gp160 for the stimulation of CTL is located in a region of high sequence variability among HIV-1 isolates, the so-called V3 loop P18. Using a panel of P18 peptides, we compared the CTL specificities of cells from two individuals immunized with vaccinia virus recombinants expressing the envelope glycoproteins from two different strains of HIV-1, IIIB and SIMI. For this purpose, CTLs specific for the IIIB P18 peptide (RIQRGPGRAFVTIGK) were compared with CTLs for the site from the SIMI isolate (TLHMGPKRAFYATGD). The results indicate that in contrast to CD8+ CTLs induced by the glycoprotein from strain IIIB, CD8+ CTLs induced by strain SIMI strongly cross-reacted with targets presenting P18 peptides as well as envelope proteins from the divergent MN and RF isolates but failed to cross-react with targets that presented the IIIB peptide. These data have implications for the design of an HIV vaccine. 相似文献
60.