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排序方式: 共有206条查询结果,搜索用时 171 毫秒
81.
Zhang YL Hernandez-Ono A Siri P Weisberg S Conlon D Graham MJ Crooke RM Huang LS Ginsberg HN 《The Journal of biological chemistry》2006,281(49):37603-37615
82.
It was shown previously that Ea4-peptide of trout pro-IGF-I exerted mitogenic activity in non-transformed cells and inhibited colony formation in a soft agar medium of established human cancer cells. Here we report that the same peptide inhibits the invasion of human breast cancer cells (MDA-MB-231) through a matrigel membrane in a dose-dependent manner. The expression of urokinase-type plasminogen activator (uPA), tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor 1 (PAI1) genes in MDA-MB-231 cells were downregulated by treatment with rtEa4-peptide. The inhibition of expression of these genes in response to rtEa4-peptide treatment was reduced to the control level when inhibitors for c-Jun N-terminal kinase 1/2 (JNK1/2), mitogen activated protein kinase kinase 1/2 (Mek1/2), p38 mitogen activated protein kinase (p38 MAPK), phosphatidylinositol 3-kinase (PI3K), and phosphokinase C (PKC) were used. These results suggest that inhibition of invasion of MDA-MB-231 cells by rtEa4-peptide may be mediated via the suppression of uPA, tPA, and PAI1 gene activities through signal transduction pathways. 相似文献
83.
The identity and activity of an entomopathogenic fungus belonging to the Entomophthora muscae species complex and infecting Musca domestica in poultry houses from La Plata, Argentina, is reported. Entomophthora caused natural infections between September 2001 and September 2003. Primary conidia of this fungus were on average 29.5
± 1.2 × 23.4 ± 2.4 μm and contained, on average, 10.5 ± 0.1 nuclei (range: 7–15) with an average diameter of 4.8 ± 0.1 μm.
This fungus is identified as E. ferdinandii Keller (this specific epithet includes a nomenclaturally required spelling correction); this is a first record of E. ferdinandii in South America and of any member of the E. muscae species complex from flies in Argentina. 相似文献
84.
Oftedal L Myhren L Jokela J Gausdal G Sivonen K Døskeland SO Herfindal L 《Biochimica et biophysica acta》2012,1818(12):3000-3009
The two novel cyanobacterial cyclic lipopeptides, anabaenolysin (Abl) A and B permeabilised mammalian cells, leading to necrotic death. Abl A was a more potent haemolysin than other known biodetergents, including digitonin, and induced discocyte-echinocyte transformation in erythrocytes. The mitochondria of the dead cells appeared intact with regard to both ultrastructure and membrane potential. Also isolated rat liver mitochondria were resistant to Abl, judged by their ultrastructure and lack of cytochrome c release. The sparing of the mitochondria could be related to the low cholesterol content of their outer membrane. In fact, a supplement of cholesterol in liposomes sensitised them to Abl. In contrast, the prokaryote-directed cyclic lipopeptide surfactin lysed preferentially non-cholesterol-containing membranes. In silico comparison of the positions of relevant functional chemical structures revealed that Abl A matched poorly with surfactin in spite of the common cyclic lipopeptide structure. Abl A and the plant-derived glycolipid digitonin had, however, predicted overlaps of functional groups, particularly in the cholesterol-binding tail of digitonin. This may suggest independent evolution of Abl and digitonin to target eukaryotic cholesterol-containing membranes. Sub-lytic concentrations of Abl A or B allowed influx of propidium iodide into cells without interfering with their long-term cell viability. The transient permeability increase allowed the influx of enough of the cyanobacterial cyclic peptide toxin nodularin to induce apoptosis. The anabaenolysins might therefore not only act solely as lysins, but also as cofactors for the internalisation of other toxins. They represent a potent alternative to digitonin to selectively disrupt cholesterol-containing biological membranes. 相似文献
85.
Mona H. Fenstad Matthew P. Johnson Linda T. Roten Per A. Aas Siri Forsmo Kjetil Klepper Christine E. East Lawrence J. Abraham John Blangero Shaun P. Brennecke Rigmor Austgulen Eric K. Moses 《PloS one》2010,5(9)
Background
Preeclampsia is a serious pregnancy complication, demonstrating a complex pattern of inheritance. The elucidation of genetic liability to preeclampsia remains a major challenge in obstetric medicine. We have adopted a positional cloning approach to identify maternal genetic components, with linkages previously demonstrated to chromosomes 2q, 5q and 13q in an Australian/New Zealand familial cohort. The current study aimed to identify potential functional and structural variants in the positional candidate gene TNFSF13B under the 13q linkage peak and assess their association status with maternal preeclampsia genetic susceptibility.Methodology/Principal Findings
The proximal promoter and coding regions of the positional candidate gene TNFSF13B residing within the 13q linkage region was sequenced using 48 proband or founder individuals from Australian/New Zealand families. Ten sequence variants (nine SNPs and one single base insertion) were identified and seven SNPs were successfully genotyped in the total Australian/New Zealand family cohort (74 families/480 individuals). Borderline association to preeclampsia (p = 0.0153) was observed for three rare SNPs (rs16972194, rs16972197 and rs56124946) in strong linkage disequilibrium with each other. Functional evaluation by electrophoretic mobility shift assays showed differential nuclear factor binding to the minor allele of the rs16972194 SNP, residing upstream of the translation start site, making this a putative functional variant. The observed genetic associations were not replicated in a Norwegian case/control cohort (The Nord-Trøndelag Health Study (HUNT2), 851 preeclamptic and 1,440 non-preeclamptic women).Conclusion/Significance
TNFSF13B has previously been suggested to contribute to the normal immunological adaption crucial for a successful pregnancy. Our observations support TNFSF13B as a potential novel preeclampsia susceptibility gene. We discuss a possible role for TNFSF13B in preeclampsia pathogenesis, and propose the rs16972194 variant as a candidate for further functional evaluation. 相似文献86.
The preferred substrates for transglutaminase 2 in a complex wheat gluten digest are Peptide fragments harboring celiac disease T-cell epitopes 总被引:1,自引:0,他引:1
Dørum S Arntzen MØ Qiao SW Holm A Koehler CJ Thiede B Sollid LM Fleckenstein B 《PloS one》2010,5(11):e14056
Background
Celiac disease is a T-cell mediated chronic inflammatory disorder of the gut that is induced by dietary exposure to gluten proteins. CD4+ T cells of the intestinal lesion recognize gluten peptides in the context of HLA-DQ2.5 or HLA-DQ8 and the gluten derived peptides become better T-cell antigens after deamidation catalyzed by the enzyme transglutaminase 2 (TG2). In this study we aimed to identify the preferred peptide substrates of TG2 in a heterogeneous proteolytic digest of whole wheat gluten.Methods
A method was established to enrich for preferred TG2 substrates in a complex gluten peptide mixture by tagging with 5-biotinamido-pentylamine. Tagged peptides were isolated and then identified by nano-liquid chromatography online-coupled to tandem mass spectrometry, database searching and final manual data validation.Results
We identified 31 different peptides as preferred substrates of TG2. Strikingly, the majority of these peptides were harboring known gluten T-cell epitopes. Five TG2 peptide substrates that were predicted to bind to HLA-DQ2.5 did not contain previously characterized sequences of T-cell epitopes. Two of these peptides elicited T-cell responses when tested for recognition by intestinal T-cell lines of celiac disease patients, and thus they contain novel candidate T-cell epitopes. We also found that the intact 9mer core sequences of the respective epitopes were not present in all peptide substrates. Interestingly, those epitopes that were represented by intact forms were frequently recognized by T cells in celiac disease patients, whereas those that were present in truncated versions were infrequently recognized.Conclusion
TG2 as well as gastrointestinal proteolysis play important roles in the selection of gluten T-cell epitopes in celiac disease. 相似文献87.
Line Sletner Britt Nakstad Chittaranjan S. Yajnik Kjersti M?rkrid Siri Vangen Mari H. V?rdal Ingar M. Holme K?re I. Birkeland Anne Karen Jenum 《PloS one》2013,8(8)
Background
Neonates from low and middle income countries (LAMIC) tend to have lower birth weight compared with Western European (WE) neonates. Parental height, BMI and maternal parity, age and educational level often differ according to ethnic background, and are associated with offspring birth weight. Less is known about how these factors affect ethnic differences in neonatal body composition.Objectives
To explore differences in neonatal body composition in a multi-ethnic population, and the impact of key parental factors on these differences.Methods
A population-based cohort study of pregnant mothers, fathers and their offspring, living in Oslo, Norway. Gender- and gestational-specific z-scores were calculated for several anthropometric measurements, with the neonates of WE ethnic origin as reference. Mean z-scores for neonates with LAMIC origin, and their parents, are presented as outcome variables.Results
537 singleton, term neonates and their parents were included. All anthropometric measurements were smaller in neonates with LAMIC origin. Abdominal circumference and ponderal index differed the most from WE (mean z-score: −0.57 (95% CI:−0.69 to −0.44) and −0.54 (−0.66 to −0.44), and remained so after adjusting for parental size. Head circumference and skin folds differed less, and length the least (−0.21 (−0.35 to −0.07)). These measures became comparable to WEs when adjusted for parental factors.Conclusions
LAMIC origin neonates were relatively “thin-fat”, as indicated by reduced AC and ponderal index and relatively preserved length and skin folds, compared with neonates with WE origin. This phenotype may predispose to type 2 diabetes. 相似文献88.
Pacharaporn Chaisri Artit Chingsungnoen Prof. Sineenat Siri 《Biotechnology journal》2013,8(11):1323-1331
Electrospun scaffolds derived from poly(ϵ-caprolactone) (PCL), a well known biodegradable material, have an architecture that is suitable for hosting cells. However, their biomedical applications are restricted because these scaffolds lack the bioactivity necessary to stimulate cell responses. In this work, a repetitive Arg-Gly-Asp (rRGD) peptide was produced as a cell-stimulating agent to provide the PCL scaffold with bioactivity. DNA encoding rRGD was amplified by polymerase chain reaction using overlap primers without a DNA template, and cloned into a protein expression vector to produce a His-tag fusion peptide. In an in vitro cell adhesion assay, the purified rRGD peptide, comprising 30 RGD repeats, promoted a 1.5-fold greater cell adhesion than the commercial tripeptide RGD. The rRGD peptide was immobilized onto an electrospun PCL scaffold that had been pretreated with argon plasma and graft-polymerized with acrylic acid. Fourier transform infrared (FTIR) analysis indicated that covalently linked rRGD peptide was present on the scaffold. The PCL scaffold with immobilized rRGD showed significantly changed hydrophilic properties and an enhanced adhesion and proliferation of mouse fibroblast cells by 2.3- and 2.9-fold, respectively, compared to the PCL scaffold alone. Through its ability to promote cell adhesion and proliferation, the rRGD peptide has great potential as a stimulant for improving the suboptimal cell-matrix interaction of polymeric scaffolds for tissue engineering applications. 相似文献
89.
Niewerth H Bergander K Chhabra SR Williams P Fetzner S 《Applied microbiology and biotechnology》2011,91(5):1399-1408
2-Alkyl-4(1H)-quinolones (AQs) and related derivatives, which exhibit a variety of biological properties, are secondary metabolites produced
by, e.g., Pseudomonas and Burkholderia spp. Due to their main role as signaling molecules in the quorum sensing system of Pseudomonas aeruginosa, 2-heptyl-4(1H)-quinolone (HHQ) and its 3-hydroxy derivative, termed the “Pseudomonas quinolone signal” (PQS), have received considerable attention. Since chemical synthesis of different AQs is complex, we assessed
the applicability of recombinant P. putida KT2440 strains for the biosynthetic production of AQs. In mineral salts medium supplemented with octanoate and anthranilate,
batch cultures of P. putida KT2440 [pBBR-pqsABCD] produced about 45 μM HHQ, 30% and 70% of which were localized in the culture supernatant and methanolic cell extract, respectively.
2,4-Dihydroxyquinoline and minor amounts of C3- to C13-saturated and C7:1 to C13:1 monounsaturated AQs were formed as by-products. Mass spectrometry and nuclear magnetic resonance analyses spectroscopy indicated
that unsaturated AQs having the same molecular mass are cis and trans isomers rather than position isomers, with the double bond located between the α and β carbon of the alkyl chain. Supplementing
the cultures with hexanoate instead of octanoate shifted the AQ profile towards increased formation of C5-AQ. Individual AQs can be prepared from concentrated methanolic extracts by preparative high-performance liquid chromatography
(HPLC). Regioselective hydroxylation of HHQ to PQS can be achieved in >90% yield by biotransformation with P. putida KT2440 [pBBR-pqsH]. PQS can be isolated from methanolic cell extracts by HPLC, or be precipitated as Fe(III)-PQS complex. Preparation of a
library of AQs will facilitate studies on the biological functions of these compounds. 相似文献
90.