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31.
Diversity of Helicobacter pylori cagA and vacA genes in Costa Rica: its relationship with atrophic gastritis and gastric cancer 总被引:3,自引:0,他引:3
Con SA Takeuchi H Valerín AL Con-Wong R Con-Chin GR Con-Chin VG Nishioka M Mena F Brenes F Yasuda N Araki K Sugiura T 《Helicobacter》2007,12(5):547-552
BACKGROUND: Associations between Helicobacter pylori gene diversity and gastric cancer have not been reported on in Costa Rica, despite its being one of the countries with the highest gastric cancer incidence and mortality rates in the world. The aim of this study was to determine the prevalence of H. pylori cagA and vacA genes and investigate whether it could be correlated with atrophic gastritis (AG) and gastric cancer (GC) in Costa Rica. MATERIALS AND METHODS: Genomic DNAs from isolates of 104 patients classified into two groups: non-atrophic gastritis group (n = 68) and atrophic gastritis group (n = 36), were subjected to PCR-based genotyping of cagA and vacA genes and their correlation with clinical outcome was investigated. Total DNA extractions from gastric tissues of 25 H. pylori-infected gastric cancer patients were utilized for comparative purposes. RESULTS: The presence of cagA (75.3%), vacA s1b (75.3%), and vacA m1 (74.2%) was detected, and colonization by strains with different vacA genotypes in the same stomach was found in 9.7% of the patients. Age- and sex-adjusted vacA s1b and vacA m1 were associated with GC while only vacA m1 was significantly associated with AG. A tendency for association between cagA and vacA s1b, and AG was reported. CONCLUSIONS: The prevalence status of the cagA and vacA (s1/m1) genes in Costa Rica seems to fall between that found in European/North American and East Asian countries, and both cagA and vacA seem to have clinical relevance in this country. 相似文献
32.
Yano S Haruta H Ikeda T Kikuchi T Murakami M Moriguchi M Wakayama M 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2011,879(29):3247-3252
D-Aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (AxD-NAase) offers a novel biotechnological application, the production of D-amino acid from the racemic mixture of N-acyl-DL-amino acids. However, its substrate specificity is biased toward certain N-acyl-D-amino acids. To construct mutant AxD-NAases with substrate specificities different from those of wild-type enzyme, the substrate recognition site of the AxD-NAase was rationally manipulated based on computational structural analysis and comparison of its primary structure with other D-aminoacylases with distinct substrate specificities. Mutations of amino acid residues, Phe191, Leu298, Tyr344, and Met346, which interact with the side chain of the substrate, induced marked changes in activities toward each substrate. For example, the catalytic efficiency (k(cat)/K(m)) of mutant F191W toward N-acetyl-D-Trp and N-acetyl-D-Ala was enhanced by 15.6- and 1.5-folds, respectively, compared with that of the wild-type enzyme, and the catalytic efficiency (k(cat)/K(m)) of mutant L298A toward N-acetyl-D-Trp was enhanced by 4.4-folds compared with that of the wild-type enzyme. Other enzymatic properties of both mutants, such as pH and temperature dependence, were the same as those of the wild-type enzyme. The F191W mutant in particular is considered to be useful for the enzymatic production of D-Trp which is an important building block of some therapeutic drugs. 相似文献
33.
Kubo A Stull R Takeuchi M Bonham K Gouon-Evans V Sho M Iwano M Saito Y Keller G Snodgrass R 《PloS one》2011,6(9):e24058
In order to define the molecular mechanisms regulating the specification and differentiation of pancreatic β-islet cells, we investigated the effect of upregulating Pdx1 and Ngn3 during the differentiation of the β-islet-like cells from murine embryonic stem (ES) cell-derived activin induced-endoderm. Induced overexpression of Pdx1 resulted in a significant upregulation of insulin (Ins1 and Ins2), and other pancreas-related genes. To enhance the developmental progression from the pancreatic bud to the formation of the endocrine lineages, we induced the overexpression express of Ngn3 together with Pdx1. This combination dramatically increased the level and timing of maximal Ins1 mRNA expression to approximately 100% of that found in the βTC6 insulinoma cell line. Insulin protein and C-peptide expression was confirmed by immunohistochemistry staining. These inductive effects were restricted to c-kit(+) endoderm enriched EB-derived populations suggesting that Pdx1/Ngn3 functions after the specification of pancreatic endoderm. Although insulin secretion was stimulated by various insulin secretagogues, these cells had only limited glucose response. Microarray analysis was used to evaluate the expression of a broad spectrum of pancreatic endocrine cell-related genes as well as genes associated with glucose responses. Taken together, these findings demonstrate the utility of manipulating Pdx1 and Ngn3 expression in a stage-specific manner as an important new strategy for the efficient generation of functionally immature insulin-producing β-islet cells from ES cells. 相似文献
34.
Purification and characterization of hyperthermotolerant leucine aminopeptidase from Geobacillus thermoleovorans 47b 总被引:1,自引:0,他引:1
Deejing S Yoshimune K Lumyong S Moriguchi M 《Journal of industrial microbiology & biotechnology》2005,32(7):269-276
A thermophilic bacterium, which we designated as Geobacillus thermoleovorans 47b was isolated from a hot spring in Beppu, Oita Prefecture, Japan, on the basis of its ability to grow on bitter peptides as a sole carbon and nitrogen source. The cell-free extract from G. thermoleovorans 47b contained leucine aminopeptidase (LAP; EC 3.4.11.10), which was purified 164-fold to homogeneity in seven steps, using ammonium sulfate fractionation followed by the column chromatography using DEAE-Toyopearl, hydroxyapatite, MonoQ and Superdex 200 PC gel filtration, followed again by MonoQ and hydroxyapatite. The enzyme was a single polypeptide with a molecular mass of 42,977.2 Da, as determined by matrix-assisted laser desorption ionization and time-of-flight mass spectrometry, and was found to be thermostable at 90°C for up to 1 h. Its optimal pH and temperature were observed to be 7.6–7.8 and 60°C, respectively, and it had high activity towards the substrates Leu-p-nitroanilide (p-NA)(100%), Arg-p-NA (56.3%) and LeuGlyGly (486%). The Km and Vmax values for Leu-p-NA and LeuGlyGly were 0.658 mM and 25.0 mM and 236.2 mol min–1 mg–1 protein and 1,149 mol min–1 mg–1 protein, respectively. The turnover rate (kcat) and catalytic efficiency (kcat/ Km) for Leu-p-NA and LeuGlyGly were 10,179 s–1 and 49,543 s–1 and 15,470 mM–1 s–1 and 1981.7 mM–1 s–1, respectively. The enzyme was strongly inhibited by EDTA, 1,10-phenanthroline, dithiothreitol, -mercaptoethanol, iodoacetate and bestatin; and its apoenzyme was found to be reactivated by Co2+ . 相似文献
35.
Characterization of salt-tolerant glutaminase from Stenotrophomonas maltophilia NYW-81 and its application in Japanese soy sauce fermentation 总被引:1,自引:0,他引:1
Wakayama M Yamagata T Kamemura A Bootim N Yano S Tachiki T Yoshimune K Moriguchi M 《Journal of industrial microbiology & biotechnology》2005,32(9):383-390
Glutaminase from Stenotrophomonas maltophilia NYW-81 was purified to homogeneity with a final specific activity of 325 U/mg. The molecular mass of the native enzyme was
estimated to be 41 kDa by gel filtration. A subunit molecular mass of 36 kDa was measured with SDS-PAGE, thus indicating that
the native enzyme is a monomer. The N-terminal amino acid sequence of the enzyme was determined to be KEAETQQKLANVVILATGGTIA.
Besides l-glutamine, which was hydrolyzed with the highest specific activity (100%), l-asparagine (74%), d-glutamine (75%), and d-asparagine (67%) were also hydrolyzed. The pH and temperature optima were 9.0 and approximately 60°C, respectively. The enzyme
was most stable at pH 8.0 and was highly stable (relative activities from 60 to 80%) over a wide pH range (5.0–10.0). About
70 and 50% of enzyme activity was retained even after treatment at 60 and 70°C, respectively, for 10 min. The enzyme showed
high activity (86% of the original activity) in the presence of 16% NaCl. These results indicate that this enzyme has a higher
salt tolerance and thermal stability than bacterial glutaminases that have been reported so far. In a model reaction of Japanese
soy sauce fermentation, glutaminase from S. maltophilia exhibited high ability in the production of glutamic acid compared with glutaminases from Aspergillus oryzae, Escherichia coli, Pseudomonas citronellolis, and Micrococcus luteus, indicating that this enzyme is suitable for application in Japanese soy sauce fermentation. 相似文献
36.
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38.
Hori T Yokomizo T Ago H Sugahara M Ueno G Yamamoto M Kumasaka T Shimizu T Miyano M 《The Journal of biological chemistry》2004,279(21):22615-22623
The bifunctional leukotriene B(4) 12-hydroxydehydrogenase/15-oxo-prostaglandin 13-reductase (LTB(4) 12-HD/PGR) is an essential enzyme for eicosanoid inactivation. It is involved in the metabolism of the E and F series of 15-oxo-prostaglandins (15-oxo-PGs), leukotriene B(4) (LTB(4)), and 15-oxo-lipoxin A(4) (15-oxo-LXA(4)). Some nonsteroidal anti-inflammatory drugs (NSAIDs), which primarily act as cyclooxygenase inhibitors also inhibit LTB(4) 12-HD/PGR activity. Here we report the crystal structure of the LTB(4) 12-HD/PGR, the binary complex structure with NADP(+), and the ternary complex structure with NADP(+) and 15-oxo-PGE(2). In the ternary complex, both in the crystalline form and in solution, the enolate anion intermediate accumulates as a brown chromophore. PGE(2) contains two chains, but only the omega-chain of 15-oxo-PGE(2) was defined in the electron density map in the ternary complex structure. The omega-chain was identified at the hydrophobic pore on the dimer interface. The structure showed that the 15-oxo group forms hydrogen bonds with the 2'-hydroxyl group of nicotine amide ribose of NADP(+) and a bound water molecule to stabilize the enolate intermediate during the reductase reaction. The electron-deficient C13 atom of the conjugated enolate may be directly attacked by a hydride from the NADPH nicotine amide in a stereospecific manner. The moderate recognition of 15-oxo-PGE(2) is consistent with a broad substrate specificity of LTB(4) 12-HD/PGR. The structure also implies that a Src homology domain 3 may interact with the left-handed proline-rich helix at the dimer interface and regulate LTB(4) 12-HD/PGR activity by disruption of the substrate binding pore to accommodate the omega-chain. 相似文献
39.
Narita M Suzuki M Imai S Narita M Ozaki S Kishimoto Y Oe K Yajima Y Yamazaki M Suzuki T 《Life sciences》2004,74(21):2655-2673
In the present study, we demonstrated whether a neuropathic pain-like state induced by sciatic nerve ligation in rodents could cause a long-lasting change in intracellular signaling in both supraspinal and spinal cord related to the suppression of morphine's effect. Mice with sciatic nerve ligation exhibited a significant suppression of the morphine-induced antinociception. Under this condition, phosphorylated-conventional protein kinase C-like immunoreactivity (p-cPKC-IR) and phosphorylated-micro-opioid receptor (p-MOR)-IR were clearly increased on the ipsilateral side in the dorsal horn of the spinal cord of nerve-ligated mice. It is of interest to note that astroglial hypertrophy as well as its proliferation was also noted in this area of sciatic nerve-ligated mice. Like nerve injury, the increase in cPKC activities and astroglial hypertrophy/proliferation in this region was observed by repeated morphine treatment. These findings suggest that the phosphorylation of both cPKC and MOR in the dorsal horn of the spinal cord by sciatic nerve ligation may play a substantial role in the suppression of morphine-induced antinociception under a neuropathic pain-like state. Sciatic nerve injury also caused a significant inhibition of MOR-mediated G-protein activation onto GABAergic neurons and a dramatic reduction in ERK activities onto dopaminergic neurons in the ventral tegmental area (VTA) regulating the rewarding effect of opioids. Furthermore, we found that the inhibition of ERK cascade in the VTA by treatment with specific inhibitors suppressed the morphine-induced rewarding effect in normal mice. These findings provide evidence that the direct reduction in MOR function and the persistent decrease in ERK activity of dopaminergic neurons in the VTA may contribute to the suppression of the morphine-induced rewarding effect under a neuropathic pain-like state. Conclusively, our recent findings provide novel evidences for the mechanism underlying the less sensitivity to opioids under a neuropathic pain-like state. 相似文献
40.
Cabanillas-Beltrán H LLausás-Magaña E Romero R Espinoza A García-Gasca A Nishibuchi M Ishibashi M Gomez-Gil B 《FEMS microbiology letters》2006,265(1):76-80
During 2003 and during late September of 2004, more than 1230 cases of gastroenteritis were reported in the south of Sinaloa State, north-western Mexico. All cases were attributed to the consumption of raw or undercooked shrimp collected at the Huizache-Caimanero lagunary system. Vibrio parahaemolyticus was identified by standard biochemical methods, and many strains were positive for PCR amplifications of the tlh and tdh genes and negative for the trh gene. A representative strain belonged to the O3:K6 serogroup. This is the first outbreak of gastroenteritis caused by the pandemic strains of O3:K6 V. parahaemolyticus in México. 相似文献