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91.
Loś R Malm A Biernasiuk A Korona-Głowniak I Kosikowska U 《Medycyna do?wiadczalna i mikrobiologia》2004,56(1):57-65
The cell surface hydrophobicity is one of the non specific factors of adhesion influencing the ability of microorganisms to colonize nasopharynx. The aim of this paper was to evaluate via salt aggregation test (SAT) the cell surface hydrophobicity of 150 strains of gram-negative rods isolated from the throat or/and nasal specimens of healthy people. It has been found that among the nonfermenting rods hydrophobic strains were predominant. In contrast, the isolates of Enterobacteriaceae family were characterized by the distinctive features of the cell surface within particular genera or even species. The obtained results show that, despite differences in cell surface hydrophobicity, numerous species of gram-negative rods have the ability to colonize the mucous membrane of upper respiratory tract. This suggests that the cell surface hydrophobicity is rather a feature of species or genus, but it is not related to the ecological niche of microorganisms in human body. 相似文献
92.
Janda I Devedjiev Y Derewenda U Dauter Z Bielnicki J Cooper DR Graf PC Joachimiak A Jakob U Derewenda ZS 《Structure (London, England : 1993)》2004,12(10):1901-1907
The bacterial heat shock protein Hsp33 is a redox-regulated chaperone activated by oxidative stress. In response to oxidation, four cysteines within a Zn2+ binding C-terminal domain form two disulfide bonds with concomitant release of the metal. This leads to the formation of the biologically active Hsp33 dimer. The crystal structure of the N-terminal domain of the E. coli protein has been reported, but neither the structure of the Zn2+ binding motif nor the nature of its regulatory interaction with the rest of the protein are known. Here we report the crystal structure of the full-length B. subtilis Hsp33 in the reduced form. The structure of the N-terminal, dimerization domain is similar to that of the E. coli protein, although there is no domain swapping. The Zn2+ binding domain is clearly resolved showing the details of the tetrahedral coordination of Zn2+ by four thiolates. We propose a structure-based activation pathway for Hsp33. 相似文献
93.
Sliwa A Góralska J Czech U Gruca A Polus A Zapała B Dembińska-Kieć A 《Acta biochimica Polonica》2012,59(1):39-41
Increased ROS generation by the overload by metabolic substrates mitochondria paralleled by decrease of antioxidant activity are typical events found in metabolic syndrome and diabetes type 2. Metabolites of beta-carotene (BC) such as retinoic acid (RA), as well as low concentration of reactive oxygen species (ROS) modify the mitochondrial bioenergetic function. The aim of the study was to investigate the effect of beta-carotene on mitochondrial activity in human preadipocytes. BC used in concentrations, 10 or 30 μM, decreased mitochondrial membrane potential, inhibited mitochondrial respiration and decreased cellular ATP content. We conclude, that BC, the known antioxidant may decrease oxidative phosphorylation capacity of mitochondria. 相似文献
94.
Magdalena Ostafin Michal Przemyslaw Pruchniak Olga Ciepiela Abraham Zeev Reznick Urszula Demkow 《Analytical biochemistry》2016
A unique strategy, in which invading microorganisms are being caught in web-like structures composed mainly of DNA, involves a recently described phenomenon called NETosis. This process seems to be related to the production of reactive oxygen species (ROS). In our study, the influence of diphenyleneiodonium chloride (DPI), which diminishes ROS production, was assessed in the context of neutrophil extracellular trap (NET) release. According to protocol, two distinguished procedures were compared, the first one involving DPI elimination from sample before cell activation and the second one proceeding without the step of inhibitor washout. The kinetics of DNA release was monitored by fluorometric assay, and NET formation was observed by fluorescent microscopy. The addition of DPI to the sample led to a reduction of extracellular DNA release. The strongest inhibition was noticed after treatment with 10 μM DPI, which was removed from medium before stimulation with phorbol-12-myristate-13-acetate (PMA). Our findings confirmed that DPI is able to block NET creation. However, the addition of DPI together with PMA or the addition of inhibitor initially and then washing it out before stimulation resulted in different levels of NET formation. Finally, DPI that remained in the system induced specific morphological changes in the neutrophils' nuclei that was not observed in the DPI washed out from sample. 相似文献
95.
96.
Siwek A Stączek P Wujec M Stefańska J Kosikowska U Malm A Jankowski S Paneth P 《Journal of molecular modeling》2011,17(9):2297-2303
4-Benzoyl-1-(4-methyl-imidazol-5-yl)-carbonylthiosemicarbazide (1) was synthesized, and its antibacterial and type IIA topoisomerase (DNA gyrase and topoisomerase IV) activity evaluated.
(1) was found to have high therapeutic potential against opportunistic Gram-positive bacteria, and inhibitory activity against
topoisomerase IV (IC50 = 90 μM) but not against DNA gyrase. An increase in activity against topoisomerase IV (IC50 = 14 μM) was observed when the imidazole moiety of (1) was replaced with the indole group in 4-benzoyl-1-(indol-2-yl)-carbonylthiosemicarbazide (2). However, (2) showed only weak antibacterial activity. Although the results of the bacterial type IIA topoisomerases inhibition study
did not parallel antibacterial activities, our observations strongly imply that a 4-benzoylthiosemicarbazide scaffold can
be developed into an efficient Gram-positive antibacterial targeting topoisomerase IV. The difference in activity against
type IIA topoisomerases between (1) and (2) was further investigated by docking studies, which suggested that these compounds target the ATP binding pocket. 相似文献
97.
Alexander H. Benz Christoph Renné Erik Maronde Marco Koch Urszula Grabiec Sonja Kallendrusch Benjamin Rengstl Sebastian Newrzela Sylvia Hartmann Martin-Leo Hansmann Faramarz Dehghani 《PloS one》2013,8(12)
Background
Cannabinoid receptor 1 (CB1) is expressed in certain types of malignancies. An analysis of CB1 expression and function in Hodgkin lymphoma (HL), one of the most frequent lymphomas, was not performed to date.Design and Methods
We examined the distribution of CB1 protein in primary cases of HL. Using lymphoma derived cell lines, the role of CB1 signaling on cell survival was investigated.Results
A predominant expression of CB1 was found in Hodgkin-Reed-Sternberg cells in a vast majority of classical HL cases. The HL cell lines L428, L540 and KM-H2 showed strong CB1-abundance and displayed a dose-dependent decline of viability under CB1 inhibition with AM251. Further, application of AM251 led to decrease of constitutively active NFκB/p65, a crucial survival factor of HRS-cells, and was followed by elevation of apoptotic markers in HL cells.Conclusions
The present study identifies CB1 as a feature of HL, which might serve as a potential selective target in the treatment of Hodgkin lymphoma. 相似文献98.
Katarzyna Robak Maria Balcerek Urszula Dziekońska-Kubczak Piotr Dziugan 《Biotechnology progress》2019,35(3):e2789
This research shows the effect of dilute acid pretreatment with various sulfuric acid concentrations (0.5–2.0% [wt/vol]) on enzymatic saccharification and fermentation yield of rye straw. After pretreatment, solids of rye straw were suspended in Na citrate buffer or post-pretreatment liquids (prehydrolysates) containing sugars liberated after hemicellulose hydrolysis. Saccharification was conducted using enzymes dosage of 15 or 25 FPU/g cellulose. Cellulose saccharification rate after rye straw pretreatment was enhanced by performing enzymatic hydrolysis in sodium citrate buffer in comparison with hemicellulose prehydrolysate. The maximum cellulose saccharification rate (69%) was reached in sodium citrate buffer (biomass pretreated with 2.0% [wt/vol] H2SO4). Lignocellulosic complex of rye straw after pretreatment was subjected to separate hydrolysis and fermentation (SHF) or separate hydrolysis and co-fermentation (SHCF). The SHF processes conducted in the sodium citrate buffer using monoculture of Saccharomyces cerevisiae (Ethanol Red) were more efficient compared to hemicellulose prehydrolysate in respect with ethanol yields. Maximum fermentation efficiency of SHF processes obtained after rye straw pretreatment at 1.5% [wt/vol] H2SO4 and saccharification using enzymes dosage of 25 FPU/g in sodium citrate buffer, achieving 40.6% of theoretical yield. However, SHCF process using cocultures of pentose-fermenting yeast, after pretreatment of raw material at 1.5% [wt/vol] H2SO4 and hydrolysis using enzymes dosage of 25 FPU/g, resulted in the highest ethanol yield among studied methods, achieving 9.4 g/L of ethanol, corresponding to 55% of theoretical yield. 相似文献
99.
An optimal control problem for cancer chemotherapy is considered that includes immunological activity. In the objective a
weighted average of several quantities that describe the effectiveness of treatment is minimized. These terms include (i)
the number of cancer cells at the terminal time, (ii) a measure for the immunocompetent cell densities at the terminal point
(included as a negative term), (iii) the overall amount of cytotoxic agents given as a measure for the side effects of treatment
and (iv) a small penalty on the terminal time that limits the overall therapy horizon which is assumed to be free. This last
term is essential in obtaining a well-posed problem formulation. Employing a Gompertzian growth model for the cancer cells,
for various scenarios optimal controls and corresponding responses of the system are calculated. Solutions initially follow
a full dose treatment, but then at one point switch to a singular regimen that only applies partial dosages. This structure
is consistent with protocols that apply an initial burst to reduce the tumor volume and then maintain a small volume through
lower dosages. Optimal controls end with either a prolonged period of no dose treatment or, in a small number of scenarios,
this no dose interval is still followed by one more short burst of full dose treatment. 相似文献
100.
Janecka A Fichna J Kosson P Zalewska-Kaszubska J Krajewska U Mirowski M Rozalski M 《Regulatory peptides》2004,120(1-3):237-241
In the present study, we reported on the synthesis of two new mu-opioid peptide analogs, [D-1-Nal3]morphiceptin and [D-1-Nal4]-morphiceptin [1-Nal=3-(1-naphthyl)-alanine] which expressed receptor binding affinities at least at the level of the primary opioid ligands. The new analogs also labeled mu-opioid receptors on the cells of human breast cancer MCF-7 cell line with affinity much higher than that of endomorphins and morphiceptin, the well-known mu-selective opioid peptides. However, none of the tested peptides significantly decreased cell proliferation of MCF-7 cells. 相似文献