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51.
Regulation of cyclin-dependent kinase inhibitor p21<Superscript>WAF1/CIP1</Superscript> by protein kinase Cδ-mediated phosphorylation 总被引:1,自引:0,他引:1
Oh YT Chun KH Park BD Choi JS Lee SK 《Apoptosis : an international journal on programmed cell death》2007,12(7):1339-1347
Cyclin-dependent kinase (CDK) inhibitor p21WAF1/CIP1(-/-)-null mice have an increased incidence of tumor formation. Here, we demonstrate that p21WAF1/CIP1 is unstable in HeLa cells treated with siRNA duplexes that target PKCδ. PKCδ phosphorylates p21WAF1/CIP1 at a serine residue (146Ser) located in its C-terminal domain. In cells treated with 12-O-tetradecanoylphorbol 13-acetate, the levels of both p21WAF1/CIP1 and its 146Ser-phosphorylated form increased significantly. We also show that a substitution, resulting from a single nucleotide polymorphism
(SNP) at 149Asp found in certain cancer patients, strongly compromises PKCδ-mediated phosphorylation at 146Ser and results in cells that are relatively resistant to TNFα-induced apoptosis. Thus, post-translational phosphorylation
of p21WAF1/CIP1 is important from an apoptotic cell death, and may also have patho-physiological relevance for the development of human cancer. 相似文献
52.
Kang S Kim EY Bahn YJ Chung JW Lee do H Park SG Yoon TS Park BC Bae KH 《Cellular & molecular biology letters》2007,12(1):139-147
Oxidative stress has been implicated in the pathogenesis of neuronal degenerative diseases. It is also widely known that oxidative
stress induces mitogen-activated protein kinase (MAPK) signaling cascades. In this study, we used proteomic analysis to investigate
the role of the MAPK pathway in oxidative stress-induced neuronal cell death. The results demonstrated that several proteins,
including eukaryotic translation elongation factor 2 (eEF2) and enolase I, showed a differential expression pattern during
the neuronal cell death process, and this was MAPK pathway dependent. Several chaperone and cytoskeletal proteins including
heat shock protein 70, calreticulin, vimentin, prolyl 4-hydroxylase β polypeptide, and transgelin 2 were up-or down-regulated,
despite their expressions not depending on the MAPK pathway. These findings strongly suggest that the expressions of proteins
which play protective roles are independent of the MAPK pathway. On the other hand, eEF2 and enolase I may be the downstream
targets of the MAPK pathway. 相似文献
53.
Moon HR Park AY Kim KR Chun MW Jeong LS 《Nucleosides, nucleotides & nucleic acids》2007,26(10-12):1653-1657
Novel L-bicyclocarba-d4T (1), an enantiomer of D-N-MCd4T has been enantiopurely synthesized as a potent anti-HIV agent starting from (R)-epichlorohydrin using tandem alkylation, chemoselective reduction of ester in the presence of lactone functional group, Grignard reaction, RCM reaction, and Mitsunobu reaction as key steps. L-N-MCd4T (1) was found to be very potent anti-HIV-1 (EC(50) = 6.76 microg/mL) agent with no cytotoxicity. 相似文献
54.
Jeong LS Gunaga P Kim HO Tosh DK Lee HW Choe SA Moon HR Gao ZG Jacobson KA Chun MW 《Nucleosides, nucleotides & nucleic acids》2007,26(8-9):1011-1014
Stereoselective functionalization of the 1'-position of 4'-thionucleosides was achieved using a stereoselective S(N)2 reaction controlled by 5-membered ring coordination. 相似文献
55.
Jeong LS Lee JA Kim HO Tosh DK Moon HR Lee SJ Lee KM Sheen YY Chun MW 《Nucleosides, nucleotides & nucleic acids》2007,26(8-9):1021-1024
Novel 2'-C-methyl-cyclopropyl-fused carbocyclic nucleosides as potential anti-HCV agents were stereoselectively synthesized, utilizing regioselective cleavage of the isopropylidene group and cyclic sulfate chemistry as key steps. 相似文献
56.
Chun MW Lee HW Kim JH Kim HO Lee KM Pal S Moon HR Jeong LS 《Nucleosides, nucleotides & nucleic acids》2007,26(6-7):729-732
Homo-apioneplanocin A (1) as a potential inhibitor of S-adenosylhomocysteine hydrolase was synthesized from D-ribose, employing stereoselective hydroxymethylation, regioselective oxidation, and regio- and chemoselective hydroboration as key steps. 相似文献
57.
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59.
A novel one-step electrochemical method for DNA detection is described. The procedure utilizes a reaction catalyzed by a peroxidase-mimicking DNAzyme to produce a product, which forms an insoluble precipitation layer on the surface of an electrode. A rationally designed forward primer, conjugated with a peroxidase DNAzyme complementary sequence at its 5′-end, is used for PCR amplification of target DNA. As a result, the DNAzyme sequence is produced by amplification only when the target DNA is present in the sample. The PCR product is then subjected to the precipitation reaction on the electrode surface using an electrolyte assay buffer containing 4-chloronaphthol, hydrogen peroxide, ferrocenemethanol, hemin, and 5′-lambdaexonuclease. Finally, analysis is carried out using Faradaic impedance spectroscopy. The impedance value was found to greatly increase when target DNA is present owing to the formation of a precipitation layer on the electrode surface caused by the catalytic action of the DNAzyme. In contrast, no impedance increase is observed when a control sample not containing target DNA is utilized. By employing this strategy, target DNA from Chlamydia trachomatis was reliably detected within a 10 min period following precipitation without the need for complicated secondary procedures. This effort has led to the development of a highly convenient electrochemical one-step method for DNA detection that utilizes a peroxidase-mimicking DNAzyme, which is specifically designed to undergo amplification during PCR of target DNA. 相似文献
60.
Kim BC Zhao X Ahn HK Kim JH Lee HJ Kim KW Nair S Hsiao E Jia H Oh MK Sang BI Kim BS Kim SH Kwon Y Ha S Gu MB Wang P Kim J 《Biosensors & bioelectronics》2011,26(5):1980-1986
This paper describes highly stable enzyme precipitate coatings (EPCs) on electrospun polymer nanofibers and carbon nanotubes (CNTs), and their potential applications in the development of highly sensitive biosensors and high-powered biofuel cells. EPCs of glucose oxidase (GOx) were prepared by precipitating GOx molecules in the presence of ammonium sulfate, then cross-linking the precipitated GOx aggregates on covalently attached enzyme molecules on the surface of nanomaterials. EPCs-GOx not only improved enzyme loading, but also retained high enzyme stability. For example, EPC-GOx on CNTs showed a 50 times higher activity per unit weight of CNTs than the conventional approach of covalent attachment, and its initial activity was maintained with negligible loss for 200 days. EPC-GOx on CNTs was entrapped by Nafion to prepare enzyme electrodes for glucose sensors and biofuel cells. The EPC-GOx electrode showed a higher sensitivity and a lower detection limit than an electrode prepared with covalently attached GOx (CA-GOx). The CA-GOx electrode showed an 80% drop in sensitivity after thermal treatment at 50°C for 4 h, while the EPC-GOx electrode maintained its high sensitivity with negligible decrease under the same conditions. The use of EPC-GOx as the anode of a biofuel cell improved the power density, which was also stable even after thermal treatment of the enzyme anode at 50°C. The excellent stability of the EPC-GOx electrode together with its high current output create new potential for the practical applications of enzyme-based glucose sensors and biofuel cells. 相似文献