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排序方式: 共有238条查询结果,搜索用时 31 毫秒
41.
Nikhil Baban Ghate Dipankar Chaudhuri Abhishek Das Sourav Panja Nripendranath Mandal 《PloS one》2015,10(5)
Free iron typically leads to the formation of excess free radicals, and additional iron deposition in the liver contributes to the oxidative pathologic processes of liver disease. Many pharmacological properties of the insectivorous plant Drosera burmannii Vahl. have been reported in previous studies; however, there is no evidence of its antioxidant or hepatoprotective potential against iron overload. The antioxidant activity of 70% methanolic extract of D. burmannii (DBME) was evaluated. DBME showed excellent DPPH, hydroxyl, hypochlorous, superoxide, singlet oxygen, nitric oxide, peroxynitrite radical and hydrogen peroxide scavenging activity. A substantial iron chelation (IC50 = 40.90 ± 0.31 μg/ml) and supercoiled DNA protection ([P]50 = 50.41 ± 0.55 μg) were observed. DBME also displayed excellent in vivo hepatoprotective activity in iron-overloaded Swiss albino mice compared to the standard desirox treatment. Administration of DBME significantly normalized serum enzyme levels and restored liver antioxidant enzymes levels. DBME lowered the raised levels of liver damage parameters, also reflected from the morphological analysis of the liver sections. DBME also reduced liver iron content by 115.90% which is also seen by Perls’ staining. A phytochemical analysis of DBME confirms the presence of various phytoconstituents, including phenols, flavonoids, carbohydrates, tannins, alkaloids and ascorbic acid. Alkaloids, phenols and flavonoids were abundantly found in DBME. An HPLC analysis of DBME revealed the presence of purpurin, catechin, tannic acid, reserpine, methyl gallate and rutin. Purpurin, tannic acid, methyl gallate and rutin displayed excellent iron chelation but exhibited cytotoxicity toward normal (WI-38) cells; while DBME found to be non-toxic to the normal cells. These findings suggest that the constituents present in DBME contributed to its iron chelation activity. Additional studies are needed to determine if DBME can be used as a treatment for iron overload diseases. 相似文献
42.
We isolated and sequenced a cDNA encoding mouse proteasome subunit LMP3 from a macrophage cDNA library. The gene encodes a 264-amino-acid protein with a calculated molecular mass of 29.11 kDa and an isoelectric point (pl) of 5.44. Comparison of the predicted protein sequence with that of the human and rat homologues, N3, revealed 11 and eight changes, respectively, in the cleaved NH2-terminal presequence of the precursor protein (pre-LMP3), and six and 10 changes, respectively, in the processed product. To corroborate the predicted molecular mass and pI, we analyzed LMP3 by immunoprecipitation with a mAb to human N3 that crossreacts with mouse LMP3. Precursor and processed forms of LMP3 were identified by 2D NEPHGE-PAGE, and their mobilities suggest the Lmp3 clone encodes the entire protein sequence. 相似文献
43.
miRISC and the CCR4–NOT complex silence mRNA targets independently of 43S ribosomal scanning 下载免费PDF全文
Duygu Kuzuoğlu‐Öztürk Dipankar Bhandari Eric Huntzinger Maria Fauser Sigrun Helms Elisa Izaurralde 《The EMBO journal》2016,35(11):1186-1203
miRNAs associate with Argonaute (AGO) proteins to silence the expression of mRNA targets by inhibiting translation and promoting deadenylation, decapping, and mRNA degradation. A current model for silencing suggests that AGOs mediate these effects through the sequential recruitment of GW182 proteins, the CCR4–NOT deadenylase complex and the translational repressor and decapping activator DDX6. An alternative model posits that AGOs repress translation by interfering with eIF4A function during 43S ribosomal scanning and that this mechanism is independent of GW182 and the CCR4–NOT complex in Drosophila melanogaster. Here, we show that miRNAs, AGOs, GW182, the CCR4–NOT complex, and DDX6/Me31B repress and degrade polyadenylated mRNA targets that are translated via scanning‐independent mechanisms in both human and Dm cells. This and additional observations indicate a common mechanism used by these proteins and miRNAs to mediate silencing. This mechanism does not require eIF4A function during ribosomal scanning. 相似文献
44.
Influence of cropping and N-fertilization on changes in different forms of nitrogen in an alluvial soil 总被引:7,自引:0,他引:7
Water was sampled from an acid forest soil 1 year after a Sitka spruce crop had been clear-felled. In samples extracted using
porous ceramic cups, total dissolved nitrogen varied according to depth from 2.6 to 3.6 mg.l−1. In the organic horizons, dissolved nitrogen was mainly in organic form. As it passed down the profile, it was progressively
transformed to nitrate. Nitrification was obviously active in this acid soil. The role of dissolved organic nitrogen should
not be underestimated in nutrient cycling studies. 相似文献
45.
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47.
Lauck M Alvarado-Mora MV Becker EA Bhattacharya D Striker R Hughes AL Carrilho FJ O'Connor DH Pinho JR 《Journal of virology》2012,86(7):3952-3960
Hepatitis C virus (HCV) is the leading cause of liver disease worldwide. In this study, we analyzed four treatment-naïve patients infected with subtype 1a and performed Roche/454 pyrosequencing across the coding region. We report the presence of low-level drug resistance mutations that would most likely have been missed using conventional sequencing methods. The approach described here is broadly applicable to studies of viral diversity and could help to improve the efficacy of direct-acting antiviral agents (DAA) in the treatment of HCV-infected patients. 相似文献
48.
The ubiquitin-proteasome system 总被引:10,自引:0,他引:10
The 2004 Nobel Prize in chemistry for the discovery of protein ubiquitination has led to the recognition of cellular proteolysis
as a central area of research in biology. Eukaryotic proteins targeted for degradation by this pathway are first ‘tagged’
by multimers of a protein known as ubiquitin and are later proteolyzed by a giant enzyme known as the proteasome. This article
recounts the key observations that led to the discovery of ubiquitin-proteasome system (UPS). In addition, different aspects
of proteasome biology are highlighted. Finally, some key roles of the UPS in different areas of biology and the use of inhibitors
of this pathway as possible drug targets are discussed. 相似文献
49.
Rita Ghosh Sudipta Bhowmik Angshuman Bagchi Dipankar Das Somnath Ghosh 《European biophysics journal : EBJ》2010,39(8):1243-1249
Acridines and their derivatives are well-known probes for nucleic acids as well as being relevant in the field of drug development
to establish new chemotherapeutic agents. We have shown from molecular modelling studies that 9-phenyl acridine and some of
its derivatives can act as inhibitors of topoisomerase I and thus have potential to act as anticancer agents. Rational design
of new compounds for therapeutics requires knowledge about their structural stability and interactions with various cellular
macromolecules. In this regard it is important to know how these molecules would interact with DNA. Here we report the interaction
of 9-phenyl acridine (ACPH) with calf thymus DNA (CT-DNA) based on various biophysical and molecular modelling studies. Spectrophotometric
studies indicated that ACPH binds to CT-DNA. DNA melting studies revealed that binding of ACPH to CT-DNA resulted in a small
increase in melting temperature, which is unlikely in case of classical intercalator; rather, it indicates external binding.
Viscosity measurements show that ACPH exhibits groove binding. Competitive binding of ACPH to CT-DNA pre-bound to ethidium
bromide (EB) showed slow quenching. Measurement of the binding constant of ACPH by fluorescent intercalator displacement (FID)
assay corroborated the notion that there was groove binding. Molecular modelling studies also supported this finding. Results
indicate that binding of ACPH is through partial intercalation in the minor groove of DNA. 相似文献
50.
Shreya Datta Megan E. Bucks Dipankar Koley Pei Xin Lim Sergey N. Savinov 《Bioorganic & medicinal chemistry》2010,18(16):6099-6108
Upregulation of structurally homologous oncoproteins Hdm2 and Hdmx has been linked to the depletion or inactivation of their common regulation target the tumor suppressor p53 protein leading to the progression of cancer. The restoration of the p53 function, rendered suppressed or dormant by these negative regulators, establishes, therefore, a unique opportunity for a targeted induction of apoptosis in cancers that retain wild-type p53. While several small molecules have been reported to rescue the tumor suppressor by antagonizing the Hdm2–p53 interaction, these agents displayed limited application scope by being ineffective in tumors enriched with active Hdmx. Here, we describe the use of a genetic selection system and encoded library of conformationally pre-organized peptides to perform functional profiling of each regulator revealing specific recognition features that guide the antagonism of Hdm2–p53 and Hdmx–p53 interactions. Structure–activity relationship analysis of the most effective leads identified functional and structural elements mediating selective recognition of the two structurally related regulators, while providing convenient starting points for further activity optimization. 相似文献