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排序方式: 共有550条查询结果,搜索用时 187 毫秒
31.
David Bednar Koen Beerens Eva Sebestova Jaroslav Bendl Sagar Khare Radka Chaloupkova Zbynek Prokop Jan Brezovsky David Baker Jiri Damborsky 《PLoS computational biology》2015,11(11)
There is great interest in increasing proteins’ stability to enhance their utility as biocatalysts, therapeutics, diagnostics and nanomaterials. Directed evolution is a powerful, but experimentally strenuous approach. Computational methods offer attractive alternatives. However, due to the limited reliability of predictions and potentially antagonistic effects of substitutions, only single-point mutations are usually predicted in silico, experimentally verified and then recombined in multiple-point mutants. Thus, substantial screening is still required. Here we present FireProt, a robust computational strategy for predicting highly stable multiple-point mutants that combines energy- and evolution-based approaches with smart filtering to identify additive stabilizing mutations. FireProt’s reliability and applicability was demonstrated by validating its predictions against 656 mutations from the ProTherm database. We demonstrate that thermostability of the model enzymes haloalkane dehalogenase DhaA and γ-hexachlorocyclohexane dehydrochlorinase LinA can be substantially increased (ΔT
m = 24°C and 21°C) by constructing and characterizing only a handful of multiple-point mutants. FireProt can be applied to any protein for which a tertiary structure and homologous sequences are available, and will facilitate the rapid development of robust proteins for biomedical and biotechnological applications. 相似文献
32.
Shakri Banerjee Trina Dutta Sagar Lahiri Shinjinee Sengupta Anushila Gangopadhyay Suresh Kumar Karri Sandeep Chakraborty Debasish Bhattacharya Anil K. Ghosh 《Biochemistry and Biophysics Reports》2015
BackgroundsSpontaneous deamidation and isoaspartate (IsoAsp) formation contributes to aging and reduced longevity in cells. A protein-l-isoaspartate (d-aspartate) O-methyltransferase (PCMT) is responsible for minimizing IsoAsp moieties in most organisms.MethodsPCMT was purified in its native form from yeast Candida utilis. The role of the native PCMT in cell survival and protein repair was investigated by manipulating intracellular PCMT levels with Oxidized Adenosine (AdOx) and Lithium Chloride (LiCl). Proteomic Identification of possible cellular targets was carried out using 2-dimensional gel electrophoresis, followed by on-Blot methylation and mass spectrometric analysis.ResultsThe 25.4 kDa native PCMT from C. utilis was found to have a Km of 3.5 µM for AdoMet and 33.36 µM for IsoAsp containing Delta Sleep Inducing Peptide (DSIP) at pH 7.0. Native PCMT comprises of 232 amino acids which is coded by a 698 bp long nucleotide sequence. Phylogenetic comparison revealed the PCMT to be related more closely with the prokaryotic homologs. Increase in PCMT levels in vivo correlated with increased cell survival under physiological stresses. PCMT expression was seen to be linked with increased intracellular reactive oxygen species (ROS) concentration. Proteomic identification of possible cellular substrates revealed that PCMT interacts with proteins mainly involved with cellular housekeeping. PCMT effected both functional and structural repair in aged proteins in vitro.General significanceIdentification of PCMT in unicellular eukaryotes like C. utilis promises to make investigations into its control machinery easier owing to the familiarity and flexibility of the system. 相似文献
33.
Li Y Sagar MB Wassler M Shelat H Geng YJ 《Biochemical and biophysical research communications》2007,357(1):157-161
Over-consumption of ethanol (EtOH) represents a major health problem. This study was to test the cytotoxicity of EtOH in cardiac stem cells or myoblasts, and the potential protective effect of apolipoprotein-J (ApoJ), a stress-responding, chaperone-like protein in high-density lipoprotein, on EtOH-injured cardiac myoblasts. In culture, EtOH-exposed canine fetal myoblasts underwent apoptosis in a concentration- and time-dependent manner. Expression ApoJ by cDNA transfection markedly reduced EtOH-induced apoptosis in the cells. ApoJ expression also restored partially the mitochondrial membrane potential and prevented the release of cytochrome-c from mitochondria into cytoplasma. Thus, ApoJ serves as a cytoprotective protein that protects cardiac stem cells against EtOH cytotoxicity. 相似文献
34.
Jayesh Sagar Boussad Chaib Kevin Sales Marc Winslet Alexander Seifalian 《Cancer cell international》2007,7(1):9
For over 30 years, stem cells have been used in the replenishment of blood and immune systems damaged by the cancer cells
or during treatment of cancer by chemotherapy or radiotherapy. Apart from their use in the immuno-reconstitution, the stem
cells have been reported to contribute in the tissue regeneration and as delivery vehicles in the cancer treatments. The recent
concept of 'cancer stem cells' has directed scientific communities towards a different wide new area of research field and
possible potential future treatment modalities for the cancer. Aim of this review is primarily focus on the recent developments
in the use of the stem cells in the cancer treatments, then to discuss the cancer stem cells, now considered as backbone in
the development of the cancer; and their role in carcinogenesis and their implications in the development of possible new
cancer treatment options in future. 相似文献
35.
Dalal Subhamita Adhikary Jayashree Roy Anup Biswas Shampa Sarkar Mukhopadhyay Prabir Kumar Acharya Sagar Ghosh Amlan 《Molecular biology reports》2022,49(9):8369-8380
Molecular Biology Reports - On the background of the epidemiological link between diabetes and oral cancer, the present study aimed to analyze the potential involvement of selected glucose... 相似文献
36.
37.
BackgroundThe initial next-generation sequencing technologies produced reads of 25 or 36 bp, and only from a single-end of the library sequence. Currently, it is possible to reliably produce 300 bp paired-end sequences for RNA expression analysis. While read lengths have consistently increased, people have assumed that longer reads are more informative and that paired-end reads produce better results than single-end reads. We used paired-end 101 bp reads and trimmed them to simulate different read lengths, and also separated the pairs to produce single-end reads. For each read length and paired status, we evaluated differential expression levels between two standard samples and compared the results to those obtained by qPCR.ResultsWe found that, with the exception of 25 bp reads, there is little difference for the detection of differential expression regardless of the read length. Once single-end reads are at a length of 50 bp, the results do not change substantially for any level up to, and including, 100 bp paired-end. However, splice junction detection significantly improves as the read length increases with 100 bp paired-end showing the best performance. We performed the same analysis on two ENCODE samples and found consistent results confirming that our conclusions have broad application.ConclusionsA researcher could save substantial resources by using 50 bp single-end reads for differential expression analysis instead of using longer reads. However, splicing detection is unquestionably improved by paired-end and longer reads. Therefore, an appropriate read length should be used based on the final goal of the study.
Electronic supplementary material
The online version of this article (doi:10.1186/s13059-015-0697-y) contains supplementary material, which is available to authorized users. 相似文献38.
The present study is focused on purification, characterization and comparison of phycoerythrins from three different marine cyanobacterial cultures--hormidium sp. A27 DM, Lyngbya sp. A09 DM and Halomicronema sp. A32 DM. 'Phycoerythrin' was successfully purified and characterized. On SDS-PAGE, the PE purified from all three young cultures showed four bands--corresponding to α and β subunits of each of PE-I and PE-II. However, phycoerythrin purified after prolonged growth of Phormidium sp. A27 DM and Halomicronema sp. A32DM showed only one band corresponding to 14 kDa whereas Lyngbya sp. A09 DM continued to produce uncleaved phycoerythrin. The absorption spectra of purified PEs from all the three young and old cultures showed variations however the fluorescence studies of the purified PEs in all cases gave the emission spectra at around 580 nm. The described work is of great importance to understand the role of phycoerythrin in adapting cyanobacteria to stress conditions. 相似文献
39.
Tyrosine phosphorylation of mitochondrial pyruvate dehydrogenase kinase 1 is important for cancer metabolism 总被引:1,自引:0,他引:1
Hitosugi T Fan J Chung TW Lythgoe K Wang X Xie J Ge Q Gu TL Polakiewicz RD Roesel JL Chen GZ Boggon TJ Lonial S Fu H Khuri FR Kang S Chen J 《Molecular cell》2011,44(6):864-877
Many tumor cells rely on aerobic glycolysis instead of oxidative phosphorylation for their continued proliferation and survival. Myc and HIF-1 are believed to promote such a metabolic switch by, in part, upregulating gene expression of pyruvate dehydrogenase (PDH) kinase 1 (PDHK1), which phosphorylates and inactivates mitochondrial PDH and consequently pyruvate dehydrogenase complex (PDC). Here we report that tyrosine phosphorylation enhances PDHK1 kinase activity by promoting ATP and PDC binding. Functional PDC can form in mitochondria outside of the matrix in some cancer cells and PDHK1 is commonly tyrosine phosphorylated in human cancers by diverse oncogenic tyrosine kinases localized to different mitochondrial compartments. Expression of phosphorylation-deficient, catalytic hypomorph PDHK1 mutants in cancer cells leads to decreased cell proliferation under hypoxia and increased oxidative phosphorylation with enhanced mitochondrial utilization of pyruvate and reduced tumor growth in xenograft nude mice. Together, tyrosine phosphorylation activates PDHK1 to promote the Warburg effect and tumor growth. 相似文献
40.
Stimulation of the tail nerve (pedal nerve 9, p9) of the mollusk, Aplysia
californica, causes release of serotonin (5-HT), which mediates sensitization of withdrawal responses. There are about 35 serotonin-immunoreactive
(5-HT-ir) axons in p9, yet the cell bodies of these axons have not been located. Backfills of p9 were combined with 5-HT immunohistochemistry
to locate the cell bodies of 5-HT-ir neurons with axons in p9. About 100 neurons had axons in p9. Only about ten neurons,
however, were both backfilled and 5-HT-ir. These double-labeled neurons were all located in the pedal ganglion associated
with p9, which had a total of approximately 42 5-HT-ir somata. The discrepancy between the number of 5-HT-ir axons and double-labeled
cell bodies is not likely due to neurons having multiple axons in the nerve; intracellular fills suggest that these neurons
do not branch before entering p9. Additionally, no evidence was found for peripheral 5-HT-ir cell bodies that project axons
centrally through p9. Thus, approximately 70% of the neurons that give rise to the 5-HT-ir axons in tail nerve are unaccounted
for, but likely to reside in the pedal ganglion. 相似文献