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排序方式: 共有202条查询结果,搜索用时 15 毫秒
11.
Colocalization, physical, and functional interaction between Werner and Bloom syndrome proteins 总被引:1,自引:0,他引:1
von Kobbe C Karmakar P Dawut L Opresko P Zeng X Brosh RM Hickson ID Bohr VA 《The Journal of biological chemistry》2002,277(24):22035-22044
The RecQ helicase family comprises a conserved group of proteins implicated in several aspects of DNA metabolism. Three of the family members are defective in heritable diseases characterized by abnormal growth, premature aging, and predisposition to malignancies. These include the WRN and BLM gene products that are defective in Werner and Bloom syndromes, disorders which share many phenotypic and cellular characteristics including spontaneous genomic instability. Here, we report a physical and functional interaction between BLM and WRN. These proteins were coimmunoprecipitated from a nuclear matrix-solubilized fraction, and the purified recombinant proteins were shown to interact directly. Moreover, BLM and WRN colocalized to nuclear foci in three human cell lines. Two regions of WRN that mediate interaction with BLM were identified, and one of these was localized to the exonuclease domain of WRN. Functionally, BLM inhibited the exonuclease activity of WRN. This is the first demonstration of a physical and functional interaction between RecQ helicases. Our observation that RecQ family members interact provides new insights into the complex phenotypic manifestations resulting from the loss of these proteins. 相似文献
12.
Level of free polyamines, their key metabolic enzymes, and other features related to ageing were examined during stipule and pod wall development in pea (Pisum sativum). Free polyamine titre (per unit fresh mass) in both the organs, the specific activities of arginine decarboxylase and ornithine decarboxylase in the pod wall, gradually decreased with maturation. In stipule, these enzymes attained peak activity at 15 days after pod emergence and declined thereafter. Ornithine decarboxylase activity was greater in pod wall than in stipule; while, arginine decarboxylase activity was higher in stipule. Activity of degradative enzyme diamine oxidase increased with the onset of senescence in both the organs. Chlorophyll and electrical conductance had a inverse relationship throughout the experimental period, whereas, the chlorophyll content was directly related with polyamine levels in both stipule and pod wall during aging. On the other hand, protein and RNA contents were positively correlated with free polyamines throughout the test period in stipule, but in the pod wall this was true only for the later stages of development. 相似文献
13.
Rapid degradation of ferulic acid via 4-vinylguaiacol and vanillin by a newly isolated strain of bacillus coagulans 总被引:3,自引:0,他引:3
Karmakar B Vohra RM Nandanwar H Sharma P Gupta KG Sobti RC 《Journal of biotechnology》2000,80(3):195-202
A new strain Bacillus coagulans BK07 was isolated from decomposed wood-bark, based on its ability to grow on ferulic acid as a sole carbon source. This strain rapidly decarboxylated ferulic acid to 4-vinylguaiacol, which was immediately converted to vanillin and then oxidized to vanillic acid. Vanillic acid was further demethylated to protocatechuic acid. Above 95% substrate degradation was obtained within 7 h of growth on ferulic acid medium, which is the shortest period of time reported to date. The major degradation products, was isolated and identified by thin-layer chromatography, high performance liquid chromatography and 1H-nuclear magnetic resonance spectroscopy were 4-vinylguaiacol, vanillin, vanillic acid and protocatechuic acid. 相似文献
14.
A novel series of elliptical gold (Au0) nanoparticles (18–40 nm) embedded antimony glass (K2O-B2O3-Sb2O3) dichroic nanocomposites have been synthesized by a single-step melt-quench in-situ thermochemical reduction technique. X-ray
and selected area electron diffractions manifest growth of Au0 nanoparticles along the (111) and (200) crystallographic planes. The transmission electron microscopic image reveals elliptical
Au0 nanoparticles having an aspect ratio varying in the range 1.2–2.1. The dichroic behavior of the nanocomposites arises due
to elliptical shape of the Au0 nanoparticles. These nanocomposites show strong surface plasmon resonance (SPR) band of Au nanoparticles in the range 610–681 nm
and it exhibit red-shifts with increasing Au concentration. They, when co-doped with Sm2O3 and excited at 949 nm, exhibit about sevenfold enhancement of the upconverted red emission transition of 4G5/2→6H9/2 at 636 nm due to local electric field enhancement effect of Au0 nanoparticles induced by its SPR. These nanocomposites are the promising materials for laser, display, and various nanophotonic
applications. 相似文献
15.
Karmakar B Yakovenko K Kobyliansky E 《Anthropologischer Anzeiger; Bericht über die biologisch-anthropologische Literatur》2007,65(4):383-390
Qualitative finger and palmar dermatoglyphics of 547 individuals (293 males, 254 females) belonging to the Chuvashian population of Russia were studied to determine sexual dimorphism. The pattern types are not uniformly distributed on 10 fingers. Sex difference is homogeneous in all fingers whereas palmar patterns reflect the better sex variations for three palmar configurational areas (II, III, and IV). This is perhaps due to embryological development, having a relatively longer growth period compared with fingers (Cummins 1929). The present results of the Chuvashian population are not similar to the results of the five Indian populations of our previous study (Karmakar et al. 2002), perhaps due to a major ethnic difference. 相似文献
16.
Karmakar S Banik NL Patel SJ Ray SK 《Apoptosis : an international journal on programmed cell death》2007,12(11):2077-2087
Glioblastoma is the most prevalent and highly malignant brain tumor that continues to defy current treatment strategies. This
investigation used all-trans retinoic acid (ATRA) and taxol (TXL) as a combination therapy for controlling the growth of human glioblastoma T98G xenografted
in athymic nude mice. Histopathological examination revealed that ATRA induced differentiation and combination of ATRA and
TXL caused more apoptosis than either treatment alone. Combination therapy decreased expression of telomerase, nuclear factor
kappa B (NFκВ), and inhibitor-of-apoptosis proteins (IAPs) indicating suppression of survival factors while upregulated Smac/Diablo.
Combination therapy also changed expression of Bax and Bcl-2 proteins leading to increased Bax:Bcl-2 ratio, mitochondrial
release of cytochrome c and apoptosis-inducing factor (AIF), and activation of caspase-9. Increased activities of calpain and caspase-3 degraded
270 kD α-spectrin at the specific sites to generate 145 kD spectrin breakdown product (SBDP) and 120 kD SBDP, respectively.
Further, increased activity of caspase-3 cleaved inhibitor-of-caspase-activated DNase (ICAD). In situ double immunofluorescent
labelings showed overexpression of calpain, caspase-12, caspase-3, and AIF during apoptosis, suggesting involvement of both
caspase-dependent and caspase-independent pathways for apoptosis. Our investigation revealed that treatment of glioblastoma
T98G xenografts with the combination of ATRA and TXL induced differentiation and multiple molecular mechanisms for apoptosis. 相似文献
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19.
In order to preserve genetic information in stress conditions, bacterial DNA is organized into higher order nucleoid structure. In this paper, with the help of Atomic Force Microscopy, we show the different structural changes in mycobacterial nucleoid at different points of growth in the presence of different concentrations of glucose in the medium. We also observe that in Mycobacterium smegmatis, two different Dps proteins (Dps1 and Dps2) promote two types of nucleoid organizations. At the late stationary phase, under low glucose availability, Dps1 binds to DNA to form a very stable toroid structure. On the other hand, under the same condition, Dps2-DNA complex forms an incompletely condensed toroid and finally forms a further stable coral reef structure in the presence of RNA. This coral reef structure is stable in high concentration of bivalent ion like Mg(2+). 相似文献
20.
Advanced glycation end products (AGEs) are known to be involved in the pathogenesis of several diseases, in particular diabetes, via signaling through their receptor. Numerous studies have been carried out on protein-sugar interactions at very high concentrations of the latter. The objective of this investigation was to determine the effects of nonenzymatic glycation induced by reducing sugars on the secondary structure of human serum albumin (HSA) under different physiological conditions and to correlate that with expression of RAGE (receptor for advanced glycation end products) on HUVECs (human umbilical vein endothelial cells) in a controlled hemodynamic environment. Our results indicate that RAGE expression is shear stress modulated and that glycated HSA enhances the expression further. The secondary structure of AGE-HSA derived from glucose at 20 mM contains higher α-helical content and elicits maximum expression of the receptor. The effect of shear stress at 10 dynes cm(-2) is independent of AGE-HSA. 相似文献