全文获取类型
收费全文 | 84篇 |
免费 | 1篇 |
国内免费 | 1篇 |
专业分类
86篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2014年 | 7篇 |
2013年 | 9篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2010年 | 5篇 |
2009年 | 4篇 |
2008年 | 9篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 3篇 |
2004年 | 4篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1992年 | 2篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有86条查询结果,搜索用时 15 毫秒
1.
R Manjunath S I Chung A B Mukherjee 《Biochemical and biophysical research communications》1984,121(1):400-407
Uteroglobin, a progesterone induced, pregnancy related protein, can be incorporated into higher molecular weight proteins by human placental Factor XIIIa. This process is time dependent, requires CaCl2 and can be inhibited by the addition of polylysine, dansylcadavarine or histamine. Crosslinking of uteroglobin into higher molecular weight proteins can also be brought about by guinea pig liver transglutaminase. Such a process may be involved in the modification of epididymal spermatozoa to suppress their antigenicity. 相似文献
2.
Treatment of Sendai virus with , followed by freezing and thawing resulted in a loss of hemolytic and cell fusion activities as well as infectivity without affecting hemagglutinating and neuraminidase activities. The anti-hemolytic activity of this compound was reversed by the addition of phosphatidyl choline to the virus samples. was successfully used for photoaffinity labeling of a specific virion site, and we confirmed the affected site of the glucoside to be the lipid components in the viral envelopes. 相似文献
3.
Rapid and highly sensitive electrochemical determination of alkaline phosphatase using a composite tyrosinase biosensor 总被引:1,自引:0,他引:1
The use of an amperometric graphite-Teflon composite tyrosinase biosensor for the rapid monitoring of alkaline phosphatase (ALP), with no need of an incubation step and using phenyl phosphate as the substrate, is reported. Phenol generated by the action of ALP is monitored at the tyrosinase composite electrode through the electrochemical reduction of the o-quinone produced to catechol, which produces a cycle between the tyrosinase substrate and the electroactive product, giving rise to the amplification of the biosensor response and to the sensitive detection of ALP. The current was measured at -0.10 V 5 min after the addition of ALP. As a compromise between high ALP activity and high sensitivity for the detection of phenol, a pH of 8.5 was chosen. The substrate concentration was also optimized. A linear calibration plot was obtained for ALP between 2.0 x 10(-13) and 2.5 x 10(-11), with a detection limit of 6.7 x 10(-14) M. Different types of milk were analyzed with good results, using an extremely simple and rapid procedure. 相似文献
4.
Yan Du Mei‐ju Zhang Lan‐lan Li Xiao‐Lin Xu Hao Chen Yu‐bin Feng Yan Li Xiao‐qin Peng Fei‐hu Chen 《Journal of cellular and molecular medicine》2020,24(12):6952-6965
Acute myeloid leukaemia (AML) remains a therapeutic challenge and improvements in chemotherapy are needed. 4‐Amino‐2‐trifluoromethyl‐phenyl retinate (ATPR), a novel all‐trans retinoic acid (ATRA) derivative designed and synthesized by our team, has been proven to show superior anticancer effect compared with ATRA on various cancers. However, its potential effect on AML remains largely unknown. Lactate dehydrogenase B (LDHB) is the key glycolytic enzyme that catalyses the interconversion between pyruvate and lactate. Currently, little is known about the role of LDHB in AML. In this study, we found that ATPR showed antileukaemic effects with RARα dependent in AML cells. LDHB was aberrantly overexpressed in human AML peripheral blood mononuclear cell (PBMC) and AML cell lines. A lentiviral vector expressing LDHB‐targeting shRNA was constructed to generate a stable AML cells with low expression of LDHB. The effect of LDHB knockdown on differentiation and cycle arrest of AML cells was assessed in vitro and vivo, including involvement of Raf/MEK/ERK signalling. Finally, these data suggested that ATPR showed antileukaemic effects by RARα/LDHB/ ERK‐glycolysis signalling axis. Further studies should focus on the underlying leukaemia‐promoting mechanisms and investigate LDHB as a therapeutic target. 相似文献
5.
Humayun Pervez Mohammad S. Iqbal Muhammad Younas Tahir Faiz-ul-Hassan Nasim Muhammad Iqbal Choudhary Khalid Mohammed Khan 《Journal of enzyme inhibition and medicinal chemistry》2013,28(6):848-854
A series of 15 previously reported N4-substituted isatin-3-thiosemicarbazones 3a-o has been screened for cytotoxic, antibacterial, antifungal and urease inhibitory activities. Compounds 3b, 3e and 3n proved to be active in cytotoxicity assay; 3e exhibited a high degree of cytotoxic activity (LD50 = 1.10 × 10? 5 M). Compound 3h exhibited significant antibacterial activity against B. subtilis, whereas compounds 3a, 3k and 3l displayed significant antifungal activity against one or more fungal strains i.e. T. longifusus, A. flavus and M. canis. In human urease enzyme inhibition assay, compounds 3g, 3k and 3m proved to be the most potent inhibitors, exhibiting relatively pronounced inhibition of the enzyme. These compounds, being non-toxic, could be potential candidates for orally effective therapeutic agents to treat certain clinical conditions induced by bacterial ureases like H. pylori urease. This study presents the first example of inhibition of urease by isatin-thiosemicarbazones and as such provides a solid basis for further research on such compounds to develop more potent inhibitors. 相似文献
6.
The nuclearity, bonding and H-bonded networks of copper(I) halide complexes with thiophene-2-carbaldehyde thiosemicarbazones {(C4H3S)HC2N3-N(H)-C1(S)N1HR} are influenced by R substituents at N1 atom. Thiophene-2-carbaldehyde-N1-methyl thiosemicarbazone (HttscMe) or thiophene-2-carbaldehyde-N1-ethyl thiosemicarbazone (HttscEt) have yielded halogen-bridged dinuclear complexes, [Cu2(μ-X)2(η1-S-Htsc)2(Ph3P)2] (Htsc, X: HttscMe, I, 1; Br, 2; Cl, 3; HttscEt, I, 4; Br, 5; Cl, 6), while thiophene-2-carbaldehyde-N1-phenyl thiosemicarbazone (HttscPh) has yielded mononuclear complexes, [CuX(η1-S-HttscPh)2] (X, I, 7a; Br 8; Cl, 9) and a sulfur bridged dinuclear complex, [Cu2(μ-S-HttscPh)2(η1-S-HttscPh)2I2] 7b co-existing with 7a in the same unit cell. These results are in contrast to S-bridged dimers [Cu2(μ-S-Httsc)2(η1-Br)2(Ph3P)2] · 2H2O and [Cu2(μ-S-Httsc)2(η1-Cl)2(Ph3P)2] · 2CH3CN obtained for R = H and X = Cl, Br (Httsc = thiophene-2-carbaldehyde thiosemicarbazone) as reported earlier. The intermolecular CHPh?π interaction in 1-3 (2.797 Å, 1; 3.264 Å, 2; 3.257 Å, 3) have formed linear polymers, whereas the CHPh?X and N3?HCH interactions in 4-6 (2.791, 2.69 Å, 5; 2.776, 2.745 Å, 6, respectively) have led to the formation of H-bonded 2D polymer. The PhN1H?π, interactions (2.547 Å, 8, 2.599 Å, 9) have formed H-bonded dimers only. The Cu?Cu separations are 3.221-3.404 Å (1-6). 相似文献
7.
To study the role the phenyl group plays in producing local anesthetic block, a sequence of n-alkanols and phenyl-substituted alkanols (Φ-alkanols) were characterized in their ability to block Na channels. The sequence
of n-alkanols studied possess 3–5 carbons (propanol-pentanol). The action of phenol and 3-Φ-alkanols (benzyl alcohol, phenethyl
alcohol, 3-phenyl-1-propanol) were also studied. Na currents (I
Na
) were recorded from single frog skeletal muscle fibers using the Vaseline-gap voltage clamp technique. I
Na
s were recorded prior to, during, and following the removal of the solutes in Ringer's solution.
All alkanols and phenol acted to block I
Na
in a dose-dependent manner. Effective doses to produce half block (ED50) of I
Na
or Na conductance (G
Na
) were obtained from dose-response relations for all solutes used. The block of G
Na
depended on voltage, and could be separated into voltage-dependent and -independent components. Each solute acted to shift
G
Na
-V relations in a depolarized direction and reduce the maximum G
Na
and slope of the relation. All solutes acted to speed up I
Na
kinetics and cause hyperpolarizing shifts in steady-state inactivation. The magnitude of the kinetic changes increased with
dose.
Size was an important variable in determining the magnitude of the changes in I
Na
; however, size alone was not sufficient to predict the changes in I
Na
. ED50s for G
Na
and AP block could be predicted as a function of intrinsic molar volume, hydrogen bond acceptor basicity (β) and donor acidity
(α), and polarity (P) of the solutes.
The equivalency of ED50 predictions for AP and G
Na
block can be explained by the fact that AP block arises from channel block and solute-induced changes in I
Na
kinetics. Φ-alkanols were more effective at blocking and inactivating Na channels than their unsubstituted counterparts.
Phenyl-substituted alkanols are more likely to interact with the channel than their unsubstituted counterparts.
Received: 11 August 2000/Revised: 21 December 2000 相似文献
8.
Chen S 《Amino acids》2004,26(3):291-298
Summary. A variety of -amino acids are enantioresolved for the first time on naphthylethylcarbamate--cyclodextrin bonded phases (i.e., SN- and RN--CD) using the acetonitrile-based mobile phase after their pre-column derivatization with phenyl isothiocyanate in alkaline medium. The resolution is better obtained on RN--CD phase and fails to reproduce if the amino acid is N-benzoylated or N-carbobenzyloxylated under the same chromatographic conditions. The enhanced resolution is believed to be due to the re-location of the hydrogen receptor site from sulfur to nitrogen on the isothiocyanyl fragment of derivatizing reagent, which in turn changes the enantioselectivity. Also, the sulfur atom is larger in size and subject to steric hindrance more significantly in comparison with oxygen. The carboxyl group of amino acid is essential toward a satisfactory resolution. The position of the amino group on the backbone affects the resolution as well. Finally, the resolution is either not observed or unsatisfactory in the reversed- or normal phase mode for most of the amino acids examined in this study. 相似文献
9.
Anna Czubatka-Bieńkowska Joanna Sarnik Anna Macieja Grzegorz Galita Zbigniew J. Witczak Tomasz Poplawski 《Bioorganic & medicinal chemistry letters》2017,27(12):2713-2720
Thiosemicarbazides and their analogs have shown potential medical applications as antiviral, antibacterial and anticancer drugs. We designed, synthesized and evaluated in vitro anticancer activity against ovarian (A2780), cervix (HeLa), colon (LoVo), breast (MCF-7) and brain (MO59J) human cancer cell lines of seven novel compounds –S-glycosylated thiosemicarbazones. We assessed the cyto- and genotoxic properties of all novel compounds using a variety of methods including comet assay, XTT assay, various fluorescent assays and toxicology PathwayFinder expression array. We tried to evaluate their possible mechanism of action with particular attention to induction of DNA damage and repair, apoptosis, oxidative stress analysis and cellular response in terms of changes in gene expression. The most sensitive cell line was human ovarian cancer. The results revealed that the major activity against A2780 cancer cell line displayed by our compounds is induction of DNA damage. This effect is not associated with apoptosis or oxidative stress induction and the resulting damage will not lead to cell cycle arrest. We also observed up-expression of heat shock related genes and NQO1 gene in response to our compounds. The second effect seems to be specific to glycosylated S-bond compounds as we observed it earlier. Upregulation of heat shock protein encoding genes suggest that our compounds induce stressful conditions. The nature of this phenomena (heat shock, pH shift or hypoxia) needs further study. 相似文献
10.
β-Galactosidase (EC: 3.2.1.23), one of the glycosidases detected in Erythrina indica seeds, was purified to 135 fold. Amongst the four major glycosidases detected β-galactosidase was found to be least glycosylated, and was not retained by Con-A CL Seralose affinity matrix. A homogenous preparation of the enzyme was obtained by ion-exchange chromatography, followed by gel filtration. The enzyme was found to be a dimmer with a molecular weight of 74 kDa and 78 kDa, by gel filtration and SDS-PAGE, respectively. The optimum pH and optimum temperature for enzyme activity were 4.4 and 50 °C, respectively. The enzyme showed a Km value of 2.6 mM and Vmax of 3.86 U/mg for p-nitrophenyl-β-D-galactopyranoside as substrate and was inhibited by Zn2+ and Hg2+. The enzyme activity was regulated by feed back inhibition as it was found to be inhibited by β-D-galactose. Chemical modification studies revealed involvement of tryptophan and histidine for enzyme activity. Involvement of tryptophan was also supported by fluorescence studies and one tryptophan was found to be present in the active site of β-galactosidase. Circular dichroism studies revealed 37% α helix, 27% β sheet and 38% random coil in the secondary structure of the purified enzyme. 相似文献