首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   105篇
  免费   13篇
  2023年   6篇
  2022年   2篇
  2021年   6篇
  2020年   6篇
  2019年   5篇
  2018年   3篇
  2017年   10篇
  2016年   3篇
  2015年   2篇
  2014年   8篇
  2013年   10篇
  2012年   11篇
  2011年   16篇
  2010年   6篇
  2009年   2篇
  2008年   3篇
  2007年   1篇
  2006年   3篇
  2005年   2篇
  2004年   1篇
  2003年   6篇
  2002年   5篇
  1990年   1篇
排序方式: 共有118条查询结果,搜索用时 15 毫秒
91.
We investigated effects of vitamin C and E (VCE) administration on desflurane-induced oxidative toxicity and element changes in the blood of operative patients under desflurane general anesthesia. Forty American Society of Anesthesiologists I or II Physical Status adult patients were scheduled for elective surgery. The patients were randomly divided into two groups. Control and VCE group was introduced to anesthesia with desflurane. VCE was administreted to patients in the control and VCE group before 1 hour of anesthesia with desflurane. Baseline (preoperative) and postoperative (at the 1st, the 24th, and 72th h), blood samples were taken from the first and second groups. Erythrocyte and plasma lipid peroxidation levels at the 1st, 24th, and 72th hours were higher in the control than in baseline group, although their levels at the same periods were lower in the VCE group than in the control. Vitamin E levels at the postoperative 1st and 24th hours and erythrocyte glutathione peroxidase (GSH-Px) activity at the postoperative 1st, 24th, and 72th hours was lower than in baseline values. Erythrocyte GSH-Px activity and plasma vitamins A, C, and E levels at the postoperative 1st, 24th, and 72th hours were higher in the VCE group than in the control group. Erythrocyte and plasma reduced glutathione, plasma β-carotene, and serum copper, while zinc, selenium, aluminum, iron, magnesium, and calcium levels did not differ between preoperative and postoperative periods in both groups. In conclusion, VCE combination prevented the desflurane-induced vitamin E and GSH-Px consumptions to strengthen the antioxidant levels in the blood of operative patients.  相似文献   
92.
Novel enamine derivatives were synthesized from the reaction of lactone and chalcones and their antiproliferative and cytotoxic activities against six cancer cell lines (e. g., HeLa, HT29, A549, MCF7, PC3 and Hep3B) and one normal cell lines (e. g., FL) were investigated along with their mode of interactions with CT‐DNA. Most of the enamine derivatives with IC50 values of 86–168 μM demonstrated much stronger antiproliferative activity than the starting molecules against the cancer cells. While, among the enamine derivatives, four compounds displayed higher cytotoxic potency than the control drugs (5‐fluorouracil and cisplatin) against the Hep3B cell lines, these compounds did not exhibit any significant toxicity against normal cells, FL. The UV/VIS spectral data suggest that eight compounds cause hypochromism with a slight bathochromic shift (~6 nm), indicating that they bind to the DNA by way of an intercalative or minor groove binding mode. The binding constants of the compounds are in the range of 0.1×103 M?1–2.3×104 M?1. The antiproliferative activity of studied enamine derivatives could possibly be due to their DNA binding as well as their cytotoxic properties. In addition to these assays, the chalcones and enamine derivatives were investigated by molecular docking to calculate the synergistic effect of antiproliferative activities against six human cancer cell lines.  相似文献   
93.
Akin M  Turgut S  Ayada C  Polat Y  Balci YI  Erdoğan F 《Gene》2011,487(1):80-83
The current study was conducted to assess 3435C>T multidrug resistance 1 gene polymorphism and the efficacy of high dose methylprednisolone (HDMP) in childhood acute idiopathic thrombocytopenic purpura patients.

Methods

A total of 31 childhood acute Idiopathic thrombocytopenic purpura patients (17 females, 14 males) between the ages of 2 and 16 years of age were included in the study. High-dose methylprednisolone was given at a dose of 30 mg/kg/day for 3 days and 20 mg/kg/day for 4 days, consecutively and intravenously. Polymerase chain reaction-restriction fragment length polymorphism was used for the detection of C3435T single nucleotide polymorphism. Fragments obtained were 238 bp to T/T genotype, 172 bp and 60 bp fragments to the C/C genotype, and 238 bp, 172 bp and 60 bp to the C/T genotype.

Results

The distribution of CC, CT, and TT genotypes were 19.0%, 61.3%, and 19.4%, respectively. Both allele frequencies of C and T were the same — 50%. There was no significant difference in genotype and allele distribution between the patients with ITP and the control group (χ2 = 0.84 p = 0.65, χ2 = 0.2 p = 0.63, respectively). There were no significant differences in age, gender, and pre- and post-treatment platelet counts between CC, CT, and TT genotypes of the MDR gene. Response to treatment shows no significant difference between genotype and allele groups.

Conclusion

In our study, there was no difference in the HDMP treatment response between MDR1 gene genotypes. However, it should be noted that this study includes a small group of patients. Our data should therefore be considered preliminary, awaiting further confirmatory studies on an expanded patient base.  相似文献   
94.
We have designed and synthesized novel irreversible serine protease inhibitors containing aliphatic sulfonyl fluorides as an electrophilic trap. These substituted taurine sulfonyl fluorides derived from taurine or protected amino acids were conveniently synthesized from β-aminoethanesulfonyl chlorides using KF/18-crown-6 or from β-aminoethanesulfonates using DAST. Their potency of irreversible inhibition of serine proteases is described in different enzyme assays using chymotrypsin leading to binding affinities up to 22 μM.  相似文献   
95.
Baller-Gerold Syndrome (BGS) is a rare autosomal recessive disorder that is apparent at birth. The disorder is characterized by distinctive malformations of the skull and facial area and bones of the forearms and hands. We report a 4 year old boy in whom the clinical features of craniosynostosis and bilateral absent thumbs and radii led to a diagnosis of Baller-Gerold syndrome. Physical examination revealed that the heart was localized to the right side. Echocardiography confirmed dextrocardia. Dextrocardia has not previously been reported with Baller-Gerold syndrome. To the best of our knowledge, this is the first reported case of Baller-Gerold syndrome associated with dextrocardia.  相似文献   
96.
Abiotic stresses, such as high temperature and drought, are major limiting factors of crop production and growth. Coronatine (COR), a structural and functional analog of jasmonates, is suggested to have a role in abiotic stress tolerance. The aim of our study was to examine whether pretreatment with COR enhances the tolerance of chickpea (Cicer arietinum L. cv ICC 4958) roots to PEG-induced osmotic stress, heat stress, and their combination. Therefore, seedlings raised hydroponically in a growth chamber for 15 days were pretreated with or without COR at 0.01 μM for 24 h and then exposed to 6 % PEG 6000-induced osmotic stress or heat (starting at 35 °C and then gradually increased 1 °C every 15 min and kept at 44 °C for 1 h) stress for 3 days. After different treatment periods, the changes in relative growth rate (RGR); malondialdehyde (MDA), proline (Pro), and hydrogen peroxide (H2O2) contents; and the activities of antioxidant enzymes/isoenzymes in roots of chickpea seedlings with or without 0.01 μM COR application were studied. RGR in roots was increased by COR application. Under all stress conditions, H2O2, MDA, and Pro levels increased sharply, but pretreatment with COR significantly reduced them. Moreover, COR increased the activities of H2O2 scavenger enzymes such as catalase (CAT) under heat stress, ascorbate peroxidase (POX) under PEG stress, and CAT and POX under combined stresses. Therefore, COR might alleviate adverse effects of PEG stress and heat stress and combined stresses on roots of chickpea by reduction of H2O2 production, enhancing or keeping the existent activity of antioxidant enzymes, thereby preventing membrane peroxidation.  相似文献   
97.
Molecular Biology Reports - Coronavirus-19 is still considered a pandemic that influences the world. Other molecular alterations should be clearer besides the increasing cytokine storm and...  相似文献   
98.
Apilarnil is 3–7 days old drone larvae. It is an organic bee product known to be rich in protein. In this study, the biological activities of Apilarnil were determined by its antioxidant and enzyme inhibition effects. Antioxidant activities were determined by Fe3+, Cu2+, Fe3+-TPTZ ((2,4,6-tris(2-pyridyl)-s-triazine), reducing ability and 1,1-diphenyl-2-picrylhydrazyl (DPPH⋅) scavenging assays. Also, its enzyme inhibition effects were tested against carbonic anhydrase I and II isoenzymes (hCA I, hCA II), acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Antioxidant activity of Apilarnil was generally lower than the standard molecules in the applied methods. In DPPH⋅ radical scavenging assay, Apilarnil exhibited higher radical scavenging than some standards. Enzyme inhibition results towards hCA I (IC50: 14.2 μg/mL), hCA II: (IC50: 11.5 μg/mL), AChE (IC50: 22.1 μg/mL), BChE (IC50: 16.1 μg/mL) were calculated. In addition, the quantity of 53 different phytochemical compounds of Apilarnil was determined by a validated method by LC/MS/MS. Compounds with the highest concentrations (mg analyte/g dry extract) were determined as quinic acid (1091.045), fumaric acid (48.714), aconitic acid (47.218), kaempferol (39.946), and quercetin (27.508). As a result, it was determined that Apilarnil had effective antioxidant profile when compared to standard antioxidants.  相似文献   
99.
The emerging need for rapid screening and identification methods for microbiological purposes necessitates the combined uses of high-tech instruments. In this work, electrospray ionization mass spectrometry was used to visualize the relation of ten newly isolated moderately halophilic microorganisms, to Halomonas salina DSMZ 5928 and Halomonas halophila DSMZ 4770. The method was based on the global analysis of the metabolites in culture media and is termed as metabolic footprinting. Since it was not possible to gain insight into the similarities solely based on the visual inspection of the chromatograms, principal component (PC) analysis was applied on the data. Three PCs alone were able to explain 99% of the information in the data set. The score plots revealed the relation of the new isolates to the two type strains whereas the loading plots gave important clues on the significant ions responsible for the observed clustering. Loading plots also indicated inversely correlated ions that give clues on differing metabolic pathways. The work described here offers a potentially useful way for preliminary rapid phenotypic characterization of new and closely related isolates and a method for screening of similar microorganisms for different and valuable secondary metabolites.  相似文献   
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号