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   172篇
  免费   7篇
  179篇
  2023年   2篇
  2022年   1篇
  2021年   8篇
  2020年   4篇
  2019年   1篇
  2018年   7篇
  2017年   1篇
  2016年   12篇
  2015年   9篇
  2014年   12篇
  2013年   10篇
  2012年   15篇
  2011年   19篇
  2010年   9篇
  2009年   9篇
  2008年   12篇
  2007年   2篇
  2006年   8篇
  2005年   4篇
  2004年   8篇
  2003年   3篇
  2002年   9篇
  2001年   1篇
  2000年   1篇
  1999年   2篇
  1996年   2篇
  1995年   2篇
  1992年   2篇
  1991年   1篇
  1986年   1篇
  1985年   1篇
  1965年   1篇
排序方式: 共有179条查询结果,搜索用时 14 毫秒
131.
Hazelnut oil (HO) is rich in monounsaturated fatty acids and antioxidants. We wanted to investigate the effect of HO on lipid levels and prooxidant-antioxidant status in rabbits fed a high-cholesterol (HC) diet. An HC diet caused significant increases in lipids and lipid peroxide levels in the plasma, liver, and aorta together with histopathological atherosclerotic changes in the aorta. Glutathione levels, glutathione peroxidase, and glutathione transferase activities decreased significantly, but superoxide dismutase activity and vitamin E and C levels remained unchanged in the livers of rabbits following HC diet. HO supplementation reduced plasma, liver, and aorta lipid peroxide levels and aorta cholesterol levels together with amelioration in atherosclerotic lesions in the aortas of rabbits fed an HC diet, without any decreasing effect on cholesterol levels in the plasma or liver. HO did not alter the antioxidant system in the liver in the HC group. Our findings indicate that HO reduced oxidative stress and cholesterol accumulation in the aortas of rabbits fed an HC diet.  相似文献   
132.

Aim

The aim of our study was the dosimetric and physical evaluation of the CK and IMRT treatment plans for 16 patients with localized prostate cancer.

Background

Intensity modulated radiation therapy (IMRT) is one of the recent technical advances in radiotherapy. The prostate is a well suited site to be treated with IMRT. The challenge of accurately delivering the IMRT needs to be supported by new advances such as image-guidance and four-dimensional computed conformal radiation therapy (4DCRT) tomography. CyberKnife (CK) provides real time orthogonal X-ray imaging of the patient during treatment course to follow gold fiducials installed into the prostate and to achieve motion correlation between online acquired X-ray imaging and digital reconstructed radiographs (DRRs) which are obtained from planning computed tomography images by translating and rotating the treatment table in five directions.

Methods and materials

Sixteen IMRT and CK plans were performed to be compared in terms of conformity (CI), heterogeneity indices (HI), percentage doses of 100% (V100), 66% (V66), 50% (V50), 33% (V33) and 10% (V10) volumes of the bladder and rectum. Dose-volume histograms for target and critical organs, (CI) and indices (HI) and isodose lines were analyzed to evaluate the treatment plans.

Results

Statistically significant differences in the percentage rectal doses delivered to V10, V33, and V50 of the rectum were detected in favor of the CK plans (p values; <0.001, <0.001 and 0.019, respectively). The percentage doses for V66 and V100 of the rectum were larger in CK plans (13%, 2% in IMRT and 21%, 3% in CK plans, respectively). Percentage bladder doses for V10 and V33 were significantly lower in CK plans [96% in IMRT vs 48% in CK (p < 0.001) and 34% in IMRT vs 24% in CK (p = 0.047)]. Lower percentage doses were observed for V50, V66 of the bladder for the IMRT. They were 5.4% and 3.45% for IMRT and 13.4% and 8.05% for CK, respectively. Median CI of planning target volume (PTV) for IMRT and CK plans were 0.94 and 1.23, respectively (p < 0.001).

Conclusion

Both systems have a very good ability to create highly conformal volumetric dose distributions. Median HI of PTV for IMRT and CK plans were 1.08 and 1.33, respectively (p < 0.001).  相似文献   
133.
134.
Background: It was suggested that gastric colonization with Helicobacter pylori (H. pylori) was associated with suboptimal nutrition and growth in childhood. Furthermore, several studies indicated a relationship between H. pylori colonization and alterations in the circulating levels of growth‐related molecules (GRM). Accordingly, in this study, we investigate the effect of H. pylori infection on GRMs and on the growth of healthy school children, taking into consideration the effect of their economic status (ES) and anthropometric indices of their parents. Methods: To acquire sociodemographic and anthropometric nutritional parameters and to detect H. pylori‐specific serum IgG antibodies and growth‐related molecules, we evaluated a total of 473 children attending four different primary and secondary schools in Istanbul. Subsequently, we assessed the effect of H. pylori on growth‐related parameters (weight for age SDS, height for age SDS, BMI SDS, TSF, and waist‐to‐hip ratio) and on GRMs (leptin, ghrelin, and insulin‐like growth factor‐1 (IGF‐1)), controlling for age, gender, family income, household crowding (HC), breastfeeding, maternal and paternal BMI SDS, and midparental height SDS with complex statistical models. Results: Of the 473 children (275 F/198 M, age 6–15 years; mean: 10.3 ± 0.1 years), 161 (34%) were H. pylori‐positive. The prevalence of H. pylori was significantly higher in lower economic status (ES) groups, in children living in crowded houses, and in older age groups. Using simple statistical models, we did not find any significant associations between H. pylori infection and the growth parameters. However, in complex models for height for age SDS and for weight for age SDS, there was a significant interaction between H. pylori infection status and ES. Whereas in H. pylori‐positive subjects, mid‐income family children were both taller and heavier than the low‐income group, there was no such an association in H. pylorinegative subjects. Among biochemical parameters, only ghrelin levels were associated with H. pylori infection in all models. Leptin levels were associated with HC in girls, whereas none of the parameters was significantly associated with leptin levels in boys. For IGF‐1 levels, for boys, age and maternal BMI, and for girls, age and HC were significantly associated with IGF‐1 levels. Conclusion: We suggest that H. pylori may impair growth significantly only in susceptible children where unfavorable socioeconomic conditions facilitate its action, probably through mechanisms, at least in part, involving growth‐related molecules.  相似文献   
135.

Rationale

HMG-CoA reductase inhibitors such as rosuvastatin may have immunomodulatory and anti-inflammatory effects that may reduce the severity of influenza A infection. We hypothesized that rosuvastatin would decrease viral replication, attenuate lung injury, and improve mortality following influenza A infection in mice.

Methods

C57Bl/6 mice were treated daily with rosuvastatin (10 mg/kg/day) supplemented in chow (or control chow) beginning three days prior to infection with either A//Udorn/72 [H3N2] or A/WSN/33 [H1N1] influenza A virus (1×105 pfu/mouse). Plaque assays were used to examine the effect of rosuvastatin on viral replication in vitro and in the lungs of infected mice. We measured cell count with differential, protein and cytokines in the bronchoalveolar lavage (BAL) fluid, histologic evidence of lung injury, and wet-to-dry ratio on Day 1, 2, 4, and 6. We also recorded daily weights and mortality.

Results

The administration of rosuvastatin had no effect on viral clearance of influenza A after infection. Weight loss, lung inflammation and lung injury severity were similar in the rosuvastatin and control treated mice. In the mice infected with influenza A (A/WSN/33), mortality was unaffected by treatment with rosuvastatin.

Conclusions

Statins did not alter the replication of influenza A in vitro or enhance its clearance from the lung in vivo. Statins neither attenuated the severity of influenza A-induced lung injury nor had an effect on influenza A-related mortality. Our data suggest that the association between HMG CoA reductase inhibitors and improved outcomes in patients with sepsis and pneumonia are not attributable to their effects on influenza A infection.  相似文献   
136.
Fourier Transform Infra-red and Raman Spectroscopies indicate that 7 alpha-hydroxycholesterol and 7-ketocholesterol have a diminished capacity to condense (increase the packing order of) fluid-state dipalmitoylphosphatidylcholine (DPPC) acyl chains when compared with the effects of cholesterol and the other oxidized sterols studied. DPPC head groups were also more ordered by 7-ketocholesterol over the temperature range 10 degrees - 70 degrees C. Primary effects of these sterols appear to be associated with the hydrophillic regions of the DPPC bilayer, although packing arrangements with acyl chains are also involved. Phosphate and acyl chain ester groups were observed to possess a packing order which was invariant which indicates that these may be the target groups in the interaction with 7-ketocholesterol. A surprising observation was the synergistic amplification of the effects of 7-ketocholesterol by the presence of cholesterol in the DPPC bilayer.  相似文献   
137.
The aim of the present study was to evaluate the protective effects of the NF-кB inhibition with pyrrolidine-dithiocarbamate (PDTC) in ischemia–reperfusion (I/R) injury in the rat bladder. Twenty-four Sprague-Dawley male rats were divided into three groups. Group I; (n = 8) control, group II; (n = 8) I/R group; group III (n = 8) I/R and PDTC treatment. Superoxide dismutase (SOD), catalase (CAT), and gluatathione-S-transferase (GST) enzymes was studied in bladder tissue. Lipid peroxidation (as TBARS) levels in tissue homogenate were measured with thiobarbituric acid reaction. All the slides were stained with NF-кB, p53 and HSP60 immunohistochemistry for detection genome destruction and tissue stress, respectively. Our results show that the mean TBARS levels were significantly higher in group II (p < 0.05). The TBARS levels were significantly decreased in group III compared with the group II (p < 0.05). CAT, SOD and GST activities were decreased in group II, but these enzymes levels were significantly increased in group III according to the group II (p < 0.05). Under microscopic evaluation NF-кB expression increased significantly in group II compared to the group I (p < 0.05) and then decreased in group III (p < 0.05). HSP60 and p53 expression in group II was increased significantly compared with group I. Under microscopic evaluation we detected that HSP60 and p53 expression was increased significantly in group II compared with group I. In group III PDTC administration was decreased the HSP60 and p53 expression, this difference was statistically significant (p < 0.05). The results of the present study have demonstrated that NF-кB inhibition with PDTC protects and provides beneficial effects on ischemia/reperfusion stress related bladder tissue destruction.  相似文献   
138.
The aim was to investigate the prevalence of VKORC1 and CYP2C9 genotypes in patients requiring anticoagulant therapy in two different region’s populations of Turkey. The recent cohort included 292 patients that needed anticoagulant therapy, and who had a history of deep vein thrombosis and/or pulmonary artery thromboembolism. Genomic DNA was isolated from peripheral blood samples and the StripAssay reverse hybridization or Real Time PCR technique was used for genotype analysis. Genotypes for CYP2C9 were detected as follows: 165 (56.5?%) for CYP2C9*1/*1, 67 (23.0?%) for CYP2C9*1/*2, 25 (8.6?%) for CYP2C9*1/*3, 9 (3.0?%) for CYP2C9*2/*2, 21 (7.2?%) for CYP2C9*2/*3, 5(1.7?%) for CYP2C9*3/*3 for CYP2C9 and the allele frequencies were: 0.723 for allele*1, 0.182 for allele*2 and 0.095 for allele*3 respectively. Genotypes for VKORC1 were detected as follows: 64 (21.9?%) for GG, 220 (75.4?%) for GA and 8 (2.7?%) for AA alleles. The G allele frequency was detected as 0.596, and the A allele frequency was 0.404. The VKORC1 1639 G>A and CYP2C9 mutation prevalence and allele frequency of the current results from two different populations (Sivas and Canakkale) showed similarly very variable profiles when compared to the other results from the Turkish population.  相似文献   
139.
Drug synergy allows a therapeutic effect to be achieved with lower doses of component drugs. Drug synergy can result when drugs target the products of genes that act in parallel pathways (‘specific synergy’). Such cases of drug synergy should tend to correspond to synergistic genetic interaction between the corresponding target genes. Alternatively, ‘promiscuous synergy’ can arise when one drug non‐specifically increases the effects of many other drugs, for example, by increased bioavailability. To assess the relative abundance of these drug synergy types, we examined 200 pairs of antifungal drugs in S. cerevisiae. We found 38 antifungal synergies, 37 of which were novel. While 14 cases of drug synergy corresponded to genetic interaction, 92% of the synergies we discovered involved only six frequently synergistic drugs. Although promiscuity of four drugs can be explained under the bioavailability model, the promiscuity of Tacrolimus and Pentamidine was completely unexpected. While many drug synergies correspond to genetic interactions, the majority of drug synergies appear to result from non‐specific promiscuous synergy.  相似文献   
140.
The aim of this study was to compare hematological, some biochemical parameters, and serum trace element concentrations in horses with or without pica. Fifteen horses with pica (group I) and another 15 healthy horses without pica (group II) were used. The hematological parameters were not changed between the two groups. In group I, hemoglobin values were lower than those of group II. However, the difference in hemoglobin values between the two groups was not significant (P > 0.05). Serum iron and copper concentrations and the copper/zinc ratio were lower in group I than those of group II (P < 0.05). The other biochemical parameters were not found to be statistically different between the two groups (P > 0.05). It was concluded that serum iron and copper deficiency may play an important role for the etiology of pica in horses. Prophylactic use of iron and copper supplements in horses may be beneficial to prevent pica.  相似文献   
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