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   872篇
  免费   44篇
  国内免费   1篇
  917篇
  2023年   5篇
  2022年   16篇
  2021年   22篇
  2020年   22篇
  2019年   17篇
  2018年   20篇
  2017年   32篇
  2016年   43篇
  2015年   54篇
  2014年   54篇
  2013年   63篇
  2012年   68篇
  2011年   83篇
  2010年   51篇
  2009年   38篇
  2008年   55篇
  2007年   58篇
  2006年   38篇
  2005年   44篇
  2004年   33篇
  2003年   21篇
  2002年   25篇
  2001年   5篇
  2000年   4篇
  1999年   1篇
  1998年   5篇
  1997年   1篇
  1996年   4篇
  1995年   1篇
  1993年   3篇
  1992年   1篇
  1991年   1篇
  1990年   3篇
  1989年   5篇
  1987年   1篇
  1986年   3篇
  1985年   1篇
  1984年   1篇
  1983年   2篇
  1978年   2篇
  1977年   1篇
  1975年   2篇
  1973年   2篇
  1972年   1篇
  1971年   3篇
  1970年   1篇
  1959年   1篇
排序方式: 共有917条查询结果,搜索用时 15 毫秒
851.
Background

Thyroid cancer is the most common malignant tumor of the endocrine system seen in the thyroid gland. More than 90% of thyroid cancers comprise papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC). Although anaplastic thyroid carcinoma (ATC) accounts for less than 2% of thyroid cancer. But patients’ lifespan after diagnosis is about 6 months. Surgical interventions, radioactive iodine use, and chemotherapy are not sufficient in the treatment of ATC, so alternative therapies are needed.

Methods and results

The WST-1 assay test was performed to evaluate the anti-proliferative effects of Valproic acid (VPA). Also, the effect of VPA on miRNAs affecting histone deacetylase was determined by Quantitative RT-PCR. In the SW1736 cell line, IC50 dose for VPA was found 1.6 mg/ml. In our study, the level of oncogenic genes expression in cells treated with VPA, including miR-184, miR-222-5p, miR-124-3p, and miR-328-3p, decreased. Also, the expression of tumor inhibitory genes including miR-323-5p, miR-182-5p, miR-138-5p, miR-217, miR-15a-5p, miR-29b-3p, miR-324-5p and miR-101-5p increased significantly.

Conclusions

VPA can ad-just countless gene expression patterns, including microRNAs (miRNAs), by targeting histone deacetylase (HDAC). However, further studies are required for more accurate results.

  相似文献   
852.
853.
Aspiration pneumonitis refers to acute chemical lung injury caused by aspiration of sterile gastric contents. The aim of this study was to evaluate the role of quercetin (QC) in acid aspiration-induced lung injury in rats. Twenty-eight female Sprague–Dawley rats were used and divided into the following groups (n = 7): sham (aspirated normal saline, S), hydrochloric acid (aspirated HCl), S plus treatment with QC (S + QC), and HCl plus treatment with QC (HCl + QC). After aspiration, the treatment groups received QC 60 mg/kg/day intraperitoneally once a day for 7 days. As a result of acid aspiration, an increase was observed in the levels of serum clara cell protein-16 (CC-16) and advanced oxidation protein products, whereas there was a decrease in serum thiobarbituric acid-reactive substances, superoxide dismutase (SOD), and catalase levels. There was a significant decrease in peribronchial inflammatory cell infiltration, alveolar septal infiltration, alveolar edema, and alveolar exudate scores, except in the alveolar histiocytes in the HCl + QC group. The expression of nitric oxide synthase, which increased after aspiration in the HCl group, showed a statistically significant decrease after the QC treatment. After the treatment with QC, an increase in the serum SOD level was observed, whereas a significant decrease was determined in the serum CC-16 level relative to that of the aspiration group (HCl). The antioxidant QC is effective in the treatment of lung injury following acid aspiration and can be used as a serum CC-16 biomarker in predicting the severity of oxidative lung injury.  相似文献   
854.
Chitin and chitosan were extracted from six different aquatic invertebrate species. Species dry weights varied between 5 % and 20 % chitin, and the chitosan productivity of these chitins varied between 66 % and 74 %. Chitin and chitosan structures were characterized by FTIR, TGA, XRD, and SEM. FTIR results showed that the chitins obtained from the organisms were observed in α form. Chitin thermal stabilities were in the order Ranatra linearis?>?Anax imperator?>?Hydrophilus piceus?>?Notonecta glauca?>?Agabus bipustulatus?>?Asellus aquaticus, and chitosan thermal stabilities in the order N. glauca?>?A. bipustulatus?>?A. imperator?>?R. linearis?>?H. piceus?>?A. aquaticus. The crystalline index values of chitins varied between 76.4 % and 90.6 %. Their surface morphology was examined by SEM, revealing nanofibre structures. These six aquatic invertebrate species with characterized chitin and chitosan structures may be used as alternative chitin and chitosan sources for various technological purposes.  相似文献   
855.
Recurrent vulvovaginal candidiasis (RVVC) is defined as having four or more symptomatic vulvovaginal candidiasis (VVC) attacks within a year. This study aimed to investigate whether Human Dectin-1 Y238X Gene Polymorphism plays a role in RVVC pathogenesis. In order to examine and explore this aim, an experimental study was undergone. The clinical study design was conducted with 50 women diagnosed with RVVC and had four or more symptomatic VVC attacks who were included in the experimental group; while 50 women who did not have previous RVVC history and diagnosis and did not have vaginal discharge and itching in the past year were included in the control group. Blood samples were collected from these patients and transferred to EDTA tubes, to investigate the Dectin-1 Y238X gene polymorphism, and stored at ?80°. When Dectin-1 genotypes were compared, there was no significant difference between the two groups (p = 0.452, p = 0.615, p = 0.275). History of familial RVVC was significantly higher in the experimental group (p = 0.001). When the multivariate analysis was used to evaluate factors that could determine RVVC frequency, history of familial RVVC was found to increase the frequency of RVVC attacks by 3.3 units. This study is the first-of-its-kind to investigate the correlation between Dectin-1 Y238X polymorphism, which has not been previously studied in the Turkish population, and RVVC. The result of this study suggests that there is no correlation between this polymorphism and RVVC.  相似文献   
856.
Evidence suggests that peripheral nerve injury occurs during the early stages of disease with mild glycemic dysregulation. Two proteins, neuron-specific enolase (NSE) and neurofilament light chain (NFL), have been examined previously as possible markers of neuronal damage in the pathophysiology of neuropathies. Herein, we aimed to determine the potential value of circulatory NSE and NFL mRNA levels in prediabetic patients and in those with peripheral neuropathy. This prospective clinical study included 45 prediabetic patients and 30 age- and sex-matched controls. All prediabetic patients were assessed with respect to diabetes-related microvascular complications, such as peripheral neuropathy, retinopathy and nephropathy. mRNA levels of NSE and NFL were determined in the blood by real-time polymerase chain reaction. NSE mRNA levels were similar between prediabetic and control groups (p > 0.05), whereas NFL mRNA levels were significantly higher in prediabetics than in controls (p < 0.001). NSE mRNA levels did not significantly differ between prediabetic patients with and without peripheral neuropathy (p > 0.05), while NFL mRNA levels were significantly higher in prediabetics with peripheral neuropathy than in those without (p = 0.038). According to correlation analysis, NFL mRNA levels were positively correlated with the Douleur Neuropathique 4 questionnaire score in prediabetic patients (r = 0.302, p = 0.044). This is the first study to suggest blood NFL mRNA as a surrogate marker for early prediction of prediabetic peripheral neuropathy, while NSE mRNA levels may be of no diagnostic value in prediabetic patients.  相似文献   
857.
The chitin structures of two common European species belonging to Insecta (Melolontha melolontha) and Crustacea (Oniscus asellus) were isolated. The same procedure is followed for chitin isolations for both the species. First, HCl was used for removing of minerals in the organisms, and then, the protein structure was removed by using NaOH. Chitins obtained from these two species were characterized physicochemically. Physicochemical properties of chitins isolated from the insect and the crustacean were compared to each other. The chitin content for dry weights of M. melolontha and O. asellus were recorded as 13–14 and 6–7 %, respectively. The results of Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray diffraction analysis were found to be more or less similar. The surface morphologies of chitins were examined via environmental scanning electron microscopy and nanofibers, and pore structures were observed. While the chitin nanofibers of O. asellus were adherent to each other, nanofibers of M. melolontha were non-adherent. On the other hand, the number of pores was much higher in the chitin from M. melolontha than in the chitin from O. asellus. Looking at the elemental analysis results, the M. melolontha chitin was found to be more pure than the O. asellus chitin. For this reason, M. melolontha has been considered more attractive source for chitin than O. asellus.  相似文献   
858.
859.
Obesity is known to lead to complications involving several systems. The basic mechanism in obesity-related complications is chronic inflammation and increased oxidative stress. Trace element levels in obese children may vary due to poor nutritional habits. The purpose of this study was to investigate the relation between serum paraoxonase (PON1) and arylesterase (ARE) levels, markers of the oxidant–antioxidant balance in the body, and serum zinc (Zn), copper (Cu), manganese (Mn), and selenium (Se) concentrations in obese children. Fifty-seven overweight patients aged 6–17 and 48 age- and sex-matched healthy children were included in the study. Serum PON1 and ARE activity levels were measured, together with Cu, Zn, Mn, Se, total cholesterol, triglyceride, low-density lipoprotein, high-density lipoprotein, very low-density lipoprotein, glucose, aspartate amino transferase, and alanine amino transferase levels. PON1 and ARE activity levels were significantly lower in obese patients compared to those in healthy individuals (P?<?0.05). Various changes were determined in Cu, Zn, Mn, and Se levels between the study and control groups (P?<?0.05). In terms of the relation between trace elements and PON1 and ARE levels, a significant positive correlation was determined between serum Se and PON1 levels in the study group (P?<?0.05, r?=?0.31). No significant correlation was determined between other trace element levels and PON1 and ARE levels (P?>?0.05). In conclusion, the detection in our study of a positive correlation between Se and PON1 levels in obese children may be significant in terms of showing a relation between Se and antioxidant systems in obese children.  相似文献   
860.
Joubert syndrome and related disorders (JSRDs) are genetically heterogeneous and characterized by a distinctive mid-hindbrain malformation. Causative mutations lead to primary cilia dysfunction, which often results in variable involvement of other organs such as the liver, retina, and kidney. We identified predicted null mutations in CSPP1 in six individuals affected by classical JSRDs. CSPP1 encodes a protein localized to centrosomes and spindle poles, as well as to the primary cilium. Despite the known interaction between CSPP1 and nephronophthisis-associated proteins, none of the affected individuals in our cohort presented with kidney disease, and further, screening of a large cohort of individuals with nephronophthisis demonstrated no mutations. CSPP1 is broadly expressed in neural tissue, and its encoded protein localizes to the primary cilium in an in vitro model of human neurogenesis. Here, we show abrogated protein levels and ciliogenesis in affected fibroblasts. Our data thus suggest that CSPP1 is involved in neural-specific functions of primary cilia.  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