全文获取类型
收费全文 | 1079篇 |
免费 | 175篇 |
国内免费 | 51篇 |
专业分类
1305篇 |
出版年
2024年 | 3篇 |
2023年 | 43篇 |
2022年 | 84篇 |
2021年 | 96篇 |
2020年 | 104篇 |
2019年 | 133篇 |
2018年 | 108篇 |
2017年 | 52篇 |
2016年 | 46篇 |
2015年 | 42篇 |
2014年 | 74篇 |
2013年 | 104篇 |
2012年 | 55篇 |
2011年 | 71篇 |
2010年 | 40篇 |
2009年 | 33篇 |
2008年 | 29篇 |
2007年 | 33篇 |
2006年 | 22篇 |
2005年 | 25篇 |
2004年 | 17篇 |
2003年 | 16篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 6篇 |
1999年 | 8篇 |
1998年 | 8篇 |
1997年 | 13篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1305条查询结果,搜索用时 0 毫秒
71.
Pan Chen Ying Miao PuJun Yan Xiao Jie Wang ChunXia Jiang Yi Lei 《Journal of cellular physiology》2019,234(12):21915-21924
Diabetic retinopathy (DR) remains the leading cause of blindness in adults with diabetes mellitus. Numerous microRNAs (miRNAs) have been identified to modulate the pathogenesis of DR. The main purpose of this study was to evaluate the potential roles of miR-455-5p in high glucose (HG)-treated retinal pigment epithelial (RPE) cells and underlying mechanisms. Our present investigation discovered that the expression of miR-455-5p was apparently downregulated in ARPE-19 cells stimulated with HG. In addition, forced expression of miR-455-5p markedly enhanced cell viability and restrained HG-induced apoptosis accompanied by decreased BCL2-associated X protein (Bax)/B-cell leukemia/lymphoma 2 (Bcl-2) ratio and expression of apoptotic marker cleaved caspase-3 during HG challenged. Subsequently, augmentation of miR-455-5p remarkably alleviated HG-triggered oxidative stress injury as reflected by decreased the production of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) content as well as NADPH oxidase 4 expression, concomitant with enhanced the activities of superoxide dismutase, catalase, and GPX stimulated with HG. Furthermore, enforced expression of miR-455-5p effectively ameliorated HG-stimulated inflammatory response as exemplified by repressing the secretion of inflammatory cytokines interleukin 1β (IL-1β), IL-6, and tumour necrosis factor-α in ARPE-19 cells challenged by HG. Most importantly, we successfully identified suppressor of cytokine signaling 3 (SOCS3) as a direct target gene of miR-455-5p, and miR-455-5p negatively regulated the expression of SOCS3. Mechanistically, restoration of SOCS3 abrogated the beneficial effects of miR-455-5p on apoptosis, accumulation of ROS, and inflammatory factors production in response to HG. Taken together, these findings demonstrated that miR-455-5p relieved HG-induced damage through repressing apoptosis, oxidant stress, and inflammatory response by targeting SOCS3. The study gives evidence that miR-455-5p may serve as a new potential therapeutic agent for DR treatment. 相似文献
72.
73.
Sean W. Mateer Jocelle Cardona Ellen Marks Bridie J. Goggin Susan Hua Simon Keely 《Journal of visualized experiments : JoVE》2016,(108)
The epithelial barrier is the first innate defense of the gastrointestinal tract and selectively regulates transport from the lumen to the underlying tissue compartments, restricting the transport of smaller molecules across the epithelium and almost completely prohibiting epithelial macromolecular transport. This selectivity is determined by the mucous gel layer, which limits the transport of lipophilic molecules and both the apical receptors and tight junctional protein complexes of the epithelium. In vitro cell culture models of the epithelium are convenient, but as a model, they lack the complexity of interactions between the microbiota, mucous-gel, epithelium and immune system. On the other hand, in vivo assessment of intestinal absorption or permeability may be performed, but these assays measure overall gastrointestinal absorption, with no indication of site specificity. Ex vivo permeability assays using "intestinal sacs" are a rapid and sensitive method of measuring either overall intestinal integrity or comparative transport of a specific molecule, with the added advantage of intestinal site specificity. Here we describe the preparation of intestinal sacs for permeability studies and the calculation of the apparent permeability (Papp)of a molecule across the intestinal barrier. This technique may be used as a method of assessing drug absorption, or to examine regional epithelial barrier dysfunction in animal models of gastrointestinal disease. 相似文献
74.
目的:探讨腹膜透析(PD)和血液透析(HD)对终末期肾脏疾病(ESRD)患者钙磷代谢及微炎症状态的影响。方法:选择2016年1月~2017年2月我院收治的ESRD患者94例为研究对象,采用随机数字表法分为PD组(47例)和HD组(47例),PD组给予非卧床持续性PD治疗,HD组给予HD治疗,治疗6个月后比较两组血清钙磷代谢水平和微炎症状态,并统计两组并发症的发生率。结果:治疗6个月后,两组血清钙水平与治疗前相比显著升高,血清磷水平显著降低(P0.05),但HD组与PD组比较无差异(P0.05);治疗6个月后,两组血清C-反应蛋白(CRP)水平较治疗前明显升高,且HD组高于PD组,差异有统计学意义(P0.05),治疗6个月后,两组降钙素原(PCT)水平与治疗前相比显著降低,差异有统计学意义(P0.05),但HD组与PD组比较无差异(P0.05);PD组感染、低蛋白血症的发生率高于HD组,HD组高血压、心律失常、充血性心衰的发生率高于PD组,差异均有统计学意义(P0.05)。结论:PD和HD治疗均可改善ESRD患者钙磷代谢紊乱,但两者都将加剧患者微炎症反应,其中HD对患者微炎症状态的影响更大。 相似文献
75.
76.
Luise Ehlers Karen Bannert Sarah Rohde Peggy Berlin Johannes Reiner Mats Wiese Julia Doller Markus M. Lerch Ali A. Aghdassi Fatuma Meyer Luzia Valentini Ottavia Agrifoglio Cornelia C. Metges Georg Lamprecht Robert Jaster 《Journal of cellular and molecular medicine》2020,24(15):8304-8314
Muscle wasting represents a constant pathological feature of common chronic gastrointestinal diseases, including liver cirrhosis (LC), inflammatory bowel diseases (IBD), chronic pancreatitis (CP) and pancreatic cancer (PC), and is associated with increased morbidity and mortality. Recent clinical and experimental studies point to the existence of a gut‐skeletal muscle axis that is constituted by specific gut‐derived mediators which activate pro‐ and anti‐sarcopenic signalling pathways in skeletal muscle cells. A pathophysiological link between both organs is also provided by low‐grade systemic inflammation. Animal models of LC, IBD, CP and PC represent an important resource for mechanistic and preclinical studies on disease‐associated muscle wasting. They are also required to test and validate specific anti‐sarcopenic therapies prior to clinical application. In this article, we review frequently used rodent models of muscle wasting in the context of chronic gastrointestinal diseases, survey their specific advantages and limitations and discuss possibilities for further research activities in the field. We conclude that animal models of LC‐, IBD‐ and PC‐associated sarcopenia are an essential supplement to clinical studies because they may provide additional mechanistic insights and help to identify molecular targets for therapeutic interventions in humans. 相似文献
77.
Conventional models for predicting the fate of xenobiotic organic trace chemicals, identified, and calibrated using data obtained in batch experiments spiked with reference substances, can be limited in predicting xenobiotic removal in wastewater treatment plants (WWTPs). At stake is the level of model complexity required to adequately describe a general theory of xenobiotic removal in WWTPs. In this article, we assess the factors that influence the removal of diclofenac and carbamazepine in activated sludge, and evaluate the complexity required for the model to effectively predict their removal. The results are generalized to previously published cases. Batch experimental results, obtained under anoxic and aerobic conditions, were used to identify extensions to, and to estimate parameter values of the activated sludge modeling framework for Xenobiotic trace chemicals (ASM‐X). Measurement and simulation results obtained in the batch experiments, spiked with the diclofenac and carbamazepine content of preclarified municipal wastewater shows comparably high biotransformation rates in the presence of growth substrates. Forward dynamic simulations were performed using full‐scale data obtained from Bekkelaget WWTP (Oslo, Norway) to evaluate the model and to estimate the level of re‐transformable xenobiotics present in the influent. The results obtained in this study demonstrate that xenobiotic loading conditions can significantly influence the removal capacity of WWTPs. We show that the trace chemical retransformation in upstream sewer pipes can introduce considerable error in assessing the removal efficiency of a WWTP, based only on parent compound concentration measurements. The combination of our data with those from the literature shows that solids retention time (SRT) can enhance the biotransformation of diclofenac, which was not the case for carbamazepine. Model approximation of the xenobiotic concentration, detected in the solid phase, suggest that between approximately 1% and 16% of the total solid carbamazepine and diclofenac concentrations, respectively, is due to sorption—the remainder being non‐bioavailable and sequestered. We demonstrate the effectiveness of the model's predictive power over conventional tools in a statistical analysis, performed at four levels of structural complexity. To assess WWTP retrofitting needs to remove xenobiotic trace chemicals, we suggest using mechanistic models, e.g., ASM‐X, in regional risk assessments. For preliminary evaluations, we present operating charts that can be used to estimate average xenobiotic removal rates in WWTPs as a function of SRT and the xenobiotics mass loads normalised to design treatment capacity. Biotechnol. Bioeng. 2012; 109: 2757–2769. © 2012 Wiley Periodicals, Inc. 相似文献
78.
R Alan Harris Dorottya Nagy-Szakal Sabina AV Mir Eibe Frank Reka Szigeti Jess L Kaplan Jiri Bronsky Antone Opekun George D Ferry Harland Winter Richard Kellermayer 《Epigenetics》2014,9(8):1131-1137
Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P < 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD. 相似文献
79.
Kwi Baek Kim 《Journal of Exercise Nutrition & Biochemistry》2014,18(4):371-378
[Purpose]
This study was carried out to investigate the effects of different training modes on IL-6 and CRP in patients with type 2 diabetes mellitus (T2DM).[Methods]
The subjects consisted of 16 middle-aged women with type 2 diabetes mellitus (T2DM), all of whom had no other complications. The 16 subjects were randomly assigned to two experimental groups: the circuit training group (CTG, n = 8) and aerobic training group (ATG, n = 8). Based on measured THR (target heart rate) for maximum oxygen consumption rate, the circuit training group (CTG) exercised at 60% intensity, 60 min/day, 5 sets, 3 days/week for 12 weeks. Based on measured THR (target heart rate) for maximum oxygen consumption rate, the aerobic training group (ATG) exercised at 60% intensity (which was increased gradually in weeks 4, 7, and 10) 60 min/day, 3 days/week for 12 weeks.[Results]
The results are as follows. Significant decreases in the post training values of weight, % Fat, BMI, IL-6 and CRP (p < .05) were observed in the CTG compared to pre-training. However, there were no differences in the physical characteristic and blood inflammatory factors between the groups (ATG & CTG).[Conclusion]
In conclusion, the results of this study suggest that circuit training (CT) may be considered as an effective training mode for helping to decrease the blood inflammatory factors (IL-6 and CRP) in patients with type 2 diabetes mellitus (T2DM). 相似文献80.
Simon Trapp Ali A. Aghdassi Juliane Glaubitz Matthias Sendler Frank Ulrich Weiss Jens Peter Kühn Marie-Luise Kromrey Ujjwal M. Mahajan Petra Pallagi Zoltán Rakonczay Jr Viktória Venglovecz Markus M. Lerch Peter Hegyi Julia Mayerle 《Journal of cellular and molecular medicine》2021,25(10):4658-4670
Mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR) are an established risk factor for cystic fibrosis (CF) and chronic pancreatitis. Whereas patients with CF usually develop complete exocrine pancreatic insufficiency, pancreatitis patients with CFTR mutations have mostly preserved exocrine pancreatic function. We therefore used a strain of transgenic mice with significant residual CFTR function (CFTRtm1HGU) to induce pancreatitis experimentally by serial caerulein injections. Protease activation and necrosis were investigated in isolated acini, disease severity over 24h, pancreatic function by MRI, isolated duct stimulation and faecal chymotrypsin, and leucocyte function by ex vivo lipopolysaccharide (LPS) stimulation. Pancreatic and lung injury were more severe in CFTRtm1HGU but intrapancreatic trypsin and serum enzyme activities higher than in wild-type controls only at 8h, a time interval previously attributed to leucocyte infiltration. CCK-induced trypsin activation and necrosis in acini from CFTRtm1HGU did not differ from controls. Fluid and bicarbonate secretion were greatly impaired, whereas faecal chymotrypsin remained unchanged. LPS stimulation of splenocytes from CFTRtm1HGU resulted in increased INF-γ and IL-6, but decreased IL-10 secretion. CFTR mutations that preserve residual pancreatic function significantly increase the severity of experimental pancreatitis—mostly via impairing duct cell function and a shift towards a pro-inflammatory phenotype, not by rendering acinar cells more susceptible to pathological stimuli. 相似文献