全文获取类型
收费全文 | 580篇 |
免费 | 22篇 |
国内免费 | 8篇 |
学科分类
医药卫生 | 610篇 |
出版年
2023年 | 4篇 |
2022年 | 12篇 |
2021年 | 11篇 |
2020年 | 6篇 |
2019年 | 37篇 |
2018年 | 63篇 |
2017年 | 20篇 |
2016年 | 11篇 |
2015年 | 23篇 |
2014年 | 50篇 |
2013年 | 44篇 |
2012年 | 64篇 |
2011年 | 46篇 |
2010年 | 51篇 |
2009年 | 23篇 |
2008年 | 34篇 |
2007年 | 25篇 |
2006年 | 23篇 |
2005年 | 11篇 |
2004年 | 5篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1987年 | 1篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1973年 | 1篇 |
排序方式: 共有610条查询结果,搜索用时 15 毫秒
1.
Metabolic pathways leading to lipid biosynthesis in four different developmental stages of Schistosoma mansoni were explored and quantified by incubation in the presence of labeled precursors in a chemically defined medium. At the schistosomulum stage and in male, female, or paired worms, glycerol and oleate incorporation into neutral lipids, mainly in the form of triacylglycerols, was greater than into phospholipids, whereas in 11-and 15-day-old worms, synthesis mainly led to phospholipids. Incorporation into phospholipids was recovered largely in phosphatidylcholine, and distribution into other phospholipids depended on the developmental stage. Incorporation of choline and ethanolamine into their respective phospholipids represented up to 15% of the parasitic phospholipid content. The formation of phosphatidylcholine by phosphatidylethanolamine methylation occurred mainly in the immature parasitic stages. Inositol incorporation was also measurable, whereas [14C]serine incorporation was low or undetectable. Addition of 1-palmitoyl-2-[14C]oleyl phosphatidylcholine revealed a very high uptake of this phospholipid by the immature stages but further metabolism was not detectable. In contrast, adult S. mansoni were completely unable to take up or absorb this exogenous phospholipid. The most striking aspect of this study was the relatively high metabolic activity in 11-day-old worms and the lower but sustained activity on day 15 and at the schistosomulum stage. By comparison, biosynthetic activity in adult S. mansoni, on which research studies have been focused until now, was very low. We also discuss the participation of lipid metabolism in the constant renewal of the membrane complex which is essential to parasitism by S. mansoni. 相似文献
2.
Wangen Wang Yanran HePei Lin Yunfei LiRuifen Sun Wen GuJie Yu Ronghua Zhao 《Journal of ethnopharmacology》2014
Ethnopharmacology relevance
Raw and processed Polygoni Multiflori Radix (PMR and PMRP) are used in the prevention and treatment of non-alcoholic fatty liver disease (NAFLD), hyperlipidemia or related diseases. In our previous research, 2, 3, 5, 4′-tetrahydroxy-stilbene-2-O-β-d-glucoside (TSG) displayed the most important role in the total cholesterol (TC) lowering effect among all the chemical constituents of Polygonum multiflorum. Emodin and physcion displayed more favorable triglyceride (TG) reducing effects than TSG. However, there are few researches focus on the approach and mechanism of how do Polygonum multiflorum exhibit good lipid regulation activity. The targeted sites of active substances of Polygonum multiflorum are still not clearly elucidated. This research pays close attention to how major chemical components of Polygonum multiflorum affect the TC and TG contents in liver cells.Materials and methods
In this research, a sensitive, accurate and rapid in vitro model, steatosis hepatic L02 cell, was used to explore target sites of active chemical substances of Polygonum multiflorum for 48 h. Steatosis hepatic L02 cell was exposed to emodin, physcion and TSG, respectively. The contents of four key enzymes in the pathway of synthesis and decomposition of TC and TG were investigated after exposure. Meanwhile, the contents of lipid transfer protein were also tested. The diacylgycerol acyltransferase 1 (DGAT1) controlled the biosynthesis of TG from free fatty acids while 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) limited the biosynthesis of TC. Hepatic triglyceride lipase (HTGL) and cholesterol 7α-hydroxylase (CYP7A) played the key role in the lipolysis procedure of TG and TC.Results
The synthesis of TC and TG in steatosis L02 cells were apparently increased in the model group compared to the control group. Intracellular contents of HMG-CoA reductase and DGAT1 increased 32.33% and 56.52%, while contents of CYP7A and HTGL decreased 21.61% and 47.37%. Emodin, physcion and TSG all showed down-regulation effects on HMG-CoA reductase, while up-regulation effects on CYP7A. The most remarkable effect on HMG-CoA reductase was found on emodin. Emodin could reduce the DGAT1 content from 438.44±4.51 pg/mL in model group to 192.55±9.85 pg/mL (100 μm). The content of HTGL in 300 μm physcion group was 3.15±0.15 U/mL, which was more significantly effective than the control, lovastatin and fenofibrate group.Conclusions
TSG could raise the content of CYP7A and then promote the lipolysis of cholesterol. Moreover, TSG also showed the best LDL-reducing effect. Emodin could inhibit HMG-CoA reductase and DGAT1, which were key enzymes in the synthesis of TC and TG. Physcion increased the content of HTGL, and then could boost the lipolysis of triglyceride. At the same time, physcion showed the best VLDL-reducing effect. In view of the above conclusions, we contributed the lipid regulation activity to an overall synergy of TSG, emodin and physcion. 相似文献3.
4.
缺铁性贫血患者输注PRC前后血清SF、FA和VitB12水平的临床意义 总被引:1,自引:0,他引:1
目的:探讨了缺铁性贫血(IDA)患者输注悬浮红细胞(PRC)前后血清铁蛋白(SF)、叶酸(FA)和维生素B12(VitB12)水平的变化。方法:应用放射免疫分析对32例缺铁性贫血患者进行了输注PRC前后血清SF、FA和VitB12水平测定,并以35名正常健康人作比较。结果:缺铁性贫血患者在输注PRC前血清SF水平非常显著地低于正常人组(P〈0.01),而血清FA、VitB12水平显著高于正常人组(P〈0.01),经治疗2周后除SF水平与正常人比较仍有差异外(P〈0.05),而FA和VitB12水平则与正常人比较无显著性差异(P〉0.05)。结论:输注PRC对缺铁性贫血患者具有一定的治疗作用,有重要的临床价值。 相似文献
5.
Wan B Hao L Qiu Y Sun Z Cao Q Zhang Y Zhu T Wang H Zhang Y 《Experimental and molecular pathology》2006,81(3):211-216
Systemic administration of mice with folic acid (FA) has been used for studying the pathogenesis of acute renal failure. However, the molecular mechanisms by which FA induces acute renal failure remain poorly understood. We found that CD-1 mice treated with FA developed acute renal failure characterized by increased blood urea nitrogen, necrosis, and apoptosis of tubular epithelial cells. Compared to control mice, tumor necrosis factor-alpha (TNF-alpha) was markedly elevated in blood and kidneys of these FA-treated mice, accompanied by markedly reduced expression of anti-apoptotic protein BclxL in their kidneys. In vivo administration of FA-treated CD-1 mice with neutralizing anti-TNF-alpha antibody restored the expression of BclxL in kidneys and inhibited the necrosis and apoptosis of renal tubular epithelial cells, leading to the amelioration of acute renal failure. In ex vivo cultures, we found that FA enhanced production of TNF-alpha, decreased expression of BclxL protein, and induced apoptosis of mouse cortical tubule (MCT) cells. Addition of neutralizing anti-TNF-alpha antibody, but not control IgG, in the cultures markedly blocked the apoptotic death of FA-treated MCT cells and restored expression of BclxL to the same levels as those MCT cells cultured in the absence of FA. All these results suggest that TNF-alpha is a critical inflammatory cytokine responsible for FA-mediated acute renal failure. Furthermore, in vivo administration of anti-TNF-alpha antibody may be proved as an effective approach for acute renal failure prevention and treatment. 相似文献
6.
Kevin Zhe-Yang Xu Chenchen Zhu Moon Sun Kim Johji Yamahara Yuhao Li 《Journal of ethnopharmacology》2009
Aims of the study
Fatty liver is the most common cause of abnormal liver function tests. We investigated the effect and its underlying mechanism of pomegranate flower (PGF), a traditional antidiabetic medicine, on fatty liver.Materials and methods
At the endpoint of treatment of male Zucker diabetic fatty (ZDF) rats with PGF extract (500 mg/kg, p.o. × 6 weeks), liver weight index, hepatic lipid contents (enzymatic colorimetric methods) and droplet accumulation (Oil Red O staining) were determined. Gene profiles (RT-PCR) were analyzed in the liver of ZDF rats and in human liver-derived HepG2 cell line.Results
PGF-treated ZDF rats showed reduced ratio of liver weight to tibia length, hepatic triglyceride contents and lipid droplets. These effects were accompanied by enhanced hepatic gene expression of peroxisome proliferator-activated receptor (PPAR)-alpha, carnitine palmitoyltransferase-1 and acyl-CoA oxidase (ACO), and reduced stearoyl-CoA desaturase-1. In contrast, PGF showed minimal effects on expression of genes responsible for synthesis, hydrolysis or uptake of fatty acid and triglycerides. PGF treatment also increased PPAR-alpha and ACO mRNA levels in HepG2 cells.Conclusion
Our findings suggest that this Unani medicine ameliorates diabetes and obesity-associated fatty liver, at least in part, by activating hepatic expression of genes responsible for fatty acid oxidation. 相似文献7.
As the population ages, the economic and societal impacts of neurodegenerative and neuropsychiatric disorders are expected to rise sharply. Like dementia, late-life depressive disorders are common and are linked to increased disability, high healthcare utilisation, cognitive decline and premature mortality. Considerable heterogeneity in the clinical presentation of major depression across the life cycle may reflect unique pathophysiological pathways to illness; differentiating those with earlier onset who have grown older (early-onset depression), from those with illness onset after the age of 50 or 60 years (late-onset depression). The last two decades have witnessed significant advances in our understanding of the neurobiology of early- and late-onset depression, and has shown that disturbances of fronto-subcortical functioning are implicated. New biomedical models extend well beyond perturbations of traditional monoamine systems to include altered neurotrophins, endocrinologic and immunologic system dysfunction, inflammatory processes and gene expression alterations. This more recent research has highlighted that a range of illness-specific, neurodegenerative and vascular factors appear to contribute to the various phenotypic presentations. This review highlights the major features of late-life depression, with specific reference to its associated aetiological, clinical, cognitive, neuroimaging, neuropathological, inflammatory and genetic correlates. Data examining the efficacy of pharmacological, non-pharmacological and novel treatments for depression are discussed. Ultimately, future research must aim to evaluate whether basic biomedical knowledge can be successfully translated into enhanced health outcomes via the implementation of early intervention paradigms. 相似文献
8.
S L Mackenzie G S Sundaram H S Sodhi 《Clinica chimica acta; international journal of clinical chemistry》1973,43(2):223-229
A technique is described for the detection of free fatty acids, triglycerides, wax esters and cholesterol esters on thin-layer Chromatographic plates. The fatty acids present in each fraction can be recovered from the plates after detection and quantitatively measured by gas-liquid chiomatography. This procedure has been sucessfully applied to the analysis of skin surface lipids. 相似文献
9.
Jesús Almendral Marta Pombo Jesús Martínez-Alday José M. González-Rebollo Enrique Rodríguez-Font José Martínez-Ferrer Eduardo Castellanos F. Javier García-Fernández Francisco Ruiz-Mateas 《Revista espa?ola de cardiología》2014
This report discusses a selection of the most relevant articles on cardiac arrhythmias and pacing published in 2013. The first section discusses arrhythmias, classified as regular paroxysmal supraventricular tachyarrhythmias, atrial fibrillation, and ventricular arrhythmias, together with their treatment by means of an implantable cardioverter defibrillator. The next section reviews cardiac pacing, subdivided into resynchronization therapy, remote monitoring of implantable devices, and pacemakers. The final section discusses syncope. 相似文献
10.
Newcombe PA Sheffield JK Juniper EF Marchant JM Halsted RA Masters IB Chang AB 《Chest》2008,133(2):386-395
BACKGROUND: Chronic cough affects at least 7% of children, and the impact of this on families is significant. Although adult cough-specific quality-of-life (QOL) instruments have been shown to be a useful cough outcome measure, no suitable cough-specific QOL for parents of children with chronic cough exists. This article compares two methods of item reduction (clinical impact and psychometric) and reports on the statistical properties of both QOL instruments. METHOD: One hundred seventy children (97 boys and 73 girls; median age, 4 years; interquartile range, 3 to 7.25 years) and one of their parents participated. A preliminary 50-item parent cough-specific QOL (PC-QOL) questionnaire was developed from conversations with parents of children with chronic cough (ie, cough for > 3 weeks). Parents also completed generic QOL questionnaires (eg, Pediatric Quality of Life Inventory, version 4.0 [PedsQL4.0] and the 12-item Short Form Health Survey, version 2 [SF-12v2]). RESULTS: The clinical impact and psychometric method of item reduction resulted in 27-item and 26-item PC-QOL questionnaires, respectively, with approximately 50% of items overlapping. Internal consistency among the final items from both methods was excellent. Some evidence for concurrent and criterion validity of both methods was established as significant correlations were found between subscales of the PC-QOL questionnaire and the scales of the SF-12v2 and PedsQL4.0 scores. The PC-QOL questionnaire derived from both methods was sensitive to change following an intervention. CONCLUSION: Chronic cough significantly impacts on the QOL of both parents and children. Although the PC-QOL questionnaires derived from a clinical impact method and from a psychometric method contained different items, both versions were shown to be internally consistent and valid. Further testing is required to compare both final versions to objective and subjective cough measures. 相似文献